seniors

Exercise improves brain function in older adults with MCI

  • A short exercise program improved cognition and brain blood flow in older adults with mild cognitive impairment.

A small study has found that a 12-week exercise program significantly improved cognition in both older adults with MCI and those who were cognitively healthy, but that effect on blood flow in the brain was different in these two groups.

While the exercise increased cerebral blood flow in the frontal cortex of those in the healthy group, those with MCI experienced decreases in cerebral blood flow. It has been speculated that the brain responds to early difficulties by increasing cerebral blood flow. This suggests that exercise may have the potential to reduce this compensatory blood flow and improve cognitive efficiency in those who are in the very early stages of Alzheimer's Disease.

The exercise training program consisted of four 30-minute sessions of moderate-intensity treadmill walking per week.

Both working memory and verbal fluency were tested (using the Rey Auditory Verbal Learning Test, and the Controlled Oral Word Association Test).

Changes in cerebral blood flow were measured in specific brain regions that are known to be involved in the pathogenesis of Alzheimer's disease, including the insula, the anterior cingulate cortex, and the inferior frontal gyrus.

Among those with MCI, decreased blood flow in the left insula and anterior cingulate cortex was strongly associated with improved verbal fluency.

https://www.eurekalert.org/pub_releases/2019-01/uom-usf013119.php

Reference: 

Alfini, A. J. et al. 2019. Resting Cerebral Blood Flow After Exercise Training in Mild Cognitive Impairment. Journal of Alzheimer's Disease, 67 (2), 671-684.

 

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Intensive hypertension treatment reduces risk of cognitive impairment

  • A large clinical trial comparing the effects on cardiovascular disease of standard blood pressure control vs stricter control, has found that stricter control significantly reduced the risk of mild cognitive impairment.

A clinical trial involving 9361 older adults (50+) with hypertension but without diabetes or history of stroke has found that intensive control of blood pressure significantly reduced the risk of developing mild cognitive impairment.

While there was also a 15% reduction in dementia, this result did not reach statistical significance. This may have been due to the small number of new cases of dementia in the study groups.

Participants were randomly assigned to a systolic blood pressure goal of either less than 120 mm HG (intensive treatment) or less than 140 mm HG (standard treatment). They were then classified after five years as having no cognitive impairment, MCI or probable dementia.

The trial was stopped early due to its success in reducing cardiovascular disease. As a result, participants were on intensive blood pressure lowering treatment for a shorter period than originally planned. This impacted the number of cases of dementia occurring.

Hypertension affects more than half of Americans over age 50 and more than 75% of those older than 65.

https://www.eurekalert.org/pub_releases/2019-01/wfbm-lbp012419.php

Reference: 

The SPRINT MIND Investigators for the SPRINT Research Group. (2019). Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial. JAMA, 321(6), 553–561.

 

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Psychological distress a risk factor for dementia

  • A large Danish study has found that the greater number of symptoms of distress in late midlife, the more likely the individual was to develop dementia later in life.

Survey data from 6,807 Danish older adults (average age 60) in the Copenhagen City Heart Study, has found that being distressed in late midlife is associated with a higher risk of dementia in later life.

The survey measured “vital exhaustion”, which is operationalized as feelings of unusual fatigue, increased irritability and demoralization and can be considered an indicator of psychological distress. Vital exhaustion is suggested to be a response to unsolvable problems in individuals' lives, in particular when being incapable of adapting to prolonged exposure to stressors.

The study found a dose-response relation between symptoms of vital exhaustion reported in late midlife and the risk of dementia later in life:

  • for every additional symptom, dementia incidence increased by 2%
  • those reporting 5 to 9 symptoms had a 25% higher risk of dementia compared to those with no symptoms
  • those reporting 10 to 17 symptoms (the maximum) had a 40% higher risk of dementia compared with not having symptoms.

