Effects of Postnatal Stress on Visual and Auditory Evoked Potentials

Abstract

Maturation of visual and auditory evoked potentials (mainly the P₃ wave) of 10 controls and of 10 infants exposed to recurrent postnatal stressful events (crying spells lacking organic basis) have been compared. The course of maturation of P₃ waves may serve as indicator of growth and nature of cognitive processes (including perception). Recurrent crying spells seemed to delay appearance of visual P₃ wave, prolonged its latency, and delayed appearance of visible differences in the shape of visual P₃ wave upon exposure of the subjects to different visual experiences. A compensatory increase of maturation of the auditory P₃ wave appeared. The results suggest that recurrent exposure to stressful events during the early postnatal period may delay the ability of the infant to use visual perception to register exogenous events and may create memory banks of auditory engrams with unusual contents (including memory traces of stresses), a potential basis for future auditory hallucinations.