

Background: Epidemiological studies indicated that compulsive ordering and arranging, and a preoccupation with symmetry are common presentations of obsessive-compulsive disorder (OCD). Objective: The goal of the current study was to develop and obtain preliminary psychometric data for the objective and quantitative measurement of symmetry and arrangement symptoms in OCD. Method: Twenty-eight normal volunteers were administered computer based assessment tasks with 4 different conditions with or without target and distraction. Primary dependent variables included several indices of time and click of arranging behaviors. Construct validity for the task was examined by comparing the novel behavioral measures with standardized measures such as Symmetry, Ordering and Arranging Questionnaire (SOAQ), Obsessive Compulsive Inventory-Revised (OCI-R), Beck depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Quality of life scale (QOL). Result: We found significant positive correlation between behavioral parameters and standardized scales for OCD (total time and SOAQ: r2=0.623, P<0.001; total number of clicks and ‘ordering’ subscore of OCI-R: r2=0.541, P<0.01). There was no significant correlation between behavioral parameters and other scales measuring constructs less relevant to ordering and arranging. A main effect of target only was observed on behavioral parameters. Conclusion: This study therefore provides preliminary data to support the use of this task as a novel behavioral measure of compulsive symptoms related with symmetry, ordering and arranging.