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J Am Acad Audiol 2019; 30(08): 731-734
DOI: 10.3766/jaaa.18030
Articles
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

AutoAdaptive: A Noise Level–Sensitive Beamformer for MED EL Cochlear Implant Patients

Michael F. Dorman
*   Arizona State University, Tempe, AZ
,
Sarah Cook Natale
*   Arizona State University, Tempe, AZ
› Author Affiliations
Further Information

Publication History

Publication Date:
25 May 2020 (online)

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Abstract

Background:

When cochlear implant (CI) listeners use a directional microphone or beamformer system to improve speech understanding in noise, the gain in understanding for speech presented from the front of the listener coexists with a decrease in speech understanding from the back. One way to maximize the usefulness of these systems is to keep a microphone in the omnidirectional mode in low noise and then switch to directional mode in high noise.

Purpose:

The purpose of this experiment was to assess the levels of speech understanding in noise allowed by a new signal processing algorithm for MED EL CIs, AutoAdaptive, which operates in the manner described previously.

Research Design:

Seven listeners fit with bilateral CIs were tested in a simulation of a crowded restaurant with speech presented from the front and from the back at three noise levels, 45, 55, and 65 dB SPL.

Data Collection and Analysis:

The listeners were seated in the middle of an array of eight loudspeakers. Sentences from the AzBio sentence lists were presented from loudspeakers at 0 or 180° azimuth. Restaurant noise at 45, 55, and 65 dB SPL was presented from all eight loudspeakers. The speech understanding scores (words correct) were subjected to a two-factor (speaker location and noise level), repeated measures, analysis of variance with posttests.

Results:

The analysis of variance showed a main effect for level and location and a significant interaction. Posttests showed that speech understanding scores from front and back loudspeakers did not differ significantly at the 45- and 55-dB noise levels but did differ significantly at the 65-dB noise level—with increased scores for signals from the front and decreased scores for signals from the back.

Conclusions:

The AutoAdaptive feature provides omnidirectional benefit at low noise levels, i.e., similar levels of speech understanding for talkers in front of, and in back of, a listener and beamformer benefit at higher noise levels, i.e., increased speech understanding for signals from in front. The automatic switching feature will be of value to the many patients who prefer not to manually switch programs on their CIs.

Key Words

beamformer - cochlear implant - directional microphone

This work was conducted at Arizona State University and was supported by a grant from MED EL Corporation.


 

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