Functional magnetic resonance imaging study of frontal lobe activation during word generation in obsessive-compulsive disorder

Background: Functional imaging studies have demonstrated abnormal patterns of brain activity in obsessive-compulsive disorder, which consistently sugg est the alteration of frontal lobe functioning. We performed a brain activa tion study in obsessive-compulsive disorder using a cognitive task involvin g the frontal lobes. Methods: Twenty patients and 20 healthy control subjects were assessed with functional magnetic resonance imaging during a phonologically guided word generation task. The study analysis was based on the comparison of group av erage time-course functional changes occurring at the site of largest front al cortex activation during alternating rest and task periods. Results: In terms of relative signal changes, patients showed a significant ly greater activation during word generation and a defective suppression of this activation during the following rest period. Both abnormal imaging fi ndings significantly correlated with the severity of the clinical process a ssessed by the Yale-Brown Obsessive- Compulsive Scale. Conclusions: The results indicate that functional magnetic resonance imagin g during cognitive challenge may be useful to reveal distinctive features o f latent brain dysfunction in obsessive-compulsive disorder. (C) 1999 Socie ty of Biological Psychiatry.