Electrophysiological (CNV) analysis of personality traits under stress.

Contingent negative variation (CNV) recordings were performed in 55 healthy volunteers under stress condition (experimentally induced pain). A total of 20 subjects were included in the control group (no painful administration). In the tested group (n = 35) the painful stimulus was delivered before S1, between S2 and S1, and before S2. In the control group there were no changes in CNV parameters. Conversely, among the tested group a positive correlation was found between CNV values (whenever the painful stimulus was administered before S1 as well as before S2) and the highest scores in the State Trait Anxiety Inventory X 2 test. In addition, all individuals displayed the appearance of a positive deflection with a latency of about 300 ms from S2 when the experimental stress was given before S2. Furthermore, the postimperative negative variation (PINV) appeared in 13 out of 35 subjects. There was a strong correlation between the latter electrophysiological phenomenon and the Nowlis test. Our findings suggest that CNV study is useful for the investigation of personality traits in human beings under stress conditions.