Zaltz Yael, Goldsworthy Raymond L, Kishon-Rabin Liat, Eisenberg Laurie S
Department of Communication Disorders, Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel.
USC Tina and Rick Caruso Department of Otolaryngology-Head & Neck Surgery Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
J Assoc Res Otolaryngol. 2018 Apr;19(2):193-209. doi: 10.1007/s10162-017-0653-5. Epub 2018 Jan 8.
Cochlear implant (CI) users find it extremely difficult to discriminate between talkers, which may partially explain why they struggle to understand speech in a multi-talker environment. Recent studies, based on findings with postlingually deafened CI users, suggest that these difficulties may stem from their limited use of vocal-tract length (VTL) cues due to the degraded spectral resolution transmitted by the CI device. The aim of the present study was to assess the ability of adult CI users who had no prior acoustic experience, i.e., prelingually deafened adults, to discriminate between resynthesized "talkers" based on either fundamental frequency (F0) cues, VTL cues, or both. Performance was compared to individuals with normal hearing (NH), listening either to degraded stimuli, using a noise-excited channel vocoder, or non-degraded stimuli. Results show that (a) age of implantation was associated with VTL but not F0 cues in discriminating between talkers, with improved discrimination for those subjects who were implanted at earlier age; (b) there was a positive relationship for the CI users between VTL discrimination and speech recognition score in quiet and in noise, but not with frequency discrimination or cognitive abilities; (c) early-implanted CI users showed similar voice discrimination ability as the NH adults who listened to vocoded stimuli. These data support the notion that voice discrimination is limited by the speech processing of the CI device. However, they also suggest that early implantation may facilitate sensory-driven tonotopicity and/or improve higher-order auditory functions, enabling better perception of VTL spectral cues for voice discrimination.
人工耳蜗（CI）使用者发现很难区分不同的说话者，这或许可以部分解释为什么他们在多说话者环境中理解语音存在困难。最近基于语后聋人工耳蜗使用者的研究结果表明，这些困难可能源于人工耳蜗设备传输的频谱分辨率下降，导致他们对声道长度（VTL）线索的利用有限。本研究的目的是评估没有先前声学经验的成年人工耳蜗使用者，即语前聋成年人，基于基频（F0）线索、VTL线索或两者来区分重新合成的“说话者”的能力。将其表现与听力正常（NH）的个体进行比较，这些个体听的是使用噪声激励声道 vocoder 处理的降质刺激或未降质刺激。结果表明：（a）植入年龄与区分说话者时的VTL线索有关，但与F0线索无关，对于那些较早植入的受试者，区分能力有所提高；（b）人工耳蜗使用者在安静和噪声环境下的VTL辨别与语音识别得分之间存在正相关，但与频率辨别或认知能力无关；（c）早期植入人工耳蜗的使用者表现出与听vocoder处理刺激的听力正常成年人相似的语音辨别能力。这些数据支持了语音辨别受人工耳蜗设备语音处理限制的观点。然而，它们也表明早期植入可能有助于感觉驱动的音调定位和/或改善高阶听觉功能，从而能够更好地感知用于语音辨别的VTL频谱线索。
