Lifelong Mental Activity and the Amyloid Plaque of Alzheimer's
An Active Mind Delays Alzheimer's
Scientists have long known that people who live their lives undertaking activities that challenge their minds can prevent or delay the onset of Alzheimer's disease. In one study, published in the June 2003 issue of "The New England Journal of Medicine," researchers looked at a group of senior citizens aged 75 and older. They found that over the course of 20 years those who frequently read, played board games such as chess, did crossword puzzles, played cards or musical instruments or did other things requiring mental activity, were 66% less likely to get Alzheimer's disease relative to those who were not so mentally active. They further found that physical activity such as walking or climbing stairs had no effect on the incidence of Alzheimer's disease. Other studies have confirmed the connection between frequent mental stimulation and delay/prevention of Alzheimer's disease.
Mental Activity and the Accumulation of Amyloid Plaque
Intensive research into the causes and physiology of Alzheimer's disease has revealed the presence of clumps of a sticky substance called amyloid plaque in the brains of people who die of Alzheimer's disease. This plaque arises from the enzymatic breakdown of a large protein in the brain called amyloid precursor protein. Fragments from the breakdown of this protein accumulate as aggregates in the spaces between the nerve cells in the brain. These aggregates become sticky plaques that disrupt the flow of nerve signals from one cell to another leading to the eventual death of nerve cells and the observed symptoms of Alzheimer's disease. A combination of genetic and environmental factors are involved in causing the formation of these amyloid plaques.
Now, scientists have evidence that correlates a person's level of participation in mentally stimulating activities over his/her lifetime with the accumulation of amyloid plaque in the brain. In a paper published online in January 2012 in the "Archives of Neurology," researchers provided data that for the first time links mental activity to the build up of the amyloid plaque of Alzheimer's disease. Study subjects consisted of three groups: 65 healthy adults with an average age of 76, 10 Alzheimer's patients with an average age of 75 and 11 young people (average age 25) to act as a control. The researchers followed the subjects for about five years, and used PET scans to assay plaque accumulation in the brain. The healthy subjects filled out a questionnaire at the beginning of the study in which they detailed their participation in mentally stimulating activities over the course of their lives starting at age 6. When the researchers put the PET scan and questionnaire data together, it became clear that subjects who ranked in the top one-third in terms of amount of participation in mentally stimulating activity had plaque accumulation comparable to the younger controls. Those in the bottom one-third had plaque accumulation comparable to that of the Alzheimer's patients. This connection between greater participation in mentally stimulating activities and significantly lower plaque accumulation was independent of physical activity, gender and level of education.
In commenting on the results of this study, the researchers point out that they believe the effect of mental activity on amyloid plaque levels is greater for people who are active over their whole lifetime, particularly during youth and in middle age. A high level of mental activity starting in old age is not nearly as effective.
Chess and Alzheimer's
Would you consider yourself to be a person with a high level of participation in mentally stimulating activities?
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