Frequent 'heading' in soccer can lead to brain injury and cognitive impairment

December, 2011

A small study extends the evidence that even mild concussions can cause brain damage, with the finding that frequent heading of the ball in soccer can cause similar damage.

American football has been in the news a lot in recent years, as evidence has accumulated as to the brain damage incurred by professional footballers. But American football is a high-impact sport. Soccer is quite different. And yet the latest research reveals that even something as apparently unexceptional as bouncing a ball off your forehead can cause damage to your brain, if done often enough.

Brain scans on 32 amateur soccer players (average age 31) have revealed that those who estimated heading the ball more than 1,000-1,500 times in the past year had damage to white matter similar to that seen in patients with concussion.

Six brain regions were seen to be affected: one in the frontal lobe and five in the temporo-occipital cortex. These regions are involved in attention, memory, executive functioning and higher-order visual functions. The number of headings (obviously very rough estimates, based presumably on individuals’ estimates of how often they play and how often they head the ball on average during a game) needed to produce measurable decreases in the white matter integrity varied per region. In four of temporo-occipital regions, the threshold number was around 1500; in the fifth it was only 1000; in the frontal lobe, it was 1300.

Those with the highest annual heading frequency also performed worse on tests of verbal memory and psychomotor speed (activities that require mind-body coordination, like throwing a ball).

This is only a small study and clearly more research is required, but the findings indicate that we should lower our ideas of what constitutes ‘harm’ to the brain — if repetition is frequent enough, even mild knocks can cause damage. This adds to the evidence I discussed in a recent blog post, that even mild concussions can produce long-lasting trauma to the brain, and it is important to give your brain time to repair itself.

At the moment we can only speculate on the effect such repetition might have to the vulnerable brains of children.

The researchers suggest that heading should be monitored to prevent players exceeding unsafe exposure thresholds.


Kim, N., Zimmerman, M., Lipton, R., Stewart, W., Gulko, E., Lipton, M. & Branch, C. 2011. PhD Making Soccer Safer for the Brain: DTI-defined Exposure Thresholds for White Matter Injury Due to Soccer Heading. Presented November 30 at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.



tags memworks: 

tags problems: 


Older news items (pre-2010) brought over from the old website


School-age lead exposures most harmful to IQ

A number of studies have connected higher blood concentration of lead in toddlers with reduced IQ at school age. Now data from two points — children in Cincinnati during the early 1980s; children Rochester, N.Y., during the mid-1990s — has revealed confirmed earlier indications that IQ losses are most predictable from comparisons of a child’s blood-lead level at age 6 compared to the level at age 2, and that the level at age 5-6 is more important than that at age 2 (although that is when most testing is done). Lead-level at age 6 also correlated with reduced brain tissue in certain brain regions in adulthood, especially in those regions relating to judgment, self-control, and mood (and an increased level of criminal behavior).

[509] Hornung, R. W., Lanphear B. P., & Dietrich K. N.
(2009).  Age of Greatest Susceptibility to Childhood Lead Exposure: A New Statistical Approach.
Environmental Health Perspectives.

Children more vulnerable to harmful effects of lead

A study has found that children are more vulnerable to the harmful effects of lead at age 6 than they at younger ages. The study found that children's average blood lead concentrations peaked at 13.9 micrograms of lead per deciliter of blood at age 2, then declined to an average of 7.3 micrograms per deciliter by age 6. For children with the same average blood lead levels through age 6, however, those who received more of their exposure at age 6 had substantially greater decrements in intellectual ability (with lower IQ and reduced volume of gray matter in the prefrontal cortex) than those more heavily exposed at age 2. The Centers for Disease Control and Prevention recommends public health actions be initiated at blood lead levels greater than 10 micrograms per deciliter, despite lower levels being consistently shown to be associated with adverse effects.

The Cincinnati Children's Hospital Medical Center study was presented May 4, 2008, at the annual meeting of the Pediatric Academic Societies in Honolulu.

Early lead exposure impedes later recovery from brain injury

We know that lead exposure in early years can affect the brain. We also know that it increases the risk of various disorders later in life. Now a rat study reveals that animals exposed to lead earlier in life were significantly less able to recover from an induced stroke than those not so exposed. The study only looked at a short time-frame, so it is not yet known if the lead-exposed animals would catch up in their recovery in a longer period of time. There was some recovery in the lead group, but then it leveled off. The control group continued to get better. The findings support the suggestion that lead poisoning impairs neural plasticity.

[698] Schneider, J. S., & Decamp E.
(2007).  Postnatal lead poisoning impairs behavioral recovery following brain damage.
Neurotoxicology. 28(6), 1153 - 1157.

ADHD linked to genetic and environmental interactions

A study of 172 children who were enrolled in a community-based study of low levels of lead exposure has found evidence that increasing lead exposure is linked to impairment on a number of executive functions (impaired in those with ADHD), but that certain genetic and biological factors seemed to predispose an individual to the negative effects of lead exposure. For instance, only children with certain variations of the DRD4 gene seemed vulnerable to lead's adverse effects on attentional flexibility. Boys were more vulnerable to this effect than girls.

The study was presented on May 1, 2006, at the annual Pediatric Academic Societies meeting in San Francisco.

Lead exposure may affect recovery from brain injury

Lead exposure at a young age can hurt the brain's development and cause learning and behavioral problems. Now it seems that it might also affect a child’s ability to recover from brain injury. A new study found young rats exposed to low levels of lead took significantly longer to recover from a brain injury than those animals that weren't lead-exposed, as well as recovering less well.

Dr. Schneider presented the findings Oct. 25, 2004, at the Society for Neuroscience's annual meeting in San Diego.

Environmental damage to brains of children

A new report suggests that the brains of children in many parts of Europe are suffering greater damage from environmental risks than previously recognized. A meeting in Malta of European delegates preparing for a ministerial conference on environment and health, being held in Budapest in June, were given preliminary results from a comprehensive study on environmental threats to children's health, being conducted by the WHO and the University of Udine, Italy. The full report is to be published at the Budapest conference. The findings suggest lead is the single most important damaging chemical for children. In 2001, the estimated percentage of European children in urban areas with elevated blood levels (above 10 micrograms per decilitre) ranged from 0.1% to 30.2%.

Pros and cons of therapy for lead exposure

Lead chelation therapy is widely used to treat lead-exposed children, and is increasingly being used for the treatment of autism in children. However, a rat study has now found that, although the treatment can indeed significantly reduce learning and behavioral problems that result from lead exposure, when rats with no lead in their systems were treated, they showed declines in their learning and behavior that were similar to the rats that were exposed to lead. The findings suggest that lead chelation therapy should only be used, as recommended, for children with at least moderate lead exposure.

[429] Stangle, D. E., Smith D. R., Beaudin S. A., Strawderman M. S., Levitsky D. A., & Strupp B. J.
(2006).  Succimer Chelation Improves Learning, Attention, and Arousal Regulation in Lead-Exposed Rats but Produces Lasting Cognitive Impairment in the Absence of Lead Exposure.
Environmental Health Perspectives. 115(2), 201 - 209.


Workers exposed to lead show more cognitive problems later in life

A follow-up of the 1982 Lead Occupational Study, which assessed the cognitive abilities of 288 lead-exposed and 181 non-exposed male workers in eastern Pennsylvania, has found that among the lead-exposed workers, those with higher cumulative lead had significantly lower cognitive scores. The clearest inverse relationships were between cumulative lead and spatial ability, learning and memory, and overall cognitive score. This linkage was more significant in the older lead-exposed men (55 years and older). Their cognitive scores were significantly different from those of younger lead-exposed men even when the researchers controlled for current blood levels of lead. In other words, even when men no longer worked at the battery plants, their earlier prolonged exposure was enough to matter.

[406] Khalil, N., Morrow L. A., Needleman H., Talbott E. O., Wilson J. W., & Cauley J. A.
(2009).  Association of cumulative lead and neurocognitive function in an occupational cohort.
Neuropsychology. 23(1), 10 - 19.

Full text available at

Reading ability protects brain from lead exposure

Cognitive reserve is a concept that has been chiefly discussed in terms of protecting against age-related cognitive decline and Alzheimer’s, but a new study has found evidence that it can also protect against long-term lead exposure. The study of 112 smelter workers found that the cognitive effects of lead were 2.5 times greater in workers with low reading ability, compared to those with high reading ability (defined as a reading level of 12th grade or higher). Motor speed, however, was comparable in both groups — demonstrating that the nervous system was impaired similarly in both groups.

[258] Bleecker, M. L., Ford D. P., Celio M. A., Vaughan C. G., & Lindgren K. N.
(2007).  Impact of cognitive reserve on the relationship of lead exposure and neurobehavioral performance.
Neurology. 69(5), 470 - 476.

Long-term lead exposure linked to cognitive decline in older adults

A study of nearly a thousand randomly selected Baltimore residents, all between 50 and 70 years old and consequently exposed to higher levels of lead prior to the 1980s when lead was used extensively in commercial products, has revealed higher lead levels in the bone were consistently associated with worse cognitive performance on tests, equivalent to two to six years of aging. Blood lead levels were not associated with a difference in cognitive performance. The study also found bone lead levels were significantly higher in African Americans compared to Caucasians.

[845] Shih, R. A., Glass T. A., Bandeen-Roche K., Carlson M. C., Bolla K. I., Todd A. C., et al.
(2006).  Environmental lead exposure and cognitive function in community-dwelling older adults.
Neurology. 67(9), 1556 - 1562.

Lead exposure leads to brain cell loss and damage years later

A study of 532 former employees of a chemical manufacturing plant who had not been exposed to lead for an average of 18 years has found that the higher their lead levels were, the more likely they were to have smaller brain volumes and greater amounts of brain damage. 36% had white matter lesions. The results confirm earlier findings in this same population that people with occupational lead exposure experience declines in their thinking and memory skills years after their exposure.

[514] Youssem, D., Stewart W. F., Schwartz B. S., Davatzikos C., Shen D., Liu D., et al.
(2006).  Past adult lead exposure is linked to neurodegeneration measured by brain MRI.
Neurology. 66(10), 1476 - 1484.

tags lifestyle: 

Multiple sclerosis

Older news items (pre-2010) brought over from the old website

MS can affect children's IQ, thinking skills

Multiple sclerosis typically starts in young adulthood, but about 5% start in childhood or adolescence. A study of 63 children under age 18 with MS has found that they more likely to have low IQ scores than healthy controls. Five of the children with MS had IQ scores of less than 70 (none of the controls did), 15 had IQ scores between 70 and 89 (compared to two of the controls), and 31% of the MS children met the criteria for cognitive impairment compared to less than 5% of the controls. Low IQs were correlated with younger age at onset. About 30% of the children with MS also had language difficulties, which is not common in adults with MS. It may be that children are particularly vulnerable to the effects of MS because their brain is still developing.

[1261] Lopez, M., Patti F., Vecchio R., Pozzilli C., Bianchi V., Roscio M., et al.
(2008).  Cognitive and psychosocial features of childhood and juvenile MS.
Neurology. 70(20), 1891 - 1897.

Smoking marijuana impairs cognitive function in MS patients

A study of 140 Canadians with multiple sclerosis has found that those (10) who were defined as current marijuana users performed 50% slower on tests of information processing speed compared to matched MS patients who did not smoke marijuana. There was also a significant association between smoking marijuana and emotional problems such as depression and anxiety.

[1339] Ghaffar, O., & Feinstein A.
(2008).  Multiple sclerosis and cannabis. A cognitive and psychiatric study.
Neurology. 01.wnl.0000304046.23960.25 - 01.wnl.0000304046.23960.25.

Preconditioning could prevent injury to dendrites in neurological diseases

New research has revealed a previously unknown mechanism by which brain cells can be damaged during chronic neurodegenerative diseases such as Alzheimer's, multiple sclerosis, Parkinson's and dementia associated with HIV. When inflammation occurs in the brain, nerve impulses can become toxic. Instead of triggering the formation of memories, these impulses can inflict injury on neurons and disrupt neural function. Understanding this mechanism could provide a new path for drugs to treat the diseases, perhaps by chemical preconditioning to induce adaptations in nerve cells that would enable the cells to better withstand toxic attacks, prevent injury, and preserve function.

[760] Bellizzi, M. J.
(2005).  Synaptic activity becomes excitotoxic in neurons exposed to elevated levels of platelet-activating factor.
Journal of Clinical Investigation. 115(11), 3185 - 3192.

Ginkgo may improve executive function in MS patients

A study of 39 MS patients found that those receiving ginkgo biloba were about 13% faster on a Stroop test (measures a person's ability to pay attention and to sort conflicting information). Such a difference would be comparable to differences in scores between healthy people ages 30 to 39 and those ages 50 to 59. The benefit appeared to be greatest for those who had certain problems with the Stroop test.

The study was presented at the American Academy of Neurology's 57th Annual Meeting in Miami Beach, Fla.

Alzheimer's drug improves cognition in MS patients

An estimated 50% of multiple sclerosis patients suffer some degree of cognitive impairment. A pilot study suggests that donepezil, a drug widely used for treating dementia in Alzheimer's patients, may improve memory and cognition in MS patients who are mild to moderately cognitively impaired. The trial involved 69 MS patients. Over 65% of those given donepezil showed cognitive improvement, compared to 32% of those receiving a placebo.

The study was presented by Laura Krupp at the American Academy of Neurology 56th Annual Meeting in San Francisco, Calif., on April 27.

