Gene variant may protect memory and thinking skills in older people

Studies on the roundworm C. elegans have revealed that the molecules required for learning and memory are the same from C. elegans to mammals, suggesting that the basic mechanisms underlying learning and memory are ancient, and that this animal can serve as a testing ground for treatments for age-related memory loss. Intriguingly, a comparison of two known regulators of longevity — reducing calorie intake and reducing activity in the insulin-signaling pathway (achieved through genetic manipulation) — has found that these two treatments produce very different effects on 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 largest ever trial of fish oil supplements has found no evidence that they offer benefits for cognitive function in older people. The British study enrolled 867 participants aged 70-80 years, and lasted two years. After two years, those receiving fish oil capsules had significantly higher levels of omega-3 fatty acids in their blood than those receiving placebo capsules. However, cognitive function did not decline in either group over the period. The researchers caution that it may be that more time is needed for benefits to show.

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.

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.

A new study provides more support for the idea that cognitive decline in older adults is a product of a growing inability to ignore distractions. Moreover, the study, involving 21 older adults (60-80) shown random sequences of pictures containing faces and scenes and asked to remember only the scene or the face, reveals that being given forewarning about which specific pictures would be relevant (say the second, or the fourth) did not help.

An imaging study involving 79 volunteers aged 44 to 88 has found lower volumes of gray matter and faster rates of decline in the frontal and medial temporal lobes of those who ranked high in neuroticism traits, compared with those who ranked high in conscientious traits. These are brain regions particularly affected by aging. The idea that this might occur derived from the well-established effects of chronic stress on the brain. This is the first study to investigate whether the rate and extent of cognitive decline with age is influenced by personality variables.

Following on from studies showing that a Mediterranean-like diet may be associated with a lower risk of Alzheimer's disease and may lengthen survival in people with Alzheimer's, a six-year study of 712 New Yorkers has revealed that those who were most closely following a Mediterranean-like diet were 36% less likely to have brain infarcts (small areas of dead tissue linked to thinking problems), compared to those who were least following the diet. Those moderately following the diet were 21% less likely to have brain damage.

A long-running study involving 930 70-year-old Swedish men has found that those who were among the bottom 25% on the Trail Making Test B were three times more likely to have a stroke or a brain infarction compared to those in the top 25%. Performance on the Trail Making Test A and the MMSE did not predict brain infarction or stroke. Test B measures the ability to execute and modify a plan, while Test A measures attention and visual-motor abilities, and the MMSE is a standard test of general cognitive decline.

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.