Memory in Normal Aging

The problem of 'destination amnesia'

Two studies demonstrate why knowing whether you’ve told someone something is difficult for all of us, and that this is particularly so as you get older.

A number of studies have found that source memory (knowing where you heard/read/experienced something) is a particular problem for older adults. Destination memory (knowing who you’ve told) is an area that has been much less studied. Last year I reported on why destination memory is difficult for all of us (my report is repeated below). A follow-up study has found not only that destination memory is a particular problem for older adults, but that it is in fact a worse problem than source memory. Moreover, destination amnesia (falsely believing you've told someone something) is not only more common among older adults, but is associated with greater confidence in the false belief.

The study compared the performance of 40 students (aged 18-30) and 40 healthy older adults (aged 60-83). In the first task, the participant read out loud 50 interesting facts to 50 celebrities (whose faces appeared on a computer screen), and were then tested on their memory of which fact they told to which famous person. In the second task, they had to remember which famous person told them which particular fact. Older adults' performance was 21% worse than their younger counterparts on the destination memory test, but only 10% worse (50% vs 60%) on the source memory test. This latter difference was not statistically significant.

The 2009 study, involving 60 students, found good reason for destination memory to be so poor — apparently outgoing information is less integrated with context than incoming information is. In the study, 50 random facts were linked with the faces of 50 famous people; half the students then “told” each fact to one of the faces, reading it aloud to the celebrity’s picture. The other half read each fact silently and saw a different celebrity moments afterward. In the subsequent memory test, students who simulated telling the facts did 16% worse. In another experiment using personal facts, it was significantly worse.

However, the final experiment found that you could improve your destination memory by saying the name of the person you’re speaking to, as you tell them. The findings also suggest that self-focus is an important factor: increasing self-focus (e.g. by telling a personal story) worsened destination memory; reducing self-focus (e.g. by naming the listener) improved it.

Reference: 

[1809] Gopie, N., Craik F. I. M., & Hasher L. (2010).  Destination memory impairment in older people.. Psychology and Aging.

[396] Gopie, N., & MacLeod C. M. (2009).  Destination Memory: Stop Me if I've Told You This Before. Psychological Science. 20(12), 1492 - 1499.

Common medications increase risk of mild cognitive impairment

A large study of older African-Americans has found taking common medications with anticholinergic effects was correlated with an increased risk of developing mild cognitive impairment.

Anticholinergics are widely used for a variety of common medical conditions including insomnia, allergies, or incontinence, and many are sold over the counter. Now a large six-year study of older African-Americans has found that taking one anticholinergic significantly increased an individual's risk of developing mild cognitive impairment and taking two of these drugs doubled this risk. The risk was greater for those who didn’t have the ‘Alzheimer’s gene’, APOE-e4.

This class of drugs includes Benadryl®, Dramamine®, Excedrin PM®, Nytol®, Sominex®, Tylenol PM®, Unisom®, Paxil®, Detrol®, Demerol® and Elavil® (for a more complete list of medications with anticholinergic effects, go to http://www.indydiscoverynetwork.org/AnticholienrgicCognitiveBurdenScale....).

Low vitamin D levels associated with cognitive decline

Another study shows that older adults with low levels of vitamin D have higher levels of cognitive decline, particularly in executive function (but not attention).

Another study has come out showing that older adults with low levels of vitamin D are more likely to have cognitive problems. The six-year study followed 858 adults who were age 65 or older at the beginning of the study. Those who were severely deficient in vitamin D were 60% more likely to have substantial cognitive decline, and 31% more likely to have specific declines in executive function, although there was no association with attention. Vitamin D deficiency is common in older adults in the United States and Europe (levels estimated from 40% to 100%!), and has been implicated in a wide variety of physical disease.

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Helping older adults remember whether they’ve done something

Older adults are more likely to forget that they've done something. A new study has found that doing something unusual (such as putting a hand on their head) at the same time helps seniors remember having done the task.

Previous research has shown that older adults are more likely to incorrectly repeat an action in situations where a prospective memory task has become habitual — for example, taking more medication because they’ve forgotten they’ve already taken it. A new study has found that doing something unusual at the same time helps seniors remember having done the task. In the study, older adults told to put a hand on their heads whenever they made a particular response, reduced the level of repetition errors to that of younger adults. It’s suggested that doing something unusual, like knocking on wood or patting yourself on the head, while taking a daily dose of medicine may be an effective strategy to help seniors remember whether they've already taken their daily medications.

Older brains make good use of 'useless' information

A new study finds a decision-making advantage to the increased difficulty older brains have in filtering out irrelevant information.

