Interindividual variability of negative contingent variation (CNV).

The use of CNV in clinical practice requires the choice of a standardised p rotocol, the constitution of reference normative data and the consideration of intra- and interindividual variability. For this purpose, we recorded C NV in 86 control subjects 44 men and 42 women, 18 to 62 years old (mean age = 34 +/- 13 years) during a reaction time paradigm with a warning signal a nd a 1-second S1-S2 interval. Moreover, the role of inter-stimulation inter val was analysed in a group of 12 subjects through the comparison of record ings made with 1- and 3-second intervals. The CNV amplitude, its morphology and topographic distribution as well as its resolution mode and evolution through the recording were studied. The subjects' performances and their in teractions with electroencephalographic data were also included in the anal yses. Our results underscore the contribution of age and gender and psychol ogical factors to CNV variability. CNV amplitude (both M1 and M2) increased and changed topographic distribution toward more central sites in older. M en had faster reaction times than women and lower post-S1 P300. Moreover, t he life events-related stress and the subject's current anxiety level were accompanied by a decreased CNV amplitude. (C) 2001 Editions scientifiques e t medicales Elsevier SAS.