Results were adjusted for gender, marital status, lower educational level, lifestyle factors and comorbidities.

https://www.eurekalert.org/pub_releases/2019-01/ip-pdi011719.php

Full paper available at: https://content.iospress.com/articles/journal-of-alzheimers-disease/jad180478

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Poor sleep in older adults may increase Alzheimer’s risk

  • Older people who spend less time in slow-wave sleep (deep sleep) have higher levels of the Alzheimer’s brain protein tau.

Poor sleep has been associated with Alzheimer's disease risk, but a new study suggests a specific aspect of sleep is important.

The study, involving 119 older adults (60+), of whom 80% were cognitively normal and the remainder very mildly impaired, found that decreased slow-wave sleep coincided with higher levels of tau in the brain and a higher tau-to-amyloid ratio in the cerebrospinal fluid.

Amyloid plaques and tau tangles develop for decades before cognitive symptoms of dementia emerge. Identifying the process at an early stage offers a possible window of opportunity for successful intervention.

Participants’ sleep at home was monitored over the course of a normal week, and participants also kept sleep logs of nighttime sleep and daytime napping. Thirty-eight people underwent PET brain scans for amyloid-beta and tau proteins, and 104 people underwent spinal taps to provide cerebrospinal fluid. Twenty-seven did both.

Those with increased tau pathology actually slept more, during both night and day, but their quality of sleep was poorer. In fact, daytime napping alone was significantly associated with high levels of tau, making it a useful indicator of risk.

https://www.futurity.org/alzheimers-disease-sleep-1954732/

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Lower tau levels may obscure early Alzheimer’s in black patients

  • Two large studies show an association between the Alzheimer's protein tau and the Alzheimer's gene APOE4, but the association varies across race and gender.

Data from 1,215 older adults, of whom 173 (14%) were African-American, has found that, although brain scans showed no significant differences between black and white participants, cerebrospinal fluid (CSF) showed significantly lower levels of the brain protein tau in African-Americans.

While both groups showed the same (expected) pattern of higher tau levels being associated with greater chance of cognitive impairment, the absolute amounts of tau protein were consistently lower in African-Americans.

However, when APOE status was taken into account, it was found that those who held the low-risk variants of the “Alzheimer’s gene” had similar levels of tau, regardless of race. It was only African-Americans with the APOE4 gene variant that showed lower levels of tau.

This suggests that the APOE4 risk factor has different effects in African-Americans compared to non-Hispanic white Americans, and points to the need for more investigation into how Alzheimer’s develops in various populations.

Interestingly, another study, using data from 1798 patients (of whom 1690 were white), found that there was a strong gender difference in the association between APOE status and tau levels in the CSF.

Previous research has shown that the link between APOE4 and Alzheimer's is stronger in women than men. This study points to a connection with tau levels, as there was no gender difference in the association between APOE and amyloid-beta levels, amyloid plaques, or tau tangles.

https://www.futurity.org/alzheimers-disease-black-patients-1951502/

Reference: 

Morris JC, Schindler SE, McCue LM, et al. Assessment of Racial Disparities in Biomarkers for Alzheimer Disease. JAMA Neurol. Published online January 07, 2019. doi:10.1001/jamaneurol.2018.4249

Hohman TJ, Dumitrescu L, Barnes LL, et al. Sex-Specific Association of Apolipoprotein E With Cerebrospinal Fluid Levels of Tau. JAMA Neurol. 2018;75(8):989–998. doi:10.1001/jamaneurol.2018.0821

 

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Older adults' distractability can be used to help put a face to a name

  • A small study has used older adults’ inability to ignore irrelevant information to improve their memory for face-name pairs.

One important reason for the greater cognitive problems commonly experienced as we age, is our increasing difficulty in ignoring distracting and irrelevant information. But it may be that in some circumstances that propensity can be used to help memory.

