UC Irvine

The oldest-old (people over age 90) are the fastest growing segment of the population in Asia and most of the world. With age as the strongest risk factor for dementia and AD, the oldest-old portend enormous public health, economic and social challenges. Investigations of cognition in this age group can provide clues to our understanding of dementia and cognitive loss at all ages. Intriguingly, about half of non-demented oldest-old have high levels of AD pathology at autopsy, but nonetheless maintain good cognitive performance during life. These individuals appear resilient to the deleterious effects of these neuropathologic changes. Conversely, approximately half of demented individuals in this age group are deemed to have insufficient amounts of any neuropathologic changes factor and clinical pathological investigations from The 90+ Study, a longitudinal population-based study of more than 1600 oldest-old based in Southern California, USA, will be presented. The impact of reducing or eliminating Alzheimer disease in this age group will be quantified. Finally, Preventing Cognitive Decline and Dementia, a recent report from the National Academies of Science, Engineering and Medicine, will be summarized. Growing understanding of AD and other dementia-associated brain changes will provide strategies to maintain memory and cognitive abilities at all ages.