Auditory Research Center, Caruso Department of Otolaryngology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
Auditory Research Center, Caruso Department of Otolaryngology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States; Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, United States.
Hear Res. 2021 Sep 15;409:108319. doi: 10.1016/j.heares.2021.108319. Epub 2021 Jul 24.
Cochlear implants are medical devices that have been used to restore hearing to more than half a million people worldwide. Most recipients achieve high levels of speech comprehension through these devices, but speech comprehension in background noise and music appreciation in general are markedly poor compared to normal hearing. A key aspect of hearing that is notably diminished in cochlear implant outcomes is the sense of pitch provided by these devices. Pitch perception is an important factor affecting speech comprehension in background noise and is critical for music perception. The present article summarizes two experiments that examine the robustness and resolution of pitch perception as provided by cochlear implant stimulation timing. The driving hypothesis is that pitch conveyed by stimulation timing cues is more robust and better resolved when provided by variable pulse rates than by modulation frequency of constant-rate stimulation. Experiment 1 examines the robustness for hearing a large, one-octave, pitch difference in the presence of interfering electrical stimulation. With robustness to interference characterized for an otherwise easily discernible pitch difference, Experiment 2 examines the resolution of discrimination thresholds in the presence of interference as conveyed by modulation frequency or by pulse rate. These experiments test for an advantage of stimulation with precise temporal cues. The results indicate that pitch provided by pulse rate is both more robust to interference and is better resolved compared to when provided by modulation frequency. These results should inform the development of new sound processing strategies for cochlear implants designed to encode fundamental frequency of sounds into precise temporal stimulation.
人工耳蜗是一种医疗设备,已被用于帮助全球超过 50 万人恢复听力。大多数使用者通过这些设备获得了较高的言语理解能力,但与正常听力相比,他们在背景噪声中的言语理解能力和对音乐的欣赏能力都明显较差。人工耳蜗植入物的一个重要的听觉方面是其提供的音高感知能力明显下降。音高感知是影响背景噪声中言语理解的一个重要因素,对音乐感知也至关重要。本文总结了两项实验,这些实验研究了人工耳蜗刺激定时提供的音高感知的稳健性和分辨率。主要假设是,当由变化的脉冲率提供时,刺激定时线索所传达的音高比由恒速刺激的调制频率提供时更稳健、分辨率更好。实验 1 研究了在存在电刺激干扰的情况下,感知一个大的、一个八度的音高差异的稳健性。通过对容易分辨的音高差异的干扰特征进行稳健性测试,实验 2 研究了在存在干扰的情况下,调制频率或脉冲率所传达的辨别阈值的分辨率。这些实验测试了精确时间线索刺激的优势。结果表明,与由调制频率提供的音高相比,由脉冲率提供的音高具有更强的抗干扰能力,分辨率也更高。这些结果应该为新的人工耳蜗声音处理策略的发展提供信息,这些策略旨在将声音的基频编码成精确的时间刺激。