The study involved 25 younger (17-23) and 32 older adults (60-86), who were shown the faces and names of 24 different people and told to learn them. The names were written in bright blue text and placed on the forehead, and each photo was shown for 3 seconds. After the learning session, participants were immediately tested on their recall of the name for each face. The test was self-paced. Following a 10 minute interval, during which they were given psychological tests, they were shown more photos of faces, but this time were told to ignore the text — their task was to push a button when they saw the same face appear twice in a row. The text was varied: sometimes names, sometimes words, and sometimes nonwords. Ten of the same faces and names from the first task were repeated in the series of 108 trials; all items were repeated three times (thus, 30 repeated face-name pairs; 30 other face-name pairs; 24 face-word pairs; 24 face-nonword pairs). The photos were each displayed for 1.5 seconds. A delayed memory test was given after another 10 minutes of psychological testing. A cued-recall test was followed by a forced-choice recognition test.

Unsurprisingly, overall younger adults remembered more names than older adults, and both groups remembered more on the second series, with younger adults improving more. But younger adults showed no benefit for the repeated face-name pairs, while — on the delayed recall task only — older adults did.

Interestingly, there was no sign, in either group, of repeated names being falsely recalled or recognized. Nor did they significantly affect familiarity.

It seems that this sort of inadvertent repetition doesn’t improve memory for items (faces, names), but, specifically, the face-name associations. The study builds on previous research indicating that older adults hyperbind distracting names and attended faces, which produces better learning of these face-name pairs.

It’s suggested that repetition as distraction might act as a sort of covert retrieval practice that relies on a nonconscious process specifically related to the priming of relational associations. Perhaps older adults’ vulnerability to distraction is not simply a sign of degeneration, but reflects a change of strategy to one that increases receptiveness to environmental regularities that have predictive value. Younger adults have narrowed attention that, while it allows them greater focus on the task, also stops them noticing information that is immediately irrelevant but helpful further down the track.

The researchers are working on a training program to help older adults with MCI use this benefit to better remember faces and names.

https://www.eurekalert.org/pub_releases/2018-03/bcfg-oad031618.php

Reference: 

Biss, Renée K., Rowe, Gillian, Weeks, Jennifer C., Hasher, Lynn, Murphy, Kelly J. 2018. Leveraging older adults’ susceptibility to distraction to improve memory for face-name associations. Psychology and Aging, 33(1), 158-164.

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Rigorous exercise does not slow dementia decline

  • A study involving nearly 500 people with dementia has found that a rigorous physical exercise program did nothing to slow their decline.

A number of studies have found that physical exercise can help delay the onset of dementia, however the ability of exercise to slow the decline once dementia has set in is a more equivocal question. A large new study answers this question in the negative.

The study involved 494 people with mild-to-moderate dementia (average age 77; 61% male), of whom 329 were randomly assigned to a four-month aerobic and strength exercise programme and 165 were assigned to usual care. The exercise program was personalized, and involved two 60-90 minute gym sessions every week, plus a further hour at home. Nearly two-thirds of the exercise group attended more than three-quarters of the gym sessions.

While the exercise group did get physically fitter, their cognitive fitness (as measured by ADAS-cog score) actually worsened slightly.

The researchers emphasize that this was a specialized and intense exercise program, and in no way should it be taken to mean that gentle exercise, which is good for dementia sufferers, should be avoided.

https://www.theguardian.com/society/2018/may/16/rigorous-exercise-makes-dementia-worse-study-concludes

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Gist memory may be why false memories are more common in older adults

  • Gist processing appears to play a strong role in false memories.
  • Older adults rely on gist memory more.
  • Older adults find it harder to recall specific sensory details that would help confirm whether a memory is true.

Do older adults forget as much as they think, or is it rather that they ‘misremember’?

A small study adds to evidence that gist memory plays an important role in false memories at any age, but older adults are more susceptible to misremembering because of their greater use of gist memory.

