COCHLEAR IMPLANT DEVICE FAILURE - DIAGNOSIS AND MANAGEMENT

Complete, irreversible failures of the implanted receiver-stimulator o f the Cochlear Corporation multichannel implant are relatively rare. H owever, as the implanted patient population grows, malfunctions may be expected. From the over 200 patients implanted at the University of M ichigan Medical Center, 6 patients with a complete and irreversible co chlear implant receiver-stimulator failure have been identified and tr eated. This represents a 3% failure rate. The amount of ti me between initial implantation and device failure ranged from 6 months to 3.5 ye ars. Determination of device failure was made using psychophysical, el ectrophysiologic, and averaged electrode voltage measurements. The mea surement of the average electrode voltages proved to be useful in dete rmining the condition of the implant. Physiologic changes causing redu ced electrical excitability were ruled out using psychophysical or ele ctrophysiologic promontory testing. All patients were successfully exp lanted and reimplanted.