Negative stereotypes about aging affect how well older adults remember

March, 2012

Another study has come out supporting the idea that negative stereotypes about aging and memory affect how well older adults remember. In this case, older adults reminded of age-related decline were more likely to make memory errors.

In the study, 64 older adults (60-74; average 70) and 64 college students were compared on a word recognition task. Both groups first took a vocabulary test, on which they performed similarly. They were then presented with 12 lists of 15 semantically related words. For example, one list could have words associated with "sleep," such as "bed," "rest," "awake," "tired" and "night" — but not the word “sleep”. They were not told they would be tested on their memory of these, rather they were asked to rate each word for pleasantness.

They then engaged in a five-minute filler task (a Sudoku) before a short text was read to them. For some, the text had to do with age-related declines in memory. These participants were told the experiment had to do with memory. For others, the text concerned language-processing research. These were told the experiment had to do with language processing and verbal ability.

They were then given a recognition test containing 36 of the studied words, 48 words unrelated to the studied words, and 12 words related to the studied words (e.g. “sleep”). After recording whether or not they had seen each word before, they also rated their confidence in that answer on an 8-point scale. Finally, they were given a lexical decision task to independently assess stereotype activation.

While young adults showed no effects from the stereotype manipulation, older adults were much more likely to falsely recognize related words that had not been studied if they had heard the text on memory. Those who heard the text on language were no more likely than the young adults to falsely recognize related words.

Note that there is always quite a high level of false recognition of such items: young adults, and older adults in the low-threat condition falsely recognized around half of the related lures, compared to around 10% of unrelated words. But in the high-threat condition, older adults falsely recognized 71% of the related words.

Moreover, older adults’ confidence was also affected. While young adults’ confidence in their false memories was unaffected by threat condition, older adults in the high-threat condition were more confident of their false memories than older adults in the low-threat condition.

The idea that older adults were affected by negative stereotypes about aging was supported by the results of the lexical decision task, which found that, in the high-threat condition, older adults responded more quickly to words associated with negative stereotypes than to neutral words (indicating that they were more accessible). Young adults did not show this difference.


Thomas, A. K., & Dubois, S. J. (2011). Reducing the burden of stereotype threat eliminates age differences in memory distortion. Psychological science, 22(12), 1515-7. doi:10.1177/0956797611425932


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Cognitive decline begins in middle age

February, 2012

A large ten-year study of middle-aged to older adults (45-70) has found that cognitive decline begins in the 45-55 decade, with reasoning ability the most affected by age.

The age at which cognitive decline begins has been the subject of much debate. The Seattle longitudinal study has provided most of the evidence that it doesn’t begin until age 60. A more recent, much larger study that allows both longitudinal and cross-sectional analysis suggests that, depressingly, mid-to-late forties might be closer to the mark.

A long-term British study known as Whitehall II began in 1985, when all civil servants aged 35-55 in 20 London-based departments were invited to participate. In 1997-9, 5198 male and 2192 female civil servants, aged 45-70 at this point, were given the first of three rounds of cognitive testing. The second round took place in 2002-4, and the third in 2007-9.

Over these ten years, all cognitive scores except vocabulary declined in all five age categories (45-49, 50-54, 55-59, 60-64, and 65-70 at baseline). Unsurprisingly, the decline was greater with increasing age, and greatest for reasoning. Men aged 45-9 at baseline showed a 3.6% decline in reasoning, compared to a 9.6% decline for those aged 65-70. Women were less affected by age: while showing the same degree of decline when younger, the oldest showed a 7.4% decline.

None of the other cognitive tasks showed the same age-related deterioration as reasoning, which displayed a consistently linear decline with advancing age. The amount of decline over ten years was roughly similar for each age group for short-term memory and phonemic and semantic fluency (although the women displayed more variability in memory, in a somewhat erratic pattern which may perhaps reflect hormonal changes — I’m speculating here). Moreover, the amount of decline in each decade for these functions was only about the same as reasoning’s decline in the younger decades — about -4% in each decade.

Men and women differed significantly in education (33% of men attended university compared to 21% of women; 57% of women never finished secondary school compared to 39% of men). It is therefore unsurprising that men performed significantly better on all cognitive tests except memory (noting that the actual differences in score were mostly quite small: 16.9/35 vs 16.5 for phonemic fluency; 16.7/35 vs 15.8 for semantic fluency; 25.7/33 vs 23.1 for vocabulary; 48.7/65 vs 41.6 for reasoning).

The cognitive tests included a series of 65 verbal and mathematical reasoning items of increasing difficulty (testing inductive reasoning), a 20-word free recall test (short-term verbal memory), recalling as many words as possible beginning with “S” (phonemic fluency) and recalling members of the animal category (semantic fluency), and a multi-choice vocabulary test.

The design of the study allowed both longitudinal and cross-sectional analyses to be carried out. Cross-sectional data, although more easily acquired, has been criticized as conflating age effects with cohort differences. Generations differ on several relevant factors, of which education is the most obvious. The present study semi-confirmed this, finding that cross-sectional data considerably over-estimated cognitive decline in women but not men — reflecting the fact that education changed far more for women than men in the relevant time periods. For example, in the youngest group of men, 30% had less than a secondary school education and 42% had a university degree, and the women showed a similar pattern, with 34% and 40%. However, for those aged 55-59 at baseline, the corresponding figures were 38% and 29% for men compared to 58% and 17% for women.

The principal finding is of course that measurable cognitive decline was evident in the youngest group, meaning that at some point during that 45-55 decade, cognitive faculties begin to decline. Of course, it should be emphasized that this is a group effect — individuals will vary in the extent and timing of any cognitive decline.

(A side-note: During the ten year period, 305 participants died. The probability of dying was higher in those with poorer cognitive scores at baseline.)



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Why a select group of seniors retain their cognitive abilities

December, 2011

Comparison of the brains of octogenarians whose memories match those of middle-aged people reveals important differences between their brains and those of cognitively-normal seniors.

A certain level of mental decline in the senior years is regarded as normal, but some fortunate few don’t suffer from any decline at all. The Northwestern University Super Aging Project has found seniors aged 80+ who match or better the average episodic memory performance of people in their fifties. Comparison of the brains of 12 super-agers, 10 cognitively-normal seniors of similar age, and 14 middle-aged adults (average age 58) now reveals that the brains of super-agers also look like those of the middle-aged. In contrast, brain scans of cognitively average octogenarians show significant thinning of the cortex.

The difference between the brains of super-agers and the others was particularly marked in the anterior cingulate cortex. Indeed, the super agers appeared to have a much thicker left anterior cingulate cortex than the middle-aged group as well. Moreover, the brain of a super-ager who died revealed that, although there were some plaques and tangles (characteristic, in much greater quantities, of Alzheimer’s) in the mediotemporal lobe, there were almost none in the anterior cingulate. (But note an earlier report from the researchers)

Why this region should be of special importance is somewhat mysterious, but the anterior cingulate is part of the attention network, and perhaps it is this role that underlies the superior abilities of these seniors. The anterior cingulate also plays a role error detection and motivation; it will be interesting to see if these attributes are also important.

While the precise reason for the anterior cingulate to be critical to retaining cognitive abilities might be mysterious, the lack of cortical atrophy, and the suggestion that super-agers’ brains have much reduced levels of the sort of pathological damage seen in most older brains, adds weight to the growing evidence that cognitive aging reflects clinical problems, which unfortunately are all too common.

Sadly, there are no obvious lifestyle factors involved here. The super agers don’t have a lifestyle any different from their ‘cognitively average’ counterparts. However, while genetics might be behind these people’s good fortune, that doesn’t mean that lifestyle choices don’t make a big difference to those of us not so genetically fortunate. It seems increasingly clear that for most of us, without ‘super-protective genes’, health problems largely resulting from lifestyle choices are behind much of the damage done to our brains.

It should be emphasized that these unpublished results are preliminary only. This conference presentation reported on data from only 12 of 48 subjects studied.


Harrison, T., Geula, C., Shi, J., Samimi, M., Weintraub, S., Mesulam, M. & Rogalski, E. 2011. Neuroanatomic and pathologic features of cognitive SuperAging. Presented at a poster session at the 2011 Society for Neuroscience conference.


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The positive side of age-related cognitive change

The brain changes as we age, but it's not all bad! Experience changes our brains in a good way.

