Accurate Guitar Tuning by Cochlear Implant Musicians

Modern cochlear implant (CI) users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to <0.5 Hz. One subject had normal contralateral hearing and produced more accurate tuning with CI than his normal ear. To understand these counterintuitive findings, we presented tones sequentially and found that tuning error was larger at ∼30 Hz for both subjects. A third subject, a non-musician CI user with normal contralateral hearing, showed similar trends in performance between CI and normal hearing ears but with less precision. This difference, along with electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task.

人工耳蜗（Cochlear Implant，CI）使用者通常可正常理解言语，但因音调感知能力欠佳，难以欣赏音乐。不过仍有部分失聪音乐人可借助人工耳蜗开展演奏。本研究获得了出人意料的实验结果：借助人工耳蜗的音乐人可仅通过人工耳蜗可靠地完成吉他调音，且在受控实验条件下，可将同时呈现的音调匹配误差控制在0.5赫兹以内。其中一名受试者对侧听力正常，其借助人工耳蜗完成的调音精度甚至高于其正常听力的耳朵。为阐释这些反直觉的实验发现，我们采用顺序呈现音调的实验范式，结果发现两名受试者在约30赫兹频段的调音误差均显著增大。第三名受试者为非音乐人，系人工耳蜗使用者且对侧听力正常，其在人工耳蜗与正常听力耳朵的表现上呈现出相似趋势，但精度更低。结合电信号分析结果，该差异表明：精准调音并非通过辨别音调实现，而是通过感知节拍完成，这实际上将频谱任务转化为了时间辨别任务。