Effect of adaptive beamforming and noise reduction algorithms on speech intelligibility and noise tolerance in bimodal cochlear implant users

Abstract

Objective

To evaluate the effect of a directional microphone (beamformer) and continuous noise reduction algorithms (CNRs) in bimodally aided cochlear implant (CI) users and to find the optimum hearing aid (HA) and CI settings of the beamformer and CNRs.

Methods

Speech reception threshold (SRT) and acceptable noise level (ANL) were assessed in twelve adult CI users for unilateral CI, unilateral HA and bimodal listening. To assess the effect of the UltraZoom beamformer and the ClearVoice™ and NoiseBlock CNRs on SRT and ANL, speech was presented from the front in multi-source speech-shaped noise.

Results

With unilateral CI, application of UltraZoom resulted in a significant improvement of the median SRT and ANL by 3.8 and 4.3 dB, respectively. For bimodal listening with UltraZoom, a significant improvement of 3.5 dB in median SRT was found. There was no significant effect of using the CNRs on speech intelligibility in noise or noise tolerance in either listening condition.

Conclusion

UltraZoom should be applied on the CI to improve speech intelligibility in face to face conversations with multi-source background noise. However, due to the heterogeneous data, no recommendations for the settings of UltraZoom on the HA or of ClearVoice/NoiseBlock on either device can be given.

Trial registration

German Clinical Trials Register identifier: DRKS00010807

Keywords:

• Cochlear implant
• Hearing aid
• Bimodal fitting
• Speech reception threshold
• Acceptable noise level
• Directional microphone
• Continuous noise reduction

Disclosure statement

A.M. changed affiliation during the writing of the manuscript and is now employed at Advanced Bionics GmbH. Y.O. has nothing to disclose. M.B. is an employee at Advanced Bionics GmbH. A.A. reports grants and non-financial support from Advanced Bionics AG, grants and non-financial support from Cochlear Ltd, grants and non-financial support from MED-EL Gesellschaft m.b.H., grants and non-financial support from Oticon, Inc., outside the submitted work. S.A. reports grants and non-financial support from Cochlear Ltd, grants and non-financial support from MED-EL Gesellschaft m.b.H., outside the submitted work. T.W. reports a grant and non-financial support from Advanced Bionics AG, during the conduct of the study; grants and non-financial support from Advanced Bionics AG, non-financial support from Cochlear Deutschland GmbH & Co. KG, grants and non-financial support from MED-EL Deutschland GmbH, non-financial support from Oticon Medical Oticon GmbH, outside the submitted work.

Additional information

Funding

This work was supported by Advanced Bionics AG [grant number ZVS20150618b].