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

Experienced air traffic controllers work smarter, not harder, making up for normal mental aging

A study involving 36 air traffic controllers and 36 age- and education-matched non-controllers, with 18 older (average age 57) and 18 younger adults (average age 24) per group has found that although predictable age-related declines were observed in most of the standard tests of cognitive function, in the simulated air traffic control task, experience helped the older controllers to compensate to a significant degree for age-related declines, especially in their performance of the more complex simulations.

[313] Nunes, A., & Kramer A. F.
(2009).  Experience-based mitigation of age-related performance declines: evidence from air traffic control.
Journal of Experimental Psychology. Applied. 15(1), 12 - 24.

When emotions involved, older adults may perform memory tasks better than young adults

A study involving 72 young adults (20-30 years old) and 72 older adults (60-75) has found that regulating emotions – such as reducing negative emotions or inhibiting unwanted thoughts – is a resource-demanding process that disrupts the ability of young adults to simultaneously or subsequently perform tasks, but doesn’t affect older adults. In the study, most of the participants watched a two-minute video designed to induce disgust, while the rest watched a neutral two-minute clip. Participants then played a computer memory game. Before playing 2 further memory games, those who had watched the disgusting video were instructed either to change their negative reaction into positive feelings as quickly as possible or to maintain the intensity of their negative reaction, or given no instructions. Those young adults who had been told to turn their disgust into positive feelings, performed significantly worse on the subsequent memory tasks, but older adults were not affected. The feelings of disgust in themselves did not affect performance in either group. It’s speculated that older adults’ greater experience allows them to regulate their emotions without cognitive effort.

[200] Scheibe, S., & Blanchard-Fields F.
(2009).  Effects of regulating emotions on cognitive performance: what is costly for young adults is not so costly for older adults.
Psychology and Aging. 24(1), 217 - 223.

Aging brains allow negative memories to fade

Another study has found that older adults (average age 70) remember fewer negative images than younger adults (average age 24), and that this has to do with differences in brain activity. When shown negative images, the older participants had reduced interactions between the amygdala and the hippocampus, and increased interactions between the amygdala and the dorsolateral frontal cortex. It seems that the older participants were using thinking rather than feeling processes to store these emotional memories, sacrificing information for emotional stability. The findings are consistent with earlier research showing that healthy seniors are able to regulate emotion better than younger people.

[680] St Jacques, P. L., Dolcos F., & Cabeza R.
(2009).  Effects of aging on functional connectivity of the amygdala for subsequent memory of negative pictures: a network analysis of functional magnetic resonance imaging data.
Psychological Science: A Journal of the American Psychological Society / APS. 20(1), 74 - 84.

'Super-aged' brains reveal secrets of sharp memory in old age

While we take for granted that we’ll lose some cognitive ability as we get older, it’s also true that some very old people have brains just as quick as they always were. Now a post-mortem study of the brains of five of these "super aged" has revealed that these brains do indeed differ from normal elderly brains; specifically, by having much fewer tau tangles. Tau tangles are characteristic of Alzheimer's patients, but they are not restricted to them; until now, it’s been assumed that aging brings about the accumulation of these tangles. However, amyloid plaques, also characteristic of Alzheimer’s and found in smaller quantities in aging brains, were found in “normal” quantities, pointing to the tangles as the critical factor.

The findings were presented November 16, at the Society for Neuroscience annual meeting in Washington, D.C.

Confidence in memory performance helps older adults remember

A study involving 335 adults aged 21 to 83 found that control beliefs were related to memory performance on a word list recall task for middle-aged and older adults, but not for younger adults. This was partly because middle-aged and older adults who perceived greater control over cognitive functioning were more likely to use strategies to help their memory. In other words, the more you believe there are things you can do to remember information, the more likely you are to make an effort to remember.

Lachman, M.E. & Andreoletti, C. 2006. Strategy Use Mediates the Relationship Between Control Beliefs and Memory Performance for Middle-Aged and Older Adults. J Gerontol B Psychol Sci Soc Sci, 61, P88-P94.

'Sharp' older brains are not the same as younger brains

We know that many older adults still retain the mental sharpness of younger people, but studies comparing brain activity in older and younger adults suggests they perform differently. A rat study has now found the first solid evidence that still "sharp" older brains do indeed store and encode memories differently than younger brains. Comparison of those older rats who had retained their cognitive abilities with those who had not, also revealed that those with impaired cognition had lost the ability to modify the strength of the communications between synapses (synaptic communication is the means by which memories are encoded and stored). But the competent seniors also differed from the younger rats in the mechanism most used to bring about synaptic change.

[1316] Lee, H-K., Min S S., Gallagher M., & Kirkwood A.
(2005).  NMDA receptor-independent long-term depression correlates with successful aging in rats.
Nat Neurosci. 8(12), 1657 - 1659.

An advantage of age

A study comparing the ability of young and older adults to indicate which direction a set of bars moved across a computer screen has found that although younger participants were faster when the bars were small or low in contrast, when the bars were large and high in contrast, the older people were faster. The results suggest that the ability of one neuron to inhibit another is reduced as we age (inhibition helps us find objects within clutter, but makes it hard to see the clutter itself). The loss of inhibition as we age has previously been seen in connection with cognition and speech studies, and is reflected in our greater inability to tune out distraction as we age. Now we see the same process in vision.

[1356] Betts, L. R., Taylor C. P., Sekuler A. B., & Bennett P. J.
(2005).  Aging Reduces Center-Surround Antagonism in Visual Motion Processing.
Neuron. 45(3), 361 - 366.

Effect of expectations on older adults’ memory performance

A study involving 193 participants and two experiments, each with a younger (17 – 35 years old) and older (57 – 82 years old) group of adults, has investigated how negative stereotypes about aging influences older adults' memory. Participants were exposed to stereotype-related words in the context of another task (scrambled sentence, word judgment) in order to prime positive and negative stereotypes of aging. Results show memory performance in older adults was lower when they were primed with negative stereotypes than when they were primed with positive stereotypes. Age differences in memory between young and older adults were significantly reduced following a positive stereotype prime, with young and older adults performing at almost identical levels in some situations.

[1414] Hess, T. M., Hinson J. T., & Statham J. A.
(2004).  Explicit and implicit stereotype activation effects on memory: do age and awareness moderate the impact of priming?.
Psychology and Aging. 19(3), 495 - 505.

Cognitive abilities are fairly stable and may be correlated with longevity

The Scottish Mental Survey assessed 87,498 eleven-year-olds in 1932, and another 70,805 in 1947. In a fascinating follow-up to this study, over 1000 of these students have been contacted and re-assessed, on the exact same tests. It was found that, first of all, the seniors did rather better than they had at age 11, and that differences in mental ability remained fairly stable with age. Mental ability at 11 was also found to be significantly correlated with survival — those who scored highly were more likely to have survived, with the exception that men with high ability were more likely to die in active service in World War II. People of lower ability had a greater tendency to lung and stomach cancer. More results from this landmark study are expected.

These preliminary findings were presented by Professor Ian Deary from the Department of Psychology, University of Edinburgh at a symposium on aging at the Australian National University.

Compensating strategies for aging memories

PET scans of the prefrontal cortex reveal that older adults who perform better on a simple memory task display more activity on both sides of the brain, compared to both older adults who do less well, and younger adults. Although this seems counter-intuitive – the older adults who perform less well show activity patterns more similar to that of younger adults, this supports recent theory that the brain may change tactics as it ages, and that older people whose brain is more flexible can compensate for some aspects of memory decline. Whether this flexibility is neurological, or something that can be taught, is still unknown.

[449] Cabeza, R., Anderson N. D., Locantore J. K., & McIntosh A. R.
(2002).  Aging gracefully: compensatory brain activity in high-performing older adults.
NeuroImage. 17(3), 1394 - 1402.

Training can improve age-related memory decline in elderly

Older adults show two kinds of cognitive-processing deficits: under-recruitment, where appropriate areas of the brain are less likely to be utilized without specific instruction, and non-selective recruitment, where non-relevant regions of the brain are more likely to be used. A recent imaging study confirmed that older adults were less likely than younger ones to use the critical frontal regions when performing a memory task, and more likely to use cortical regions that are not as useful. However, when subjects were given specific strategy instructions, the older adults showed increased activity in the frontal regions, and their remembering improved. Even with this support however, older adults still showed a greater tendency to use brain regions that were not useful.

