The Effect of Binaural Beamforming Technology on Speech Intelligibility in Bimodal Cochlear Implant Recipients

Abstract

Although the benefit of bimodal listening in cochlear implant users has been agreed on, speech comprehension remains a challenge in acoustically complex real-life environments due to reverberation and disturbing background noises. One way to additionally improve bimodal auditory performance is the use of directional microphones. The objective of this study was to investigate the effect of a binaural beamformer for bimodal cochlear implant (CI) users. This prospective study measured speech reception thresholds (SRT) in noise in a repeated-measures design that varied in listening modality for static and dynamic listening conditions. A significant improvement in SRT of 4.7 dB was found with the binaural beamformer switched on in the bimodal static listening condition. No significant improvement was found in the dynamic listening condition. We conclude that there is a clear additional advantage of the binaural beamformer in bimodal CI users for predictable/static listening conditions with frontal target speech and spatially separated noise sources.

Keywords: Bimodal hearing; Binaural beamformer; Cochlear implant; Fitting; Hearing aid.

Fig. 1.

The hearing thresholds of the individual participants for the ear with the hearing aid. The dashed line displays the mean hearing loss.

Fig. 2.

A schematic representation of the test environment. The cochlear implant (CI) user is in the middle of 5 loudspeakers, all at a distance of 1 m. The target signal is coming from S0 for the static listening condition and randomly from the loudspeaker at −45° or 45° for the dynamic listening condition.

Fig. 3.

The results of the speech perception in noise test for the 6 listening conditions. p values are corrected for multiple comparisons of the Wilcoxon signed-rank test. Asterisks denote significant differences. The error bars represent the standard errors of the mean. CI, cochlear implant; SRT, speech reception threshold.

Fig. 4.

The results of the speech perception in noise test for individual participants for the dynamic and static listening conditions. CI, cochlear implant; SRT, speech reception threshold.