Music and tone perception with dichotic stimulations

描述(申请人提供)：在过去的二十年里，许多极聋的人从人工耳蜗术中受益。人工耳蜗提供的言语感知已被证明是相当成功的。然而，用目前的人工耳蜗系统来感知音调语言中的音乐或词汇音调仍然是一个挑战。这是因为仅由几个电极提供的电刺激中的低光谱分辨率阻止了音调信息的传输。本研究项目旨在研究双侧植入对提高频谱分辨率，从而改善音乐和音调知觉的可能益处。对于双侧植入物，可以用更多的频段来分析输入信号，这些频段的数量等于两个植入物中的电极总数。声道将被二分分配，即奇数索引声道被分配给一只耳朵，偶数索引声道被分配给另一只耳朵。因此，两种植入物中的每个电极都会收到独一无二但精炼两倍的光谱信息。与分配相同通道或重复光谱信息的传统双侧植入物相比，这一新策略将双侧植入物的光谱分辨率提高了一倍。建议的新策略将使用噪声激励声码器进行模拟，并在双侧种植患者中进行验证。这项研究的具体目的是(1)评估通过双眼刺激将光谱分辨率加倍的新策略对音乐和音调感知的好处；(2)测试在操纵两个植入物的相对位置的条件下，双眼呈现的刺激融合得如何。对于音乐感知，将使用传统的熟悉旋律识别测试。此外，还将使用改进的旋律测试，要求听者检测旋律中特定音符的音高变化。对于词汇声调知觉，将使用四种选择的强迫选择范式。语音测试(即辅音和元音识别测试)也将包括在这两个具体目标中。本研究的结果将进一步加深我们对复杂信号在声学和电学中的光谱融合机制的认识。这一策略的成功将极大地改善双侧种植体对音乐和音调的感知，从而显著提高双侧种植体使用者的生活质量。

DESCRIPTION (provided by applicant): Many profoundly deafened people have benefited from cochlear implant in the past twenty years. Speech perception provided by cochlear implants has proven to be quite successful. It is still a challenge, however, to perceive music or lexical tone in tone languages with the current cochlear implant system. That is because the low spectral resolution in the electric stimulation provided by only a few electrodes prevents pitch information from being transmitted. The present research project is proposed to examine the possible benefits that bilateral implantation provides for increasing spectral resolution, hence improving music and tone perception. With a bilateral implant, an input signal can be analyzed with more frequency bands, the number of which equals the total number of electrodes in both implants. The channels are to be dichotically distributed, that is, the odd-index channels are assigned to one ear, and the even-index channel assigned to the other. Each electrode in both implants therefore receives exclusive but twice as refined spectral information. This new strategy doubles spectral resolution in bilateral implants compared to traditional bilateral implants that are assigned with same channels or repeated spectral information. The proposed new strategy will be simulated using a noise-excited vocoder and validated in bilateral implant patients. The specific aims of the study are (1) to evaluate how much music and tone perception benefits from the new strategy that doubles spectral resolution via dichotic stimulation; and (2) to test how well the dichotically presented stimuli fuse under conditions in which the relative position of the two implants is manipulated. For music perception, a traditional familiar melody recognition test will be used. In addition, a modified melody test will be used, in which the listeners are required to detect pitch changes made to particular notes in a melody. For lexical tone perception, a four-alternative forced choice paradigm will be used. Speech tests (i.e., consonant and vowel recognition tests) will also be included in both specific aims. The results of the present study will further our knowledge regarding the mechanisms of spectral fusion of complex signals in both acoustic and electric hearing. The success of this strategy will greatly improve music and tone perception with bilateral implantation, hence considerably improving the life quality of bilateral implant users.