Aging is not the cause of so-called “senior moments”, mild memory lapses often experienced by older people. Robert S Wilson, PhD a neuropsychologist at Rush University Medical Center, and colleagues studied data of 354 Catholic nuns, priests, and brothers who had annual clinical evaluations for up to 13 years and who underwent brain autopsy after death. The annual clinical evaluations included detailed testing of cognitive function. The researchers found that cognitive function gradually declined with age until the last four to five years of life, when it declined rapidly. As the researchers expected, pathologic lesions, such as neurofibrillary tangles, cerebral infarction, and Lewy bodies, were related to rapid cognitive decline. However, results also showed that the presence of lesions was strongly predictive of mild changes in cognitive function, such as memory lapses. Indeed, the presence of Lewy bodies and cerebral infarction doubled the rate of gradual memory decline, whilst virtually no decline in cognitive function was noted in participants who were free of lesions. “The very early mild cognitive changes once thought to be normal aging are really the first signs of progressive dementia, in particular Alzheimer’s disease.” said Dr Wilson. “The pathology in the brain related to Alzheimer’s and other dementias has a much greater impact on memory function in old age than we previously recognized. Our study finds that Alzheimer’s disease and related dementias are the root cause of virtually all loss of cognition and memory in old age. They aren’t the only contributing factors; other factors affect how vulnerable we are to the pathology and to its effects. But the pathology does appear to be the main force that is driving cognitive decline in old age.”
