Executive functioning mediates the link between other neuropsychological domains and daily functioning: a Project FRONTIER study

Background: The purpose of this study was to examine the mediating impact of executive functioning on the link between other neuropsychological domain scores and informant-based rating of functional status. Methods: Data on 181 participants were analyzed from an ongoing epidemiological study of rural health, Project FRONTIER (mean age = 64.6 +/- 13.8 years, 69% women, 42% Mexican American). Executive functioning was assessed by the EXIT25 and other neuropsychological domains were assessed via the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Informant-based rating of functional status was assessed via the Clinical Dementia Rating Scale sum of boxes scores (CDR SB). Results: RBANS Index scores were each significantly (p < 0.05) related to CDR SB scores and EXIT25 scores. EXIT25 score was a significant partial mediator of the link between four RBANS indices (Immediate Memory, Attention, Visuospatial/Construction, Delayed Memory) and CDR SB scores, and a complete mediator of the fifth index (Language). Conclusion: Executive functioning is a mediator of the link between other neuropsychological domains and daily functioning. Neuropsychological assessments that do not measure executive functioning will provide only a partial clinical picture with adults and elders.