Attention and vigilance functions in normal aging

Clinical observation and considerable research have documented that a slowing of cognitive processing occurs in many healthy older persons. The neuropsychological characterization of this slowing, however, remains unclear, as does its neuroanatomic basis. In a preliminary attempt to help clarify this issue, we conducted two studies with healthy older individuals to evaluate whether declines in immediate and/or sustained attention appear with advancing age. In Study I, 166 subjects aged 50-69 and 70-90 were given several standard tests of immediate attention. No major differences in simple attentional function emerged. In Study II, 38 subjects in the same age ranges were administered tests of sustained attention. Significant differences between groups were seen on a digit cancellation task, despite similar performances on other measures requiring visual scanning and psychomotor speeded responses. The results of the two studies suggest that whereas simple attention tends to remain stable with aging, sustained attention appears to decline after the age of 70. This factor likely contributes to the general slowing of cognition often reported in the elderly, and may be associated with specific age-related neuroanatomic changes.