Ginkgo biloba may slow cognitive decline in patients with mild multiple sclerosis

A six-month double-blind, placebo-controlled pilot study of 23 individuals with mild multiple sclerosis found that patients who took the herb Ginkgo biloba performed better on neuropsychological tests compared to those who took the inactive placebo.

Corey-Bloom, J., Kenney, C. & Norman, M. 2002. Paper presented at the annual meeting of the American Academy of Neurology on April 18 in Denver, Colorado.

Alzheimer's drug may help cognitive impairment in patients with multiple sclerosis

Cognitive problems affect up to 60% of patients with multiple sclerosis. Treatment of MS has until now paid little attention to this aspect of the disease. A preliminary study of 17 patients with advanced MS and severe cognitive impairment found that a drug currently used to treat mild to moderate dementia from Alzheimer’s disease was noticeably effective in improving the cognitive functioning in many of the MS patients. A study of 240 patients at 21 hospitals and medical centers is now about to commence.

Driving problems for those with Multiple Sclerosis

People who suffer from cognitive difficulties related to Multiple Sclerosis (MS) may have a slower driving reaction time and increased risk of accidents. The study compared 13 people with MS who exhibited cognitive difficulties, 15 people with MS who did not exhibit cognitive difficulties, and 17 people without MS. Based on two computerized driving tests, those with MS who exhibited cognitive difficulties had a slower response time by 1,721 milliseconds than the other MS participants. In addition, 29 percent of these people tested as high risk for accident involvement.

[2573] Schultheis, M. T., Garay E., & DeLuca J.
(2001).  The influence of cognitive impairment on driving performance in multiple sclerosis.
Neurology. 56(8), 1089 - 1094.

tags problems: 


Older news items (pre-2010) brought over from the old website

Children’s PTSD symptoms linked to poor hippocampus function

An imaging study comparing brain activity during a verbal memory task of 16 10- to 17-year-olds who had PTSD symptoms with a control group of 11 young people, has found that while hippocampal activity was similar in both groups when the word list was presented, those with PTSD symptoms made more errors on the recall part of the test and showed less hippocampus activity than control subjects doing the same task. Additionally, those with the worst hippocampus function were also most likely to experience a specific set of PTSD symptoms — "avoidance and numbing", including difficulty remembering the trauma, feeling cut off from others and lack of emotion. The research helps explain why traumatized children behave as they do and could improve treatments.

[898] Carrion, V. G., Haas B. W., Garrett A., Song S., & Reiss A. L.
(2009).  Reduced Hippocampal Activity in Youth with Posttraumatic Stress Symptoms: An fMRI Study.
J. Pediatr. Psychol.. jsp112 - jsp112.

PTSD Linked to Nearly Double Dementia Risk in Veterans

Data from 181,093 veterans aged 55 years and older without dementia (53,155 veterans diagnosed with PTSD and 127,938 veterans without PTSD) found that PTSD patients were nearly twice as likely to develop incident dementia compared to veterans without PTSD. Results were similar when we excluded those with a history of traumatic brain injury, substance abuse or depression.

Yaffe, K. et al. 2009. Post-traumatic stress disorder and risk of dementia among U.S. veterans. Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.

Cognitive therapy useful in treating post-traumatic stress disorder in early stages

A study of 248 adults with early symptoms of post-traumatic stress disorder (PTSD) following a traumatic event that had occurred no more than four weeks earlier (ie before PTSD can be formally diagnosed) compared 12 weeks’ treatment of either cognitive therapy (which helps people change unproductive or harmful thought patterns), cognitive behavioral therapy (which helps desensitize patients’ upsetting reactions to traumatic memories), an antidepressant (selective serotonin reuptake inhibitor) known to be helpful in treating chronic PTSD, placebo or no intervention at all. It was found that symptoms of PTSD were significantly less severe in those who received cognitive therapy or cognitive behavioral therapy compared to those treated with medication, placebo, or no treatment at all.

The study was presented at the American College of Neuropsychopharmacology (ACNP) annual meeting.

Some brain injuries may reduce the likelihood of PTSD

A study of combat-exposed Vietnam War veterans shows that those who suffered injuries to the amygdala or the ventromedial prefrontal cortex were less likely to develop post-traumatic stress disorder than those who suffered damage in other areas or had no head injuries (in fact none of those whose amygdala was damaged developed PTSD). The findings suggest that treatment designed to inhibit the activity of these two areas might provide relief from PTSD.

[1328] Koenigs, M., Huey E. D., Raymont V., Cheon B., Solomon J., Wassermann E. M., et al.
(2008).  Focal brain damage protects against post-traumatic stress disorder in combat veterans.
Nat Neurosci. 11(2), 232 - 237.

Effectiveness of most PTSD therapies is uncertain

A review of 53 studies of pharmaceuticals and 37 studies of psychotherapies used in PTSD treatment has concluded that because of shortcomings in many of the studies, there is not enough reliable evidence to draw conclusions about the effectiveness of most treatments. However, sufficient evidence exists to conclude that exposure therapies — such as exposing individuals to a real or surrogate threat in a safe environment to help them overcome their fears — are effective.

Work could lead to first drug for post-traumatic stress disorder

Researchers have found the molecular mechanism that governs the formation of fears stemming from traumatic events. It was found that inhibiting a kinase (kinases are enzymes that change proteins) called Cdk5 facilitates the extinction of fear learned in a particular context, while increasing that kinase's activity in the hippocampus led to the fear persisting. The work could lead to the first drug to treat PTSD.

[259] Sananbenesi, F., Fischer A., Wang X., Schrick C., Neve R., Radulovic J., et al.
(2007).  A hippocampal Cdk5 pathway regulates extinction of contextual fear.
Nat Neurosci. 10(8), 1012 - 1019.

Anticipation strengthens memory

An imaging study has revealed that the amygdala and the hippocampus become activated when a person is anticipating a difficult situation (some type of gruesome picture). Moreover, the higher the level of activation during this anticipation, the better the pictures were remembered two weeks later. The study demonstrates how expectancy can affect long-term memory formation, and suggests that the greater our anxiety about a situation, the better we’ll remember that situation. If it’s an unpleasant one, this will only reinforce the anxiety, setting up a vicious cycle. The study has important implications for the treatment of psychological conditions such as post-traumatic stress disorder and social anxiety.

[354] Mackiewicz, K. L., Sarinopoulos I., Cleven K. L., & Nitschke J. B.
(2006).  The effect of anticipation and the specificity of sex differences for amygdala and hippocampus function in emotional memory.
Proceedings of the National Academy of Sciences. 103(38), 14200 - 14205.

Prevalence of combat-related PTSD

Two large independent studies funded by the US government have assessed the impact of the Vietnam War on the prevalence of PTSD in US veterans. The National Vietnam Veterans Readjustment Study (NVVRS) estimated prevalence to be 15.2% while the Vietnam Experience Study (VES) estimated the prevalence to be 2.2%. A new study explains this discrepancy by reanalyzing both data sets using varying criteria. Prevalence estimates for combat-related PTSD of 2.5% and 2.9% for the VES and the NVVRS, respectively, were found when a narrow and specific set of criteria were used, while prevalence estimates 12.2% and 15.8% for the VES and NVVRS, respectively, were found when broader and more sensitive criteria were used.

[427] Thompson, W. W., Gottesman I. I., & Zalewski C.
(2006).  Reconciling disparate prevalence rates of PTSD in large samples of US male Vietnam veterans and their controls.
BMC Psychiatry. 6, 19 - 19.

Why traumatic memories have the power they do

In the first imaging study to look at retrieval of emotional memories after a long period (one year after encoding), researchers found that people did recall emotional images, both pleasant and unpleasant, better than emotionally-neutral images. This recall was associated with higher activity in both the amygdala and the hippocampus. The synchronicity of activity between these two regions suggested that each region triggers the other, creating a self-reinforcing "memory loop" in which an emotional cue might trigger recall of the event, which then loops back to a re-experiencing of the emotion of the event. The findings suggest why people subject to traumatic events may be trapped in a cycle of emotion and recall that aggravates post-traumatic stress disorder, and may also suggest why therapies in which people relive such memories and reshape perspective to make it less traumatic can help people cope with such memories.

[198] Dolcos, F., LaBar K. S., & Cabeza R.
(2005).  Remembering one year later: Role of the amygdala and the medial temporal lobe memory system in retrieving emotional memories.
Proceedings of the National Academy of Sciences of the United States of America. 102(7), 2626 - 2631.

Visuospatial tasks during trauma may reduce intrusive memories

In three experiments, researchers found that viewers who performed a visuospatial task (tapping out a specified pattern on a hidden keyboard) while watching a 12.5-minute trauma video with five scenes of horrific content suffered fewer intrusive memories in the following week than viewers who performed a verbal task. This may occur because the same types of memory resources may be involved in processing both particular visuospatial tasks and the sensory aspects of traumatic stimuli. On the other hand, verbal distraction – counting down by threes -- was associated with a greater number of subsequent intrusions, suggesting that verbal interference might interfere with processing that helps the viewer make sense of the traumatic images. While more research is needed, this suggests a hopeful new approach to dealing not only with PTSD but also other psychological disorders now thought to involve intrusive imagery, such as worry (generalized anxiety disorder), insomnia, social phobia, agoraphobia, psychosis and others.

Holmes, E.A., Brewin, C.R. & Hennessy, R.G. 2004. Trauma Films, Information Processing, and Intrusive Memory Development. Journal of Experimental Psychology: General, 133 (1)

Losing consciousness helps prevent PTSD

Current thinking holds that traumatic brain injury alone may be sufficient to protect patients from developing posttraumatic stress disorder, but new research suggests this protection extends chiefly to those who lose consciousness (for a significant period) during their ordeal. The study was small and requires replication with a bigger sample.

Glaesser, J., Neuner, F., Lütgehetmann, R., Schmidt, R. & Elbert, T. 2004. Posttraumatic stress disorder in patients with traumatic brain injury. BMC Psychiatry, 4, 5.

The article is available at:

Reducing the trauma of traumatic memories

For some, stressful memories can reawaken intense fear, with undesirable consequences. A new study involving mice has found that such stress induces a change in the expression of the acetylcholinesterase gene, which normally produces a vital protein that adheres to neuronal synapses. Following stress, however, the same gene produces large quantities of a protein with modified properties that results in heightened electrical signals in the nerve cells communicating through these synapses. The effect is to create reactions of extreme fright or immobilizing shock. Later encounter with a context which triggers those stressful memories can set off that same neuronal reaction. The researchers have developed an "antisense" agent that acts to neutralize the process whereby the modified protein is produced, thereby preventing the extreme reaction.

[1002] Soreq, H., Blank T., Nijholt I., Farchi N., Kye M., Sklan E. H., et al.
(2003).  Stress-induced alternative splicing of acetylcholinesterase results in enhanced fear memory and long-term potentiation.
Mol Psychiatry. 9(2), 174 - 183.

tags problems: 


Older news items (pre-2010) brought over from the old website

Nerve-cell transplants help brain-damaged rats recover lost ability to learn

After destroying neurons in the subiculum of 48 adult rats, some were given hippocampal cells taken from newborn transgenic mice. On spatial memory tests two months later, the rats given cell transplants performed as well as rats which had not had their subiculums damaged; however, those without transplants had significantly impaired performance. The new cells were found to have mainly settled in the dentate gyrus, where they appeared to promote the secretion of two types of growth factors, namely BDNF and basic fibroblast growth factor (bFGF).

Rekha, J. et al. 2009. Transplantation of hippocampal cell lines restore spatial learning in rats with ventral subicular lesions. Behavioral Neuroscience, 123(6), 1197-1217.

Amino acid diet helps brain-injured mice

In a study in which brain-injured mice received a cocktail of three branched chain amino acids (BCAAs), specifically leucine, isoleucine and valine, in their drinking water, those who received the cocktail showed normal learning ability and normal activity in the hippocampus. BCAAs are crucial precursors of two neurotransmitters—glutamate and GABA, which function together to maintain an appropriate balance of brain activity. Previously, it’s been found that people with severe brain injuries showed mild functional improvements after receiving BCAAs through an intravenous line. It’s suggested that receiving the BCAAs as a dietary supplement could have a more sustained, measured benefit than that seen when patients receive BCAAs intravenously, in which the large IV dose may flood brain receptors and have more limited benefits.

[584] Cole, J. T., Mitala C. M., Kundu S., Verma A., Elkind J. A., Nissim I., et al.
(2010).  Dietary branched chain amino acids ameliorate injury-induced cognitive impairment.
Proceedings of the National Academy of Sciences. 107(1), 366 - 371.

Greater dementia risk in former N.F.L. players

A study commissioned by the National Football League reports that Alzheimer’s disease or similar memory-related diseases appear to have been diagnosed in the league’s former players vastly more often than in the national population: five times the national average among those 50 and older (6.1%)and 19 times for those aged 30 through 49. The findings are consistent with several recent studies regarding N.F.L. players and the effects of their occupational head injuries. The study involved a phone survey of 1,063 retired players (from an original random list of 1,625), who were asked questions derived from the standard National Health Interview Survey. Some health issues were reported at higher than the population rate (sleep apnea and elevated cholesterol — both risk factors for cognitive problems).

Stroke patients regain sight after intensive brain training

In a surprising and exciting finding, stroke victims left partially blind have been trained to use undamaged parts of their brains to improve their vision. The training program, involving an hour a day for at least nine months, forced them to process visual signals with parts of their brain that had not been damaged by the stroke. The seven patients in the study ranged in age from their 30s to 80s, and had suffered a stroke between eight months and three-and-a-half years previously. Impaired vision is a very common result of a stroke.

