KU Leuven, Department of Neurosciences, ExpORL, Herestraat 49 Bus 721, B-3000, Leuven, Belgium.
Hear Res. 2020 Aug;393:107961. doi: 10.1016/j.heares.2020.107961. Epub 2020 May 12.
Elevated hearing thresholds in hearing impaired adults are usually compensated by providing amplification through a hearing aid. In spite of restoring hearing sensitivity, difficulties with understanding speech in noisy environments often remain. One main reason is that sensorineural hearing loss not only causes loss of audibility but also other deficits, including peripheral distortion but also central temporal processing deficits. To investigate the neural consequences of hearing impairment in the brain underlying speech-in-noise difficulties, we compared EEG responses to natural speech of 14 hearing impaired adults with those of 14 age-matched normal-hearing adults. We measured neural envelope tracking to sentences and a story masked by different levels of a stationary noise or competing talker. Despite their sensorineural hearing loss, hearing impaired adults showed higher neural envelope tracking of the target than the competing talker, similar to their normal-hearing peers. Furthermore, hearing impairment was related to an additional increase in neural envelope tracking of the target talker, suggesting that hearing impaired adults may have an enhanced sensitivity to envelope modulations or require a larger differential neural tracking of target versus competing talker to segregate speech from noise. Lastly, both normal-hearing and hearing impaired participants showed an increase in neural envelope tracking with increasing speech understanding. Hence, our results open avenues towards new clinical applications, such as neuro-steered prostheses as well as objective and automatic measurements of speech understanding performance.
听力受损成年人的听力阈值升高通常通过助听器提供放大来补偿。尽管恢复了听力敏感度，但在嘈杂环境中理解言语的困难仍然存在。一个主要原因是，感音神经性听力损失不仅导致可听度丧失，还导致其他缺陷，包括外围失真和中央时处理缺陷。为了研究言语感知困难背后的大脑中听力损伤的神经后果，我们比较了 14 名听力受损成年人和 14 名年龄匹配的正常听力成年人对自然语音的 EEG 反应。我们测量了句子和故事的神经包络跟踪，这些句子和故事被不同水平的固定噪声或竞争说话者掩蔽。尽管听力受损成年人存在感音神经性听力损失，但他们对目标的神经包络跟踪高于竞争说话者，与正常听力成年人相似。此外，听力损伤与目标说话者的神经包络跟踪的额外增加有关，这表明听力受损成年人可能对包络调制具有更高的敏感性，或者需要更大的目标与竞争说话者之间的神经跟踪差异来将言语与噪声分离。最后，正常听力和听力受损参与者的神经包络跟踪都随着言语理解能力的提高而增加。因此，我们的研究结果为新的临床应用开辟了道路，例如神经引导的假体以及言语理解性能的客观和自动测量。
