In August 2008, Neurobiology of Aging published the interesting observations of den Dunnen, et al. of the post-mortem body of a 115 year old woman, which showed no evidence of atherosclerosis. Her brain was devoid of the amyloid plaques characteristic of Alzheimer’s disease and neural density was on par with healthy persons 60-80 year of age. Pre-mortem psychological testing of the woman at ages 112 and 115 found her cognitive abilities to be well above average, scoring better than the average healthy 60-75 year old. Indeed, the authors describe her repeatedly as “alert and attentive” and interpret their findings as follows:
“Our observations indicate that the limits of human cognitive function extend far beyond the range that is currently enjoyed by most individuals and that brain disease, even in supercentenarians, is not inevitable.”
This lack of pathophysiology and retention of mental abilities in old age is encouraging and should motivate us to take the best care of our bodies as possible, so that our latest years remain some of our best ones. However, it should be noted that while the woman’s Mini Mental State Examination (MMSE) score only dropped one point (from 27 to 26) from age 112 to 115, and her immediate recall ability and orientation did not deteriorate, she performed worse at age 115 at more complex tasks such as those testing working memory and mathematical calculation skills. In addition, though no amyloid deposits were found in her brain, the other hallmark of AD, neurofibrillary tangles, were observed in the medial temporal lobe, possibly indicating the very earliest stages of AD.
While brain disease at 100 may not be inevitable, and we will certainly enjoy our healthy lives as long as we have them, ultimately even the healthiest supercentenarians succumb to the progression of aging and its entourage of aging-related diseases. Cracking the mystery of aging will require multiple approaches, and studies of the oldest-lived among us provide clues as to which lines of inquiry are the best leads to follow.