[1040] Huxlin, K. R., Martin T., Kelly K., Riley M., Friedman D. I., Burgin S. W., et al.
(2009).  Perceptual Relearning of Complex Visual Motion after V1 Damage in Humans.
J. Neurosci.. 29(13), 3981 - 3991.

Patients who recover well from head injury 'work harder' to perform at same level as healthy people

People who make a full recovery from head injury often report "mental fatigue" and feeling "not quite the same" – even though they scored well on standard cognitive tests. Now brain imaging reveals that even with recovered head injury patients performing as well as matched controls on a series of working memory tests, their brains were working harder — specifically, showing more activity in regions of the prefrontal cortex and posterior cortices. All the patients had diffuse axonal injury, the most common consequence of head injuries resulting from motor vehicle accidents, falls, combat-related blast injuries, and other situations where the brain is rattled violently inside the skull causing widespread disconnection of brain cells.

[798] Turner, G. R., & Levine B.
(2008).  Augmented neural activity during executive control processing following diffuse axonal injury.
Neurology. 71(11), 812 - 818.

Feed TBI patients early and well

Analysis of the results of 797 comatose brain trauma patients treated at 21 trauma centers in New York over six years has found that patients who did not get fed within five or seven days were two-fold and four-fold more likely to die in the two week period following initial trauma. The amount of nutrition in the first 5 days was related to death; every 10-kcal/kg decrease in caloric intake was associated with a 30–40% increase in mortality rates. The findings overturn current guidelines for TBI patient care, pointing to the importance of aggressive early nutrition.

[832] Härtl, R., Gerber L. M., Ni Q., & Ghajar J.
(2008).  Effect of early nutrition on deaths due to severe traumatic brain injury.
Journal of Neurosurgery. 109(1), 50 - 56.

Head injuries result in widespread brain tissue loss one year later

A study of traumatic brain injury (TBI) patients who span the full range of severity from mild to moderate and severe has revealed that the more severe the injury, the greater the loss of brain tissue one year after injury, particularly white matter. Researchers were surprised at the extent of tissue loss, which was widespread even in patients who had no obvious lesions, and was discernible even in the mild TBI group.

[408] Levine, B., Kovacevic N., Nica E. I., Cheung G., Gao F., Schwartz M. L., et al.
(2008).  The Toronto traumatic brain injury study: Injury severity and quantified MRI.
Neurology. 70(10), 771 - 778.

Brain-injured war veterans show a faster decline in cognitive functioning as they age

A study of Vietnam war veterans who suffered brain injuries during the conflict has found that the men show a faster decline in their cognitive functioning as they grow older than veterans without such injuries. Greater intelligence and a higher level of education before the injury was sustained were associated with a smaller decline in cognitive functioning — perhaps because of  a greater number of neural connections, enabling the brain to recover better from injury.

[388] Raymont, V., Greathouse A., Reding K., Lipsky R., Salazar A., & Grafman J.
(2008).  Demographic, structural and genetic predictors of late cognitive decline after penetrating head injury.
Brain: A Journal of Neurology. 131(Pt 2), 543 - 558.

Early lead exposure impedes later recovery from brain injury

We know that lead exposure in early years can affect the brain. We also know that it increases the risk of various disorders later in life. Now a rat study reveals that animals exposed to lead earlier in life were significantly less able to recover from an induced stroke than those not so exposed. The study only looked at a short time-frame, so it is not yet known if the lead-exposed animals would catch up in their recovery in a longer period of time. There was some recovery in the lead group, but then it leveled off. The control group continued to get better. The findings support the suggestion that lead poisoning impairs neural plasticity.

[698] Schneider, J. S., & Decamp E.
(2007).  Postnatal lead poisoning impairs behavioral recovery following brain damage.
Neurotoxicology. 28(6), 1153 - 1157.

Imaging shows structural changes in mild traumatic brain injury

A study involving patients with all severities of traumatic brain injury has found that abnormalities in white matter existed across the spectrum, and that diffusion tensor imaging could identify structural changes even in patients with mild traumatic brain injury, who had minimal or no loss of consciousness, and even in those with no self-reported cognitive deficit. The imaging could also distinguish between axonal damage (tearing of the axons that allow one neuron to communicate with another) in white matter versus abnormalities in the myelin.

[397] Kraus, M. F., Susmaras T., Caughlin B. P., Walker C. J., Sweeney J. A., & Little D. M.
(2007).  White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study.
Brain. 130(10), 2508 - 2519.

Stem cells improved memory in mice after brain injury

Brain damage in mice that significantly impaired memory was repaired through the introduction of neural stem cells. Interestingly, the stem cells did not primarily replace the dead neurons, but somehow supported the injured neurons by, it is thought, making beneficial proteins called neurotrophins. If so, it may be that a similar effect can be achieved by creating a drug that increases the release of neurotrophins.

[546] Yamasaki, T. R., Blurton-Jones M., Morrissette D. A., Kitazawa M., Oddo S., & LaFerla F. M.
(2007).  Neural Stem Cells Improve Memory in an Inducible Mouse Model of Neuronal Loss.
J. Neurosci.. 27(44), 11925 - 11933.

Successful treatment for chronic TBI in rat study

A rat study has found that hyperbaric oxygen therapy (HBOT) improved spatial learning and memory in a model of chronic traumatic brain injury.

[1169] Harch, P. G., Kriedt C., Van Meter K. W., & Sutherland R J.
(2007).  Hyperbaric oxygen therapy improves spatial learning and memory in a rat model of chronic traumatic brain injury.
Brain Research. 1174, 120 - 129.

Drug improves memory loss for traumatic brain injury patients

A study involving 157 men and women with traumatic brain injury found attention and verbal memory test scores significantly improved among those with moderate to severe memory impairment who took rivastigmine for 12 weeks. However, the drug was not effective for patients with less severe memory loss. Rivastigmine, a drug used to treat Alzheimer’s, is thought to enhance the function of acetylcholine, a neurotransmitter involved in memory and learning.

[485] Katz, D. I., Gunay I., Silver J. M., Koumaras B., Chen M., Mirski D., et al.
(2006).  Effects of rivastigmine on cognitive function in patients with traumatic brain injury.
Neurology. 67(5), 748 - 755.

More light on adult neurogenesis; implications for dementia and brain injuries

New research has demonstrated that adult mice produce multi-purpose, or progenitor, cells in the hippocampus, and indicates that the stem cells ultimately responsible for adult hippocampal neurogenesis actually reside outside the hippocampus, producing progenitor cells that migrate into the neurogenic zones and proliferate to produce new neurons and glia. The finding may help in the development of repair mechanisms for people suffering from dementia and acquired brain injury.

[977] Bull, N. D., & Bartlett P. F.
(2005).  The Adult Mouse Hippocampal Progenitor Is Neurogenic But Not a Stem Cell.
J. Neurosci.. 25(47), 10815 - 10821.

Concussions increase chance of age-related cognitive impairment

A study involving retired National Football League players found that they had a 37% higher risk of Alzheimer's than other U.S. males of the same age. Some 60.8% of the retired players reported having sustained at least one concussion during their professional playing career, and 24% reported sustaining three or more concussions. Those with three or more concussions had a five-fold greater chance of having been diagnosed with mild cognitive impairment and a three-fold prevalence of reported significant memory problems compared to those players without a history of concussion. As the study was based on self-reported answers to the health questions, further studies are needed to confirm the findings, but it does seem likely that head injuries earlier in life increase the chance of developing dementia or mild cognitive impairment.

[345] Guskiewicz, K. M., Marshall S. W., Bailes J., McCrea M., Cantu R. C., Randolph C., et al.
(2005).  Association between recurrent concussion and late-life cognitive impairment in retired professional football players.
Neurosurgery. 57(4), 719-726; discussion 719-726 - 719-726; discussion 719-726.

Shift in brain's language-control site offers rehab hope

Language activity in right-handed people is initially localized in the left side of the brain, but a new study shows that this gradually becomes a function shared by both sides. From ages 5 to 25, language activity increases in the dominant hemisphere; from 25 to 67, the nondominant hemisphere increasingly shares the load. The discovery gives new hope for rehabilitation of brain function in adults after stroke or traumatic brain injuries.

[2575] Szaflarski, J. P., Holland S. K., Schmithorst V. J., & Byars A. W.
(2006).  fMRI study of language lateralization in children and adults.
Human Brain Mapping. 27(3), 202 - 212.

Post-concussion migraine may signal greater neurocognitive impairment

Another study suggesting sports’ concussions should be taken more seriously. The study found that young athletes who experienced migraine headache symptoms (even one week after concussion) were likely to have increased neurocognitive impairment. Headaches are reported in as many as 86% of such injuries; the researchers suggest that athletes should not be allowed to return to play before the headache resolves.

[889] Mihalik, J. P., Stump J. E., Collins M. W., Lovell M. R., Field M., & Maroon J. C.
(2005).  Posttraumatic migraine characteristics in athletes following sports-related concussion.
Journal of Neurosurgery. 102(5), 850 - 855.

Lead exposure may affect recovery from brain injury

Lead exposure at a young age can hurt the brain's development and cause learning and behavioral problems. Now it seems that it might also affect a child’s ability to recover from brain injury. A new study found young rats exposed to low levels of lead took significantly longer to recover from a brain injury than those animals that weren't lead-exposed, as well as recovering less well.

[366] Dye, M. W. G., Green S. C., & Bavelier D.
(2009).  Increasing Speed of Processing With Action Video Games.
Current Directions in Psychological Science. 18(6), 321 - 326.

After serious head injury, survivors may still be able to learn without awareness

Severe closed-head injury (CHI), like that caused in a car accident, can impair the ability for purposeful learning. New research suggests however, that severe-CHI survivors may still be able to learn without awareness that they’re learning. In the first study of implicit learning in CHI using a perceptual task, participants were asked to identify the location of a target number -- 6 -- on a computer screen, as it moved in a seemingly random fashion around a matrix of numbers. The target’s location was actually determined by an underlying pattern of relationships between that location and the arrangement of other numbers in the display. Despite slower search rates, the CHI group’s improvement in locating the “6” was consistent with that of the control group. These findings suggest an alternative approach to remediation for such sufferers — for example, therapists could “teach” complex skills by breaking them down into sub-components that can be learned implicitly and/or made automatic. The findings also support the idea that different neural mechanisms might underlie explicit and implicit learning.

[1327] Nissley, H. M., & Schmitter-Edgecombe M.
(2002).  Perceptually based implicit learning in severe closed-head injury patients.
Neuropsychology. 16(1), 111 - 122.

Skill-specific exercises better for people who suffer from attention problems following stroke or brain injury

Treatment programs for people who suffer from attention problems following a stroke or other traumatic brain injuries often involve abstract cognitive exercises designed to directly restore impaired attention processes. But a review of 30 studies involving a total of 359 participants shows that an alternative and lesser-used therapy that teaches patients to relearn the tasks that affect their daily lives the most may be more effective. In this specific skills approach, people with brain damage learn to perform attention skills in a way that is different from non-brain-damaged people. In one study, for example, participants whose brain injuries affected their ability to drive a car used small electric cars in the lab to practice specific driving exercises, such as steering between pylons that were moved closer and closer together. Those that practiced specific exercises showed substantial improvement on a variety of driving related tasks compared to those who drove the car, but did not practice the exercises.

[2548] Park, N. W., & Ingles J. L.
(2001).  Effectiveness of attention rehabilitation after an acquired brain injury: A meta-analysis..
Neuropsychology. 15(2), 199 - 210.

tags problems: 


Additional brief reports

Genes for autism and schizophrenia only active in developing brains

February 11, 2013

Genes linked to autism and schizophrenia are only switched on during the early stages of brain development, according to a study in mice.

It has been suspected for a long time that if the development of the cortex is disrupted by genetic abnormalities or environmental stress (such as prematurity) this would have long-lasting adverse effects on brain development and could lead to problems like ADHD or autism. This study defines genes that are important in mice at this critical period and this does indeed seem to include genes known to predispose to autism and schizophrenia.

Scientists investigate inherited causes of autism

February 4, 2013

Two new studies investigate the role recessive genes play in ASD. These genes can be passed on through generations, but their effects are seen only if an individual inherits two identical copies of the gene – one from each parent.

One study found that approximately 5% of autism cases could be linked to inherited, recessive mutations that completely disrupt gene function. A second study found that autism risk could also be attributed to inherited mutations that resulted in only a partial loss of gene function.

The number of different genetic mutations uncovered by the two studies supports the long-held theory that autism is a heterogeneous condition with many different genetic causes.

Gene target shows promise for autism

January 3, 2013

Mouse study found that chemically normalizing excessive levels of protein synthesis induced by a variant of the EIF4E gene, whose mutation is associated with autism, significantly reduced autistic-like behaviors. The mice were less likely to engage in repetitive behaviors, more likely to interact with other mice, and were successful in navigating mazes that differed from those they previously solved.

Air pollution drives up autism risk

Exposure to traffic-related air pollution during pregnancy and the first year of life was associated with a more than two-fold risk of autism. Exposure to regional pollution was also associated with autism even if the mother did not live near a busy road.

note criticism of the study:

Autism risk test is 70% accurate

September 12, 2012

A new genetic test predicted a person’s risk of developing an autism spectrum disorder with over 70% accuracy. Participants were all of central European descent. The test uses 237 genetic markers (SNPs) in 146 genes and related cellular pathways.