Gist memory is about remembering the broad story, not the details. We use schemas a lot. Schemas are concepts we build over time for events and experiences, in order to relieve the cognitive load. They allow us to respond and process faster. We build schemas for such things as going to the dentist, going to a restaurant, attending a lecture, and so on. Schemas are very useful, reminding us what to expect and what to do in situations we have experienced before. But they are also responsible for errors of perception and memory — we see and remember what we expect to see.

As we get older, we do of course build up more and firmer schemas, making it harder to really see with fresh eyes. Which means it’s harder for us to notice the details, and easier for us to misremember what we saw.

A small study involving 20 older adults (mean age 75) had participants look at 26 different pictures of common scenes (such as a farmyard, a bathroom) for about 10 seconds, and asked them to remember as much as they could about the scenes. Later, they were shown 300 pictures of objects that were either in the scene, related to the scene (but not actually in the scene), or not commonly associated to the scene, and were required to say whether or not the objects were in the picture. Brain activity was monitored during these tests. Performance was also compared with that produced in a previous identical study, involving 22 young adults (mean age 23).

As expected and as is typical, there was a higher hit rate for schematic items and a higher rate of false memories for schematically related lures (items that belong to the schema but didn’t appear in the picture). True memories activated the typical retrieval network (medial prefrontal cortex, hippocampus/parahippocampal gyrus, inferior parietal lobe, right middle temporal gyrus, and left fusiform gyrus).

Activity in some of these regions (frontal-parietal regions, left hippocampus, right MTG, and left fusiform) distinguished hits from false alarms, supporting the idea that it’s more demanding to retrieve true memories than illusory ones. This contrasts with younger adults who in this and previous research have displayed the opposite pattern. The finding is consistent, however, with the theory that older adults tend to engage frontal resources at an earlier level of difficulty.

Older adults also displayed greater activation in the medial prefrontal cortex for both schematic and non-schematic hits than young adults did.

While true memories activated the typical retrieval network, and there were different patterns of activity for schematic vs non-schematic hits, there was no distinctive pattern of activity for retrieving false memories. However, there was increased activity in the middle frontal gyrus, middle temporal gyrus, and hippocampus/parahippocampal gyrus as a function of the rate of false memories.

Imaging also revealed that, like younger adults, older adults also engage the ventromedial prefrontal cortex when retrieving schematic information, and that they do so to a greater extent. Activation patterns also support the role of the mediotemporal lobe (MTL), and the posterior hippocampus/parahippocampal gyrus in particular, in determining true memories from false. Note that schematic information is not part of this region’s concern, and there was no consistent difference in activation in this region for schematic vs non-schematic hits. But older adults showed this shift within the hippocampus, with much of the activity moving to a more posterior region.

Sensory details are also important for distinguishing between true and false memories, but, apart from activity in the left fusiform gyrus, older adults — unlike younger adults — did not show any differential activation in the occipital cortex. This finding is consistent with previous research, and supports the conclusion that older adults don’t experience the recapitulation of sensory details in the same way that younger adults do. This, of course, adds to the difficulty they have in distinguishing true and false memories.

Older adults also showed differential activation of the right MTG, involved in gist processing, for true memories. Again, this is not found in younger adults, and supports the idea that older adults depend more on schematic gist information to assess whether a memory is true.

However, in older adults, increased activation of both the MTL and the MTG is seen as rates of false alarms increase, indicating that both gist and episodic memory contribute to their false memories. This is also in line with previous research, suggesting that memories of specific events and details can (incorrectly) provide support for false memories that are consistent with such events.

Older adults, unlike young adults, failed to show differential activity in the retrieval network for targets and lures (items that fit in with the schema, but were not in fact present in the image).

What does all this mean? Here’s what’s important:

  • older adults tend to use schema information more when trying to remember
  • older adults find it harder to recall specific sensory details that would help confirm a memory’s veracity
  • at all ages, gist processing appears to play a strong role in false memories
  • memory of specific (true) details can be used to endorse related (but false) details.

