In a critical review of studies of training programs for elderly
individuals with cognitive deficits, the author found that decrements of
cognitive function with aging are not small. In 70-year-old normal
individuals, losses are on the order of 20%-40%, depending on the process
tested and the testing method. Although long-term effects are poorly
documented, training programs for normal elderly individuals have been
shown to improve selected cognitive processes, including memory, to about
the same degree that some of these processes decline with aging.