Sound localization, speech and tone recognition for stimuli presented from the rear in bilateral cochlear implant users

Abstract

Objective

To assess any differences in spatial listening ability of cochlear implant recipients when using both or only one of two bilateral cochlear implants (BCIs) for stimuli originating from behind the subject.

Design

Twelve loudspeakers were placed in the rear horizontal plane of the subjects to test the sound localisation performance of BCI users and normal-hearing listeners (NHLs) with or without interfering noise. Stimuli were presented via two rear loudspeakers simultaneously during the speech recognition test. In the tone recognition test, another anechoic chamber was used with stimuli presenting from a loudspeaker behind the participants.

Study sample

Twenty-seven NHLs and eleven BCI users.

Results

Average root-mean-square (RMS) error for the bilateral condition was significantly lower than that for the right and left cochlear implant (CI) conditions with or without interfering noises (p < 0.05). Average speech or tone recognition scores for the bilateral condition and the right and left CI conditions were not statistically significant (p > 0.05).

Conclusion

Sound localisation with BCIs was significantly more accurate than with either implant alone. Speech and tone recognition scores were not better with two compared to those of one activated implant. Given the small number of subjects, the results should be considered as preliminary.

Keywords:

• Sound localisation
• bilateral cochlear implants
• speech recognition
• tone recognition

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by the National Key Research and Development Program of China [No. 2016YFC0905200, 2016YFC0905202] and the National Natural Science Foundation of China [NSFC; grant numbers 81420108010 and 81970889 to F.C, 81700915 to X.X, 81500785 to N.G, and 81900932 to X.J].