CUSTOM PROGRAM FOR IMPROVING THE MUSIC PERCEPTION WITH ADVANCED BIONICS’ SYSTEM

Boyle P (1), Wansbury V (3), Gazibegovic D (1), Rocca C (1,2).

(1)Advanced Bionics Europe; (2) Mary Hare, London, UK; (3) Portland, London, UK.

Objectives: A reasonable understanding of speech in quiet, and in some noise, is common for the large majority of cochlear implant recipients. The perception of music for many however, is still disappointing. This work investigates programs created specifically to enhance music perception.

Methods: A range of program parameters was selected which might impact music perception. Changes to parameters were made iteratively, one at a time, while listening to familiar pieces of music played from CD.  Electrode contacts showing no pitch differentiation from their neighbours were removed. Different settings of input dynamic range (IDR) were evaluated, along with linear amplification or input Automatic Gain Control (AGC). Stimulation rate was manipulated based on the electrical dynamic range being measured for a series of stimulation rates. Frequency response was modified through the channel gain settings. These changes were systematically made for two musically trained participants. Both were bilaterally implanted, used the Harmony processor and attended several programming sessions. A questionnaire was used to capture responses.

Results: For music a larger IDR than the 60 dB default was found beneficial. However, increases beyond 70 dB were deleterious. Removing the front-end AGC was useful where the participant controlled the music’s presentation level. A lower stimulation rate than the clinical default (highest sequential rate) was preferred, indicated by a maximization of electrical dynamic range. Emphasis of both high and low parts of the spectrum was preferred, bringing out previously inaudible parts. Both participants used their music programs for music listening, but standard clinical programs for speech.

Conclusion: It appears that the default program settings for music perception are not the same as those required for optimal speech understanding. Changes were required on an individual ear basis for these bilateral users. A set of music defaults may be suggested, but should be evaluated on a larger group before being formally recommended.

E-mail: dzemalg@abionics.fr