ONTOGENY OF ELECTRICALLY-EVOKED BRAIN-STEM POTENTIALS IN NEONATALLY DEAFENED GERBILS (MERIONES-UNGUICULATUS) AFTER COCHLEAR IMPLANTATION

To investigate the ontogeny of the electrically evoked auditory brains tem response (E-ABR) we used an animal model of neonatally deafened ge rbils with an intracochlear implanted electrode. The E-ABR were record ed in three groups: normal hearing animals (NORM) and binaural deafene d without chronical electrostimulation (ED) in comparison to binaural deafened animals with chronical stimulation (BDS). In group ED the dea fening lead to inter-peak-latency II-V increase and histological degen eration in the Cochlear Nucleus. In chronical stimulated animals (BDS) we could not observe significant differences compared to unstimulated gerbils until the day after birth. In further studies longer stimulat ion periods, recordings of electrically evoked middle latency response as well as histological examinations of more central parts of the aud itory pathway will be included.