Late-life dementias, especially Alzheimer disease, have profound effects on aging individuals. Demographic trends suggest that without interventions to effectively prevent or treat Alzheimer disease and related dementias, societies that enjoy the benefits of longevity could be overwhelmed and dramatically changed by the challenges and burdens of large numbers of cognitively impaired older persons. According to a recent review, "If the pace of increase in life expectancy in developed countries over the past two centuries continues through the 21st century, most babies born since 2000 in France, Germany, Italy, the UK, the USA, Canada, Japan, and other countries with long life expectancies will celebrate their 100th birthdays."¹ In general, prevalence rates for dementia are estimated to double every 5 years after age 65. Rates of dementia in community studies increase from 30% for persons aged 85 through 89 years to 50% . . . [Full Text of this Article]