The Relation of Neuropsychological Measures to Levels of Cognitive Functioning in Elderly Individuals: A Discriminant Analysis Approach

Abstract

This study addresses the question of which tests in a comprehensive neuropsychologicaI test battery best discriminate normal, mildly, and moderate to severely cognitiveIy impaired older participants. Sixty-six geriatric participants were administered a battery of neuropsychological tests as part of an outpatient geriatric clinic evaluation. A discriminant analysis procedure using a consensus rating of global cognitive impairment as the grouping variable was employed to analyze the data. From 15 neuropsychological test measures, five representing the domains of learning and memory, visuospatial and executive functioning were identified as the best predictors of level of cognitive impairment. Findings demonstrate the utility of discriminant function analysis (DFA) procedures for developing reduced-length cognitive batteries that accurately classify participants in terms of levels of cognitive impairment and identify mild dysfunction in participants at risk of cognitive impairment. Further cross-validation studies are needed to confirm the utility of these more circumscribed batteries.