Health & age-related problems

Brain changes found in football players thought to be concussion-free

Another study adds to evidence that the extent of the problems of repeated impact to the head in football have been under-estimated.

Monitoring of 11 football players at a high school in Indiana, who wore helmets equipped with sensors that recorded impart, has revealed the problem of head injuries is deeper than was thought. Brain scans and cognitive tests, in addition to the impact data, found that some players who hadn't been diagnosed with concussions nevertheless had developed changes in brain function, correlated with cognitive impairment. The findings point to the dangers of repeated impact, regardless of whether consciousness is lost.

The research is ongoing, and aims to determine how many blows it takes to cause impairment, and whether players accumulate damage over several sessions, or recover. The work to date suggests that those who developed impairment in the absence of concussion received a large number of blows primarily to the top and front of the head. This is just above the dorsolateral prefrontal cortex, which showed changes in activation. Visual working memory was the function principally affected.

Researchers are also working to create a helmet that reduces the cumulative effect of impacts.

Old bees' memory fades too

New research shows that many old bees, like many older humans, have trouble replacing out-of-date knowledge with new memories.

I love cognitive studies on bees. The whole notion that those teeny-tiny brains are capable of the navigation and communication feats bees demonstrate is so wonderful. Now a new study finds that, just like us, aging bees find it hard to remember the location of a new home.

The study builds on early lab research that demonstrated that old bees find it harder to learn floral odors. In this new study, researchers trained bees to a new nest box while their former nest was closed off. Groups composed of mature and old bees were given several days in which to learn the new home location and to extinguish the bees' memory of their unusable former nest box. The new home was then disassembled, and groups of mixed-age bees were given three alternative nest locations to choose from (including the former nest box). Some old bees (those with symptoms of senescence) preferentially went to the former nest site, despite the experience that should have told them that it was unusable.

The findings demonstrate that memory problems and increasing inflexibility with age are not problems confined to mammals.

Cognitive effects of heavy alcohol and marijuana use in adolescents

Alcohol and marijuana abuse associated with specific cognitive impairments in adolescents, but more surprisingly family history of substance abuse can also have an effect.

A study involving 48 adolescents, of whom 19 had been diagnosed with substance abuse/dependence, and 14 had a family history of substance abuse but no history of personal use, has found that greater alcohol use was associated with a significant decrease in attention and executive function (which is involved in planning and decision-making), while greater marijuana use was associated with poorer memory. Adolescents in the substance abuse group had lower scores in attention, memory, and processing speed, compared to the other groups, while those with a family history of abuse (but no personal history) had poorer visuospatial ability.

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Women's brains grow after giving birth

A small study indicates that nurturing mothers and increased reward centers in the brain go hand-in-hand — although the jury’s still out on which comes first.

The issue of “mommy brain” is a complex one. Inconsistent research results make it clear that there is no simple answer to the question of whether or not pregnancy and infant care change women’s brains. But a new study adds to the picture.

Brain scans of 19 women two to four weeks and three to four months after they gave birth showed that grey matter volume increased by a small but significant amount in the midbrain (amygdala, substantia nigra, hypothalamus), prefrontal cortex, and parietal lobe. These areas are involved in motivation and reward, emotion regulation, planning, and sensory perception.

Mothers who were most enthusiastic about their babies were significantly more likely to show this increase in the midbrain regions. The authors speculated that the “maternal instinct” might be less of an instinctive response and more of a result of active brain building. Interestingly, while the brain’s reward regions don’t usually change as a result of learning, one experience that does have this effect is that of addiction.

While the reasons may have to do with genes, personality traits, infant behavior, or present circumstances, previous research has found that mothers who had more nurturing in their childhood had more gray matter in those brain regions involved in empathy and reading faces, which also correlated with the degree of activation in those regions when their baby cried.

A larger study is of course needed to confirm these findings.

Explaining and preventing post-surgery memory loss

More evidence of the evils of inflammation for cognitive functioning comes from a mouse study that points to a simple remedy for the cognitive impairment that often follows major surgery.

Major surgery often produces cognitive dysfunction, usually temporary, but for some, long-lasting. It has been suggested that the problem might have to do with the immune system's inflammatory response. A new mouse study provides more evidence for this.

The study found that giving the mice a common inhibitor of the inflammatory response (anti-tumor necrosis factor (TNF) antibody), before orthopedic surgery, decreased postoperative cognitive decline. It’s hoped human clinical testing of this approach will begin within a year.

Interestingly, the curry spice curcurmin, and catechins found in green tea, are also said to inhibit the tumor necrosis factor. Both of these have been implicated in reducing dementia and age-related cognitive impairment.

Memory impairment more common in people with a history of cancer

A very large study has found everyday memory problems among middle-aged and elderly are more likely in those with a history of cancer.

Confirming earlier indications from small studies, a very large nationwide survey has found that people who have had cancer are 40% more likely to experience memory problems that interfere with daily functioning.

The U.S. study involved nearly 10,000 people aged 40 and older, of whom 1,305 (13.3%) reported they had cancer or a history of cancer. Of these, 14% answered yes to the question "Are you limited in any way because of difficulty remembering or because you experience periods of confusion?" Of those who did not have a history of cancer, 8% answered yes to this question.