Unreliable neural response in autistic adults

September 20, 2012

A small study shows that autistic adults have unreliable neural sensory responses to visual, auditory, and somatosensory, or touch, stimuli. This poor response reliability appears to be a fundamental neural characteristic of autism. Non-autistic individuals showed reliably consistent brain activity to sensory information, while autistic individuals showed marked trial-by-trial variability. It’s suggested that such unreliable activity might be what’s limiting the development of social and language abilities.

Electrical Activity in the Brain Can Distinguish Children With Autism

June 27, 2012

A large study found that patterns of electrical activity in the brain can distinguish children with autism from children with typical brains as early as age 2. In general, autistic children showed reduced connectivity.

Autism and schizophrenia may share root cause

July 3, 2012

The risk of an autism spectrum disorder may be higher among people whose parents or siblings have been diagnosed with schizophrenia or bipolar disorder.

The presence of schizophrenia in parents was associated with an almost three times increased risk for autism spectrum disorders in Swedish groups. Schizophrenia in a sibling also was associated with roughly two and a half times the risk for autism in the Swedish national group and a 12 times greater risk in a sample of Israeli military conscripts (perhaps because of individuals with earlier onset schizophrenia, “which has a higher sibling recurrence”).

Bipolar disorder showed a similar pattern of association but of a lesser magnitude, study results indicate.

The ‘autism epidemic’ and diagnostic substitution

Excellent article on the question of why there’s been such an increase in autism diagnoses. The researcher makes a strong case that it is because of changes in diagnosis rather than a true increase.

Oxytocin improves brain function in children with autism

Preliminary results from an ongoing, large-scale study shows that oxytocin increased brain function in regions that are known to process social information in children and adolescents with autism spectrum disorders.

Research shows how PCBs promote dendrite growth, may increase autism risk

New research shows that PCBs, or polychlorinated biphenyls, launch a cellular chain of events that leads to an overabundance of dendrites and disrupts normal patterns of neuronal connections in the brain. "Impaired neuronal connectivity is a common feature of a number of conditions, including autism spectrum disorders." It’s suggested that PCB exposure "may increase the likelihood of autism in children whose genetic makeup already compromises the processes by which neurons form connections."

Full text available at

Protein in overdrive links to autism

March 21, 2012

A mouse study suggests that early disruptions in serotonin signaling in the brain may contribute to autism spectrum disorder. It has long been known that many children with autism have elevated blood levels of serotonin (hyperserotonemia).

People with autism possess greater ability to process information, study suggests

A small study suggests that people with autism spectrum disorders have a greater than normal capacity for processing perceptual information even from rapid presentations and are better able to detect information defined as 'critical'.

Autism mutations, scattered across many genes, merge into common network of interactions

A large study looking at the genes of children with sporadic autism" (no family history) has found that many mutations related to modifying chromatin (the tightly coiled spools of DNA in the cell), changing the way DNA is packaged. They also found that new mutations were overwhelming paternal in origin (in a ratio of 4:1), that the new mutations occurred at a rate that correlated with the age of the father.

What is also very clear from this and other recent studies is that autism risk mutations are scattered across many genes. It’s suggested that although no single gene will account for more than 1% of autism cases, collectively all of these rare mutations will account for much of the genetic basis of the disease.

Evolution's gift may also be at the root of a form of autism

May 10th, 2012

A study has identified the evolutionary changes that led the NOS1 gene to become active specifically in the parts of the developing human brain that form the adult centers for speech and language and decision-making. This pattern of NOS1 activity is controlled by a protein called FMRP and is missing in Fragile X syndrome. Fragile X syndrome, the leading inherited form of intellectual disability, is also the most common single-gene cause of autism.

Researchers discover new genes contributing to autism, links to psychiatric disorders

April 19th, 2012

A new approach to investigating hard-to-find chromosomal abnormalities has identified 33 genes associated with autism and related disorders, 22 for the first time. Several of these genes also appear to be altered in different ways in individuals with psychiatric disorders such as schizophrenia.

RNA discovery offers clue in autism puzzle

April 5, 2012

Scientists have discovered the first gene associated with autism that has genome-wide significance. Expression of MSNP1AS was increased 12-fold in the brains of people with autism. This gene controls expression of a protein called moesin, which influences brain development and immune response.

Study identifies gene expression abnormalities in autism

March 22nd, 2012

Following previous research showing a link between autism and excess brain cells in the prefrontal cortex, a study has showed that genetic mechanisms that normally regulate the number of cortical neurons are abnormal in such cases. This abnormality may not only result in too many neurons in some regions, but not enough in others.

Moreover, while the adolescent prefrontal cortex showed dysregulation in the pathways that govern cell number, cortical patterning and cell differentiation, adults showed dysregulation of signaling and repair pathways — indicating that gene expression abnormalities change across the lifespan in autism.

With autism, altered white matter in brain

March 7, 2012

Brain imaging and computer modeling shows how autistic brains tend to have poor quality white matter tracts connecting the frontal and posterior regions of the brain. This may explain social and language impairments.

This may mean that appropriate training could improve the white matter — compromised white matter in children with reading difficulties has been shown to be reparable with extensive behavioral therapy.

Autism can be detected in babies, say scientists

A study involving six- to 10-month-old babies who had an older brother or sister with autism found that brain activity while the infants were shown faces that switched between looking at them or away from them was indicative of later diagnoses of autism.

Neuroscientists find that two rare autism-related disorders are caused by opposing malfunctions in the brain

November 24, 2011

Most cases of autism are not caused by a single genetic mutation. However, several disorders with autism-like symptoms, including the rare Fragile X syndrome, can be traced to a specific mutation that leads to overproduction of proteins found in brain synapses. A new study shows that tuberous sclerosis, another rare disease characterized by autism and mental retardation, is caused by the opposite malfunction — too little synthesis of those synaptic proteins.

The findings fit into the theory that autism can be caused by a wide range of brain-synapse glitches. “The general concept is that appropriate brain function occurs within a very narrow physiological range that is tightly maintained. If you exceed that range in either direction, you have an impairment that can manifest as this constellation of symptoms, which very frequently go together — autism spectrum disorder, intellectual disability and epilepsy.”

The findings also show that not all cases of autism spectrum disorder will respond to the same kind of treatment.

Research reveals autistic individuals are in fact superior in multiple areas

Articles about neurocentrism etc

Researchers find alterations of a single gene associated with intellectual disability, epilepsy and autistic features

October 7, 2011

A study has identified the gene MBD5 as the sole causative gene for 2q23.1 deletion syndrome. MBD5 functions in regulating the expression of many genes and is responsible for the core clinical features in these individuals, including intellectual disability, epilepsy and autism spectrum disorder. They have also shown that there is an association between autism and MBD5.

New evidence for genetic basis of autism found

October 3, 2011

Some children with autism have a small deletion on chromosome 16, affecting 27 genes in a region of our genomes referred to as 16p11.2. The deletion -- which causes children to inherit only a single copy of the 27-gene cluster -- is one of the most common copy number variations (CNVs) associated with autism. A new study has found that deleting this set of genes in mice produces autistic-like behaviors: hyperactivity, difficulty adapting to a new environment, sleeping deficits, and restricted, repetitive behaviors.

Prenatal SSRI Exposure Linked to Autism Spectrum Disorder

A study suggests that use of selective serotonin reuptake inhibitors (SSRIs) during pregnancy increases the risk of autism spectrum disorder.

Inflexibility may give pupils with autism problems in multitasking

A study finds that young people with autism are inflexible when given multiple tasks, sticking rigidly to tasks in the order they are given to them, even when changing the order could save them time. They also had more difficulty remembering all the tasks they had to do.

The Risk of Aging Fathers

August 30, 2011

A mouse study has found that older males sire offspring with more copy number mutations in gene regions associated with developmental disorders, perhaps explaining why the children of older men have higher rates of schizophrenia and autism than those with younger fathers.

Diagnosed autism is more common in an IT-rich region

June 20, 2011

A Dutch study comparing prevalence of autism spectrum disorders in three geographical regions has found that diagnosed autism was significantly higher conditions in the IT-intensive region of Eindhoven (229 per 10,000, vs 84 per 10,000 and 57 per 10,000 in IT-lower regions — Haarlem and Utrecht).

Balance tips toward environment as heritability ebbs in autism?

July 4, 2011

A large twin study found that shared environmental factors accounted for 55% of strict autism and 58% of more broadly defined autism spectrum disorders (ASD). Genetic heritability accounted for 37% of autism and 38% of ASD. This dramatically reduces previous estimates of genetic heritability of autism from twin studies.

Gene linked to severity of autism's social dysfunction

April 6, 2011

Variants in the gene GRIP1 (glutamate receptor interacting protein 1) have been found to contribute to the severity of social interaction deficits in autistic individuals. This gene regulates how fast receptors travel to a cell's surface, where they are activated by a brain-signaling chemical called glutamate, allowing neurons to communicate with one another. The finding lends support to a prevailing theory that autism spectrum disorders reflect an imbalance between inhibitory and excitatory signaling at synapses.

Why Autism Strikes More Boys Than Girls

July 19, 2011

The marked gender imbalance in autism may related to a gene called retinoic acid–related orphan receptor-alpha (RORA), which interacts with certain types of estrogen and testosterone found in the brain. Autistic individuals tend to have low levels of RORA protein and the enzyme it produces (arom­a­tase). This enzyme converts testosterone to estrogen, but RORA is less active in the presence of tes­tosterone made RORA, and more active in the presence of estrogen. While the balance of sex hormones usually regulates RORA activity, an imbalance can be exacerbated by this feedback loop.

It’s suggested that low levels of RORA protein and enzyme result in an excess of testosterone, while most females are protected by their higher levels of estrogen.

'Most adults with autism go undiagnosed' -- new findings

The first ever general population survey of autism in adulthood has found that 9.8 per thousand adults in England meet official diagnostic criteria for autism spectrum disorder. Moreover, none of the cases with autism found knew that they were autistic or had received an official diagnosis of autism or asperger syndrome. The findings add support to the theory that autism is not increasing, diagnosis is just more common.

Autism linked to hundreds of spontaneous genetic mutations

June 9. 2011

The most comprehensive search yet for spontaneous genetic mutations associated with autism spectrum disorders suggests that hundreds may play a part. It also finds that girls with autism tend to have many more mutated genes than boys with the disorder, suggesting that it generally takes a larger genomic change to cause autism in girls.

A particularly interesting finding was that, while deletion of a segment of chromosome 7 (specifically, 7q11.23) is associated with Williams Syndrome (marked by hypersocial behavior), duplication of this region is associated with autism.

How common is autism?

Great discussion of why prevalence estimates can be so different, and why diagnosing autism spectrum disorders is so difficult.

Mapping data shows enhanced activity in the 'perception' part of the brain

Brain scans have determined that people with autism concentrate more brain resources in the areas associated with visual detection and identification (temporal, occipital, and parietal lobes), and conversely, have less activity in the areas used to plan and control thoughts and actions (frontal lobe).

An autism brain signature?

May 25, 2011

A genome-wide analysis of the RNA in the brains of individuals with autism has revealed that, while gene expression in the frontal lobe normally varies significantly from that in the temporal lobe due to their different functions, this tended not to be true of autistic brains. Instead, in more than 2/3 autistic individuals, the levels of gene expression between the two lobes were homogenized, as if they had similar functions.

New Genetics Work Challenges Basic Ideas about Mental Illness

May 17, 2011

Some background on genetic mutations — explaining single-nucleotide polymorphisms (SNPs), copy-number variants (CNVs), genome-wide association studies (GWAS), and how they’re being used in research into the causes of various disorders.

Researchers link spontaneous gene mutations to autism

May 16, 2011

Preliminary results suggest that as many as % of sporadic autism cases can be explained by spontaneous gene mutations. The findings are also consistent with other studies suggesting that ASDs are more likely in children born to older parents, and in particular, older fathers.

Children conceived in winter have a greater risk of autism, study finds

May 5, 2011

An examination of the birth records of children born in California during the 1990s and early 2000s has found a clear link between the month in which a child is conceived and the risk of that child later receiving a diagnosis of autism, with those conceived during winter having a significantly greater risk of autism.

Earlier studies (all much smaller) have found inconsistent results in linking autism risk to month of conception.

The mirror neuron system in autism: Broken or just slowly developing?

May 3, 2011

It’s been suggested that the mirror neuron system (neurons that activate in similar ways whether we perform actions or watch other people perform the same actions) is broken in autistic individuals, but a new study suggests that it just develops more slowly.

An interview with mirror neuron guru Vilayanur S. Ramachandran about autism and mirror neurons.

A world first: The discovery of a common genetic cause of autism and epilepsy

April 8, 2011

Researchers have identified a new gene that predisposes people to both autism and epilepsy. The synapsin gene (SYN1) plays a crucial role in the development of the membrane surrounding neurotransmitters (the synaptic vesicles), affecting communication between neurons.

Knowing Me, Knowing You: How Social Intuition Goes Awry in Autism

March 7, 2011 

It’s suggested that the social impairment characteristic of autism spectrum disorders may be related to a lack of a type of spindle neurons called Von Economo neurons. These neurons are only found in very social species, such as the great apes, elephants, and whales and ­dolphins, and are found only in the frontoinsular and anterior cingulate cortex.

Cognitive skills in children with autism vary and improve, study finds

September 15, 2010

A three year study looking at how the cognitive skills of children with ASD change over time has found that most of the children (aged 5-6 at the beginning of the study) developed better appreciation of others' thoughts and feelings, and improved ability to plan, regulate, and control their thoughts and actions. However, their ability to construct patterns from wooden blocks and search for shapes hidden in pictures did not improve over time.

