Restoring binaural hearing abilities to bilateral cochlear implant users

 描述（由申请人提供）：虽然人工耳蜗植入物已成功地使重度至极重度听力损失患者能够理解语言，但在定位声音方向和噪声中理解语言等任务中的表现仍然具有挑战性。听力正常的人的双耳听力有助于这些任务，但双侧人工耳蜗植入术并没有提供相同程度的益处。这种缺陷大部分源于现代人工耳蜗（CI）中声音转换为电刺激的方式。 现代CI通过将传入的声学信号划分为多个通道并使用恒定的高速率电脉冲序列对每个通道进行编码来进行操作。已知这种处理会影响对耳间时间差（ITD）的敏感性，这是一种对噪声环境中的声音定位和语音理解很重要的双耳cu。在双侧CI用户中，存在一个难题，即在低刺激率下出现良好的ITD敏感性，但更好的语音理解需要高刺激率。所提出的解决方案通常混合不同通道处的刺激速率，其中在低频通道中使用低速率，而在高频通道中使用高速率。这种方法假设ITD，在正常听力的听众中在低频的主导线索，应该出现在耳蜗对低频最敏感的地方。然而，在双边CI用户的ITD敏感性的测量表明，这一假设可能不一定成立，这表明，替代方法可以考虑在CI中提出ITD。 本研究的目的是测量在何种程度上带限频率调制（FM）编码内的高速率电脉冲序列可以增加双耳听力的好处，在双边CI用户。与使用混合刺激速率的解决方案相比，编码FM的新奇在于ITD提示可以呈现在所有通道上，从而最大化所有CI用户的ITD灵敏度。这项工作的目标将是证明使用FM编码来提高双耳听力能力的双边CI用户，一个结果，迄今为止还没有实现的可行性。我们的重点将是确定最佳的FM参数，最大限度地提高ITD的灵敏度，在双边CI用户。改善双耳听力能力的双边CI用户将有一个积极的影响，他们如何在日常听力的情况下，通过减少疲劳时，在嘈杂的环境中交谈，并提高学习成果的儿童双边CI通过帮助直接注意在嘈杂的教室。此外，从这些实验中获得的结果可能会影响其他听觉植入式假体，如听觉中脑和脑干植入物的信号处理的发展。

 DESCRIPTION (provided by applicant): While cochlear implants have been successful in enabling speech understanding in people who have severe-to-profound hearing loss, performance in tasks such as locating the direction of a sound and speech understanding in noise remains challenging. These tasks are aided with binaural hearing in people with normal hearing, but bilateral cochlear implantation has not provided the same degree of benefit. Much of this deficit arises from the way sounds are converted into electrical stimulation in modern day cochlear implants (CIs). Modern CIs operate by dividing the incoming acoustic signal into a number of channels and encoding each channel with a constant high-rate electrical pulse train. This processing is known to affect sensitivity to interaural time differences (ITDs), a binaural cu important for sound localization and speech understanding in noisy situations. In bilateral CI users, a conundrum exists where good ITD sensitivity occurs with low rates of stimulation but better speech understanding requires high rates of stimulation. Proposed solutions typically mix rates of stimulation at different channels, where low rates are used in low frequency channels while high rates are used in high frequency channels. This approach assumes that ITDs, a dominant cue at low frequencies in normal hearing listeners, should be presented where the cochlea is most sensitive to low frequencies. However, measurements of ITD sensitivity in bilateral CI users show that this assumption may not necessarily hold true, suggesting that alternate approaches can be considered for presenting ITDs in CIs. The objective of this research is to measure the extent to which bandlimited frequency modulations (FM) encoded within a high-rate electrical pulse train can increase binaural hearing benefits in bilateral CI users. In contrast to solutions that use mixed stimulation rates, the novelty of encoding FM is that ITD cues can be presented on all channels and thereby maximize ITD sensitivity in all CI users. The goal of this work will be to demonstrate the feasibility of using FM encoding to improve the binaural hearing abilities of bilateral CI users, an outcome that has not been achievable to date. Our focus will be on determining optimal FM parameters for maximizing ITD sensitivity in bilateral CI users. Improving the binaural hearing abilities of bilateral CI users wll have a positive impact on how they interact in everyday listening situations, by decreasing fatigue when conversing in noisy environments, and improving learning outcomes in children with bilateral CIs by helping to direct attention in a noisy classroom. In addition, the results obtained from these experiments may influence signal processing developments in other auditory implantable prostheses such as auditory mid-brain and brainstem implants.