1993 Volume 96 Issue 3 Pages 435-443,547
Contingent negative variations (CNV) were recorded in patients with tinnitus (N=20), abnormal sensations of the pharynx and larynx (ASPL) (N=26) and Meniere's disease (N=19), and compared with those of healthy adults (N=20) in order to investigate the characteristics of their information processing mechanisms in the brain. Patients were also subjected to psychological tests: Depression Score and the Cornell Medical Index test.
CNV (an event-related potential) is a slow negative cortical potential shift and can be recorded during two stimuli presented at a constant interval under conditions in which the subjects are told to press a key as quickly as possible upon an imperative stimulus (S2) following a warning stimulus (S1). S1 was a 1kHz tone burst of 300msec duration at a level of 85dB HL. S2 was a light flash. The interstimulus (S1-S2) interval was set at 2 seconds. The CNV can be divided into three components, early, middle, and late, according to latency. Statistical analysis of CNV amplitudes of the three components showed the following differences between groups.
In tinnitus patients, the mean amplitudes of both the early and middle component were significantly greater than those in healthy adults (P<0.05).
In ASPL patients, the mean amplitudes of the middle component were significantly greater than those in healthy adults (P<0.05).
In Meniere's disease, the mean amplitudes of both the middle and late component were significantly greater than those in healthy adults (P<0.05).
These results indicate that tinnitus patients are hypersensitive to tone stimuli (S1) and Meniere's disease patients manifest considerable preparation and expectancy of imperative stimuli (S2). Our results also show that CNV can estimate the severity of psychogenic factors in such patients, because a correlation between Depression Score and CNV amplitude was observed.