Aging

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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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

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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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Daily crosswords linked to sharper brain in later life

  • A very large online study has found that doing word puzzles regularly protects against age-related cognitive decline.

Data from more than 17,000 healthy people aged 50 and over has revealed that the more regularly participants engaged with word puzzles, the better they performed on tasks assessing attention, reasoning and memory.

Study participants took part in online cognitive tests, as well as being asked how frequently they did word puzzles such as crosswords. There was a direct relationship between the frequency of word puzzle use and the speed and accuracy of performance on nine cognitive tasks.

The effect was considerable. For example, on test measures of grammatical reasoning speed and short-term memory accuracy, performing word puzzles was associated with brain function equivalent to ten years younger than participants’ chronological age.

The next question is whether you can improve brain function by engaging in puzzles.

The study used participants in the PROTECT online platform, run by the University of Exeter and Kings College London. Currently, more than 22,000 healthy people aged between 50 and 96 are registered in the study. PROTECT is a 10 year study with participants being followed up annually to enable a better understanding of cognitive trajectories in this age range.

https://www.eurekalert.org/pub_releases/2017-07/uoe-dcl071417.php

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The Relationship Between the Frequency of Word Puzzle Use and Cognitive Function in a Large Sample of Adults Aged 50 to 96 Years, was presented at the Alzheimer's Association International Conference (AAIC) 2017 on July 17.

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How risky is surgery for older adults' cognitive function?

Several studies suggest that post-operative cognitive decline in older adults is due to several factors:

  • the stress of hospitalization, if unexpected
  • brain inflammation caused by an immune response from the brain’s microglia
  • post-operative delirium.

It also seems that higher levels of cognitive function, higher levels of engagement in certain cognitive activities, and better cerebrovascular health, all protect against such decline.

Unplanned hospitalizations accelerate cognitive decline in older adults

Data from the Rush Memory and Aging Project has found that emergency and urgent hospitalizations are associated with an increased rate of cognitive decline in older adults.

Non-elective hospitalizations were associated with an approximately 60% acceleration in the rate of cognitive decline from before hospitalization. Elective hospitalizations, however, were not associated with acceleration in the rate of decline at all.

Of the 930 participants (average age 81), 613 were hospitalized at least once over an average of almost five years of observation. Of those who were hospitalized, 260 (28%) had at least one elective hospital admission, and 553 (60%) had at least one non-elective hospital admission. These groups included 200 participants (22%) who had both types of hospitalizations.

The data was presented at the Alzheimer's Association International Conference in London on July 17.

https://www.eurekalert.org/pub_releases/2017-07/rumc-hac071717.php

Inflammation triggered by brain's own immune cells behind post-surgical decline

There is growing evidence that inflammation might be responsible for the cognitive decline seen in many older adults after surgery. Now a mouse study provides evidence that brain inflammation and cognitive decline following surgery are triggered by the brain's microglia.

When mice had their microglia temporarily depleted before surgery, they didn’t show any cognitive decline several days after surgery. They also had much lower levels of inflammatory molecules in the hippocampus. Controls — those not receiving the experimental drug to deplete microglia to around 5% of normal levels — did typically show a drop in cognitive performance.

Microglia levels returned to normal within two days after the treatment was stopped, and there was no sign of any impairment in surgical wound healing as a result of the intervention.

https://www.eurekalert.org/pub_releases/2017-04/uoc--cda040517.php

Delirium in older patients after surgery linked to long-term cognitive decline

A 3-year study looking at short-term and long-term cognitive decline in older patients following a surgery found that those who experienced delirium after the surgery showed significantly greater decline than those who didn’t suffer such post-surgical confusion.

The study involved 560 patients (70+), of whom 134 experienced delirium. Both groups showed a significant cognitive decline at one month, followed by a return to their previous level of cognitive function at two months and then a gradual decline for the next 34 months. However, the rate of decline over the three year follow-up was not significant for those who hadn’t experienced delirium.

Those who suffered delirium also had significantly lower cognitive function before surgery.

The odd finding that even the delirium group recovered their cognitive function at two months, before once again declining, suggests that something about the delirium triggers a cascade of events which leads to progressive, long-lasting effects.

http://www.eurekalert.org/pub_releases/2016-07/hsif-dio071416.php

Who’s more likely to develop delirium after surgery?

Delirium after surgery can lead to long-term cognitive decline in older adults — but not always. So what makes the difference?

A preliminary study involving 126 older adults suggests the answer lies in their cognitive function before surgery. Their global cognition score explained the most variation, with other significant factors including: IQCODE score, cognitive independent activities of daily living impairment, living alone, cerebrovascular disease, Charlson comorbidity index score, and exhaustion level. Taken together, these factors explained 32% of the variation in people’s outcome.

Delirium, an acute state of confusion, is a common condition affecting up to 50% of hospitalized older adults.

https://www.eurekalert.org/pub_releases/2017-03/hsif-plc031417.php

Certain leisure activities may reduce post-surgical delirium among older adults

A study of 142 older adults who underwent elective surgery found that greater participation in cognitive activities was linked with a lower incidence and lower severity of delirium.