The degree to which these memory problems are related to the treatment or to the cancer itself (or even perhaps to the experience of having cancer) is one that needs further investigation, but the researcher suggests the finding points to memory issues being more common among cancer sufferers than realized, and recommends that cognitive assessment should be a standard part of cancer treatment.

The study is noteworthy in including all cancers, rather than focusing on one. Nevertheless, I hope that we eventually see a published paper (these results were presented at conference) that also analyses the data in terms of different cancers, different treatments, and length of time since the cancer.

Earlier reports on ‘chemobrain’, and possible ways to help

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Results were presented at the Third AACR Conference on The Science of Cancer Health Disparities.

Chemotherapy alters brain tissue in breast cancer patients

More evidence for the reality of ‘chemobrain’, showing physical changes in the brain.

Over the years I’ve reported on a number of studies investigating the effect of chemotherapy on the brain. A new study uses brain imaging, before and after treatment for breast cancer, to show that there is an anatomic basis for “chemobrain” complaints. The study, involving 17 breast cancer patients treated with chemotherapy after surgery, 12 women with breast cancer who did not undergo chemotherapy after surgery, and 18 women without breast cancer, found that gray matter density decreased in the frontal lobe, temporal lobe, cerebellum and right thalamus, shortly after chemotherapy.

The areas affected are consistent with memory and executive functions like multi-tasking and processing speed being the most typically affected functions. Post-surgery scans were carried out at one month, and at one year. Gray matter density in most women had improved by one year after chemotherapy ended.

Factors linked to cognitive deficits in type 2 diabetes

Cognitive deficits and even dementia are more common in older diabetics. A new study points to three health issues that, if present, increase the risk that older diabetics will develop cognitive problems.

Type 2 diabetes is known to increase the risk of cognitive impairment in old age. Now analysis of data from 41 older diabetics (aged 55-81) and 458 matched controls in the Victoria Longitudinal Study has revealed that several other factors make it more likely that an older diabetic will develop cognitive impairment. These factors are: having higher (though still normal) blood pressure, having gait and balance problems, and/or reporting yourself to be in bad health regardless of actual problems.

Diabetes and hypertension often go together, and both are separately associated with greater cognitive impairment and dementia risk, so it is not surprising that higher blood pressure is one of the significant factors that increases risk. The other factors are less expected, although gait and balance problems have been linked to cognitive impairment in a recent study, and they may be connected to diabetes through diabetes’ effect on nerves. Negativity about one’s health may reflect emotional factors such as anxiety, stress, or depression, although depression and well-being measures were not themselves found to be mediating effects for cognitive impairment in diabetics (Do note that this study is not investigating which factors, in general, are associated with age-related cognitive impairment; it is trying to establish which factors are specifically sensitive to cognitive impairment in older diabetics).

In the U.S., type 2 diabetes occurs in over 23% of those over 60; in Canada (where this study took place) the rate is 19%. It should be noted that the participants in this study are not representative of the general population, in that they were fairly well-educated older Canadians, most of whom have benefited from a national health care system. Moreover, the study did not have longitudinal data on these various factors, meaning that we don’t know the order of events (which health problems come first? How long between the development of the different problems?). Nevertheless, the findings provide useful markers to alert diabetics and health providers.

Childhood cancer survivors show sustained benefit from common ADHD medication

Ritalin helps some survivors of childhood cancer with attention problems.

Many survivors of childhood cancer experience cognitive problems as a result of their treatment. The drug methylphenidate (marketed under several names, the best known of which is Ritalin) has previously been shown to help attention problems in such survivors in the short term. Now a new study demonstrates that it can also be of benefit in the long term.

The study tested attention, social skills and behavior in survivors who had been on the drug for a year, comparing them to a similar group of unmedicated survivors. Although the drug did not lead to a significant gain in measured academic skills in math, reading and spelling, many did show improvements to attention that put them back in the normal range.

Nevertheless, the results also emphasize the need for other approaches, given that many did not benefit from the drug, and some may not be good candidates for medical or other reasons. The treatment group included 35 survivors of brain tumors and 33 of acute lymphoblastic leukemia (ALL). Any who suffered from ADHD before their cancer were excluded from the study.

Alcohol dependence damages both episodic memory and awareness of memory

Adding to the evidence that chronic alcohol abuse produces various cognitive deficits, a new study reveals that it’s also linked to poor metamemory.

Metamemory (understanding your own memory capabilities) is important for learning. Now a study involving 28 alcoholics has found that, compared to controls, they not only performed more poorly on a test of episodic memory, but they were less accurate in their assessments of how good their memory was. The episodic memory task involved learning 20 pairs of items, followed by a recall and a recognition test 20 minutes later. Before the recognition test, participants rated their ability to recognize each nonrecalled word among 4 items. The alcoholics were relatively unaware of their memory deficits and believed that their memory was much better than it was. On a questionnaire of their general memory capacities, they also tended to report themselves as much more capable than they were. Their over-estimation was related to their low performance on tests of executive function.

The finding has implications for any recovery program, since alcoholics will tend to believe that they have mastered any learning long before they have.

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