Examination of the Cros Type Hearing Aid

Abstract

This study was designed to examine the CROS type hearing aid under a number of listening conditions, both advantageous and disadvantageous, in order to determine whether the relative merits of the instrument could be demonstrated in the laboratory. CNC word lists were presented against a background of cafeteria noise to evaluate the performance of 20 unilaterally impaired subjects under five unaided and five aided listening conditions. Speech intelligibility scores obtained under the experimental conditions were converted to deterioration scores relative to better ear discrimination in quiet. Deterioration of unaided speech scores ranged from 14% under the most favorable listening condition to 58% under the least favorable condition. Deterioration of aided scores ranged from a low of 20% to a high of 39%. The results suggest that while the CROS hearing aid enhances intelligibility under favorable use conditions, it degrades speech intelligibility in some demanding situations.