[761] Logan, J. M., Sanders A. L., Snyder A. Z., Morris J. C., & Buckner R. L.
(2002).  Under-recruitment and nonselective recruitment: dissociable neural mechanisms associated with aging.
Neuron. 33(5), 827 - 840.

How aging brains compensate for cognitive decline

Evidence from a series of studies using functional positron emission tomography (PET) images suggests that one way older adults may compensate for age-related cognitive decline is by using additional regions of the brain to perform memory and information processing tasks. For example, simple short-term memory tasks involve the same brain regions in both older and younger adults, but older adults also activate a frontal cortex region that young adults use only when performing complex short-term memory tasks. This may explain why performance of older adults on complex memory tasks is usually significantly poorer than that of younger adults - the frontal cortex region that young adults will activate to help with complex short-term memory tasks is already preoccupied in older adults, and is less available to help when the task becomes more complex.

The research was conducted by University of Michigan researchers under the leadership of cognitive neuroscientist Patricia Reuter-Lorenz, and presented at the annual meeting of the American Psychological Association in San Francisco.

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Aging - specific failures

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

Failing recall not an inevitable consequence of aging

New research suggests age-related cognitive decay may not be inevitable. Tests of 36 adults with an average age of 75 years found that about one out of four had managed to avoid memory decline. Those adults who still had high frontal lobe function had memory skills “every bit as sharp as a group of college students in their early 20s." (But note that most of those older adults who participated were highly educated – some were retired academics). The study also found that this frontal lobe decline so common in older adults is associated with an increased susceptibility to false memories – hence the difficulty often experienced by older people in recalling whether they took a scheduled dose of medication.

The research was presented on August 8 at the American Psychological Association meeting in Toronto.

Older adults better at forgetting negative images

It seems that this general tendency, to remember the good, and let the bad fade, gets stronger as we age. Following recent research suggesting that older people tend to regulate their emotions more effectively than younger people, by maintaining positive feelings and lowering negative feelings, researchers examined age differences in recall of positive, negative and neutral images of people, animals, nature scenes and inanimate objects. The first study tested 144 participants aged 18-29, 41-53 and 65-80. Older adults recalled fewer negative images relative to positive and neutral images. For the older adults, recognition memory also decreased for negative pictures. As a result, the younger adults remembered the negative pictures better. Preliminary brain research suggests that in older adults, the amygdala is activated equally to positive and negative images, whereas in younger adults, it is activated more to negative images. This suggests that older adults encode less information about negative images, which in turn would diminish recall.

Charles, S.T., Mather, M. & Carstensen, L.L. 2003. Aging and Emotional Memory: The Forgettable Nature of Negative Images for Older Adults. Journal of Experimental Psychology: General, 132(2), 310-24.

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Aging - rate of cognitive decline

White matter appears to decrease faster than grey matter, but doesn't begin to decline until the forties. Presumably this relates to the decline in processing speed that is the most evident characteristic of age-related decline.

Grey matter, on the other hand, declines at a fairly constant rate from adolescence, mirroring a decline in processing ability that seems to start as early as the twenties.

Cognitive decline seems to be faster in women than men. This presumably reflects apparent gender differences in brain activity. For example, while women seem to have a greater density of brain cells in the prefrontal cortex, they also show a steeper rate of decline so that, in old age, the density is similar between the genders.

There is some evidence that individual differences in processing speed and memory are more important than age, and that personality attributes affect the rate of cognitive decline and brain atrophy.

Some gene variants, including the so-called Alzheimer’s gene, are associated with a faster rate of decline, or an earlier start. These may be triggered by activity in early adulthood. Head size in adulthood also seems to affect rate of decline. Head size in adulthood reflects not only head size at birth, but growth in the early years — pointing to the importance of providing both proper nourishment and intellectual stimulation in these early years.

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

Marital status and gender affects rate of age-related cognitive decline; education doesn’t

Analysis of data from 6,476 adults born prior to 1924 (taken from the AHEAD study), who were given five rounds of cognitive testing between 1993 and 2002, has found marital status is a significant factor in rate of cognitive decline, with widows and widowers and those who never married declining faster than married individuals. This is consistent with findings of the benefits of social stimulation and support for aging cognition. Confirming earlier indications, it was also found that women declined faster than men. Level of education did not affect rate of decline. There was an effect of socioeconomic status, in that those in the bottom quintile declined more slowly than those in the highest quintile, and non-Hispanic blacks declined more slowly than non-Hispanic whites, but the chief difference was at baseline — that is, socioeconomic status and race were a far more significant factor in the level of cognitive performance at the start of the study, compared to the rate of decline with age.

[628] Karlamangla, A. S., Miller-Martinez D., Aneshensel C. S., Seeman T. E., Wight R. G., & Chodosh J.
(2009).  Trajectories of Cognitive Function in Late Life in the United States: Demographic and Socioeconomic Predictors.
Am. J. Epidemiol.. 170(3), 331 - 342.

Evidence cognitive decline begins in late 20s

A seven-year study involving 2,000 healthy participants between the ages of 18 and 60 has revealed that in 9 of 12 tests the average age at which the top scores were achieved was 22. A notable decline in certain measures of abstract reasoning, processing speed and spatial visualization became apparent at 27. Average memory declines could be detected by about age 37. However, accumulated knowledge skills, such as improvement of vocabulary and general knowledge, actually increase at least until the age of 60. It must be remembered however that there is considerable variance from person to person.

[239] Salthouse, T. A.
(2009).  When does age-related cognitive decline begin?.
Neurobiology of Aging. 30(4), 507 - 514.

Education may not affect how fast you will lose your memory

A study involving some 6,500 older Chicago residents being interviewed 3-yearly for up to 14 years (average 6.5 years), has found that while at the beginning of the study, those with more education had better memory and thinking skills than those with less education, education was not related to how rapidly these skills declined during the course of the study. The result suggests that the benefit of more education in reducing dementia risk results simply from the difference in level of cognitive function.

[362] Wilson, R. S., Hebert L. E., Scherr P. A., Barnes L. L., Mendes de Leon C. F., & Evans D. A.
(2009).  Educational attainment and cognitive decline in old age.
Neurology. 72(5), 460 - 465.

Brain slows at 40, starts body decline

We get slower as we age, we all know that. This slowness reflects damage to the myelin sheathing (“white matter”) that coats nerve fibers and is vital for speedy conduction of electrical impulses. A study involving 72 healthy men aged 23 to 80 has found that the speed with which they could tap an index finger, and the health of the myelin in the region that orders the finger to tap, both peaked at age 39, then gradually declined with increasing age. This explains why you don’t get many world-class athletes after 40. Luckily, it probably takes a little longer before the myelin in cognitive areas starts to fray (a decade or so, it’s thought). The finding is consistent with a recent report that the system that’s supposed to repair myelin becomes less efficient with age. More research is looking at what you can do to help your myelin, but in the meantime, it’s suggested that mental and physical activity may help stimulate myelin repair, and stress may damage it.

[468] Villablanca, P., Bartzokis G., Lu P. H., Tingus K., Mendez M. F., Richard A., et al.
(2008).  Lifespan trajectory of myelin integrity and maximum motor speed.
Neurobiology of Aging.

Memory loss becoming less common in older Americans

A new nationally representative study involving 11,000 people shows a downward trend in the rate of cognitive impairment among people aged 70 and older, from 12.2% to 8.7% between 1993 and 2002. It’s speculated that factors behind this decline may be that today’s older people are much likelier to have had more formal education, higher economic status, and better care for risk factors such as high blood pressure, high cholesterol and smoking that can jeopardize their brains. In fact the data suggest that about 40% of the decrease in cognitive impairment over the decade was likely due to the increase in education levels and personal wealth between the two groups of seniors studied at the two time points. The trend is consistent with a dramatic decline in chronic disability among older Americans over the past two decades.

[1307] Langa, K. M., Larson E. B., Karlawish J. H., Cutler D. M., Kabeto M. U., Kim S. Y., et al.
(2008).  Trends in the Prevalence and Mortality of Cognitive Impairment in the United States: Is There Evidence of a Compression of Cognitive Morbidity?.
Alzheimer's & dementia : the journal of the Alzheimer's Association. 4(2), 134 - 144.

