Biomedical Engineering, City College of New York, New York City, NY, United States of America.
J Neural Eng. 2019 Jun;16(3):036008. doi: 10.1088/1741-2552/ab07fe. Epub 2019 Feb 18.
Speech signals have a remarkable ability to entrain brain activity to the rapid fluctuations of speech sounds. For instance, one can readily measure a correlation of the sound amplitude with the evoked responses of the electroencephalogram (EEG), and the strength of this correlation is indicative of whether the listener is attending to the speech. In this study we asked whether this stimulus-response correlation is also predictive of speech intelligibility.
We hypothesized that when a listener fails to understand the speech in adverse hearing conditions, attention wanes and stimulus-response correlation also drops. To test this, we measure a listener's ability to detect words in noisy speech while recording their brain activity using EEG. We alter intelligibility without changing the acoustic stimulus by pairing it with congruent and incongruent visual speech.
For almost all subjects we found that an improvement in speech detection coincided with an increase in correlation between the noisy speech and the EEG measured over a period of 30 min.
We conclude that simultaneous recordings of the perceived sound and the corresponding EEG response may be a practical tool to assess speech intelligibility in the context of hearing aids.
语音信号具有使大脑活动与语音快速波动同步的显著能力。例如，可以很容易地测量声音幅度与脑电图（EEG）诱发反应之间的相关性，而这种相关性的强度表明听众是否在关注语音。在这项研究中，我们询问这种刺激-反应相关性是否也可以预测语音可懂度。
我们假设当听者在不利的听力条件下无法理解语音时，注意力会减弱，刺激-反应相关性也会下降。为了验证这一点，我们在使用 EEG 记录大脑活动的同时，测量了听者在噪声语音中检测单词的能力。我们通过将其与一致和不一致的视觉语音配对来改变可懂度，而不改变声刺激。
对于几乎所有的受试者，我们发现，在 30 分钟的时间内，语音检测的改善与噪声语音与 EEG 之间的相关性增加相吻合。
我们的结论是，同时记录感知声音和相应的 EEG 反应可能是评估助听器环境中语音可懂度的一种实用工具。
