Abstract

Objective: Cognitive switching, the ability to shift between mental sets, is an executive function requiring flexible application of lower-level attention and processing speed abilities. More difficult switching trials on the Delis-Kaplan Executive Function System (D-KEFS) tests (i.e., color-word interference (CWI) and trails) are designed to tap into these higher order executive functions. An atypical pattern of performance was noted in a subset of individuals who perform faster on the theoretically more difficult switching trial than the standard inhibition trial of the CWI. This study examines the cognitive underpinnings which might be used to further explore the unexpected patterns of performance. Method: Archival records from 312 clinical referrals (Age, M = 65.2; SD = 10.9) seen for a neuropsychological evaluation as part of routine care in an outpatient dementia and movement disorders clinic were sampled. Participants completed a standard battery of tests which included cognitive measures of attention, executive functioning, and working memory. Zero-order correlations were calculated among primary raw scores. Results: Digit Span backward demonstrated a stronger correlation with CWI inhibition/switching (r = −0.43, p < 0.001) as compared to CWI inhibition (r = −0.35, p < 0.001). A similar pattern was found with Digit Span backward and Trails switching (r = −0.43, p < 0.001) as compared to Trails number sequencing (r = −0.29, p < 0.001). Conclusion(s): Results confirm that the CWI switching task introduces greater working memory demands over and above standard response inhibition, which for individuals with strong working memory abilities, may account for the atypical pattern of performance noted in clinical practice.