People at genetic risk for Alzheimer's age mentally just like noncarriers

A long-running study involving 6,560 people has found that carriers of the so-called ‘Alzheimer’s gene’— the APOE4 allele — does not contribute to cognitive change during most of adulthood. There was no difference in cognitive performance between carriers and non-carriers prior to the development of dementia symptoms.

[1189] Jorm, A. F., Mather K. A., Butterworth P., Anstey K. J., Christensen H., & Easteal S.
(2007).  APOE genotype and cognitive functioning in a large age-stratified population sample.
Neuropsychology. 21(1), 1 - 8.

Longevity gene also helps retain cognitive function

The Longevity Genes Project has studied 158 people of Ashkenazi, or Eastern European Jewish, descent who were 95 years of age or older. Those who passed a common test of mental function were two to three times more likely to have a common variant of a gene associated with longevity (the CETP gene) than those who did not. When the researchers studied another 124 Ashkenazi Jews between 75 and 85 years of age, those subjects who passed the test of mental function were five times more likely to have this gene variant than their counterparts. The gene variant makes cholesterol particles in the blood larger than normal.

[916] Barzilai, N., Atzmon G., Derby C. A., Bauman J. M., & Lipton R. B.
(2006).  A genotype of exceptional longevity is associated with preservation of cognitive function.
Neurology. 67(12), 2170 - 2175.

Risk of mild cognitive impairment increases with less education

A study of 3,957 people from the general population of Olmsted County, Minnesota is currently in train to find how many of those who did not have dementia might have mild cognitive impairment. A report on the findings so far suggests 9% of those aged 70 to 79 and nearly 18% of those 80 to 89 have MCI. Prevalence varied not only with age but also years of education: 25% in those with up to eight years of education, 14% in those with nine to 12 years, 9% in those with 13 to 16 years, and 8.5% in those with greater than 16 years.

Findings from this study were presented April 4 at the American Academy of Neurology meeting in San Diego.

Human cerebellum and cortex age in very different ways

Analysis of gene expression in five different regions of the brain's cortex has found that brain changes with aging were pronounced and consistent across the cortex, but changes in gene expression in the cerebellum were smaller and less coordinated. Researchers were surprised both by the homogeneity of aging within the cortex and by the dramatic differences between cortex and cerebellum. They also found that chimpanzees' brains age very differently from human brains; the findings cast doubt on the effectiveness of using rodents to model various types of neurodegenerative disease.

[951] Fraser, H. B., Khaitovich P., Plotkin J. B., Pääbo S., & Eisen M. B.
(2005).  Aging and Gene Expression in the Primate Brain.
PLoS Biol. 3(9), e274 - e274.

Childhood environment important in staving off cognitive decline

Confirming earlier studies, a British study of 215 men and women aged between 66 and 75, has found that the larger a person's head, the less likely their cognitive abilities are to decline in later years. Those with the smallest heads had a fivefold increased risk of suffering cognitive decline compared with those with the largest heads. Encouragingly, however, this doesn’t mean you’re doomed at birth — the researchers found that it wasn’t head circumference at birth that was important, but head size in adulthood. During the first year of life, babies' brains double in size, and by the time they are six, their brain weight has tripled. These, it appears, are the crucial years for laying down brain cells and neural connections — pointing to the importance of providing both proper nourishment and intellectual stimulation in these early years.

[1208] Gale, C. R., Walton S., & Martyn C. N.
(2003).  Foetal and postnatal head growth and risk of cognitive decline in old age.
Brain. 126(10), 2273 - 2278.,6903,1051264,00.html

Failing recall not an inevitable consequence of aging

New research suggests age-related cognitive decay may not be inevitable. Tests of 36 adults with an average age of 75 years found that about one out of four had managed to avoid memory decline. Those adults who still had high frontal lobe function had memory skills “every bit as sharp as a group of college students in their early 20s." (But note that most of those older adults who participated were highly educated – some were retired academics). The study also found that this frontal lobe decline so common in older adults is associated with an increased susceptibility to false memories – hence the difficulty often experienced by older people in recalling whether they took a scheduled dose of medication.

The research was presented on August 8 at the American Psychological Association meeting in Toronto.

How aging brains compensate for cognitive decline

Many of the cognitive deficits associated with advancing age are related to functions of the prefrontal cortex such as working memory, decision-making, planning and judgment. Postmortem examination of 20 brains ranging in age from 25 to 83 years, confirm that prefrontal regions may be particularly sensitive to the effects of aging. It also appears that white matter decreases at a faster rate than grey matter with age.

Kigar, D.L., Walter, A.L., Stoner-Beresh, H.J. & Witelson, S.F. 2001. Age and volume of the human prefrontal cortex: a postmortem study. Paper presented to the annual Society for Neuroscience meeting in San Diego, US.

Memory starts to decline in our mid-twenties

Studies of more than 350 men and women between the ages of 20 and 90 have found that cognitive decline starts as early as the twenties, and this decline in cognitive processing power appears to be constant - that is, the rate of decline is the same when you are in your twenties as when you are in your sixties. However young adults don't notice this decline because the loss hasn't yet become great enough to affect everyday activities.

Denise Park, who directs the Center for Aging and Cognition at the University of Michigan Institute for Social Research (ISR) presented a paper on these studies on Aug. 24 in San Francisco at the annual meeting of the American Psychological Association.

Gray matter may decline from adolescence, but white matter keeps growing until our late forties

Brain scans of 70 men, ages 19 to 76 confirms that the brain's gray matter, the cell bodies of nerve cells, declines steadily from adolescence. But surprisingly, the white matter, the fatty material that insulates the long extending branches of the nerve cells and makes nerve signals move faster, in the frontal parts of the brain appears to grow at least until the late 40's, before beginning to decline. The growth of white matter may improve the brain's ability to process information.

[1246] Bartzokis, G., Beckson M., Lu P. H., Nuechterlein K. H., Edwards N., & Mintz J.
(2001).  Age-Related Changes in Frontal and Temporal Lobe Volumes in Men: A Magnetic Resonance Imaging Study.
Arch Gen Psychiatry. 58(5), 461 - 465.

Mental faculties unchanged until the mid-40s

A large-scale study of mental abilities in adults found that mental faculties were unchanged until the mid-40s, when a marked decline began and continued at a constant rate. The ability to remember words after a delay was especially affected. Accuracy did not seem to be affected, only speed.

The paper was presented to a British Psychological Society conference in London.,4273,4108165,00.html

Gender differences in frontal lobe neuron density

A recent study has found that women have up to 15% more brain cell density in the frontal lobe, which controls so-called higher mental processes, such as judgement, personality, planning and working memory. However, as they get older, women appear to shed cells more rapidly from this area than men. By old age, the density is similar for both sexes. It is not yet clear what impact, if any, this difference has on performance.

Witelson, S.F., Kigar, D.L. & Stoner-Beresh, H.J. 2001. Sex difference in the numerical density of neurons in the pyramidal layers of human prefrontal cortex: a stereologic study. Paper presented to the annual Society for Neuroscience meeting in San Diego, US.

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Aging - extent and prevalence of cognitive decline

Most older adults do not suffer cognitive impairment. Around 30-40% of adults over 65 have the type of cognitive loss we regard as a normal consequence of age — a measurable (but slight) decline on memory tests; a feeling that you're not quite as sharp or as good at remembering, as you used to be (age-related cognitive impairment). Around 10% of adults over 65 develop mild cognitive impairment (MCI), which does impact everyday living, and is a precursor of Alzheimer's.

There are significant differences in prevalence as a function of age. For example, in the U.S., a large sample found MCI in 9% of those aged 70 to 79 and nearly 18% of those 80 to 89. Prevalence decreased with years of education: 25% in those with up to eight years of education, 14% in those with nine to 12 years, 9% in those with 13 to 16 years, and 8.5% in those with greater than 16 years.

Large-scale population surveys of mild cognitive impairment in the elderly have produced large differences in national levels, ranging from 10% to 26%.

Although women may decline at a faster rate than men, prevalence of decline may be greater among men. For example, a large Dutch survey of those aged 85 and older found more women than men had good memory (41% vs 29%) and mental speed (33% vs 28%), despite the fact that more women than men had a limited education.