Too Much, Too Young: Brain Overgrowth Correlates with the Severity of Autism Symptoms

July 27, 2010

Excess brain growth may be the first sign of autism, starting in the first year of life, if not sooner.

Scientists have the genetic causes of autism in their sights

The Autism Genome Project has identified rare genetic mutations (copy number variations (CNVs)), that were 20% more frequent in children with autism than in children without the disorder.

Alternative Biomedical Treatments for Autism: How Good Is the Evidence?

October 7, 2010

Review of alternative autism treatments.

A Crack in the Mirror Neuron Hypothesis of Autism

May 12, 2010

A new test of mirror neuron activity suggests that autistic individuals’ mirror neurons may behave normally. However, they showed more variable activity in brain regions that process visual images and execute movements. The researchers suggest that it may be faulty signaling, rather than mirror neuron problems, that underlies some of their social difficulties.

The researchers’ tests and interpretations are controversial.

Video Q&A: What is autism? - A personal view

Stem cells restore cognitive abilities impaired by brain tumor treatment

A rat study has found that transplanted stem cells restored learning and memory to normal levels four months after radiotherapy. This compares with a greater than 50% decline in cognitive function in those rats that didn’t receive the therapy. Cranial irradiation is a common treatment for brain tumors.

[803] Acharya, M. M., Christie L. - A., Lan M. L., Donovan P. J., Cotman C. W., Fike J. R., et al.
(2009).  Rescue of radiation-induced cognitive impairment through cranial transplantation of human embryonic stem cells.
Proceedings of the National Academy of Sciences. 106(45), 19150 - 19155.

Childhood brain tumors permanently impact cognition & lifestyle

A survey involving 785 CNS cancer survivors, 5,870 survivors of non-CNS cancers (such as leukemia, Hodgkin's disease, and bone tumors), and 379 siblings of CNS cancer survivors, sent at least 16 years after diagnosis, has found that CNS cancer survivors reported significantly greater neurocognitive dysfunction than their siblings and survivors of other types of cancer. Moreover, these problems were linked to lower achievement in education and in full-time employment and income, as well as less chance of being married. The worst problems were found in those who had tumors in the cortex, and those who had cranial radiation treatment.

Ellenberg, L. et al. 2009. Neurocognitive Status in Long-Term Survivors of Childhood CNS Malignancies: A Report From the Childhood Cancer Survivor Study. Neuropsychology, 23 (6), 705-717.

Therapy program has significant effect on autistic toddlers

A randomized controlled trial involving autistic toddlers aged 18 to 30 months has found that those who participated for two years in an intensive program of behavioral therapy known as the Early Start Denver Model improved 17.6 standard score points in IQ, on average, compared with 7 points in the group who received standard community intervention. They were also more likely to be re-diagnosed from autism to pervasive developmental disorder.

[1499] Dawson, G., Rogers S., Munson J., Smith M., Winter J., Greenson J., et al.
(2010).  Randomized, Controlled Trial of an Intervention for Toddlers With Autism: The Early Start Denver Model.
Pediatrics. 125(1), e17-23 - e17-23.

Study finds autistics better at problem-solving

A study involving 15 autistics and 18 non-autistics, aged 14 to 36 and IQ-matched, has found that while both groups completed patterns in a complex problem-solving test (the widely-used Raven's Standard Progressive Matrices) with equal accuracy, the autistics responded significantly faster, and showed a different pattern of brain activity. Specifically, they showed increased activity in extrastriate areas, and decreased activity in the lateral prefrontal cortex and the medial posterior parietal cortex — suggesting visual processing mechanisms may play a more prominent role in reasoning in autistics. The differences between groups did not appear when participants performed a simpler pattern-matching task.

[555] Soulières, I., Dawson M., Samson F., Barbeau E. B., Sahyoun C. P., Strangman G. E., et al.
(2009).  Enhanced visual processing contributes to matrix reasoning in autism.
Human Brain Mapping. 30(12), 4082 - 4107.

New genes implicated in autism; support new theory of cause

Research involving 104 large Middle Eastern families has implicated half a dozen new genes in autism, and more importantly, strongly supports the emerging idea that autism stems from disruptions in the brain's ability to form new connections in response to experience – consistent with autism's onset during the first year of life, when many of these connections are normally made. Just over 6% of the 88 families with autistic members showed rare, inherited deletions within DNA regions linked to autism. These affected DNA regions varied among families, further indication of autism's large variety of genetic causes. In all, the technique identified five chromosome deletions affecting at least six identifiable genes. Although the genes discovered are diverse in function, all seem to be part of a fundamental network that orchestrates the refinement and maturation of synapses in response to input from the outside world. The network itself is already known to activate at least 300 genes, so it’s no surprise that there are many ways it can be disrupted, explaining why there might be myriad genetic causes of autism, even though in essence it might be all the same problem: a disruption of the brain's ability to modify its synaptic connections in response to experience. The good news is that in all but one case the chromosome deletions didn’t actually remove a gene, they just turned it off — suggesting a possible ‘cure’ if researchers can figure out how to turn them back on.

[942] Hashmi, A., Al-Saad S., Ware J., Joseph R. M., Greenblatt R., Gleason D., et al.
(2008).  Identifying Autism Loci and Genes by Tracing Recent Shared Ancestry.
Science. 321(5886), 218 - 223.

Autism's social struggles due to disrupted communication networks in brain

And a timely imaging study has now provided the clearest evidence to date that synchronization in what might be termed the Theory of Mind network is impaired in autistic people. The Theory of Mind network (which includes the medial frontal gyrus, the anterior paracingulate, and the right temporoparietal junction) is responsible for processing the intentions and thoughts of others. In the study 12 high-functioning autistic adults and 12 controls viewed animated interacting geometric figures, and then asked to select the word from several choices that best described the interaction. The control subjects were consistently better at inferring the intention from the action than the participants with autism were. Brain scans revealed that synchronization between the frontal and posterior regions in the network was reliably lower in the group with autism. The autistic participants' brains also showed much lower activation levels in the frontal regions, and an independent assessment of their Theory of Mind abilities found these reliably correlated with activation in the right temporoparietal junction. The findings point to the need to develop interventions that could target this problem, and also indicate a way to measure an intervention’s effectiveness.

[782] Kana, R. K., Keller T. A., Cherkassky V. L., Minshew N. J., & Just M A.
(2009).  Atypical frontal-posterior synchronization of Theory of Mind regions in autism during mental state attribution.
Social Neuroscience. 4(2), 135 - 152.

New genetic link to autism identified

Three new studies, using different methods, have all implicated the same gene in the development of autism. The research follows earlier findings implicating a specific region of Chromosome 7 called 7q35. The gene — contactin-associated protein-like 2 (CNTNAP2) — is a gene in this region. The research not only points to this gene predisposing an individual to autism, it also may explain the association with late language onset, a characteristic of most autistic children. The gene was most active in developing brain structures involved in language and thought. The finding may also help explain why autism is so much more common among boys. Statistical evidence for the gene was strongest in families with autistic boys. Less of an association appeared in families with autistic boys and girls, or in families with autistic girls only.

[902] Ledbetter, D. H., Alarcón M., Abrahams B. S., Stone J. L., Duvall J. A., Perederiy J. V., et al.
(2008).  Linkage, Association, and Gene-Expression Analyses Identify CNTNAP2 as an Autism-Susceptibility Gene.
The American Journal of Human Genetics. 82(1), 150 - 159.

[538] Cook Jr., E. H., Arking D. E., Cutler D. J., Brune C. W., Teslovich T. M., West K., et al.
(2008).  A Common Genetic Variant in the Neurexin Superfamily Member CNTNAP2 Increases Familial Risk of Autism.
The American Journal of Human Genetics. 82(1), 160 - 164.

[857] Stillman, A. A., Bakkaloglu B., O'Roak B. J., Louvi A., Gupta A. R., Abelson J. F., et al.
(2008).  Molecular Cytogenetic Analysis and Resequencing of Contactin Associated Protein-Like 2 in Autism Spectrum Disorders.
The American Journal of Human Genetics. 82(1), 165 - 173.

Autism non-verbal not unintelligent

New findings suggest that the association of autism with low intelligence is a product of their language difficulties. Testing autistic kids and normal kids on two popular IQ tests — the WISC (which relies heavily on language) and Raven's Progressive Matrices (considered the best test of "fluid intelligence", and a test that doesn't require much language) found that while not a single autistic child scored in the "high intelligence" range of the WISC, a third did on the Raven's. A third of the autistics had WISC scores in the mentally retarded range, but only one in 20 scored that low on the Raven's test. The non-autistic children scored similarly on both tests. The same results occurred when the experiment was run on autistic and normal adults.

[580] Dawson, M., Soulières I., Gernsbacher M A., & Mottron L.
(2007).  The level and nature of autistic intelligence.
Psychological Science: A Journal of the American Psychological Society / APS. 18(8), 657 - 662.

Monkeys can reflect on their thoughts

A study involving two rhesus macaque monkeys has shown that a monkey can reflect on its own thoughts and assess its performance. The experiment trained the monkeys to play a video game that tested their ability to remember a particular photograph while also allowing them to make a large or a small bet on how likely they were to be right. The monkeys could also request hints for problems that would otherwise have to be solved by trial and error. Not only did the results provide clear evidence of their ability to engage in metacognition, but the study also points to a means of testing nonverbal humans, such an infants and autistic children.

[1315] Kornell, N., Son L. K., & Terrace H. S.
(2007).  Transfer of metacognitive skills and hint seeking in monkeys.
Psychological Science: A Journal of the American Psychological Society / APS. 18(1), 64 - 71.

Oxytocin may help treat two core autism symptoms

In a pilot study, researchers have found administration of oxytocin has beneficial effects on repetitive behaviors and aspects of social cognition in high-functioning autistic adults.

The research was presented at the American College of Neuropsychopharmacology's Annual Meeting.

A gene for autism

A study has found that those with two copies of a specific variant of a gene within chromosome 7, that regulates production of a protein that influences cell proliferation in various parts of the body, are substantially more likely to be autistic. The link between the MET variant and autism appears primarily in families with two or more affected children. The gene variant is not rare — roughly 47% of the population carry at least one copy of it. It may be that it is affected by prenatal environmental factors or that it interacts with other genes to derail brain formation. It is likely that there are a number of genes associated with autism. But this particular gene variant would explain controversial reports that people with autism often have immune and gastrointestinal problems.

[692] Sacco, R., Persico A. M., Levitt P., Campbell D. B., Sutcliffe J. S., Ebert P. J., et al.
(2006).  A genetic variant that disrupts MET transcription is associated with autism.
Proceedings of the National Academy of Sciences. 103(45), 16834 - 16839.

Brain enlargement may be characteristic of autism

Comparison of 164 children with autism and 214 control children (all younger than 3 years) has found significant enlargement in the volume of the cerebral cortex, in both white and grey matter, and generalized throughout the cortex. Head circumference was not significantly different at birth — an increased rate of growth occurred from around 12 months.

[315] Hazlett, H C., Poe M., Gerig G., Smith R G., Provenzale J., Ross A., et al.
(2005).  Magnetic Resonance Imaging and Head Circumference Study of Brain Size in Autism: Birth Through Age 2 Years.
Arch Gen Psychiatry. 62(12), 1366 - 1376.

Breakdown of myelin insulation in brain's wiring implicated in childhood developmental disorders

Previous research has suggested that the production of myelin (a fatty insulation coating the brain's internal wiring) is a key component of brain development through childhood and well into middle age, when development peaks and deterioration begins, and that midlife breakdown of myelin is implicated to onset of Alzheimer's disease later in life. Now new research suggests the disruption of myelination is a key neurobiological component behind childhood developmental disorders, such as autism and attention deficit/hyperactivity disorder, and addictive behaviors. The analysis also suggests that alcohol and other drugs of abuse have toxic effects on the myelination process in some adolescents.

Bartzokis, G. 2005. Adolescent Psychiatry. Hillsdale, N.J.: The Analytic Press Inc.

Why autism is associated with executive function problems

A new imaging study has revealed that autistic boys have less activation in the parts of the brain responsible for executive function (attention, reasoning and problem solving) — specifically, in the caudate nucleus, a critical part of circuits that link the prefrontal cortex of the brain. The researchers have noted similarities in the impairment of specific executive function in children with ADHD and autism.

[2574] Silk, T., Rinehart N., Bradshaw J., Tonge B., Egan G., O’Boyle M., et al.
(Submitted).  Visuospatial Processing and the Function of Prefrontal-Parietal Networks in Autism Spectrum Disorders: A Functional MRI Study.
American Journal of Psychiatry. 163(8), 1440 - 1443.

Finding supports theory that autism results from failure of brain areas to work together

An imaging study indicates people with autism remember letters as geometric shapes, compared to the more usual remembering by their names. Moreover, compared to the control group, the activated brain areas of the people with autism were less likely to work in synchrony (at the same time) while recalling the letters. This supports a theory that autism results from a failure of the various parts of the brain to work together. This theory suggests that therapies emphasizing problem solving skills and other tasks that activate multiple brain areas at the same time might benefit people with autism.

Koshino, H., Carpenter, P.A., Minshew, N.J., Cherkassky, V.L., Keller, T.A. & Just, M.A. 2005. Functional connectivity in an fMRI working memory task in high-functioning autism. NeuroImage, 24 (3), 810-821.