Nearly a third of the patients (average age 71) developed post-operative delirium. Those who did had participated in fewer leisure activities before surgery compared with people who didn't experience delirium.

Out of all the activities, reading books, using email, and playing computer games reduced the risk of delirium. Playing computer games and singing were the only two activities that predicted lower severity of delirium.

The protection afforded was dose-dependent, with each additional leisure activity reducing post-operative delirium by 8%.

http://www.eurekalert.org/pub_releases/2016-06/ags-cla062116.php

http://www.eurekalert.org/pub_releases/2016-06/w-crm062216.php

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Greater muscle strength = better cognitive function

  • While handgrip strength has been linked to dementia risk in the elderly, a new study indicates that less impaired or fragile older adults need upper and lower body strength tests — but that these, too, are correlated with cognitive function.

A Finnish study involving 338 older adults (average age 66) has found that greater muscle strength is associated with better cognitive function.

Muscle strength was measured utilising handgrip strength, three lower body exercises such as leg extension, leg flexion and leg press and two upper body exercises such as chest press and seated row.

Handgrip strength, easy to measure, has been widely used as a measure of muscle strength, and has been associated with dementia risk among the very old. However, in this study, handgrip strength on its own showed no association with cognitive function. But both upper body strength and lower body strength were independently associated with cognitive function.

It may be that handgrip strength is only useful for older, more cognitively impaired adults.

These are gender-specific associations — muscle strength was significantly greater in men, but there was no difference in cognitive performance between men and women.

The finding is supported by previous research that found a link between walking speed and cognition in older adults, and by a 2015 study that found a striking correlation between leg power and cognition.

This 10-year British study involved 324 older female twins (average age 55). Both the degree of cognitive decline over the ten year period, and the amount of gray matter, was significantly correlated with high muscle fitness (measured by leg extension muscle power). The correlation was greater than for any other lifestyle factor tested

https://www.eurekalert.org/pub_releases/2017-06/uoef-gms062617.php

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Rapid blood pressure drops in middle age linked to dementia in old age

  • A large study indicates that an inclination to dizziness on standing up is associated with a greater risk of developing cognitive impairment and dementia decades later.

Data from over 11,500 participants in the Atherosclerosis Risk in Communities (ARIC) cohort has found evidence that orthostatic hypotension in middle age may increase the risk of cognitive impairment and dementia 20 years later.

Orthostatic hypotension is the name for the experience of dizziness or light-headedness on standing up. Previous research has suggested an association between orthostatic hypotension and cognitive decline in older adults.

In this study, participants aged 45-64 were tested for orthostatic hypotension in 1987. Those with it (703, around 6%) were 40% more likely to develop dementia in the next 20 years. They also had some 15% more cognitive decline.

Orthostatic hypotension was defined as a drop of 20 mmHg or more in systolic blood pressure or 10 mmHg or more in diastolic blood pressure, when the individual stood up after 20 minutes lying down.

More work is needed to understand the reason for the association.

https://www.eurekalert.org/pub_releases/2017-03/jhub-rbp030817.php

Rawlings, Andreea. 2017. Orthostatic Hypotension is Associated with 20-year Cognitive Decline and Incident Dementia: The Atherosclerosis Risk in Communities (ARIC) Study. Presented March 10 at the American Heart Association's EPI|LIFESTYLE 2017 Scientific Sessions in Portland, Oregon.

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Both aerobic exercise & strength training improves older brains

  • A review of research has confirmed the benefits of at least moderate exercise to fight age-related cognitive decline, with different benefits for aerobic exercise and strength training.

A review of 39 studies investigating the effect of exercise on cognition in older adults (50+) confirms that physical exercise does indeed improve cognitive function in the over 50s, regardless of their cognitive status. Aerobic exercise, resistance training, multicomponent training and tai chi, all had significant effects. However, exercise sessions needed to be at least 45  minutes and moderate intensity. Because aerobic exercise and resistance training had different effects (aerobic exercise helped overall cognition, while resistance training was particularly beneficial for executive function and working memory), it’s recommended that an exercise program include both.

https://medicalxpress.com/news/2017-04-aerobic-resistance-combo-boost-brain.html

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Higher coffee consumption linked to lower dementia risk in women

  • A large study adds to evidence that caffeine helps older women fight cognitive impairment and dementia.
  • This is supported by two animal studies showing precisely how caffeine is valuable for keeping the brain healthy.

Data from the Women's Health Initiative Memory Study, involving 6,467 postmenopausal women (65+) who reported some level of caffeine consumption, has found that those who consumed above average amounts of coffee had a lower risk of developing dementia.

Caffeine intake was estimated from a questionnaire. The median intake was 172 mg per day (an 8-ounce cup of brewed coffee contains 95mg of caffeine, 8-ounces of brewed black tea contains 47mg, so slightly less than 2 cups of coffee or less than 4 cups of tea). The women were cognitively assessed annually.

