Inhibitory changes after age 60 and their relationship to measures of attention and memory.

This study examined the relationship between age and inhibitory functioning within a sample of older adults ranging in age from 60 to 85 years old. On the basis of earlier research, and confirmed by factor analysis, measures typically referred to as frontal lobe tasks were used as measures of inhibitory functioning. Findings demonstrated that inhibitory processes continued to decline with advancing age within the older sample. In addition, the role of inhibition in age-related performance deficits on a verbal list learning measure and an attention measure was examined. Hierarchical regression analyses showed that inhibition accounted for a significant proportion of the age-related variance on the two cognitive measures, whereas measures of reading speed accounted for a smaller proportion of the variance. In addition, when inhibition was first covaried out, reading speed no longer accounted for a significant proportion of the age-related variance. It is argued that inhibition is an important contributor to age-related performance decrements in cognition.