[Contribution of contingent negative variation (CNV) to the study of schizophrenia].

The authors first review neurobiological and psychopathological data supporting the use of Contingent Negative Variation (CNV) for the study of Schizophrenia. Next, results obtained with the method are presented (i.e. with S1-S2 interval = 1 sec, and recording leads = Cz and Fz) comparing 34 control subjects with 29 schizophrenic patients, all diagnosed with the "Present State Examination" test or PSE (Wing and Sartorius). In patients, reduced CNV amplitude (p less than 0.0001), together with reduced CNV resolution (p less than 0.02) and less differentiated topographical spreading (p less than 0.02) were observed relatively to controls. There is also a slower reaction time (p less than 0.02). Such abnormalities are sufficiently frequent as to allow CNV as a helping diagnostic tool, with a sensitivity rate of 83% and a specificity rate of 85%. These results are discussed with respect to the psychopathological and neurobiological problems in relation with schizophrenia.