Effect of sound processor microphone characteristics on sound localization in bilateral CI users

Objective The application of directional microphones in CI sound processors might affect interaural cues for sound localization and thus, sound localization ability. In this study, sound localization in the horizontal plane is assessed in adult bilateral CI users for application of the processors SONNET and SONNET 2 with each of the 3 microphone characteristics ‘Omni’, ‘Natural’ and ‘Adaptive’ as well as in normal-hearing listeners. We hypothesize that bilateral CI users will gain greatest localization accuracy with the microphone setting ‘Natural’.

Methods Localization ability is to be assessed six months after processor activation at the earliest. So far, 2 bilateral CI users and 2 normal-hearing subjects have been included in the study. Sound localization is investigated using 12 loudspeakers equidistantly arranged in a full circle for presentation of broadband sounds with 2 different levels and 2 different spectral shapes.

Results The two bilateral CI users showed RMS localization errors of 67,5° and 72,1° for the ‘Omni’, 57,4° and 57,1° for the ‘Natural’, and 86,2° and 84,2° for the ‘Adaptive’ microphone characteristics, respectively. The two normal-hearing subjects yielded an RMS error of 20,3° and 16,4°, respectively.

Conclusion The preliminary results are consistent with our hypothesis that the CI processor microphone characteristics ‘Natural’ is most favorable for bilateral CI users' sound localization in the horizontal plane.

Poster-PDF A-1912.PDF

Publication History

Article published online:
10 June 2020