Special training may help people with autism recognize faces

People with autism tend to activate object-related brain regions when they are viewing unfamiliar faces, rather than a specific face-processing region. They also tend to focus on particular features, such as a mustache or a pair of glasses. However, a new study has found that when people with autism look at a picture of a very familiar face, such as their mother's, their brain activity is similar to that of control subjects – involving the fusiform gyrus, a region in the brain's temporal lobe that is associated with face processing, rather than the inferior temporal gyrus, an area associated with objects. Use of the fusiform gyrus in recognizing faces is a process that starts early with non-autistic people, but does take time to develop (usually complete by age 12). The study indicates that the fusiform gyrus in autistic people does have the potential to function normally, but may need special training to operate properly.

Aylward, E. 2004. Functional MRI studies of face processing in adolescents and adults with autism: Role of experience. Paper presented February 14 at the annual meeting of the American Association for the Advancement of Science in Seattle.

Dawson, G. & Webb, S. 2004. Event related potentials reveal early abnormalities in face processing autism. Paper presented February 14 at the annual meeting of the American Association for the Advancement of Science in Seattle.

Autistic preschoolers don't recognize emotions from facial photographs

Normally developing infants notice their mothers' facial expressions and emotions in the first six months of life and are able to recognize emotions from facial expressions by age 7 months. In a recent study reported at the first International Meeting for Autism Research in San Diego last month, 3- and 4-year-old autistic, developmentally delayed and normally developing children were shown photographs of faces depicting fear and a neutral expression while brain activity was monitored. It was found that the brains of normally developing and developmentally delayed children exhibited different activity depending on the picture being viewed. However, the brain activity of the autistic children remained the same when the different pictures were shown.

Dawson, G. & Dager, S. 2001. Paper presented at the first International Meeting for Autism Research in San Diego in November. The autism meeting was held in conjunction with the annual meeting of the Society for Neuroscience.

Differences in face perception processing between autistic and normal adults

An imaging study compared activation patterns of adults with autism and normal control subjects during a face perception task. While autistic subjects could perform the face perception task, none of the regions supporting face processing in normals were found to be significantly active in the autistic subjects. Instead, in every autistic patient, faces maximally activated aberrant and individual-specific neural sites (e.g. frontal cortex, primary visual cortex, etc.), which was in contrast to the 100% consistency of maximal activation within the traditional fusiform face area (FFA) for every normal subject. It appears that, as compared with normal individuals, autistic individuals `see' faces utilizing different neural systems, with each patient doing so via a unique neural circuitry.

[704] Pierce, K., Muller R. - A., Ambrose J., Allen G., & Courchesne E.
(2001).  Face processing occurs outside the fusiform `face area' in autism: evidence from functional MRI.
Brain. 124(10), 2059 - 2073.

Autistic 3- and 4-year-olds react to a picture of a familiar toy but not to a picture of their mother

Face recognition is a specialized and highly developed memory system in humans, and a preference for face-like stimuli is evident even in newborn babies. New research has found that, unlike normally developing and even mentally retarded children, autistic 3- and 4-year-olds do not react to a picture of their mother, although they do react when they see a picture of a familiar toy. This highlights that autism is a disorder of the social brain, and may allow diagnoses of autism to be made much earlier than is now possible.

The study was reported at the annual meeting of the Society for Research in Child Development.

tags problems: 

Learning difficulties

Separate pages are available for:

Older news items (pre-2010) brought over from the old website

New screening tool helps identify children at risk

An exam, called the NICU (neonatal intensive care unit) Network Neurobehavioral Scale (NNNS), has been created to identify newborns who may have problems with school readiness and behavior at age four. This opens up the possibility of early intervention to prevent these problems. The screening exam has been tested on 1248 babies, mostly black and on public assistance. Five discrete behavioral profiles were reliably identified; the most extreme negative profile was found in 5.8% of the infants. Infants with poor performance were more likely to have behavior problems at age three, school readiness problems at age four, and low IQ at 4 ½ — 40% had clinically significant problems externalizing (impulsivity and acting out), internalizing (anxiety, depression, withdrawn personalities), and with school readiness (delays in motor, concepts and language skills), and 35% had low IQ.

[596] Liu, J., Bann C., Lester B., Tronick E., Das A., Lagasse L., et al.
(2010).  Neonatal neurobehavior predicts medical and behavioral outcome.
Pediatrics. 125(1), e90-98 - e90-98.

Cognitive dysfunction reversed in mouse model of Down syndrome

Down syndrome is characterized by specific learning impairments (for example, difficulties in using spatial and contextual information to form new memories, but less difficulty at remembering information linked to sensory cues) that point to the hippocampus as a problem area. Investigation has revealed that the problem lies in degeneration of the locus coeruleus, which sends norepinephrine to neurons in the hippocampus. Now a study using genetically engineered mice has found that norepinephrine precursor drugs improved performance in the mice within a few hours. However, the effect did wear off quite quickly too. Other research has looked at acetylcholine, which also acts at the hippocampus. The present findings suggest the best medication regimen will be one that improves both norepinephrine and acetylcholine signals. Locus coeruleus degeneration is also seen in dementia; Alzheimer’s develops among those with Down syndrome at a significantly higher rate than in the general population.

Salehi, A. et al. 2009. Restoration of Norepinephrine-Modulated Contextual Memory in a Mouse Model of Down Syndrome. Science Translational Medicine, 1 (7), 7-17.

Testing one time is not enough

A study demonstrating the perils of one-time testing gave 16 common cognitive and neuropsychological tests to groups of people ages 18-39, 50-59 and 60-97 years. The variation between scores on the same test given three times during a two-week period was as big as the variation between the scores of people in different age groups. “It's as if on the same test, someone acted like a 20-year-old on a Monday, a 45-year-old on Friday, and a 32-year-old the following Wednesday”. The study makes clear the dangers of diagnosing learning disability, progressive brain disease or impairment from head injury on the basis of testing on a single occasion. The researcher suggests we should view cognitive abilities as a distribution of many potential levels of performance instead of as one stable short-term level; that people have a range of typical performances, a one-person bell curve. It may also be that within-person variability could be a useful diagnostic marker in itself — for example, extreme fluctuations might be an early warning of mental decline.

[921] Salthouse, T. A.
(2007).  Implications of within-person variability in cognitive and neuropsychological functioning for the interpretation of change.
Neuropsychology. 21(4), 401 - 411.

Common cholesterol-lowering drug reverses learning disabilities in mice

Following their discovery that neurofibromatosis 1 (NF1) — the leading genetic cause of learning disabilities — is linked to dysfunction in a protein called Ras, researchers have successfully used a commonly prescribed cholesterol-lowering statin drug (lovastatin) to reverse the learning deficits in mice. Clinical trials with humans are being planned.

[1348] Li, W., Cui Y., Kushner S., Brown R., Jentsch J., Frankland P., et al.
(2005).  The HMG-CoA Reductase Inhibitor Lovastatin Reverses the Learning and Attention Deficits in a Mouse Model of Neurofibromatosis Type 1.
Current Biology. 15(21), 1961 - 1967.

More light on a common developmental disorder

Chromosome 22q11.2 deletion syndrome is the most common genetic deletion syndrome, and causes symptoms such as heart defects, cleft palate, abnormal immune responses and cognitive impairments. Two related studies have recently cast more light on these cognitive impairments. Previously it was known that numerical abilities were impaired more than verbal skills. The new study found children with the chromosome deletion performed more poorly on experiments designed to test visual attention orienting, enumerating, and judging numerical magnitudes. All three tasks relate to how the children mentally represent objects and the spatial relationships among them, supporting previous arguments that such visual-spatial skills are a fundamental foundation to the later learning of counting and mathematics. The second study found that such children had changes in the shape, size and position of the corpus callosum, the main bridge between the two hemispheres.

[1139] Simon, T. J., Bearden C. E., Mc-Ginn D MD., & Zackai E.
(2005).  Visuospatial and Numerical Cognitive Deficits in Children with Chromosome 22Q11.2 Deletion Syndrome.
Cortex. 41(2), 145 - 155.

[812] Simon, T. J., Ding L., Bish J. P., McDonald-McGinn D. M., Zackai E. H., & Gee J.
(2005).  Volumetric, connective, and morphologic changes in the brains of children with chromosome 22q11.2 deletion syndrome: an integrative study.
NeuroImage. 25(1), 169 - 180.

tags problems: 


Older news items (pre-2010) brought over from the old website

Inconsistent processing speed among children with ADHD

A new analytical technique has revealed that the problem with children with ADHD is not so much that they are slower at responding to tasks, but rather that their response is inconsistent. The study of 25 children with ADHD and 24 typically developing peers found that on a task in which a number on one screen needed to be mentally added to another number shown on a second screen, those with ADHD were much less consistent in their response times, although the responses they did give were just as accurate. Higher levels of hyperactivity and restlessness or impulsivity (as measured by parent survey) correlated with more slower reaction times. The finding supports the idea that what underlies impaired working memory is a problem in how consistently a child with ADHD can respond during a working memory task.

[911] Buzy, W. M., Medoff D. R., & Schweitzer J. B.
(2009).  Intra-Individual Variability Among Children with ADHD - on a Working Memory Task: An Ex-Gaussian Approach.
Child Neuropsychology. 15(5), 441 - 441.

Hyperactivity enables children with ADHD to stay alert

A study of 12 8- to 12-year-old boys with ADHD, and 11 of those without, has found that activity levels of those with ADHD increased significantly whenever they had to perform a task that placed demands on their working memory. In a highly stimulating environment where little working memory is required (such as watching a Star Wars video), those with ADHD kept just as still as their normal peers. It’s suggested that movement helps them stay alert enough to complete challenging tasks, and therefore trying to limit their activity (when non-destructive) is counterproductive. Providing written instructions, simplifying multi-step directions, and using poster checklists are all strategies that can be used to help children with ADHD learn without overwhelming their working memories.

[734] Rapport, M., Bolden J., Kofler M., Sarver D., Raiker J., & Alderson R.
(2009).  Hyperactivity in Boys with Attention-Deficit/Hyperactivity Disorder (ADHD): A Ubiquitous Core Symptom or Manifestation of Working Memory Deficits?.
Journal of Abnormal Child Psychology. 37(4), 521 - 534.

Transcendental Meditation reduces ADHD symptoms among students

A pilot study involving 10 middle school students with ADHD has found that those who participated in twice-daily 10 minute sessions of Transcendental Meditation for three months showed a dramatic reduction in stress and anxiety and improvements in ADHD symptoms and executive function. The effect was much greater than expected. ADHD children have a reduced ability to cope with stress.
A second, recently completed study has also found that three months practice of the technique resulted in significant positive changes in brain functioning during visual-motor skills, especially in the circuitry of the brain associated with attention and distractibility. After six months practice, measurements of distractibility moved into the normal range.

Grosswald, S.J., Stixrud, W.R., Travis, F. & Bateh, M.A. 2008. Use of the Transcendental Meditation technique to reduce symptoms of Attention Deficit Hyperactivity Disorder (ADHD) by reducing stress and anxiety: An exploratory study. Current Issues in Education, 10 (2)

How Ritalin works to focus attention

Ritalin has been widely used for decades to treat attention deficit hyperactivity disorder (ADHD), but until now the mechanism of how it works hasn’t been well understood. Now a rat study has found that Ritalin, in low doses, fine-tunes the functioning of neurons in the prefrontal cortex, and has little effect elsewhere in the brain. It appears that Ritalin dramatically increases the sensitivity of neurons in the prefrontal cortex to signals coming from the hippocampus. However, in higher doses, prefrontal neurons stopped responding to incoming information, impairing cognition. Low doses also reinforced coordinated activity of neurons, and weakened activity that wasn't well coordinated. All of this suggests that Ritalin strengthens dominant and important signals within the prefrontal cortex, while lessening weaker signals that may act as distractors.

[663] Devilbiss, D. M., & Berridge C. W.
(2008).  Cognition-Enhancing Doses of Methylphenidate Preferentially Increase Prefrontal Cortex Neuronal Responsiveness.
Biological Psychiatry. 64(7), 626 - 635.

Study raises questions about diagnosis, treatment of ADHD

The first large, longitudinal study of adolescents and ADHD has revealed that only about half of children diagnosed with attention-deficit hyperactivity disorder exhibit the cognitive defects commonly associated with the condition. Part of the explanation may lie in the fact that ADHD is simply the extreme end of a normal continuum of behavior that varies in the population, and its diagnosis is defined by where health professionals "draw the line" on this continuum. This finding suggests that behavior-rating scales alone are not sensitive enough to differentiate between the two groups. Researchers also found surprising results regarding the effectiveness of medicine in treating ADHD. In contrast to children in United States, youth in northern Finland are rarely treated with medicine for ADHD, yet the prevalence, symptoms, psychiatric comorbidity and cognition of the disorder is relatively the same as in the U.S., where stimulant medication is widely used. Although the medication is very effective in the short-term, the study raises questions concerning its long-term efficacy. The study also confirmed that hyperactivity and impulsivity decrease with age, while inattention increasingly predominates; that ADHD is associated with increased rates of other psychiatric problems, especially depression, anxiety, oppositional behaviors, conduct disorders, and post-traumatic stress disorder. The study of Finnish adolescents found a prevalence of 8.5% with a male/female ratio of 5.7:1.

[615] McCracken, J. T., Varilo T., Yang M. H., Nelson S. F., Peltonen L., JÄRVELIN M-R., et al.
(2007).  Prevalence and Psychiatric Comorbidity of Attention-Deficit/Hyperactivity Disorder in an Adolescent Finnish Population.
Journal of the American Academy of Child & Adolescent Psychiatry. 46(12), 1575 - 1583.

