Dennison Stephen R, Thakkar Tanvi, Kan Alan, Svirsky Mario A, Azadpour Mahan, Litovsky Ruth Y
Waisman Center, University of Wisconsin-Madison, Madison, WI 53706, USA.
Department of Psychology, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA.
J Clin Med. 2024 Mar 26;13(7):1917. doi: 10.3390/jcm13071917.
Bilaterally implanted cochlear implant (CI) users do not consistently have access to interaural time differences (ITDs). ITDs are crucial for restoring the ability to localize sounds and understand speech in noisy environments. Lack of access to ITDs is partly due to lack of communication between clinical processors across the ears and partly because processors must use relatively high rates of stimulation to encode envelope information. Speech understanding is best at higher stimulation rates, but sensitivity to ITDs in the timing of pulses is best at low stimulation rates. We implemented a practical "mixed rate" strategy that encodes ITD information using a low stimulation rate on some channels and speech information using high rates on the remaining channels. The strategy was tested using a bilaterally synchronized research processor, the CCi-MOBILE. Nine bilaterally implanted CI users were tested on speech understanding and were asked to judge the location of a sound based on ITDs encoded using this strategy. Performance was similar in both tasks between the control strategy and the new strategy. We discuss the benefits and drawbacks of the sound coding strategy and provide guidelines for utilizing synchronized processors for developing strategies.
双侧植入人工耳蜗（CI）的用户并不能始终如一地利用双耳时间差（ITD）。ITD对于恢复声音定位能力以及在嘈杂环境中理解语音至关重要。无法利用ITD部分是由于双耳临床处理器之间缺乏通信，部分是因为处理器必须使用相对较高的刺激率来编码包络信息。语音理解在较高刺激率下最佳，但对脉冲定时中ITD的敏感度在低刺激率下最佳。我们实施了一种实用的“混合率”策略，该策略在一些通道上使用低刺激率编码ITD信息，在其余通道上使用高刺激率编码语音信息。该策略使用双边同步研究处理器CCi-MOBILE进行了测试。对九名双侧植入CI的用户进行了语音理解测试，并要求他们根据使用该策略编码的ITD判断声音的位置。在控制策略和新策略之间，两项任务的表现相似。我们讨论了声音编码策略的优缺点，并为利用同步处理器开发策略提供了指导方针。
