The purpose of this investigation was to determine the impact of commonly recommended
cochlear implant (CI) speech processor placements on microphone output both with and
without single channel front-end compression. The impact of this compression use on
interaural level difference (ILD) magnitude was also evaluated for the ear-level position.
Finally, pilot localization data collected with and without single channel front-end
compression was collected on seven bilateral cochlear implant recipients. The results
revealed that differences in signal audibility due to clinical placement of CI speech
processors in ear, shoulder, and collar positions can at least partially be offset
through the use of front-end compression. These data also revealed that compression
impacted ILD cues. Preliminary data indicated that some bilaterally implanted subjects
were able to take advantage of the enhanced ILD cues when compression was turned off,
while other bilaterally implanted subjects did not localize better in the compression-off
condition.
Key Words
Cochlear implant - interaural level difference - localization - microphone location
