Thomas Mathew, Galvin John J, Fu Qian-Jie
Department of Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles, 650 Charles E. Young Drive South, CHS 62-113, Los Angeles, CA, 90095-1737, USA.
House Institute Foundation, Los Angeles, CA, 90057, USA.
Sci Rep. 2023 Mar 27;13(1):4960. doi: 10.1038/s41598-023-32135-0.
Bimodal cochlear implant (CI) listeners have difficulty utilizing spatial cues to segregate competing speech, possibly due to tonotopic mismatch between the acoustic input frequency and electrode place of stimulation. The present study investigated the effects of tonotopic mismatch in the context of residual acoustic hearing in the non-CI ear or residual hearing in both ears. Speech recognition thresholds (SRTs) were measured with two co-located or spatially separated speech maskers in normal-hearing adults listening to acoustic simulations of CIs; low frequency acoustic information was available in the non-CI ear (bimodal listening) or in both ears. Bimodal SRTs were significantly better with tonotopically matched than mismatched electric hearing for both co-located and spatially separated speech maskers. When there was no tonotopic mismatch, residual acoustic hearing in both ears provided a significant benefit when maskers were spatially separated, but not when co-located. The simulation data suggest that hearing preservation in the implanted ear for bimodal CI listeners may significantly benefit utilization of spatial cues to segregate competing speech, especially when the residual acoustic hearing is comparable across two ears. Also, the benefits of bilateral residual acoustic hearing may be best ascertained for spatially separated maskers.
双模人工耳蜗（CI）使用者在利用空间线索分离竞争性言语方面存在困难，这可能是由于声学输入频率与刺激电极位置之间的音调拓扑不匹配所致。本研究调查了在非CI耳有残余听力或双耳均有残余听力的情况下，音调拓扑不匹配的影响。在正常听力的成年人中，通过两个共置或空间分离的言语掩蔽器测量言语识别阈值（SRT），这些成年人聆听CI的声学模拟；低频声学信息可在非CI耳（双模聆听）或双耳中获得。对于共置和空间分离的言语掩蔽器，音调拓扑匹配的电听觉的双模SRT明显优于不匹配的情况。当不存在音调拓扑不匹配时，当掩蔽器空间分离时，双耳的残余听力有显著益处，但共置时则没有。模拟数据表明，对于双模CI使用者，保留植入耳的听力可能会显著有助于利用空间线索分离竞争性言语，特别是当双耳的残余听力相当时。此外，对于空间分离的掩蔽器，双侧残余听力的益处可能最为明显。
