An association between reduced interhemispheric EEG coherence in the temporal lobe and genetic risk for schizophrenia

Previous studies have suggested that schizophrenic patients show resting EEG replicate the results on the second data set. power spectrum analysis suggested that schizophrenics are cortically hypoactivated, whereas in unaffected siblings, a tendency for hyperactivation was found. In contrast, spectral coherences (0.5-5 Hz) were reduced in both data sets in the temporal lobe areas in schizophrenics and in their unaffected siblings. Changes were most pronounced for the interhemispheric coherence linking both posterior temporal lobe areas. Relative risk calculations (hs) ranged between 3.7 and 9.8, depending on phenotype definition. Thus, while power spectrum EEG abnormalities may be state-dependent, reduced coherence as a possible measure of neuronal synchronization is familial and potentially a heritable trait related to genetic risk for schizophrenia. (C) 2001 Elsevier Science B.V. All rights reserved.