Cochlear implantation facilitates the use of spatial cues to segregate competing speech in Mandarin-speaking unilaterally deaf listeners

Introduction Binaural hearing plays an important role in segregating spatially separated competing speech. Bilateral and bimodal cochlear implant (CI) patients often do not benefit from spatial cues to segregate competing speech. The aim of this study was to investigate whether CI patients with unilateral hearing loss can utilize spatial cues for recognition of target speech in the presence of symmetrically placed masker speech.

Materials & Methods SRTs for competing speech were measured in 12 adults with normal hearing (NH) and 12 unilaterally deaf CI patients (5 SSD and 7 AHL) using a modified coordinate response measure task. SRTs were measured in four conditions with different masker talkers and masker spatial (colocated with the target or placed at ±90°). Three segregation cue conditions were tested to measure masking release (MR) relative to the baseline condition (where no talker sex or spatial cues were available): 1) Talker sex, 2) Spatial, and 3) Talker sex  + spatial.

Results Overall SRTs were significantly lower for NH listeners than for SSD CI-on or AHL CI-on listeners, and significantly lower for SSD CI-on than for AHL CI-on listeners. Across all conditions, MR was significantly larger with the CI on than off. Across all CI patients, MR was highly correlated with PTA thresholds in the non-implanted ear for the Talker sex and Talker sex  + spatial conditions, but not for the Spatial condition.

Conclusion Different from bilateral or bimodal CI patients, cochlear implantation may benefit unilaterally deaf patients’ utilization of spatial cues to segregate competing speech.

Publication History

Article published online:
24 May 2022