[1367] JÄRVELIN, M-R., Smalley S. L., Lubke G. H., MUTHÉN B., Moilanen I. K., McGough J. J., et al.
(2007).  Subtypes Versus Severity Differences in Attention-Deficit/Hyperactivity Disorder in the Northern Finnish Birth Cohort.
Journal of the American Academy of Child & Adolescent Psychiatry. 46(12), 1584 - 1593.

[1030] Ebeling, H., JÄRVELIN M-R., Smalley S. L., Loo S. K., Humphrey L. A., Tapio T., et al.
(2007).  Executive Functioning Among Finnish Adolescents With Attention-Deficit/Hyperactivity Disorder.
Journal of the American Academy of Child & Adolescent Psychiatry. 46(12), 1594 - 1604.

[1104] Hurtig, T., Ebeling H., Taanila A., Miettunen J., Smalley S. L., McGough J. J., et al.
(2007).  ADHD Symptoms and Subtypes: Relationship Between Childhood and Adolescent Symptoms.
Journal of the American Academy of Child & Adolescent Psychiatry. 46(12), 1605 - 1613.

Gene predicts better outcome as cortex normalizes in teens with ADHD

Recent research found that thickening of brain areas that control attention in the right cortex (right orbitofrontal/inferior prefrontal and posterior parietal cortex ) was associated with better clinical outcomes in ADHD. A new study has found that these brain areas are thinnest in those who carry a particular variant of a gene. The version of the dopamine D4 receptor gene, called the 7-repeat variant, was found in nearly a quarter of youth with ADHD and about one-sixth of the healthy controls. Although this particular gene version increased risk for ADHD, it also made it more likely that the areas would thicken during adolescence, with consequent improvement in behaviour and performance.

Citekey 1067/ibib]</p><p><a href="">http:... TV viewing during adolescence linked with risk of attention and learning difficulties</h3><p>A long-running study of 678 families in upstate New York, surveyed children at 14, 16 and 22 years old (averages), and again when the children in the study had reached an average age of 33. At age 14, 225 (33.2%) of the teens reported that they watched three or more hours of television per day. Those who watched 1 or more hours of television per day at mean age 14 years were at higher risk of poor homework completion, negative attitudes toward school, poor grades, and long-term academic failure. Those who watched 3 or more hours of television per day were most likely to experience these outcomes, and moreover were at higher risk of subsequent attention problems and were the least likely to receive postsecondary education. Analysis of the data also indicated that television watching contributes to learning difficulties and not vice versa.</p><p>[ibib]540 not found

Drug for teen drivers with ADHD

A comparison of the effects of OROS methylphenidate (Concerta), a controlled-release stimulant, and extended release amphetamine salts (Adderall XR) on driving performance in teens with ADHD has found that treatments with Concerta led to fewer inattentive driving errors and less hyperactive or impulsive driving errors, such as speeding and inappropriate braking, compared with Adderall XR and placebo.

[1076] Cox, D. J., Merkel L. R., Moore M., Thorndike F., Muller C., & Kovatchev B.
(2006).  Relative Benefits of Stimulant Therapy With OROS Methylphenidate Versus Mixed Amphetamine Salts Extended Release in Improving the Driving Performance of Adolescent Drivers With Attention-Deficit/Hyperactivity Disorder.
Pediatrics. 118(3), e704-710 - e704-710.

ADHD linked to genetic and environmental interactions

A study of 172 children who were enrolled in a community-based study of low levels of lead exposure has found evidence that increasing lead exposure is linked to impairment on a number of executive functions (impaired in those with ADHD), but that certain genetic and biological factors seemed to predispose an individual to the negative effects of lead exposure. For instance, only children with certain variations of the DRD4 gene seemed vulnerable to lead's adverse effects on attentional flexibility. Boys were more vulnerable to this effect than girls.

The study was presented on May 1, 2006 at the annual Pediatric Academic Societies meeting in San Francisco.

Drug improves information processing in adults with ADHD

Mixed amphetamine salts extended release (MAS XR) substantially improved the speed and accuracy in information processing of young adults with attention-deficit/hyperactivity disorder (ADHD). Excitingly, the improvement persisted after the 3 weeks of treatment had been stopped for 3 weeks.

Kay, G.G. & Kardiasmenos, K.S. 2006. Effect of Mixed Amphetamine Salts Extended Release on Neurocognitive Speed in Young Adults with ADHD. Paper presented at the annual American Psychiatric Association Meeting in Toronto, Canada. Poster #NR678

Kay, G.G. & Kardiasmenos, K.S. 2006. Effect of Mixed Amphetamine Salts Extended Release on Neurocognitive Accuracy in Young Adults with ADHD. Paper presented at the annual American Psychiatric Association Meeting in Toronto, Canada. Poster #NR679

Breakdown of myelin insulation in brain's wiring implicated in childhood developmental disorders

Previous research has suggested that the production of myelin (a fatty insulation coating the brain's internal wiring) is a key component of brain development through childhood and well into middle age, when development peaks and deterioration begins, and that midlife breakdown of myelin is implicated to onset of Alzheimer's disease later in life. Now new research suggests the disruption of myelination is a key neurobiological component behind childhood developmental disorders, such as autism and attention deficit/hyperactivity disorder, and addictive behaviors. The analysis also suggests that alcohol and other drugs of abuse have toxic effects on the myelination process in some adolescents.

Bartzokis, G. 2005. Adolescent Psychiatry. Hillsdale, N.J.: The Analytic Press Inc.

ADDERALL XR significantly improves driving performance, attention in young adults with ADHD

ADDERALL XR® significantly improved driving performance, cognitive function and attention in young adults with attention-deficit/hyperactivity disorder (ADHD) in a controlled driving simulator study. An earlier study found that adults with ADHD had a significant higher incidence of traffic violations, and license suspensions than patients without ADHD — ADHD patients were five times more likely than non-ADHD patients to have five or more speeding tickets and three times more likely to have had three or more vehicular crashes.

Kay, G. 2005. The Effect of Adderall XR and Atomoxetine on Simulated Driving Safety in Young Adults with ADHD. Presented at the 18th Annual U.S. Psychiatric & Mental Health Congress in Las Vegas, NV.

Cognitive therapy for ADHD

A researcher that has previously demonstrated that working memory capacity can be increased through training, has now reported that the training software has produced significant improvement in children with ADHD — a disability that is associated with deficits in working memory. The study involved 53 children with ADHD, aged 7-12, who were not on medication for their disability. 44 of these met the criterion of more than 20 days of training. Half the participants were assigned to the working memory training program and the other half to a comparison program. 60% of those who underwent the wm training program no longer met the clinical criteria for ADHD after five weeks of training. The children were tested on visual-spatial memory, which has the strongest link to inattention and ADHD. Further research is needed to show that training improves ability on a wider range of tasks.

[583] Klingberg, T., Fernell E., Olesen P. J., Johnson M., Gustafsson P., Dahlström K., et al.
(2005).  Computerized Training of Working Memory in Children With ADHD-A Randomized, Controlled Trial.
Journal of the American Academy of Child & Adolescent Psychiatry. 44(2), 177 - 186.

tags memworks: 

tags problems: 


Older news items (pre-2010) brought over from the old website

Right parietal lobe implicated in dyscalculia

By temporarily knocking out an area in the right parietal lobe (the right intraparietal sulcus), researchers have induced dyscalculia in normal subjects, providing strong evidence that dyscalculia is caused by malfunction in this area. These findings were further validated by testing participants suffering from developmental dyscalculia. Although less well-known, dyscalculia is as prevalent as dyslexia and attention deficit hyperactivity disorder (around 5%).

Kadosh, R.C. et al. 2007. Virtual Dyscalculia Induced by Parietal-Lobe TMS Impairs Automatic Magnitude Processing. Current Biology, online ahead of print March 22

Scientists find brain function most important to math ability

A finding that an area of the brain widely thought to be involved in processing number information generally, in fact has two very separate functions, may be the key to diagnosing dyscalculia. One function is responsible for counting 'how many' things are present and the other is responsible for knowing 'how much'. The brain activity specific to estimating numbers of things is thought to be the brain network that underlies arithmetic and may be abnormal in dyscalculics.

[1336] Castelli, F., Glaser D. E., & Butterworth B.
(2006).  Discrete and analogue quantity processing in the parietal lobe: A functional MRI study.
Proceedings of the National Academy of Sciences of the United States of America. 103(12), 4693 - 4698.

Calculation difficulties in children of very low birthweight

Learning difficulties, including problems with numeracy, are common in Western populations. Many children with learning difficulty are survivors of preterm birth. Although some of these children have neurological disabilities, many are neurologically normal. A neuroimaging study of neurologically normal adolescent children who had been born preterm at 30 weeks gestation or less found an area in the left parietal lobe where children without a deficit in calculation ability have more grey matter than those who do have this deficit.

[1281] Isaacs, E. B., Edmonds C. J., Lucas A., & Gadian D. G.
(2001).  Calculation difficulties in children of very low birthweight: A neural correlate.
Brain. 124(9), 1701 - 1707.

tags problems: 

tags study: 


Older news items (pre-2010) brought over from the old website

Improving your multitasking skills

Teaching older brains to regain youthful skills

Researchers have succeeded in training seniors to multitask at the same level as younger adults. Over the course of two weeks, both younger and older subjects learned to identify a letter flashed quickly in the middle of a computer screen and simultaneously localize the position of a spot flashed quickly in the periphery as well as they could perform either task on its own. The older adults did take longer than the younger adults to reach the same level of performance, but they did reach it.

[571] Richards, E., Bennett P. J., & Sekuler A. B.
(2006).  Age related differences in learning with the useful field of view.
Vision Research. 46(25), 4217 - 4231.

Age and individual differences

Teen's ability to multi-task develops late in adolescence

A study involving adolescents between 9 and 20 years old has found that the ability to multi-task continues to develop through adolescence. The ability to use recall-guided action to remember single pieces of spatial information (such as looking at the location of a dot on a computer screen, then, after a delay, indicating where the dot had been) developed until ages 11 to 12, while the ability to remember multiple units of information in the correct sequence developed until ages 13 to 15. Tasks in which participants had to search for hidden items in a manner requiring a high level of multi-tasking and strategic thinking continued to develop until ages 16 to 17. "These findings have important implications for parents and teachers who might expect too much in the way of strategic or self-organized thinking, especially from older teenagers."

[547] Luciana, M., Conklin H. M., Hooper C. J., & Yarger R. S.
(2005).  The Development of Nonverbal Working Memory and Executive Control Processes in Adolescents.
Child Development. 76(3), 697 - 712.

About multitasking

Stress disrupts task-switching, but the brain can bounce back

A new neuroimaging study involving 20 male M.D. candidates in the middle of preparing for their board exams has found that they had a harder time shifting their attention from one task to another after a month of stress than other healthy young men who were not under stress. The finding replicates what has been found in rat studies, and similarly correlates with impaired function in an area of the prefrontal cortex that is involved in attention. However, the brains recovered their function within a month of the end of the stressful period.

[829] Liston, C., McEwen B. S., & Casey B. J.
(2009).  Psychosocial stress reversibly disrupts prefrontal processing and attentional control.
Proceedings of the National Academy of Sciences. 106(3), 912 - 917.

Full text available at

Asymmetrical brains let fish multitask

A fish study provides support for a theory that lateralized brains allow animals to better handle multiple activities, explaining why vertebrate brains evolved to function asymmetrically. The minnow study found that nonlateralized minnows were as good as those bred to be lateralized (enabling it to favor one or other eye) at catching shrimp. However, when the minnows also had to look out for a sunfish (a minnow predator), the nonlateralized minnows took nearly twice as long to catch 10 shrimp as the lateralized fish.

[737] Dadda, M., & Bisazza A.
(2006).  Does brain asymmetry allow efficient performance of simultaneous tasks?.
Animal Behaviour. 72(3), 523 - 529.

How much can your mind keep track of?

A recent study has tried a new take on measuring how much a person can keep track of. It's difficult to measure the limits of processing capacity because most people automatically break down large complex problems into small, manageable chunks. To keep people from doing this, therefore, researchers created problems the test subjects wouldn’t be familiar with. 30 academics were presented with incomplete verbal descriptions of statistical interactions between fictitious variables, with an accompanying set of graphs that represented the interactions. It was found that, as the problems got more complex, participants performed less well and were less confident. They were significantly less able to accurately solve the problems involving four-way interactions than the ones involving three-way interactions, and were completely incapable of solving problems with five-way interactions. The researchers concluded that we cannot process more than four variables at a time (and at that, four is a strain).

[415] Halford, G. S., Baker R., McCredden J. E., & Bain J. D.
(2005).  How many variables can humans process?.
Psychological Science: A Journal of the American Psychological Society / APS. 16(1), 70 - 76.

We weren't made to multitask

A new imaging study supports the view that we can’t perform two tasks at once, rather, the tasks must wait their turn — queuing up for their turn at processing.

[1070] Jiang, Y., Saxe R., & Kanwisher N.
(2004).  Functional magnetic resonance imaging provides new constraints on theories of the psychological refractory period.
Psychological Science: A Journal of the American Psychological Society / APS. 15(6), 390 - 396.

Why multitasking is a problem

Talking, walking and driving with cell phone users

Another cellphone-multitasking study! Compared with people walking alone, in pairs, or listening to their ipod, cell phone users were the group most prone to oblivious behavior: only 25% of them noticed a unicycling clown passing them on the street, compared to 51% of single individuals, 61% of music player users, and 71% of people in pairs. In fact, cell phone users even had problems walking — walking more slowly, changing direction more often, being prone to weaving, and acknowledging other people more rarely.