However, severe memory problems in the elderly have become more rare. The main reasons seem to be better physical fitness (partly due to better healthcare), higher levels of education, and greater personal wealth.

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

Most older people with mild cognitive impairment have Alzheimer's or cerebral vascular disease

Another finding from the Religious Orders Study. It seems that mild cognitive impairment is often the earliest clinical manifestation of Alzheimer’s or vascular dementia. By studying the brains of study participants after death, researchers could ascertain that, of the 37 individuals with mild cognitive impairment, 23 met pathologic criteria for Alzheimer's disease, and 12 had cerebral infarcts (5 had both). Only 9 did not have either pathology. The researchers conclude that even mild loss of cognitive function in older people should not, therefore, be viewed as normal, but as an indication of a disease process.

[893] Bennett, D. A., Schneider J. A., Bienias J. L., Evans D. A., & Wilson R. S.
(2005).  Mild cognitive impairment is related to Alzheimer disease pathology and cerebral infarctions.
Neurology. 64(5), 834 - 841.

Population level of frontotemporal dementia

A large-scale epidemiological study in the Netherlands has found an incidence of frontotemporal dementia that equates to a population level of 1.1 per 100,000. The prevalence was highest among those ages 60 to 69, at 9.4 per 100,000. The prevalence among people ages 45 to 64 was estimated to be 6.7 per 100,000. Symptoms began after age 65 in 22% of patients. Whites accounted for 99% of all cases despite an ample nonwhite population. A family history of dementia was present in 43% of patients.

[586] Ravid, R., Niermeijer M. F., Verheij F., Kremer H. P., Scheltens P., van Duijn C. M., et al.
(2003).  Frontotemporal dementia in The Netherlands: patient characteristics and prevalence estimates from a population-based study.
Brain. 126(9), 2016 - 2022.

Cognitive impairment high among older people

In the first population-based study of cognitive impairment in the United States, nearly one in four older African Americans in Indianapolis were found to have measurable cognitive problems (short of dementia or Alzheimer's). The prevalence of cognitive impairment grew significantly with age, with rates increasing by about 10 percent for every 10 years of age after age 65. Of those aged 85 and older, 38% had some degree of cognitive impairment. Surveys in other countries (which cannot be directly compared due to differences in methodology, diagnostic criteria, etc) have reported results ranging from 10.7% in Italy to 26.6% in Finland.

[992] Musick, B., Hall K. S., Hui S. L., Hendrie H. C., Unverzagt F. W., Gao S., et al.
(2001).  Prevalence of cognitive impairment: Data from the Indianapolis Study of Health and Aging.
Neurology. 57(9), 1655 - 1662.

More women than men do well on memory tests in old age

Researchers from Leiden University tested the mental functioning of 599 Dutch men and women aged 85 years. Good mental speed on word and number recognition tests was found in 33% of the women and 28% of the men. Forty one per cent of the women and 29% of the men had a good memory. This despite the fact that significantly more of the women had limited formal education compared to the men (not surprising given the time in which they grew up). The authors suggested that biological differences - such as the relative absence of cardiovascular disease in elderly women compared with men of the same age - could account for these sex differences in mental decline.

[2615] van Exel, E., Gussekloo J., de Craen A. J. M., Bootsma-van der Wiel A., Houx P., Knook D. L., et al.
(2001).  Cognitive function in the oldest old: women perform better than men.
Journal of Neurology, Neurosurgery & Psychiatry. 71(1), 29 - 32.

Severe memory problems in older adults have become more rare

Severe memory problems in older adults have become more rare, probably because of better treatments for dementia, depression and strokes. Researchers from the University of Michigan interviewed more than 10,000 people ages 70 and older from 1993 to 1998. People tested in 1998 did significantly better on the memory tests than those tested earlier. In 1998 less than 4% of those 70 and older showed severe memory problems, and only 8% of those 85 and older. Surprisingly, the greatest improvement was seen among those in their 80s and those with less than a high school education. The decline in memory problems is believed to be associated with the improvement in physical fitness seen among the elderly. It is speculated that the increase in number of women on hormone replacement therapy may also play a part.

[2616] Freedman, V. A., Aykan H., & Martin L. G.
(2001).  Aggregate Changes in Severe Cognitive Impairment Among Older Americans.
The Journals of Gerontology Series B: Psychological Sciences and Social Sciences. 56(2), S100 -S111 - S100 -S111.

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Aging - how cognitive function declines

Older adults commonly need to practice more than younger adults to achieve the same level of performance. Such age deficits are at least partly due to poorer monitoring of their learning.

Failing to immediately retrieve well-known information does become more common with age, with an increase in "tips of the tongue" evident as early as the mid-thirties. Older people tend to be less likely than younger people to actively pursue a missing word.

Older adults are less likely than younger ones to use the appropriate brain regions when performing a memory task, and more likely to use cortical regions that are not as useful. But this can be at least partly overcome if the seniors are given specific strategy instructions.

Older adults appear to be particularly impaired in context processing — particularly seen in an inability to remember where they heard (or read, or saw) something. Because context is involved in many memory processes, this may have far-reaching implications. An impaired ability to remember context may reflect frontal-lobe inefficiency rather than aging per se.

Decreased ability to remember past events is linked to an impaired ability to imagine future events.

Older adults may compensate for cognitive decline by using additional brain regions. However, the downside is that these brain regions are then not available when a task requires them specifically. This may explain older adults' poorer performance on complex short-term memory tasks.

An important (perhaps even the most important) reason for cognitive decline in older adults is now seen to be a growing inability to filter out irrelevant/distracting information and inhibit processing. There can, however, be a decision-making/problem-solving advantage to this inclusion of apparently irrelevant information.

Older adults’ greater problems with multitasking stem from their impaired ability to disengage from an interrupting task and restore the original task.

There is growing evidence that memory problems (even amnesia) reflect confusion between memories more than loss of memory, and age-related difficulties reflect increasing difficulties in replacing out-of-date information with new, or distinguishing between them.

There do seem to be some gender differences in how brains change with age, which is consistent with the evidence that general intelligence is reflected in different brain attributes for men and women.

While IQ tends to drop with age, this may simply reflect perception deficits, not cognitive ones.

Brain regions that are especially affected by age include shrinking of the frontal lobe, especially the prefrontal cortex, of the medial temporal lobe, especially the hippocampus, and (for men only) the cerebellum. Aging also tends to degrade white matter, leading to brain networks growing less coordinated. The default network is most severely disrupted. Levels of the inhibitory neurotransmitter GABA also tend to decline with age, as does the levels of dopamine. Both are important for learning and memory.

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

Factors helping you maintain cognitive function in old age

An 8-year study of over 2,500 seniors in their 70s, has found that 53% showed normal age-related decline, 16% showed major cognitive decline, and an encouraging 30% had no change or improved on the tests over the years. The most important factors in determining whether a person maintained their cognitive health was education and literacy: those with a ninth grade literacy level or higher were nearly five times as likely to stay sharp than those with lower literacy levels; those with at least a high school education were nearly three times as likely to stay sharp as those who have less education. Lifestyle factors were also significant: non-smokers were nearly twice as likely to stay sharp as smokers; those who exercised moderately to vigorously at least once a week were 30% more likely to maintain their cognitive function than those who do not exercise that often; people working or volunteering and people who report living with someone were 24% more likely to maintain cognitive function.

[909] Ayonayon, H. N., Harris T. B., For the Health ABC Study, Yaffe K., Fiocco A. J., Lindquist K., et al.
(2009).  Predictors of maintaining cognitive function in older adults: The Health ABC Study.
Neurology. 72(23), 2029 - 2035.

Better cognitive performance from US seniors compared to British

A study involving over 8,000 older Americans and over 5,000 British seniors has found a significant difference in cognitive performance between the two nationalities, with the Americans scoring on average as if they were ten years younger than the British. The U.S. advantage in "brain health" was greatest for the oldest old---those aged 85 and older. Part of the difference can be accounted for by higher levels of education and net worth in the United States, and part by significantly lower levels of depressive symptoms (possibly attributable to the much greater degree of medication in the US for depression). It was also found that dramatically more U.S. seniors reported no alcohol use (over 50%), compared to the British (15.5%). It is also speculated that the earlier retirement in Britain may be a factor, and also the greater prevalence of untreated hypertension.

