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.

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.

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.

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.

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. Extraversion, also investigated, had no effect. The study does not, however, rule out the possibility that it is reduction in brain tissue in these areas that is affecting personality. There is increasing evidence that people tend to become more neurotic and less conscientious in early-stage Alzheimer's.