The relationship of mismatch negativity to quantitative EEG and morphological findings in schizophrenia

The goal of the present study is to investigate the relationships of mismatch negativity (MMN) to other markers in schizophrenics; Quantitative EEG (QEEG), CT and psychopathological ratings. Thirty unmedicated patients (28.4+/-9.8 y, 20 M) including twenty neuroleptic-naive cases were divided into two groups before treatment; Group A consisted of ten patients with greater MMN amplitudes, while twenty patients with smaller ones were assigned to Group B. In QEEG, Group A showed a closer profile to healthy controls, indicating their function is less distorted. Group B showed greater power in slow wave, slow alpha and fast beta bands. Their greater slow wave may be implicated in cognitive impairment reflected by attenuated MMN as well as greater dilation in lateral ventricles and Sylvian fissures on CT. After pharmacological treatment with conventional neuroleptics, Group A's MMN decreased, whereas that of Group B increased. Furthermore, neuroleptics' EEG-effects observed in Group A were close to the reported profiles of healthy subjects, while those in Group B were distinct from them. Conclusively, MMN might have crucial associations to other measures underlying the brain pathology of schizophrenia. The diagnostic value of MMN as a trait-marker was discussed.