[773] Langa, K. M., Llewellyn D., Lang I., Weir D., Wallace R., Kabeto M., et al.
(2009).  Cognitive health among older adults in the United States and in England.
BMC Geriatrics. 9(1), 23 - 23.

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Memory gets worse with age if you think about it

Confirming earlier research (and what I’ve been saying for ten years), thinking that memory diminishes with age is sufficient for some elderly people to score lower on cognitive tests. Moreover, and confirming other research relating to gender and race, the study also found that a senior's ability to remember something was heavily influenced by the activation or inactivation of negative stereotypes (for example, by being told before the test that older people perform more poorly on that type of memory test). The effects of negative stereotypes were experienced more by those in their sixties than older (but those in their seventies performed worse when they felt stigmatized), and more by the very well-educated. There was some indication that these effects occur through their effect on motivation.

[1013] Hess, T. M., Hinson J. T., & Hodges E. A.
(2009).  Moderators of and Mechanisms Underlying Stereotype Threat Effects on Older Adults' Memory Performance.
Experimental Aging Research: An International Journal Devoted to the Scientific Study of the Aging Process. 35(2), 153 - 153.

Circadian clock may be critical for remembering what you learn

We know circadian rhythm affects learning and memory in that we find it easier to learn at certain times of day than others, but now a study involving Siberian hamsters has revealed that having a functioning circadian system is in itself critical to being able to remember. The finding has implications for disorders such as Down syndrome and Alzheimer's disease. The critical factor appears to be the amount of the neurotransmitter GABA, which acts to inhibit brain activity. The circadian clock controls the daily cycle of sleep and wakefulness by inhibiting different parts of the brain by releasing GABA. It seems that if it’s not working right, if the hippocampus is overly inhibited by too much GABA, then the circuits responsible for memory storage don't function properly. The effect could be fixed by giving a GABA antagonist, which blocks GABA from binding to synapses. Recent mouse studies have also demonstrated that mice with symptoms of Down syndrome and Alzheimer's also show improved learning and memory when given the same GABA antagonist. The findings may also have implications for general age-related cognitive decline, because age brings about a degradation in the circadian system. It’s also worth noting that the hamsters' circadian systems were put out of commission by manipulating the hamsters' exposure to light, in a technique that was compared to "sending them west three time zones." The effect was independent of sleep duration.

[688] Ruby, N. F., Hwang C. E., Wessells C., Fernandez F., Zhang P., Sapolsky R., et al.
(2008).  Hippocampal-dependent learning requires a functional circadian system.
Proceedings of the National Academy of Sciences. 105(40), 15593 - 15598.

Occasional memory loss tied to lower brain volume

A study of 503 seniors (aged 50-85) with no dementia found that 453 of them (90%) reported having occasional memory problems such as having trouble thinking of the right word or forgetting things that happened in the last day or two, or thinking problems such as having trouble concentrating or thinking more slowly than they used to. Such problems have been attributed to white matter lesions, which are very common in older adults, but all of the participants in the study had white matter lesions in their brains, and the amount of lesions was not tied to occasional memory problems. However it was found that those who reported having such problems had a smaller hippocampus than those who had no cognitive problems. This was most noteworthy in subjects with good objective cognitive performance.

[895] van Norden, A. G. W., Fick W. F., de Laat K. F., van Uden I. W. M., van Oudheusden L. J. B., Tendolkar I., et al.
(2008).  Subjective cognitive failures and hippocampal volume in elderly with white matter lesions.
Neurology. 71(15), 1152 - 1159.

Decline of mental skills in years before death

A long-running study of 288 people with no dementia, who were followed from age 70 to death, has found that there was substantial acceleration in cognitive decline many years prior to death. Time of onset and rate of terminal decline varied considerably across cognitive abilities, with verbal ability beginning its terminal decline 6.6 years prior to death, spatial ability 7.8 years before death, and perceptual speed 14.8 years before death. With verbal ability, it appeared that the decline was not due to age only, but due to health issues.

[212] Thorvaldsson, V., Hofer S. M., Berg S., Skoog I., Sacuiu S., & Johansson B.
(2008).  Onset of terminal decline in cognitive abilities in individuals without dementia.
Neurology. -

Aging impairs the 'replay' of memories during sleep

During sleep, the hippocampus repeatedly "replays" brain activity from recent experiences, in a process believed to be important for memory consolidation. A new rat study has found reduced replay activity during sleep in old compared to young rats, and rats with the least replay activity performed the worst in tests of spatial memory. The best old rats were also the ones that showed the best sleep replay. Indeed, the animals who more faithfully replayed the sequence of neural activity recorded during their earlier learning experience were the ones who performed better on the spatial memory task, regardless of age. The replay activity occurs during slow-wave sleep.

[1319] Gerrard, J. L., Burke S. N., McNaughton B. L., & Barnes C. A.
(2008).  Sequence Reactivation in the Hippocampus Is Impaired in Aged Rats.
J. Neurosci.. 28(31), 7883 - 7890.

White-matter changes linked to gait and balance problems

A three-year study involving 639 adults between the ages of 65 and 84 has found that people with severe white matter changes (leukoaraiosis) were twice as likely to score poorly on walking and balance tests as those people with mild white matter changes. The study also found people with severe changes were twice as likely as the mild group to have a history of falls. The moderate group was one-and-a-half times as likely as the mild group to have a history of falls. Further research will explore the effect of exercise.

[1004] Langhorne, P., O'Brien J., Scheltens P., Visser M. C., Wahlund L. O., Waldemar G., et al.
(2008).  Association of gait and balance disorders with age-related white matter changes: The LADIS Study.
Neurology. 70(12), 935 - 942.

Lack of imagination in older adults linked to declining memory

In a study in which older and younger adults were asked to think of past and future events, older adults were found to generate fewer details about past events — and this correlated with an impaired ability to imagine future events. The number of details remembered by older adults was also linked to their relational memory abilities. The findings suggest that our ability to imagine future events is based on our ability to remember the details of previously experienced ones, extract relevant details and put them together to create an imaginary event.

[287] Addis, D R., Wong A. T., & Schacter D. L.
(2008).  Age-related changes in the episodic simulation of future events.
Psychological Science: A Journal of the American Psychological Society / APS. 19(1), 33 - 41.

Brain systems become less coordinated with age, even in the absence of disease

An imaging study of the brain function of 93 healthy individuals from 18 to 93 years old has revealed that normal aging disrupts communication between different regions of the brain. The finding is consistent with previous research showing that normal aging slowly degrades white matter. The study focused on the links within two critical networks, one responsible for processing information from the outside world and one, known as the default network, which is more internal and kicks in when we muse to ourselves. “We found that in young adults, the front of the brain was pretty well in sync with the back of the brain [but] in older adults this was not the case. The regions became out of sync and they were less correlated with each other.” However, older adults with normal, high correlations performed better on cognitive tests. Among older individuals whose brain systems did not correlate, all of the systems were not affected in the same way. The default system was most severely disrupted with age. The visual system was very well preserved.

[1052] Andrews-Hanna, J. R., Snyder A. Z., Vincent J. L., Lustig C., Head D., Raichle M E.., et al.
(2007).  Disruption of Large-Scale Brain Systems in Advanced Aging.
Neuron. 56(5), 924 - 935.

Why neurogenesis is so much less in older brains

A rat study has revealed that the aging brain produces progressively fewer new nerve cells in the hippocampus (neurogenesis) not because there are fewer of the immature cells (neural stem cells) that can give rise to new neurons, but because they divide much less often. In young rats, around a quarter of the neural stem cells were actively dividing, but only 8% of cells in middle-aged rats and 4% in old rats were. This suggests a new approach to improving learning and memory function in the elderly.

[1077] Hattiangady, B., & Shetty A. K.
(2008).  Aging does not alter the number or phenotype of putative stem/progenitor cells in the neurogenic region of the hippocampus.
Neurobiology of Aging. 29(1), 129 - 147.

Senior’s memory complaints should be taken seriously

A study involving 120 people over 60 found those who complained of significant memory problems who still performed normally on memory tests had a 3% reduction in gray matter density in their brains. This compares to 4% in those diagnosed with mild cognitive impairment. This suggests that significant memory loss complaints may indicate a very early "pre-MCI" stage of dementia for some people.

