Investigating the relationship between specific executive functions and functional decline among community-dwelling older adults: results from a prospective pilot study

Background: As cognitive functions and, more specifically, executive functions (EF) seem to influence autonomy among the elderly, we investigated the role of each of the five EF sub-components (inhibition, spontaneous flexibility, reactive flexibility, planning, and updating in working memory) for the risk of functional decline. Method: A total of 137 community-dwelling participants over 75 years of age were included in a prospective cohort study and assigned to three groups: individuals with neuro-degenerative cognitive disorders, those having cognitive disorders with non-degenerative aetiology, and a control group without any cognitive problems. We measured each EF sub-component and assessed functional decline by evaluating basic (b-ADL) and instrumental activities of daily living (i-ADL) at baseline and 6 months later. We conducted three separate multiple logistic regression models to examine the extent to which the five EF facets predicted overall functional decline at the end of the follow-up period. Results: We found that people who exhibited a decline in b-ADLs or/and i-ADLs over 6 months had worse perfor- mance on inhibition and two flexibility tasks than those who did not experience a decline. The results suggest that decliners have more difficulties in managing unforeseen events. Inhibition and updating in working memory pre- dicted a decline in b-ADL while spontaneous and reactive flexibilities predicted a decline in i-ADL. Conclusion: In our sample, specific executive dysfunctions were associated with a decline in functional status. With respect to the risk of decline in b-ADL, deficits in inhibition may represent a risk factor, as it regulates over-learned activities. Bothtypes of flexibility, which allow the shifting and generating of adaptive responses, predicted decline in i-ADL. In sum, paying more attention to particular EF profiles would help clinicians to anticipate some aspects of functional decline.