Hyman, I.E.Jr, Boss, S. M., Wise, B. M., McKenzie, K. E., & Caggiano, J. M. (2009). Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone. Applied Cognitive Psychology, 9999(9999), n/a. doi: 10.1002/acp.1638.

Chronic media multitasking correlated with poor attention

Media multitasking — keeping tabs on email, texts, IM chat, the web — is routine among young people in particular. We know that humans can’t really multitask very successfully — that what we do is switch tracks, and every time we do that there’s a cost, in terms of your efficiency at the task. But what about long-term costs of chronic multitasking? A study that selected 19 students who multitasked the most and 22 who multitasked least, from a pool of 262 students, found those who multitasked least performed better on three cognitive tests that are thought to reflect ability to ignore distracting information, ability to organize things in working memory, and ability to switch between tasks. The findings can’t answer whether chronic media multitasking reduces these abilities, or whether people who are poor at these skills are more likely to succumb to chronic media multitasking, but they do demonstrate that chronic media multitasking is associated with this particular information processing style.

[890] Ophir, E., Nass C., & Wagner A. D.
(2009).  From the Cover: Cognitive control in media multitaskers.
Proceedings of the National Academy of Sciences. 106(37), 15583 - 15587.

Cell phone ringtones can pose major distraction, impair recall

Cell phones ringing during a concert is not simply irritating. It appears that in a classroom, a cell phone left to ring for 30 seconds significantly affected the students’ recall for the information presented just prior to and during the ringing. The effect was even greater when the phone’s owner rummaged frantically through her bag. Ringtones that are popular songs were even greater distractions. However, with repeated trials, people could be trained to reduce the negative effects; being warned about the distracting effects also helped people be less affected.

[1299] Shelton, J. T., Elliott E. M., Eaves S. D., & Exner A. L.
(2009).  The distracting effects of a ringing cell phone: An investigation of the laboratory and the classroom setting.
Journal of Environmental Psychology. 29(4), 513 - 521.

Police with higher multitasking abilities less likely to shoot unarmed persons

In a study in which police officers watched a video of an officer-involved shooting that resulted in the death of the officer before participating in a computer-based simulation where they were required to make split-second decisions whether to shoot or not to shoot someone, based on slides showing a person holding either a gun or a harmless object like a cell phone, it was found that among those more stressed by the video, those with a lower working memory capacity were more likely to shoot unarmed people. Working memory capacity was not a significant factor for those who did not show heightened negative emotionality in response to the video.

[739] Kleider, H. M., Parrott D. J., & King T. Z.
(2009).  Shooting behaviour: How working memory and negative emotionality influence police officer shoot decisions.
Applied Cognitive Psychology. 9999(9999), n/a - n/a.

Switchboard in the brain helps us learn and remember at the same time

It’s very common that we are required to both process new information while simultaneously recalling old information, as in conversation we are paying attention to what the other person is saying while preparing our own reply. A new study confirms what has been theorized: that there is a bottleneck in our memory system preventing us from doing both simultaneously. Moreover, the study provides evidence that a specific region in the left prefrontal cortex can resolve the bottleneck, possibly by allowing rapid switching between learning and remembering. This is supported by earlier findings that patients with damage to this area have problems in rapidly adapting to new situations and tend to persevere in old rules. The same region is also affected in older adults.

[1355] Huijbers, W., Pennartz C. M., Cabeza R., & Daselaar S. M.
(2009).  When Learning and Remembering Compete: A Functional MRI Study.
PLoS Biol. 7(1), e1000011 - e1000011.

Full text is available at

Neural bottleneck found that thwarts multi-tasking

An imaging study has revealed just why we can’t do two things at once. The bottleneck appears to occur at the lateral frontal and prefrontal cortex and the superior frontal cortex. Both areas are known to play a critical role in cognitive control. These brain regions responded to tasks irrespective of the senses involved, and could be seen to 'queue' neural activity — that is, a response to the second task was postponed until the response to the first was completed. Such queuing occurred when two tasks were presented within 300 milliseconds of each other, but not when the time gap was longer.

[896] Dux, P. E., Ivanoff J., Asplund C. L., & Marois R.
(2006).  Isolation of a Central Bottleneck of Information Processing with Time-Resolved fMRI.
Neuron. 52(6), 1109 - 1120.

How multitasking impedes learning

A number of studies have come out in recent years demonstrating that the human brain can’t really do two things at once, and that when we do attempt to do so, performance is impaired. A new imaging study provides evidence that we tend to use a less efficient means of learning when distracted by another task. In the study, 14 younger adults (in their twenties) learned a simple classification task by trial-and-error. For one set of the cards, they also had to keep a running mental count of high tones that they heard while learning the classification task. Imaging revealed that different brain regions were used for learning depending on whether the participants were distracted by the other task or not — the hippocampus was involved in the single-task learning, but not in the dual-task, when the striatum (a region implicated in procedural and habit learning) was active. Although the ability of the participants to learn didn’t appear to be affected at the time, the distraction did reduce the participants' subsequent knowledge about the task during a follow-up session. In particular, on the task learned with the distraction, participants could not extrapolate from what they had learned.

[1273] Foerde, K., Knowlton B. J., & Poldrack R. A.
(2006).  Modulation of competing memory systems by distraction.
Proceedings of the National Academy of Sciences. 103(31), 11778 - 11783.

Doing two things at once

Confirmation of what many of us know, and many more try to deny - you can't do two complex tasks simultaneously as well as you could do either one alone. Previous research has showed that when a single area of the brain, like the visual cortex, has to do two things at once, like tracking two objects, there is less brain activation than occurs when it watches one thing at a time. This new study sought to find out whether something similar happened when two highly independent tasks, carried out in very different parts of the brain, were done concurrently. The two tasks used were language comprehension (carried out in the temporal lobe), and mental rotation (carried out in the parietal lobe). The language task alone activated 37 voxels of brain tissue. The mental rotation task alone also activated 37 voxels. But when both tasks were done at the same time, only 42 voxels were activated, rather than the sum of the two (74). While overall accuracy did not suffer, each task took longer to perform.

[2546] Just, M A., Carpenter P. A., Keller T. A., Emery L., Zajac H., & Thulborn K. R.
(2001).  Interdependence of Nonoverlapping Cortical Systems in Dual Cognitive Tasks.
NeuroImage. 14(2), 417 - 426.

The costs of multitasking

Technology increasingly tempts people to do more than one thing (and increasingly, more than one complicated thing) at a time. New scientific studies reveal the hidden costs of multitasking. In a study that looked at the amounts of time lost when people switched repeatedly between two tasks of varying complexity and familiarity, it was found that for all types of tasks, subjects lost time when they had to switch from one task to another, and time costs increased with the complexity of the tasks, so it took significantly longer to switch between more complex tasks. Time costs also were greater when subjects switched to tasks that were relatively unfamiliar. They got "up to speed" faster when they switched to tasks they knew better. These results suggest that executive control involves two distinct, complementary stages: goal shifting ("I want to do this now instead of that") and rule activation ("I'm turning off the rules for that and turning on the rules for this").

[1124] Rubinstein, J. S., Meyer D. E., & Evans J. E.
(2001).  Executive Control of Cognitive Processes in Task Switching,.
Journal of Experimental Psychology: Human Perception and Performance. 27(4), 763 - 797.

Brain's halves compete for attention

Claus Hilgetag, of Boston University, and his colleagues fired focused magnetic pulses through healthy subjects' skulls for 10 minutes to induce 'hemispatial neglect'. This condition, involving damage to one side of the brain, leaves patients unaware of objects in the opposite half of their visual field (which sends messages to the damaged half of the brain). The subjects showed the traditional symptoms of hemispatial neglect. They were worse at detecting objects opposite to the numb side of their brain, and worse still if there was also an object in the functioning half of the visual field. Yet numbed subjects were better at spotting objects with the unaffected half of their brains. This behavior confirms the idea that activity in one half of the brain usually eclipses that in the opposite half. The finding supports the idea that mental activity is a tussle between the brain's many different areas.

[720] Hilgetag, C. C., Theoret H., & Pascual-Leone A.
(2001).  Enhanced visual spatial attention ipsilateral to rTMS-induced 'virtual lesions' of human parietal cortex.
Nat Neurosci. 4(9), 953 - 957.

Multitasking and driving

Why cell phones and driving don't mix

A host of studies have come out in recent years demonstrating that multitasking impairs performance and talking on a cell phone while driving a car is a bad idea. A new study helps explain why. In two different experiments, subjects were found to be four times more distracted while preparing to speak or speaking than when they were listening. The researcher expects the effect to be even stronger in real-life conversation. It was also found that subjects could complete the visual task in front of them more easily when the projected voice also was in front. This suggests that it may be easier to have all things that require attention in the same space.

[1132] Almor, A.
(2008).  Why Does Language Interfere with Vision-Based Tasks?.
Experimental Psychology (formerly "Zeitschrift für Experimentelle Psychologie"). 55(4), 260 - 268.

Talking on a cellphone while driving as bad as drinking

Yet another study has come out rubbing it in that multitasking comes with a cost, and most particularly, that you shouldn’t do anything else while driving. This study demonstrates — shockingly — that drivers are actually worse off when using a cell phone than when legally drunk. The study had 40 volunteers use a driving simulator under 4 different conditions: once while legally intoxicated, once while talking on a hands-free cell phone, once while talking on a hand-held cell phone, and once with no distractions. There were differences in behavior —drunk drivers were more aggressive, tailgated more, and hit the brake pedal harder; cell phone drivers (whether hands-free and hand-held ) took longer to hit the brakes, and got in more accidents. But in both cases drivers were significantly impaired.

[1250] Strayer, D. L., Drews F. A., & Crouch D. J.
(2006).  A Comparison of the Cell Phone Driver and the Drunk Driver.
Human Factors: The Journal of the Human Factors and Ergonomics Society. 48(2), 381 - 391.,,1809549,00.html

Performing even easy tasks impairs driving

In yet another demonstration that driving is impaired when doing anything else, a simulator study has found that students following a lead car and instructed to brake as soon as they saw the illumination of the lead car's brake lights, responded slower when required to respond to a concurrent easy task, where a stimulus - either a light flash in the lead car's rear window or an auditory tone - was randomly presented once or twice and participants had to indicate the stimulus' frequency. The finding suggests that even using a hands-free device doesn’t make it okay to talk on a cell phone while driving.

[837] Levy, J., Pashler H., & Boer E.
(2006).  Central interference in driving: is there any stopping the psychological refractory period?.
Psychological Science: A Journal of the American Psychological Society / APS. 17(3), 228 - 235.

Talking and listening impairs your ability to drive safely

A study involving almost 100 students driving virtual cars has provided evidence that people have greater difficultly maintaining a fixed speed when performing tasks that simulated conversing on a mobile phone. Both speaking and listening were equally distracting.

[203] Kubose, T. T., Bock K., Dell G. S., Garnsey S. M., Kramer A. F., & Mayhugh J.
(2006).  The effects of speech production and speech comprehension on simulated driving performance.
Applied Cognitive Psychology. 20(1), 43 - 63.

Cell phone users drive like seniors

Another study on the evils of multitasking, in particular, of talking on a cellphone while driving. This one has a nice spin — the study found that when young motorists talk on cell phones, they drive like elderly people, moving and reacting more slowly and increasing their risk of accidents. Specifically, when 18- to 25-year-olds were placed in a driving simulator and talked on a cellular phone, they reacted to brake lights from a car in front of them as slowly as 65- to 74-year-olds who were not using a cell phone. Although elderly drivers became even slower to react to brake lights when they spoke on a cell phone, they were not as badly affected as had been expected. An earlier study by the same researchers found that motorists who talk on cell phones are more impaired than drunken drivers with blood alcohol levels exceeding 0.08.

[339] Strayer, D. L., & Drew F. A.
(2004).  Profiles in Driver Distraction: Effects of Cell Phone Conversations on Younger and Older Drivers.
Human Factors: The Journal of the Human Factors and Ergonomics Society. 46(4), 640 - 649.

Complex mental tasks interfere with drivers' ability to detect visual targets

The researchers studied 12 adults who drove for about four hours on the highway north from Madrid. During the journey, drivers listened to recorded audio messages with either abstract or concrete information (acquisition task), and later were required to freely generate a reproduction of what they had just listened to (production task). Although the more receptive tasks – listening and learning -- had little or no effect on performance, there were significant differences in almost all of the measures of attention when drivers had to reproduce the content of the audio message they had just heard. Drivers also performed other tasks, either live or by phone. One was mental calculus (mentally changing between Euros and Spanish pesetas) either with an experimenter in the car, talking to the driver, or with the driver speaking by hands-free phone. One was a memory task (giving detailed information about where they were and what they were doing at a given day and time). Both tasks significantly impacted on the driver's ability to detect visual targets. In the experimental variation that examined the impact of hands-free phone conversation, message complexity made the difference. The relative safety of low-demand phone conversation -- if hands-free and voice-operated --appeared to be about the same as that of live conversation. The findings also confirm that the risk of internal distraction (one’s own thoughts) is at least as relevant as external distraction.

Goldarecena, M.A.R. & González, L.M.N. 2003. Mental Workload While Driving: Effects on Visual Search, Discrimination and Decision Making. Journal of Experimental Psychology: Applied, 9(2)

tags problems: 


Subscribe to RSS - Problems