[979] Saykin, A. J., Wishart H. A., Rabin L. A., Santulli R. B., Flashman L. A., West J. D., et al.
(2006).  Older adults with cognitive complaints show brain atrophy similar to that of amnestic MCI.
Neurology. 67(5), 834 - 842.

Alzheimer's pathology related to episodic memory loss in those without dementia

A study of 134 participants from the Religious Orders Study or the Memory and Aging Project has found that, although they didn't have cognitive impairment at the time of their death, more than a third of the participants (50) met criteria for a pathologic diagnosis of Alzheimer's disease. This group also scored significantly lower on tests for episodic memory, such as recalling stories and word lists. The results provide further support for the idea that a ‘cognitive reserve’ can allow people to tolerate a significant amount of Alzheimer's pathology without manifesting obvious dementia. It also raises the question whether we should accept any minor episodic memory loss in older adults as 'normal'.

[967] Bennett, D. A., Schneider J. A., Arvanitakis Z., Kelly J. F., Aggarwal N. T., Shah R. C., et al.
(2006).  Neuropathology of older persons without cognitive impairment from two community-based studies.
Neurology. 66(12), 1837 - 1844.

Does IQ drop with age or does something else impact intelligence?

As people grow older, their IQ scores drop. But is it really that they lose intelligence? A study has found that if college students had to perform under conditions that mimic the perception deficits many older people have, their IQ scores would also take a drop.

[234] Gilmore, G. C., Spinks R. A., & Thomas C. W.
(2006).  Age effects in coding tasks: componential analysis and test of the sensory deficit hypothesis.
Psychology and Aging. 21(1), 7 - 18.

Walking in older people is related to cognitive skills

A study of 186 adults aged 70 and older tested gait speed with and without interference (walking while reciting alternate letters of the alphabet). Walking speed was predictable from performance on cognitive tests of executive control and memory, particularly when the participant was required to recite at the same time. The findings suggest that in old age, walking involves higher-order executive-control processes, suggesting that cognitive tests could help doctors assess risk for falls. Conversely, slow gait could alert them to check for cognitive impairment.

[1812] Holtzer, R., Verghese J., Xue X., & Lipton R. B.
(2006).  Cognitive Processes Related to Gait Velocity: Results From the Einstein Aging Study..
Neuropsychology. 20(2), 215 - 223.

Immune function important for cognition

New research overturns previous beliefs that immune cells play no part in — and may indeed constitute a danger to — the brain. Following on from an earlier study that suggested that T cells — immune cells that recognize brain proteins — have the potential to fight off neurodegenerative conditions such as Alzheimer’s, researchers have found that neurogenesis in adult rats kept in stimulating environments requires these immune cells. A further study found that mice with these T cells performed better at some tasks than mice lacking the cells. The researchers suggest that age-related cognitive decline may be related to this, as aging is associated with a decrease in immune system function, suggesting that boosting the immune system may also benefit cognitive function in older adults.

[435] Ziv, Y., Ron N., Butovsky O., Landa G., Sudai E., Greenberg N., et al.
(2006).  Immune cells contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood.
Nat Neurosci. 9(2), 268 - 275.

Early life stress can lead to memory loss and cognitive decline in middle age

Age-related cognitive decline is probably a result of both genetic and environmental factors. A rat study has demonstrated that some of these environmental factors may occur in early life. Among the rats, emotional stress in infancy showed no ill effects by the time the rats reached adulthood, but as the rats reached middle age, cognitive deficits started to appear in those rats who had had stressful infancies, and progressed much more rapidly with age than among those who had had nurturing infancies. Middle-aged rats who had been exposed to early life emotional stress showed deterioration in brain-cell communication in the hippocampus.

[1274] Brunson, K. L., Kramar E., Lin B., Chen Y., Colgin L L., Yanagihara T. K., et al.
(2005).  Mechanisms of Late-Onset Cognitive Decline after Early-Life Stress.
J. Neurosci.. 25(41), 9328 - 9338.

Older people with the 'Alzheimer's gene' find it harder to remember intentions

It has been established that those with a certain allele of a gene called ApoE have a much greater risk of developing Alzheimer’s (those with this allele on both genes have 8 times the risk; those with the allele on one gene have 3 times the risk). Recent studies also suggest that such carriers are also more likely to show signs of deficits in episodic memory – but that these deficits are quite subtle. In the first study to look at prospective memory in seniors with the “Alzheimer’s gene”, involving 32 healthy, dementia-free adults between ages of 60 and 87, researchers found a marked difference in performance between those who had the allele and those who did not. The results suggest an exception to the thinking that ApoE status has only a subtle effect on cognition.

[1276] Driscoll, I., McDaniel M. A., & Guynn M. J.
(2005).  Apolipoprotein E and prospective memory in normally aging adults.
Neuropsychology. 19(1), 28 - 34.

Some brains age more rapidly than others

Investigation of the patterns of gene expression in post-mortem brain tissue has revealed two groups of genes with significantly altered expression levels in the brains of older individuals. The most significantly affected are mostly those related to learning and memory. One of the most interesting, and potentially useful, findings, is that patterns of gene expression are quite similar in the brains of younger adults. Very old adults also show similar patterns, although the similarity is less. But the greatest degree of individual variation occurs in those aged between 40 and 70. Some of these adults show gene patterns that look more like the young group, whereas others show gene patterns that look more like the old group. It appears that gene changes start around 40 in some people, but not in others. It also appears that those genes that are affected by age are unusually vulnerable to damage from agents such as free radicals and toxins in the environment, suggesting that lifestyle in young adults may play a part in deciding rate and degree of cognitive decline in later years.

[1335] Lu, T., Pan Y., Kao S-Y., Li C., Kohane I., Chan J., et al.
(2004).  Gene regulation and DNA damage in the ageing human brain.
Nature. 429(6994), 883 - 891.

Drugs to improve memory may worsen memory in some

Drugs that increase the activity of an enzyme called protein kinase A improve long-term memory in aged mice and have been proposed as memory-enhancing drugs for elderly humans. However, the type of memory improved by this activity occurs principally in the hippocampus. A new study suggests that increased activity of this enzyme has a deleterious effect on working memory (which principally involves the prefrontal cortex). In other words, a drug that helps you remember a recent event may worsen your ability to remember what you’re about to do (to take an example).

[1404] Ramos, B. P., Birnbaum S. G., Lindenmayer I., Newton S. S., Duman R. S., & Arnsten A. F. T.
(2003).  Dysregulation of protein kinase a signaling in the aged prefrontal cortex: new strategy for treating age-related cognitive decline.
Neuron. 40(4), 835 - 845.

Memory-enhancing drugs for elderly may impair working memory and other executive functions

A number of pharmaceutical companies are working on developing memory-enhancing drugs not only for patients with clinical memory impairment, but also for perfectly healthy people. Although some drugs have been found that can improve cognitive function in those suffering from impairment, the side effects preclude their use among healthy people. However, a recent study has found evidence that a well-established drug used for narcolepsy (excessive daytime sleepiness) may improve cognition in normal people, without side effects. The drug seems to particularly affect some tasks requiring planning and working memory (and in a further, as yet unpublished study, appears helpful for adults with ADHD). Whether the drug (modafinil) has anything over caffeine in terms of the cognitive benefits it brings is still debated. More interestingly, and in line with the sometimes conflicting results of these kinds of drugs on different people, the researchers suggest that the effect of drugs on cognitive function depends on the level at which the individual cognitive system is operating: if your system is mildly below par, the right brain chemical could improve performance; if it’s well below par, the same dose will have a much smaller effect; if (and this is the interesting one) it’s already operating at peak, the chemical could in fact degrade performance.

[1360] Turner, D. C., Robbins T. W., Clark L., Aron A. R., Dowson J., & Sahakian B. J.
(2003).  Cognitive enhancing effects of modafinil in healthy volunteers.
Psychopharmacology. 165(3), 260 - 269.

Magnetic resonance imaging may help predict future memory decline

A six-year imaging study of 45 healthy seniors assessed changes in brain scans against cognitive decline. They found that progressive atrophy in the medial temporal lobe was the most significant predictor of cognitive decline, which occurred in 29% of the subjects.

[490] Rusinek, H., de Santi S., Frid D., Tsui W-H., Tarshish C. Y., Convit A., et al.
(2003).  Regional brain atrophy rate predicts future cognitive decline: 6-year longitudinal MR imaging study of normal aging.
Radiology. 229(3), 691 - 696.

