Cognitive ability and inconsistency in reaction time as predictors of everyday problem solving in older adults




Burton, Catherine Louisa

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The purpose of the present investigation was to examine whether across-trials inconsistency in reaction time (RT), in addition to level of cognitive performance, is predictive of older adults’ performance on a measure of everyday problem solving through a series of three investigations. A sample of community dwelling non-demented older adults, ranging in age from 62 to 92, completed the Everyday Problems Test (EPT), a measure of everyday problem solving that indexes instrumental activities of daily living (IADLs). Performance on the EPT varied according to age, cognitive status, and education, and was significantly predicted by measures of global cognitive status, cognitive decline, and various basic cognitive abilities (i.e., speed of processing, fluid abilities, episodic memory, crystallized abilities). Both inconsistency and mean latencies on measures of RT were found to be significantly associated with concurrent EPT performance, such that slower and more inconsistent RTs were associated with poorer everyday problem solving abilities. Finally, inconsistency in RT made a unique contribution in predicting performance on the EPT two years later, over and above age, education, and various basic cognitive abilities. Structural equation modeling analyses indicated that the relationship between inconsistency in RT and future EPT performance was mediated by fluid and crystallized abilities. Neither inconsistency nor cognitive functioning were significantly associated with changes in EPT performance across two years. Examination of the relationships between IADL functioning, as assessed through self- and informant-report, and inconsistency and basic cognitive abilities demonstrated that everyday problem solving and measures of IADLs tap into related but distinct constructs. The overall pattern of results obtained lends support to the idea that inconsistency in RT represents a behavioural marker of neurological dysfunction. In addition, the present investigation is the first to suggest a relationship between inconsistency in RT and real-world outcomes, such as everyday problem solving and IADL functioning.



inconsistency, reaction time, everyday problem solving, instrumental activities of daily living, cognitive ability, aging