Left planum temporale volume reduction in schizophrenia

Background: The planum temporale, located on the posterior and superior sur face of the temporal lobe, is a brain region thought to be a biological sub strate of language and possibly implicated in the pathophysiology of schizo phrenia. To investigate further the role of planum temporale abnormalities in schizophrenia, we measured gray matter volume underlying the planum temp orale from high spatial resolution magnetic resonance imaging techniques. Methods: Sixteen male patients with chronic schizophrenia and 16 control su bjects were matched for age, sex, handedness, and parental socioeconomic st atus. Magnetic resonance imaging images were obtained from a 1.5-T magnet. Results: Gray matter volume was significantly reduced in the left planum te mporale (28.2%) in schizophrenic patients compared with normal controls. Sc hizophrenic patients showed a reversal of the left greater than right planu m temporale asymmetry found in normal controls. Heschl's gyrus (primary aud itory cortex) showed no differences between the left and right sides in eit her group. Of note, the Suspiciousness/Persecution subscale score of the Po sitive and Negative Syndrome Scale was associated with reduced left planum temporale volume in schizophrenic patients. Conclusions: Patients with schizophrenia have reduced left planum temporale gray matter and a reversal of planum temporale asymmetry, which may underl ie an impairment in language processing and symptoms of suspiciousness or p ersecution characteristic of schizophrenia.