The visual evoked potentials (VEP), brain DC potential (DP) mapping and emotional disorders were comparatively evaluated in patients with Alzheimer's disease (AD) and age-matched healthy individuals. In AD, the severity of emotional disorders correlated with the reduction of VEP late components P 4 N 4. In patients with frequent affect oscillations, the amplitude of N 3 component of the VEP and its variability was higher than in patients with rare undulations of the emotional state. In AD patients the DP levels were increased as compared to normal levels in all the brain sites investigated. The degree of emotional disorders in AD patients positively correlated with frontal DP levels. The rise in frontal DP levels and decrease in late VEP components were interrelated in AD patients.