Contingent negative variation enhancement in tinnitus patients.

Contingent negative variations recorded in 20 tinnitus patients with an average hearing level within 40 dB were compared with those from age-matched healthy controls. In addition, negative and positive potentials (N100 and P300), which are presumed to reflect stimulus information processing, were examined. Contingent negative variation amplitude was significantly greater in patients than in controls (P less than .05, ANOVA), but no significant differences were observed in the N100 and P300 latencies and amplitudes for the two groups. We interpret these results as evidence of abnormalities in the central information processing mechanism of tinnitus patients.