The authors recorded contingent negative variation (CNV) in a group of subjects affected by presenile dementia, at the onset of the symptoms, with a slight degree of intellectual deterioration. Recordings were carried out in rest basal conditions and upon administration of an insignificant distracting stimulus. Results were compared with data obtained in a group of normal subjects of the same age under the same experimental conditions. In the patients a marked decrease of the wave was observed upon the administration of a distracting stimulus.

The authors studied the modifications in contingent negative variation (CNV) in a group of rupophobic subjects. A slide-projected phobogenic or a neutral stimulus was administered 5 s prior to the warning stimulus (S₁). A marked reduction in CNV amplitude and the appearance of post-imperative negative variation were observed when the phobogenic stimulus was applied. No significant variations were noted after administration of a neutral stimulus. The results are discussed on the basis of psychological and neurophysiological findings concerning the relationship between attention, arousal and CNV.