It’s now well established that older brains tend to find it harder to filter out irrelevant information. But now a new study suggests that that isn’t all bad. The study compared the performance of 24 younger adults (17-29) and 24 older adults (60-73) on two memory tasks separated by a 10-minute break. In the first task, they were shown pictures overlapped by irrelevant words, told to ignore the words and concentrate on the pictures only, and to respond every time the same picture appeared twice in a row. The second task required them to remember how the pictures and words were paired together in the first task. The older adults showed a 30% advantage over younger adults in their memory for the preserved pairs. It’s suggested that older adults encode extraneous co-occurrences in the environment and transfer this knowledge to subsequent tasks, improving their ability to make decisions.

Reference: 

[276] Campbell, K. L., Hasher L., & Thomas R. C. (2010).  Hyper-binding: a unique age effect. Psychological Science: A Journal of the American Psychological Society / APS. 21(3), 399 - 405.

Full text available at http://pss.sagepub.com/content/early/2010/01/15/0956797609359910.full

The age you feel is more important for cognition than the age you are

More data from the National Survey of Midlife Development in the United States has revealed that cognitive abilities reflect to a greater extent how old you feel, not how old you actually are.

More data from the National Survey of Midlife Development in the United States has revealed that cognitive abilities reflect to a greater extent how old you feel, not how old you actually are. Of course that may be because cognitive ability contributes to a person’s wellness and energy. But it also may reflect benefits of trying to maintain a sense of youthfulness by keeping up with new trends and activities that feel invigorating.

Reference: 

[171] Schafer, M. H., & Shippee T. P. (2009).  Age Identity, Gender, and Perceptions of Decline: Does Feeling Older Lead to Pessimistic Dispositions About Cognitive Aging?. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences. 65B(1), 91 - 96.

Cognitive ability, not age, predicts risky decisions

A new study provides evidence that it's not age per se that affects the quality of decision-making, but individual differences in processing speed and memory.

A study involving 54 older adults (66-76) and 58 younger adults (18-35) challenges the idea that age itself causes people to become more risk-averse and to make poorer decisions. Analysis revealed that it is individual differences in processing speed and memory that affect decision quality, not age. The stereotype has arisen no doubt because more older people process slowly and have poorer memory. The finding points to the need to identify ways in which to present information that reduces the demand on memory or the need to process information very quickly, to enable those in need of such help (both young and old) to make the best choices. Self-knowledge also helps — recognizing if you need to take more time to make a decision.

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One cause of cognitive decline with age

The discovery that a particular type of dendritic spine is lost with age not only provides a target for therapy, but also emphasizes the importance of building skills and expertise when young.

A rhesus monkey study has revealed which dendritic spines are lost with age, providing a new target for therapies to help prevent age-association cognitive impairment. It appears that it is the thin, dynamic spines in the dorsolateral prefrontal cortex, which are key to learning new things, establishing rules, and planning, that are lost. Learning of a new task was correlated with both synapse density and average spine size, but was most strongly predicted by the head volume of thin spines. There was no correlation with size or density of the large, mushroom-shaped spines, which were very stable across age and probably mediate long-term memories, enabling the retention of expertise and skills learned early in life. There was no correlation with any of these spine characteristics once the task was learned. The findings underscore the importance of building skills and broad expertise when young.

Why older adults remember the good times better

An imaging study has found differences in brain activity that explain why older adults are better at remembering positive events.

An imaging study reveals why older adults are better at remembering positive events. The study, involving young adults (ages 19-31) and older adults (ages 61-80) being shown a series of photographs with positive and negative themes, found that while there was no difference in brain activity patterns between the age groups for the negative photos, there were age differences for the positive photos. In older adult brains, but not the younger, two emotion-processing regions (the ventromedial prefrontal cortex and the amygdala) strongly influenced the memory-encoding hippocampus.

The secret of sharp memory in old age

Examination of the brains from 9 “super-aged” — people over 80 whose memory performance was at the level of 50-year-olds — has found that some of them had almost no tau tangles. Are they genetically protected, or reaping the benefits of a preventive lifestyle?

Examination of the brains from 9 “super-aged” — people over 80 whose memory performance was at the level of 50-year-olds — has found that some of them had almost no tau tangles. The accumulation of tau tangles has been thought to be a natural part of the aging process; an excess of them is linked to Alzheimer’s disease. The next step is to work out why some people are immune to tangle formation, while others appear immune to the effects. Perhaps the first group is genetically protected, while the others are reaping the benefits of a preventive lifestyle.

Reference: 

The findings were presented March 23 at the 239th National Meeting of the American Chemical Society (ACS).

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