Aging and cognition.

A substantial portion of elderly people experience declines in mental capacities. While these changes are often attributable to serious dementing illnesses such as Alzheimer's disease, a surprising number result from apparently normal aging processes. The effects of senescence on cognition may be indirect (i.e., gait instability leading to falling and subsequent head trauma); however, they may have a more direct and subtle impact on the brain. The evidence available to date suggests that only a limited range of cognitive domains are susceptible to these aging effects. Perhaps the most important are short-term memory functions. The specific character of these and other age-related cognitive deficits are reviewed.