Left frontal lobe contributions to concept formation: A quantitative MRI study of performance on the Delis–Kaplan Executive Function System Sorting Test

Abstract

This study examined relationships between lobar volumes and performance on the Delis–Kaplan Executive Function System (D-KEFS) Sorting Test, a standardized measure of concept formation. There were 89 participants: 19 patients with probable Alzheimer's disease, 25 patients with frontotemporal dementia, 13 patients with semantic dementia, 12 patients with progressive nonfluent aphasia, 9 patients with probable progressive supranuclear palsy, 2 patients with possible progressive supranuclear palsy, and 9 healthy participants. We used BRAINS2 software to generate volumes of the right and left frontal, temporal, and parietal lobes. Multiple regression analysis indicated that, after controlling for Mini-Mental State Examination scores, intracranial volume, and demographic variables, only the left frontal lobe significantly predicted performance on the D-KEFS Sorting Test.

Keywords:

• Delis–Kaplan Executive Function System
• Frontal lobes
• Executive functioning
• Card sorting
• Concept formation

This research was supported in part by National Institute of Aging Grants AG019724, AG02351, AG12435, AG22983, The State of California Alzheimer's Disease Research Center of California (ARCC) Grant 01-154-20, and the Hillblom Foundation Grant 2002/2F. Disclosure: D. C. Delis and J. H. Kramer are coauthors of the D-KEFS Sorting Test and receive royalties from the test.