Associated deficits in mismatch negativity generation and tone matching inschizophrenia

Objective: Schizophrenia is associated with deficits in mismatch negativity (MMN) generation and in the ability to match two tones following brief del ay. Both deficits reflect impaired early cortical processing of auditory in formation. However, the relationship between deficits in MMN generation and tone matching performance in schizophrenia has not been established. Methods: MMN and tone matching performance was evaluated in 12 schizophreni c subjects and 12 similar aged controls. A pitch separation known to produc e non-ceiling performance in patients (5% Deltaf) was used. Narrow band fil tering of MMN data was used to enhance signal-to-noise ratio. Results: Schizophrenic subjects showed impairments in both MMN generation a nd tone matching performance. The two deficits were significantly correlate d across subjects. In addition, decreased MMN amplitude and poorer tone mat ching performance correlated with increased severity of negative symptoms. Conclusions: These findings support the concept that similar neurophysiolog ical mechanisms underlie MMN and tone matching deficits in schizophrenia. F urther, they indicate that increased sensitivity to environmental change ma y be related to social withdrawal and other negative symptoms in schizophre nia. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.