Over ten years, 388 were diagnosed with probable dementia (209) or MCI (179). Those who consumed above the median amount of caffeine had a 36% reduction in risk. The average intake in this group was 261 mg (3 cups of coffee), while the average intake for those below the median was 64 mg per day (less than one cup).

Risk factors such as hormone therapy, age, race, education, body mass index, sleep quality, depression, hypertension, prior cardiovascular disease, diabetes, smoking, and alcohol consumption, were taken into account.

The findings are consistent with other research finding a benefit for older women. It should not be assumed that the findings apply to men. It also appears that there may be a difference depending on education level. This sample had a high proportion of college-educated women.

It should also be noted that there was no clear dose-response effect — we could put more weight on the results if there was a clear relationship between amount of caffeine and benefit. Part of the problem here, however, is that it’s difficult to accurately assess the amount of caffeine, given that it’s based on self-report intake of coffee and tea, and the amount of caffeine in different beverages varies significantly.

Moreover, we do have a couple of mechanisms for caffeine to help fight age-related cognitive decline.

A recent study using rats modified to have impaired receptors for the adenosine A2A produced rats showing typical characteristics of an aging brain. In humans, too, age-related cognitive decline has been associated with over-activation of these receptors and dysfunction in glucocorticoid receptors.

The rat study shows that over-activation of the adenosine A2A receptors reduces the levels of glucocorticoid receptors in the hippocampus, which in turn impairs synaptic plasticity and cognition. In other words, it is the over-activation of the adenosine receptors that triggers a process that ends with cognitive impairment.

The point of all this is that caffeine inhibits the adenosine A2A receptors, and when the rats were given a caffeine analogue, their memory deficits returned to normal.

Another more recent study has found that caffeine increases the production of an enzyme that helps prevent tau tangles.

Building on previous research finding that an enzyme called NMNAT2 not only protects neurons from stress, but also helps prevent misfolded tau proteins (linked to Alzheimer’s, and other neurodegenerative disorders), the study identified 24 compounds (out of 1,280 tested) as having potential to increase the production of NMNAT2. One of the most effective of these was caffeine.

When caffeine was given to mice modified to produce lower levels of NMNAT2, the mice began to produce the same levels of the enzyme as normal mice.

https://www.eurekalert.org/pub_releases/2016-10/oupu-fwc100316.php

https://www.eurekalert.org/pub_releases/2016-08/ind-cai083016.php

https://www.eurekalert.org/pub_releases/2017-03/iu-cbe030717.php

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Physical activity linked to better memory for names and faces among older adults

  • A small study adds to evidence that walking improves memory in older adults, and indicates that this is particularly helpful for memory tasks the seniors find challenging.

A small study that fitted 29 young adults (18-31) and 31 older adults (55-82) with a device that recorded steps taken and the vigor and speed with which they were made, has found that those older adults with a higher step rate performed better on memory tasks than those who were more sedentary. There was no such effect seen among the younger adults.

Improved memory was found for both visual and episodic memory, and was strongest with the episodic memory task. This required recalling which name went with a person's face — an everyday task that older adults often have difficulty with.

However, the effect on visual memory had more to do with time spent sedentary than step rate. With the face-name task, both time spent sedentary and step rate were significant factors, and both factors had a greater effect than they had on visual memory.

Depression and hypertension were both adjusted for in the analysis.

There was no significant difference in executive function related to physical activity, although previous studies have found an effect. Less surprisingly, there was also no significant effect on verbal memory.

Both findings might be explained in terms of cognitive demand. The evidence suggests that the effect of physical exercise is only seen when the task is sufficiently cognitively demanding. No surprise that verbal memory (which tends to be much less affected by age) didn't meet that challenge, but interestingly, the older adults in this study were also less impaired on executive function than on visual memory. This is unusual, and reminds us that, especially with small studies, you cannot ignore the individual differences.

This general principle may also account for the lack of effect among younger adults. It is interesting to speculate whether physical activity effects would be found if the younger adults were given much more challenging tasks (either by increasing their difficulty, or selecting a group who were less capable).

Step Rate was calculated by total steps taken divided by the total minutes in light, moderate, and vigorous activities, based on the notion that this would provide an independent indicator of physical activity intensity (how briskly one is walking). Sedentary Time was the total minutes spent sedentary.

http://www.eurekalert.org/pub_releases/2015-11/bumc-slp112415.php

Reference: 

[4045] Hayes SM, Alosco ML, Hayes JP, Cadden M, Peterson KM, Allsup K, Forman DE, Sperling RA, Verfaellie M. Physical Activity Is Positively Associated with Episodic Memory in Aging. Journal of the International Neuropsychological Society [Internet]. 2015 ;21(Special Issue 10):780 - 790. Available from: http://journals.cambridge.org/article_S1355617715000910

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