Wisconsin Card Sorting Task (WCST) errors and cerebral blood flow in obsessive-compulsive disorder (OCD)

We compared Wisconsin Card Sorting Task (WCST) performance in 19 obsessive-compulsive disorder (OCD) patients and 19 individually matched healthy controls. Measures of intelligence and mood were taken into account for all participants. Within the patient group, factors such as duration and severity of symptoms (as assessed using the Yale-Brown Obsessive-Compulsive Scale, Y-BOCS) were considered. We explored the relationship between OCD WCST errors and regional cerebral blood flow (rCBF) on brain dedicated, high resolution, single photon emission tomography (SPET). We used uptake of Tc-99m-hexamethylpropylamine oxime (HMPAO) on SPET to estimate rCBF, and regional values were quantified as ratios of cerebellar blood flow. WCST results confirmed OCD patients were significantly impaired when compared with age-and sex-marched healthy volunteers. Patients made significantly more trials, more perseverative errors, and more null-sorts. OCD patients Y-BOCS 'obsessive' subtotal significantly correlated with many WCST errors. Furthermore OCD WCST null-sorts correlated significantly with SPET OCD left inferior frontal cortical rCBF (r(18) = .47, p = .05) and left caudate rCBF (r(18) = .72, P = .01). The implications of these findings are discussed in the context of other studies which examine functional imaging and neuropsychology in OCD.