Clock drawing is sensitive to executive control: A comparison of six methods

We examined six clock-drawing task (CDT) scoring systems relative to the Ex ecutive Interview (EXIT25, a measure of Executive Control Function [ECF]) a nd the Mini-Mental State Exam (MMSE). Subjects included n = 33 National Ins titute of Neurological, Communicative Disorders, and Stroke "probable" Alzh eimer's disease (AD) cases and n = 52 independent living controls. AD cases and controls differed on the EXIT25, MMSE, and all CDTs. All CDTs were sig nificantly correlated with the EXIT25 (ranging from r = .56 to r = .78). Th ese associations generally persisted after adjusting for Age, Education, an d MMSE scores. In backwards stepwise linear multivariate regression models, only CLOX An Executive Clock-Drawing Task scores contribute significantly to EXIT25 scores (R-2 = .68) and MMSE scores (R-2 = .72). Clock drawing dra ws upon both executive and general cognitive resources. CLOX explains incre mentally more variance in ECF than other CDTs.