Clinical results with a multichannel pseudobipolar system

Abstract

A receiver-stimulator and multiple-electrode array were implanted in the scala tympani of a 46-year-old totally deaf man on August 1, 1978. This patient had lost all hearing after a head injury 18 months prior to surgery. Pure-tone Bekesy and speech audiometry showed no hearing in either ear at the maximum output levels of the audiometer, and no vibrotactile responses were elicited.

A second patient, a 63-year-old man, received an implant on July 17, 1979. This patient had a progressive sensorineural hearing loss extending over 30 years due to bomb blast and chronic infection. He had no help from a hearing aid for 13 years prior to surgery. Pure-tone Bekesy audiometry under headphones revealed no hearing in the left ear, and in the right he had thresholds of 125 dB SPL at 0.125 kHz; 115 dB at 0.25 kHz, and 117 dB at 0.5 kHz. There was no speech discrimination in either ear under headphones or in a monitored sound field. His right ear was fitted with a hearing aid (Calaid G12G) by the National Acoustics Laboratory, but at its maximum output level he received only a limited gain at 5.0 kHz and could not be aided. (From Introduction)