Institute of Sound and Vibration Research, University of Southampton, Southampton, Hampshire, SO17 1BJ, United Kingdom.
J Acoust Soc Am. 2013 Aug;134(2):1348-57. doi: 10.1121/1.4812272.
A bilateral advantage for diotically presented stimuli has been observed for cochlear implant (CI) users and is suggested to be dependent on symmetrical implant performance. Studies using CI simulations have not shown a true "bilateral" advantage, but a "better ear" effect and have demonstrated that performance decreases with increasing basalward shift in insertion depth. This study aimed to determine whether there is a bilateral advantage for CI simulations with interaurally matched insertions and the extent to which performance is affected by interaural insertion depth mismatch. Speech perception in noise and self-reported ease of listening were measured using matched bilateral, mismatched bilateral and unilateral CI simulations over four insertion depths for seventeen normal hearing listeners. Speech scores and ease of listening reduced with increasing basalward shift in (interaurally matched) insertion depth. A bilateral advantage for speech perception was only observed when the insertion depths were interaurally matched and deep. No advantage was observed for small to moderate interaural insertion-depth mismatches, consistent with a better ear effect. Finally, both measures were poorer than expected for a better ear effect for large mismatches, suggesting that misalignment of the electrode arrays may prevent a bilateral advantage and detrimentally affect perception of diotically presented speech.
双侧优势已在人工耳蜗（CI）使用者中观察到，并且被认为依赖于对称的植入性能。使用 CI 模拟的研究并未显示出真正的“双侧”优势，而是显示出“更好的耳朵”效应，并表明随着插入深度向基底方向的增加，性能会下降。本研究旨在确定在具有耳间匹配插入的 CI 模拟中是否存在双侧优势，以及性能受耳间插入深度不匹配的影响程度。对于 17 名正常听力的听众，使用匹配的双侧、不匹配的双侧和单侧 CI 模拟，在四个插入深度下测量噪声中的言语感知和自我报告的聆听舒适度。随着（耳间匹配的）插入深度向基底方向的增加，言语得分和聆听舒适度降低。仅当插入深度耳间匹配且较深时，才观察到言语感知的双侧优势。对于较小到中等的耳间插入深度不匹配，没有观察到优势，这与“更好的耳朵”效应一致。最后，对于较大的不匹配，这两个指标都比预期的“更好的耳朵”效应差，这表明电极阵列的不对准可能会阻止双侧优势，并对双侧呈现的言语感知产生不利影响。
