Dorman Michael F, Natale Sarah Cook, Butts Austin M, Zeitler Daniel M, Carlson Matthew L
*Department of Speech and Hearing Science, Arizona State University, Tempe, Arizona †Virginia Mason Medical Center, Seattle, Washington ‡Mayo Clinic, Rochester, Minnesota.
Otol Neurotol. 2017 Sep;38(8):e268-e273. doi: 10.1097/MAO.0000000000001449.
The goal of the present study was to assess the sound quality of a cochlear implant for single-sided deaf (SSD) patients fit with a cochlear implant (CI).
One of the fundamental, unanswered questions in CI research is "what does an implant sound like?" Conventional CI patients must use the memory of a clean signal, often decades old, to judge the sound quality of their CIs. In contrast, SSD-CI patients can rate the similarity of a clean signal presented to the CI ear and candidate, CI-like signals presented to the ear with normal hearing.
For Experiment 1 four types of stimuli were created for presentation to the normal hearing ear: noise vocoded signals, sine vocoded signals, frequency shifted, sine vocoded signals and band-pass filtered, natural speech signals. Listeners rated the similarity of these signals to unmodified signals sent to the CI on a scale of 0 to 10 with 10 being a complete match to the CI signal. For Experiment 2 multitrack signal mixing was used to create natural speech signals that varied along multiple dimensions.
In Experiment 1 for eight adult SSD-CI listeners, the best median similarity rating to the sound of the CI for noise vocoded signals was 1.9; for sine vocoded signals 2.9; for frequency upshifted signals, 1.9; and for band pass filtered signals, 5.5. In Experiment 2 for three young listeners, combinations of band pass filtering and spectral smearing lead to ratings of 10.
The sound quality of noise and sine vocoders does not generally correspond to the sound quality of cochlear implants fit to SSD patients. Our preliminary conclusion is that natural speech signals that have been muffled to one degree or another by band pass filtering and/or spectral smearing provide a close, but incomplete, match to CI sound quality for some patients.
本研究的目的是评估为单侧聋（SSD）患者植入人工耳蜗（CI）后的声音质量。
人工耳蜗研究中一个基本的、尚未得到解答的问题是“植入物听起来是什么样的？”传统人工耳蜗患者必须依靠通常几十年前的纯净信号记忆来判断其人工耳蜗的声音质量。相比之下，SSD-CI患者可以对呈现给植入耳的纯净信号与呈现给正常听力耳的类似人工耳蜗的候选信号的相似性进行评分。
在实验1中，创建了四种类型的刺激用于呈现给正常听力耳：噪声声码器信号、正弦声码器信号、频移正弦声码器信号和带通滤波的自然语音信号。听众对这些信号与发送到人工耳蜗的未修改信号的相似性进行评分，评分范围为0至10，10表示与人工耳蜗信号完全匹配。在实验2中，使用多轨信号混合来创建沿多个维度变化的自然语音信号。
在实验1中，对于8名成年SSD-CI听众，噪声声码器信号与人工耳蜗声音的最佳中位数相似性评分为1.9；正弦声码器信号为2.9；频移信号为1.9；带通滤波信号为5.5。在实验2中，对于3名年轻听众，带通滤波和频谱模糊的组合导致评分为10。
噪声和声码器的声音质量通常与适合SSD患者的人工耳蜗的声音质量不对应。我们的初步结论是，经过带通滤波和/或频谱模糊而在一定程度上被模糊的自然语音信号，为一些患者提供了与人工耳蜗声音质量接近但不完全匹配的结果。
