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 suggest the alteration of frontal lobe functioning. We performed a brain activation study in obsessive–compulsive disorder using a cognitive task involving 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 average time-course functional changes occurring at the site of largest frontal cortex activation during alternating rest and task periods. Results: In terms of relative signal changes, patients showed a significantly greater activation during word generation and a defective suppression of this activation during the following rest period. Both abnormal imaging findings significantly correlated with the severity of the clinical process assessed by the Yale–Brown Obsessive–Compulsive Scale. Conclusions: The results indicate that functional magnetic resonance imaging during cognitive challenge may be useful to reveal distinctive features of latent brain dysfunction in obsessive–compulsive disorder.