1 Department of Linguistics, Australian Hearing Hub, Macquarie University, Sydney, Australia.
2 The HEARing Cooperative Research Centre, Melbourne, Australia.
Trends Hear. 2017 Jan-Dec;21:2331216517706396. doi: 10.1177/2331216517706396.
Listening to speech in noise is effortful, particularly for people with hearing impairment. While it is known that effort is related to a complex interplay between bottom-up and top-down processes, the cognitive and neurophysiological mechanisms contributing to effortful listening remain unknown. Therefore, a reliable physiological measure to assess effort remains elusive. This study aimed to determine whether pupil dilation and alpha power change, two physiological measures suggested to index listening effort, assess similar processes. Listening effort was manipulated by parametrically varying spectral resolution (16- and 6-channel noise vocoding) and speech reception thresholds (SRT; 50% and 80%) while 19 young, normal-hearing adults performed a speech recognition task in noise. Results of off-line sentence scoring showed discrepancies between the target SRTs and the true performance obtained during the speech recognition task. For example, in the SRT80% condition, participants scored an average of 64.7%. Participants' true performance levels were therefore used for subsequent statistical modelling. Results showed that both measures appeared to be sensitive to changes in spectral resolution (channel vocoding), while pupil dilation only was also significantly related to their true performance levels (%) and task accuracy (i.e., whether the response was correctly or partially recalled). The two measures were not correlated, suggesting they each may reflect different cognitive processes involved in listening effort. This combination of findings contributes to a growing body of research aiming to develop an objective measure of listening effort.
在噪声环境下聆听语音是一项费力的任务，尤其是对于听力受损的人来说。虽然已知努力程度与自下而上和自上而下的过程之间的复杂相互作用有关，但导致费力聆听的认知和神经生理机制仍不清楚。因此，可靠的生理测量方法来评估努力程度仍然难以捉摸。本研究旨在确定瞳孔扩张和阿尔法功率变化这两种被认为可以指示聆听努力程度的生理测量方法是否可以评估相似的过程。通过参数化改变频谱分辨率（16 通道和 6 通道噪声语音编码）和言语接受阈值（SRT；50%和 80%）来操纵聆听努力程度，19 名年轻、正常听力的成年人在噪声中执行言语识别任务。离线句子评分的结果显示目标 SRT 与言语识别任务中的真实表现之间存在差异。例如，在 SRT80%条件下，参与者的平均得分为 64.7%。因此，参与者的真实表现水平被用于随后的统计建模。结果表明，这两种测量方法似乎都对频谱分辨率（声道语音编码）的变化敏感，而瞳孔扩张仅与他们的真实表现水平（%）和任务准确性（即，响应是否正确或部分回忆）显著相关。这两种测量方法不相关，表明它们各自可能反映了参与聆听努力的不同认知过程。这些发现的结合为旨在开发聆听努力客观测量方法的不断增长的研究做出了贡献。
