Evaluating elements of executive functioning as predictors of instrumental activities of daily living (IADLs)

OBJECTIVE Executive functioning has been repeatedly linked to the integrity of instrumental activities of daily living (IADL). The present study examined the association of multiple executive functioning elements (i.e., working memory, generation, inhibition, planning, and sequencing) to IADLs among an older adult cohort at risk for future cognitive and functional decline. METHODS Seventy-two participants with prevalent but stable cardiovascular disease completed a neuropsychological protocol assessing multiple elements of executive functioning, including COWA, PASAT, DKEFS Color-Word Interference Test, DKEFS Trail-Making Test, DKEFS Tower Test, and Ruff Figural Fluency Test. Reliable informants completed a measure of IADLs. RESULTS Stepwise logistic regression selected a model involving a single significant predictor, a measure of inhibition (i.e., DKEFS Color-Word Interference Test), which had a significant regression coefficient. Subsequent correlation analyses confirmed an association between the inhibition measure and multiple IADL items. Inter-item comparisons among the IADLs revealed significant differences, such that telephone use and laundry were significantly more intact than most other IADLs while shopping and housekeeping were most compromised. CONCLUSIONS Our data suggest that inhibition, also known as susceptibility to interference, is most strongly related to IADL impairment among patients at risk for future cognitive and functional decline.