What can you do about any of this? One approach would be to make an effort to recall specific sensory details of an event rather than relying on the easier generic event that comes to mind first. So, for example, if you’re asked to go to the store to pick up orange juice, tomatoes and muesli, you might end up with more familiar items — a sort of default position, as it were, because you can’t quite remember what you were asked. If you make an effort to remember the occasion of being told — where you were, how the other person looked, what time of day it was, other things you talked about, etc — you might be able to bring the actual items to mind. A lot of the time, we simply don’t make the effort, because we don’t think we can remember.

https://www.eurekalert.org/pub_releases/2018-03/ps-fdg032118.php

Reference: 

[4331] Webb, C. E., & Dennis N. A.
(Submitted).  Differentiating True and False Schematic Memories in Older Adults.
The Journals of Gerontology: Series B.

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Lifestyle changes can prevent cognitive decline even in genetically at-risk individuals

  • A large study indicates that lifestyle changes, together with advice and support for managing vascular health, can help prevent cognitive decline even in carriers of the Alzheimer's gene.

A Finnish study involving over 1000 older adults suggests that a counselling program can prevent cognitive decline even among those with the Alzheimer’s gene.

The study involved 1,109 older adults (aged 60-77) of whom 362 were carriers of the APOE4 gene. Some of the participants received regular lifestyle counselling (general health advice), while the rest received “enhanced” lifestyle counselling, involving nutrition counselling, physical and cognitive exercises, and support in managing the risk of cardiovascular diseases.

Earlier findings from the FINGER (Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability) trial showed that the regular lifestyle counselling group had a significantly increased risk of cognitive and functional impairment compared to the group receiving enhanced counselling. This analysis shows that this holds true even for those with the Alzheimer's gene, and indeed, might even be more helpful for carriers of the risky gene.

The findings emphasize the importance of early prevention strategies that target multiple modifiable risk factors simultaneously.

https://www.eurekalert.org/pub_releases/2018-01/uoef-lcp012518.php

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The right diet may slow cognitive decline in stroke survivors

  • An observational study involving over 100 stroke survivors suggests the MIND diet may help substantially slow cognitive decline in those impaired by stroke.

A pilot study involving 106 participants of the Rush Memory and Aging Project who had experienced a stroke followed participants for an average of 5.9 years, testing their cognitive function and monitoring their eating habits using food journals. It was found that those whose diets scored highest on the MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay) diet score had substantially slower rates of cognitive decline than those who scored lowest. The estimated effect of the diet remained strong even after taking into account participants' level of education and participation in cognitive and physical activities. Those who instead scored high on the Mediterranean or DASH diets did not show the same slower decline.

Both the Mediterranean and DASH diets have been shown to be protective against coronary artery disease and stroke, but this finding suggests the MIND diet is better for overall brain health.

The MIND diet is a hybrid of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets. It has 15 components: 10 “brain-healthy food groups” and five unhealthy groups (red meat, butter, cheese, pastries and sweets, and fried or fast food).

To adhere to the MIND diet, you need to

  • eat at least three daily servings of whole grains
  • eat a green leafy vegetable and one other vegetable every day
  • drink a regular glass of wine
  • snack most days on nuts
  • have beans every other day or so
  • eat poultry and berries at least twice a week
  • eat fish at least once a week
  • limit butter to less than 1 1/2 teaspoons a day
  • eat less than 5 servings a week of sweets and pastries
  • eat less than one serving per week of whole fat cheese, and fried or fast food.

The researchers stress that this is a preliminary study, observational only. They are currently seeking participants for a wider, intervention study.

https://www.eurekalert.org/pub_releases/2018-01/rumc-mdm012418.php

Reference: 

Laurel J. Cherian & Martha Clare Morris: Presentation at the American Stroke Association's International Stroke Conference 2018 in Los Angeles, January 25.

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