Hemispheric function in disorganized type schizophrenia: performance on the Quality Extinction Test

We assessed hemisphere function in right-handed male chronic, disorganized type schizophrenic patients (N = 60, age range 18-45 years) using the Quali ty Extinction Test (QET), in comparison to 20 right-handed male healthy con trols in the same age range. The QET analysis discriminated between the dis organized schizophrenic patients and the controls. QET results indicated th at chronic schizophrenic patients were less sensitive to tactile stimuli in both hands as compared to controls. Furthermore, the sensitivity to tactil e stimuli of the left hand was less than that of the right hand in the schi zophrenic patients. In contrast, in the normal controls the sensitivity was similar in both hands. These results indicate possible right hemisphere dy sfunction together with disturbance in interhemispheric transmission throug h the corpus callosum in chronic, disorganized type schizophrenic patients. (C) 2000 Editions scientifiques et medicales Elsevier SAS.