Mouse study suggests new approach to reducing age-related cognitive decline

Young and old mice learned that a particular tone was associated with a mild electric footshock. When the tone was immediately followed by a shock, both young and aged mice easily remembered the association on the following day. When the tone was separated from the shock by several seconds, the old mice were strongly impaired in comparison to the young mice. The researchers found highly elevated levels of a calcium-activated potassium channel, the so-called SK3 channel, in the hippocampus of old, but not of young mice. When the researchers selectively downregulated SK3 channels in the hippocampus of aged mice, the impairment in learning and memory was prevented. This suggests a new approach to treating age-related memory decline.

Blank, T., Nijholt, I., Kye, M-J., Radulovic, J. & Spiess, J. 2003. Small-conductance, Ca2+-activated K+ channel SK3 generates age-related memory and LTP deficits. Nature Neuroscience, 6(9),911–912. Published online: 27 July 2003, doi:10.1038/nn1101

Rat study offers more complex model of brain aging

A study of young, middle-aged, and aged rats, trained on two memory tasks, has revealed 146 genes connected with brain aging and cognitive impairment. Importantly, the changes in gene activity had mostly begun in mid-life, suggesting that changes in gene activity in the brain in early adulthood might set off cellular or biological changes that could affect how the brain works later in life. The study provides more information on genes already linked to aging, including some involved in inflammation and oxidative stress, and also describes additional areas in which gene activity might play a role in brain aging, including declines in energy metabolism in cells and changes in the activity of neurons (nerve cells) in the brain and their ability to make new connections with each other, increases in cellular calcium levels which could trigger cell death, cholesterol synthesis, iron metabolism and the breakdown of the insulating myelin sheaths that when intact facilitate efficient communication among neurons.

[852] Blalock, E. M., Chen K-C., Sharrow K., Herman J. P., Porter N. M., Foster T. C., et al.
(2003).  Gene Microarrays in Hippocampal Aging: Statistical Profiling Identifies Novel Processes Correlated with Cognitive Impairment.
J. Neurosci.. 23(9), 3807 - 3819.

Is a dwindling brain chemical responsible for age-related cognitive decline?

A study of what are probably the world's oldest monkeys may explain age-related mental decline. The study found that the very old monkeys' nerves in the visual cortex lose their ability to discriminate between one signal and another and that this loss was directly related to the presence of a chemical called gamma-aminobutyric acid (Gaba), a neurotransmitter that appears to dwindle in old age. If a lack of GABA is indeed responsible for the old neurons' indiscriminate firing, this problem may be simple enough to treat. There already exist drugs that increase GABA production, although these drugs have yet to be carefully tested on the elderly.

[660] Leventhal, A. G., Wang Y., Pu M., Zhou Y., & Ma Y.
(2003).  GABA and its agonists improved visual cortical function in senescent monkeys.
Science (New York, N.Y.). 300(5620), 812 - 815.

Rat studies provide more evidence on why aging can impair memory

Among aging rats, those that have difficulty navigating water mazes have no more signs of neuron damage or cell death in the hippocampus, a brain region important in memory, than do rats that navigate with little difficulty. Nor does the extent of neurogenesis (birth of new cells in an adult brain) seem to predict poorer performance. Although the researchers have found no differences in a variety of markers for postsynaptic signals between elderly rats with cognitive impairment and those without, decreases in a presynaptic signal are correlated with worse cognitive impairment. That suggests that neurons in the impaired rat brains may not be sending signals correctly.

Gallagher, M. 2002. Markers for memory decline. Paper presented at the Society for Neuroscience annual meeting in Orlando, Florida, 5 November.

An enzyme that helps us to forget

A series of experiments on genetically altered laboratory mice showed those with low levels of the enzyme protein phosphatase-1 (PP1), were less likely to forget what they had learned. This enzyme appears to be critical in helping us forget unwanted information, but it may also be partly responsible for an increase in forgetting in older adults. It was found that as the mice aged, the level of PP1 increased. When the action of PP1 was blocked, the mice recovered their full learning and memory abilities.

[1357] Genoux, D., Haditsch U., Knobloch M., Michalon A., Storm D., & Mansuy I. M.
(2002).  Protein phosphatase 1 is a molecular constraint on learning and memory.
Nature. 418(6901), 970 - 975.

Age-related changes in brain dopamine may underpin the normal cognitive problems of aging

A new model suggests why and how many cognitive abilities decline with age, and offers hope for prevention. Research in the past few years has clarified and refined our ideas about the ways in which cognitive abilities decline with age, and one of these ways is in a reduced ability to recall the context of memories. Thus, for example, an older person is less likely to be able to remember where she has heard something. According to this new model, context processing is involved in many cognitive functions — including some once thought to be independent — and therefore a reduction in the ability to remember contextual information can have wide-reaching implications for many aspects of cognition. The model suggests that context processing occurs in the prefrontal cortex and requires a certain level of the brain chemical dopamine. It may be that in normal aging, dopamine levels become low or erratic. Changes in dopamine have also been implicated in Alzheimer’s, as well as other brain-based diseases.

[1180] Mumenthaler, M. S., Jagust W. J., Reed B. R., Braver T. S., Barch D. M., Keys B. A., et al.
(2001).  Context processing in older adults: evidence for a theory relating cognitive control to neurobiology in healthy aging.
Journal of Experimental Psychology. General. 130(4), 746 - 763.

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Which 'Senior moments' may signal mental decline

October, 2011

A very large survey of older women indicates which type of memory difficulties may signal age-related cognitive impairment possibly leading to dementia.

A telephone survey of around 17,000 older women (average age 74), which included questions about memory lapses plus standard cognitive tests, found that getting lost in familiar neighborhoods was highly associated with cognitive impairment that might indicate Alzheimer’s. Having trouble keeping up with a group conversation and difficulty following instructions were also significantly associated with cognitive impairment. But, as most of us will be relieved to know, forgetting things from one moment to the next was not associated with impairment!

Unsurprisingly, the more memory complaints a woman had, the more likely she was to score poorly on the cognitive test.

The 7 memory lapse questions covered:

  • whether they had recently experienced a change in their ability to remember things,
  • whether they had trouble remembering a short list of items (such as a shopping list),
  • whether they had trouble remembering recent events,
  • whether they had trouble remembering things from one second to the next,
  • whether they had difficulty following spoken or written instructions,
  • whether they had more trouble than usual following a group conversation or TV program due to memory problems,
  • whether they had trouble finding their way around familiar streets.

Because this survey was limited to telephone tests, we can’t draw any firm conclusions. But the findings may be helpful for doctors and others, to know which sort of memory complaints should be taken as a flag for further investigation.



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Memory loss in old age the price we pay for a large brain & a long life?

September, 2011

Chimpanzee brains don’t shrink with age as humans’ do. It may be that cognitive impairment and even dementia are our lot because we work our brains too hard for too long.

Comparison of 99 chimpanzee brains ranging from 10-51 years of age with 87 human brains ranging from 22-88 years of age has revealed that, unlike the humans, chimpanzee brains showed no sign of shrinkage with age. But the answer may be simple: we live much longer. In the wild, chimps rarely live past 45, and although human brains start shrinking as early as 25 (as soon as they reach maturity, basically!), it doesn’t become significant until around 50.

The answer suggests one reason why humans are uniquely vulnerable to Alzheimer’s disease — it’s all down to our combination of large brain and long life. There are other animals that experience some cognitive impairment and brain atrophy as they age, but nothing as extreme as that found in humans (a 10-15% decline in volume over the life-span). (Elephants and whales have the same two attributes as humans — large brains and long lives — but we lack information on how their brains change with age.)

The problem may lie in the fact that our brains use so much more energy than chimps’ (being more than three times larger than theirs) and thus produce a great deal more damaging oxidation. Over a longer life-span, this accumulates until it significantly damages the brain.

If that’s true, it reinforces the value of a diet high in antioxidants.


[2500] Sherwood, C. C., Gordon A. D., Allen J. S., Phillips K. A., Erwin J. M., Hof P. R., et al.
(2011).  Aging of the cerebral cortex differs between humans and chimpanzees.
Proceedings of the National Academy of Sciences. 108(32), 13029 - 13034.




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