Negative symptoms and EEG alpha in schizophrenia: a replication.

The authors previously reported that negative symptoms were associated with reduced EEG alpha power and coherence in medication-free schizophrenic inpatients. These post-hoc findings were based on resting EEG data in an eyes open condition. This report describes the replication of these results in a new sample of 17 male veterans (aged 38 +/- 8) recently hospitalized with DSM-III-R schizophrenia. All patients had been free of neuroleptic medication at least 12-14 days. The relationships between resting alpha (7.5-12.5 Hz) power and coherence and symptom ratings (as measured by subscales derived from the Brief Psychiatric Rating Scale) were examined with multivariate repeated measure analyses of covariance. Results were similar to those obtained earlier, with a main effect of negative symptoms (p = 0.05) on log alpha power, a localized effect on right frontal-parietal alpha coherence (p < 0.02), and a main effect (p < 0.03) on between-hemisphere alpha coherence. There was also a trend for an asymmetrical effect on power favoring the right side in parietal leads. Negative symptoms were associated with reduced alpha power and less alpha coherence between hemispheres and between right parietal and frontal regions. The authors discuss the implications of these results on neurodevelopmental, genetic, and attentional aspects of schizophrenia.