Cognitive Activity and Risk of Alzheimer’s Disease

The title of this post is identical to the titled of an article by Robert S. Wilson and David A. Bennet in “Current Directions in Psychological Science”, 2003, 87-91.  HM expresses his sincere apology for not reviewing this article earlier as it is central to the theme and purpose of the healthy memory blog.  HM is also livid that he has not seen this article frequently cited.

Wilson and Bennett begin their article by noting that the idea that frequent intellectual activity might help one’s mental faculties in old age predated the Roman empire.  Then they begin their review.  The examine three issues bearing upon cognitive activity and the risk of Alzheimer’s disease.  They first consider whether cognitive activity accounts for the association between education and occupational attainment and risk of Alzheimer’s disease.  They next address the behavioral mechanisms underlying the association.  Then they discus neurobiological mechanisms underlying the association.

They found that cognitive activity did decrease the risk of Alzheimer’s disease.  What is especially interesting is that even when educational level and occupational prestige were controlled for statistically, cognitive activity appeared to be the primary factor bearing upon decreased risk for Alzheimer’s disease.

As for the behavioral mechanisms reducing the risk for Alzheimer’s disease, they note that cognitively active people begin old age with better cognitive skills than less cognitively active people and these skills might be less subject to decline.  They cite two studies that support these contentions.

They address the benefits of cognitive training programs, but note that these benefits appear to be specific to the skill(s) that were trained.  They also cite studies that have found that frequency of cognitive activity, but not of physical activity is related to risk of Alzheimer’s disease.  Cognitive activity appears to be primarily associated with reduced decline in processing skills like perceptual speed and working memory.  These skills are involved in nearly all kinds of intellectual activity, so it makes sense that they would  benefit the most from the frequency of such activity.

Regarding neurobiological  mechanisms underlying the association, they discuss two possibilities.  The first is that cognitive activity directly slows the build up of the neuritic plaques and neurofibrillary tangles  that define the disease.  The second is that cognitive activity  affects the risk of Alzheimers by affecting the development or maintenance of the interconnected neural systems that underlie different forms of cognition.

The data clearly indicate that the second explanation regarding the benefits of cognitive activity is accurate.  A given amount of Alzheimer’s disease pathology was associated with less cognitive impairment in a person with more education than in a person with less education.  In other words these data suggest that variables related to education, or variables related to education such as cognitive activity affect the risk of cognitive impairment and dementia by somehow enhancing the brain’s capacity to tolerate Alzheimer/s disease pathology.

In their conclusion they write, “Because few identifiable  risk factors for Alzheimer’s disease have been identified, this area of research has important public-health implications.  Much remains to be learned, however.”

A central questions is when during the life span is cognitive activity important.  HM encourages everyone to be cognitively active, but can it start too late to be beneficial.  Absent the necessary research, the answer should be that it is never too late.  But a larger question is why is there so little research activity on this topic.  The cynical, but HM believes accurate, answer is that money is in drug treatments targeted at the defining physical symptoms, and that cognitive activity is painful and will be avoided by large numbers of people.

Perhaps these findings were not available when this paper was written, but the study makes no mention of the research that has found the brains of cadavers full of the defining plaques and tangles of the disease, whose owners of the brains never exhibited any of the behavioral or cognitive symptoms of the disease when they were alive.

The statement is frequently made that there is no current cure for Alzheimer’s.  That cure is being sought in the prevention or curing of the physical symptoms.  Although there might not be a cure, there does appear to be an effective method of precluding the cognitive and behavioral manifestations—cognitive activity.

And that is why the healthy memory blog places such heavy emphasis on growth mindsets.  Mnemonic techniques is one of the blogs categories.  Mnemonic techniques, in addition to improving memory are ideal types of cognitive activity.  Mental imagery is central to many of these techniques, so they involve both hemispheres of the brain.

© Douglas Griffith and, 2016. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and with appropriate and specific direction to the original content.


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