brain atrophy

Obesity has been linked to cognitive decline, but a new study involving 300 post-menopausal women has found that higher BMI was associated with higher cognitive scores.

Of the 300 women (average age 60), 158 were classified as obese (waist circumference of at least 88cm, or BMI of over 30). Cognitive performance was assessed in three tests: The Mini-Mental Statement Examination (MMSE), a clock-drawing test, and the Boston Abbreviated Test.

In a small study, 266 older adults with mild cognitive impairment (aged 70+) received a daily dose of 0.8 mg folic acid, 0.5 mg vitamin B₁₂ and 20 mg vitamin B₆ or a placebo for two years. Those treated with B vitamins had significantly lower levels of homocysteine at the end of the trial (high homocysteine is a known risk factor for age-related cognitive decline and dementia). Moreover, this was associated with a significantly slower rate of brain shrinkage.

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.

A study involving 105 people with Alzheimer's disease and 125 healthy older adults has compared cognitive function and brain shrinkage in those aged 60-75 and those aged 80+.

The brain tends to shrink with age, with different regions being more affected than others. Atrophy of the hippocampus, so vital for memory and learning, is associated with increased risk of developing Alzheimer’s, and has also been linked to depression.

For the first time in 27 years, clinical diagnostic criteria for Alzheimer's disease dementia have been revised, and research guidelines updated. They mark a major change in how experts think about and study Alzheimer's disease.

The updated guidelines now cover three distinct stages of Alzheimer's disease:

Imaging the brains of 10 young men who were long term users of ecstasy and seven of their healthy peers with no history of ecstasy use has revealed a significantly smaller hippocampus in those who used ecstasy. The overall proportion of gray matter was also lower, suggesting the effects of ecstasy may not be restricted to the hippocampus.

Both groups had used similar amounts of recreational drugs other than ecstasy, and drank alcohol regularly. The ecstasy group had not taken ecstasy for more than two months before the start of the study on average.

A two-year study involving 53 older adults (60+) has found that those with a mother who had Alzheimer's disease had significantly more brain atrophy than those with a father or no parent with Alzheimer's disease. More specifically, they had twice as much gray matter shrinkage, and about one and a half times more whole brain shrinkage per year.

This atrophy was particularly concentrated in the precuneus and parahippocampal gyrus. Those with the APOE4 gene also had more atrophy in the frontal cortex than those who didn’t carry the ‘Alzheimer’s gene’.

Shrinking of the frontal lobe has been associated with age-related cognitive decline for some time. But other brain regions support the work of the frontal lobe. One in particular is the cerebellum. A study involving 228 participants in the Aberdeen Longitudinal Study of Cognitive Ageing (mean age 68.7) has revealed that there is a significant relationship between grey matter volume in the cerebellum and general intelligence in men, but not women.

A study involving 171 sedentary, overweight 7- to 11-year-old children has found that those who participated in an exercise program improved both executive function and math achievement. The children were randomly selected either to a group that got 20 minutes of aerobic exercise in an after-school program, one that got 40 minutes of exercise in a similar program, or a group that had no exercise program. Those who got the greater amount of exercise improved more.