FUNDAMENTAL ASPECTS AND FIRST RESULTS OF THE CLINICAL APPLICATION OF COMBINED ELECTRIC AND ACOUSTIC STIMULATION OF THE AUDITORY SYSTEM

Abstract

Introduction

Electric stimulation of the auditory nerve via cochlear implants has made the treatment of sensory deafness possible. Advanced signal processing and stimulation paradigms have led to continuously improved results in speech understanding.

Subjects and methods

Subjects were included based on their pure-tone audiograms and speech audiometric results. Inclusion criteria were a threshold between 30 and 60 dB in the frequency range of 250 Hz to 1 kHz and >60 dB above 1 kHz in the ear to be implanted. The time course of hearing loss had to be stable or only very slowly progressive, without signs of retro cochlear pathology.

Results

Hearing could be preserved to within 10 dB in four of eight patients, in two further subjects it could be preserved partially, while two patients lost their hearing after implantation. If preserved, hearing remained stable after implantation, in three subjects it could be followed for more than one year. Four subjects have been fitted with ipsilateral hearing aids, and two subjects have not yet been fitted. The remaining two subjects only wear contralateral hearing aids.

Conclusions

Improvements in electrode design and surgical techniques, as well as pharmacological protection of the cochlea against trauma, should help to increase the success rate and allow an extended range of applications.