Visual Evoked Potentials and Event Related Potentials
in Congenitally Deaf Subjects

J. CHLUBNOVÁ, J. KREMLÁČEK, Z. KUBOVÁ, M. KUBA

Department of Pathophysiology, Faculty of Medicine, Charles University, Hradec Králové,
Czech Republic

Received June 7, 2004
Accepted January 13, 2005
On-line available February 16, 2005


Summary
The purpose was to test parameters of visual evoked potentials (VEPs) and of event-related potentials (ERPs) in deaf subjects to verify visual and cognitive CNS functions in a handicapped group of the population. Three types of visual stimuli (with dominating parvocellular or magnocellular system activation or with cognitive tasks) were used in the study. Six deaf persons (4 women, 2 men, mean age 17 years) and 6 persons with normal hearing (sex- and age-matched) were included in this pilot study. In all types of stimulation, latencies and amplitudes of main VEPs and ERPs components were evaluated. No significant latency differences were found. However, significantly reduced amplitudes were found in the occipital area for responses to motion and cognitive stimuli which might be interpreted as a part of functional reorganization of the extrastriate and cognitive cortical areas of deaf subjects.


Key words
Sign language • Pattern-reversal VEPs • Motion VEPs • Event related potentials • Deaf subjects