Goldsworthy Raymond L
Department of Otolaryngology, University of Southern California, U.S.A.
Speech Commun. 2019 May;109:24-33. doi: 10.1016/j.specom.2019.03.003. Epub 2019 Mar 21.
Conventional signal processing implemented on clinical cochlear implant (CI) sound processors is based on envelope signals extracted from overlapping frequency regions. Conventional strategies do not encode temporal envelope or temporal fine-structure cues with high fidelity. In contrast, several research strategies have been developed recently to enhance the encoding of temporal envelope and fine-structure cues. The present study examines the salience of temporal envelope cues when encoded into vocoder representations of CI signal processing. Normal-hearing listeners were evaluated on measures of speech reception, speech quality ratings, and spatial hearing when listening to vocoder representations of CI signal processing. Conventional vocoder techniques using envelope signals with noise- or tone-excited reconstruction were evaluated in comparison to a novel approach based on impulse-response reconstruction. A variation of this impulse-response approach was based on a research strategy, the Fundamentally Asynchronous Stimulus Timing (FAST) algorithm, designed to improve temporal precision of envelope cues. The results indicate that the introduced impulse-response approach, combined with the FAST algorithm, produces similar results on speech reception measures as the conventional vocoder approaches, while providing significantly better sound quality and spatial hearing outcomes. This novel approach for stimulating how temporal envelope cues are encoded into CI stimulation has potential for examining diverse aspects of hearing, particularly in aspects of musical pitch perception and spatial hearing.
临床人工耳蜗（CI）声音处理器上实现的传统信号处理基于从重叠频率区域提取的包络信号。传统策略无法高保真地编码时间包络或时间精细结构线索。相比之下，最近已经开发了几种研究策略来增强时间包络和精细结构线索的编码。本研究考察了在CI信号处理的声码器表示中编码时时间包络线索的显著性。对听力正常的听众在聆听CI信号处理的声码器表示时的言语接收、言语质量评分和空间听觉测量方面进行了评估。与基于脉冲响应重建的新方法相比，评估了使用具有噪声或音调激励重建的包络信号的传统声码器技术。这种脉冲响应方法的一种变体基于一种研究策略，即基本异步刺激定时（FAST）算法，旨在提高包络线索的时间精度。结果表明，引入的脉冲响应方法与FAST算法相结合，在言语接收测量方面产生的结果与传统声码器方法相似，同时提供了明显更好的声音质量和空间听觉结果。这种用于刺激时间包络线索如何编码到CI刺激中的新方法在研究听力的各个方面具有潜力，特别是在音乐音高感知和空间听觉方面。
