The role of spatial store and executive strategy in spatial working memory: a comparison between patients with obsessive-compulsive disorder and controls

Introduction: Patients with obsessive-compulsive disorder (OCD) showed impaired spatial working memory (SWM). We evaluated whether patients and healthy controls (HCs) differed in spatial store capacity, and whether they differed in the relative weight of spatial store capacity and/or executive strategy in SWM. Methods: Thirty inpatients with OCD and 31 age- and education-matched HCs underwent the CANTAB SWM, SRM (a measure of spatial store). The severity of OC symptoms was assessed using the Y-BOCS. Statistical significance: alpha = 0.05. Results: Patients showed poorer performance than HCs in all neuropsychological outcomes. Both poorer SRM and SWM strategy were significantly associated with poorer SWM in the entire sample. No significant interaction between SRM and Group was found, while a significant interaction between SWM strategy and Group emerged; in patients the magnitude of this association was approximately twofold larger than in HCs. OC symptom severity did not correlate with neuropsychological performance. Conclusions: Patients with OCD had poorer spatial store capacity than HCs. However, the weight of poorer executive strategy in SWM was greater in patients than HCs, whereas the weight of spatial store was similar. We provided a direct evidence that an impairment in the executive component might be the crucial factor influencing the poorer SWM of these patients.