PROBLEMS ASSOCIATED WITH APPLICATION OF THE CONTINGENT NEGATIVE VARIATION TO PSYCHIATRIC RESEARCH

As a first step in applying Walterʼs contingent negative variation (CNV) in comparative studies of psychiatric patients, data were obtained concerning the issues of contamination by activity arising in the orbit and of individual variability between different test paradigms. Subjects were 20 college students and 10 psychiatric inpatients. Looking only at the conventional CNV recording leads (vertex-mastoid), a significant CNV was obtained in two experimental paradigms. However, analysis of the spatial distribution of the potential strongly suggested that much of the recorded vertex-mastoid negative shift can be accounted for by activity associated with eye movement. The distribution of CNV closely paralleled the distribution of vertical eye movement potentials. Results in patients and nonpatients were similar. The vertex-mastoid lead placement appears to be a poor one for recording relatively uncontaminated CNV; vertex-temporal derivation appears promising, although a smaller negative shift was recorded there.CNV measurements of the same subjects obtained under two experimental conditions were poorly correlated with each other, suggesting that the CNV responsiveness under any one condition does not characterize the individual. It was concluded that application of CNV recording to psychiatric research presents serious methodological and interpretive difficulties.