2017 Volume 9 Issue 1 Pages 42-49
Few studies have evaluated prefrontal cortex (PFC) activity using near-infrared spectroscopy (NIRS) during the performance of multiple neuropsychological tasks in patients with obsessive-compulsive disorder (OCD). The aims of the current study were 1) to examine the patterns of hemodynamic changes in PFC regions, as measured by NIRS, during various neuropsychological tasks in OCD patients and normal controls, and 2) to clarify the relationship between PFC activity and other comorbid symptoms. Fourteen patients with OCD diagnosed using DSM-5, and 16 age- and gender-matched healthy volunteers were enrolled in this study. Brain activity was measured using NIRS during the administration of several neuropsychological test batteries. We compared hemodynamic changes and psychometric and executive functioning test results between the groups. We also examined the relationships between the variables using structural equation modeling (SEM). The OCD group showed significantly lower activity in the dorso-lateral PFC (DLPFC) during the verbal fluency (VFT) and Tower of London (ToL) tasks. Hemodynamic changes in the left DLPFC during the VFT were negatively correlated with OCD severity. The findings analyzed using SEM indicated that brain activity observed in the specific regions had robust direct or indirect relationships with comorbid symptoms, such as depressive or anxiety status, in the OCD group. The current study supports the view that a variety of psychopathological features observed in OCD patients might be explained by abnormal brain activity in the PFC, particularly in the left DLPFC.
