Functional brain imaging in obsessive-compulsive disorder secondary to neurological lesions

Obsessive-compulsive disorder (OCD) may result from a range of neurological lesions in frontal and basal ganglia areas. However, relatively few studies have explored functional brain imaging in acquired OCD. Methods: Charts of patients presenting to our Neuropsychiatry Unit where obsessive- compulsive symptoms appeared secondary to neurological lesions were reviewed. Demographic information and clinical diagnoses were collated, and brain SPECT scans reviewed. Six patients with various neurological conditions presented with OCD. All demonstrated decreased blood flow in the temporal lobes as well as cortical perfusion abnormalities in the frontal lobes (focal areas of decreased perfusion in one patient, focal areas of increased perfusion in two, and a combination of focal increased and decreased frontal perfusion in three cases). Abnormal blood flow may be seen in a number of different brain regions in acquired OCD. It is unclear whether these changes reflect primary neurological lesions or secondary changes to compensate for such damage. However, increased frontal blood flow in OCD may be hypothesized to reflect a compensatory mechanism.