Altered parallel auditory processing in schizophrenia patients

Patients with schizophrenia have impaired auditory processing that has been demonstrated by diminished P50 response to paired auditory stimuli in even t-related potential (ERP) studies, Cerebral processing can also be studied with magnetoencephalography (MEG), With a whole-head MEG, which enables one to simultaneously measure brain activity in both hemispheres, we investiga ted whether early parallel auditory processing is impaired in schizophrenia . Sequences of tones were monaurally presented to schizophrenia patients an d healthy controls in a passive condition, and the event-related magnetic f ields were recorded simultaneously over both auditory cortices, The interhe mispheric latency difference of the P50m, but not that of the N100m, was si gnificantly shorter in the patient group in the right-ear but not in the le ft-ear stimulus condition. Further, the ipsilateral P50m was significantly earlier in schizophrenia patients in the right-ear condition. This result s uggests that schizophrenia affects the consecutive preconscious auditory pr ocessing in a different manner.