Department of ENT/Audiology and EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
Ear Hear. 2012 Mar-Apr;33(2):291-300. doi: 10.1097/AUD.0b013e3182310019.
Recent research has demonstrated that pupil dilation, a measure of mental effort (cognitive processing load), is sensitive to differences in speech intelligibility. The present study extends this outcome by examining the effects of masker type and age on the speech reception threshold (SRT) and mental effort.
In young and middle-aged adults, pupil dilation was measured while they performed an SRT task, in which spoken sentences were presented in stationary noise, fluctuating noise, or together with a single-talker masker. The masker levels were adjusted to achieve 50% or 84% sentence intelligibility.
The results show better SRTs for fluctuating noise and a single-talker masker compared with stationary noise, which replicates results of previous studies. The peak pupil dilation, reflecting mental effort, was larger in the single-interfering speaker condition compared with the other masker conditions. Remarkably, in contrast to the thresholds, no differences in peak dilation were observed between fluctuating noise and stationary noise. This effect was independent of the intelligibility level and age.
To maintain similar intelligibility levels, participants needed more mental effort for speech perception in the presence of a single-talker masker and then with the two other types of maskers. This suggests an additive interfering effect of speech information from the single-talker masker. The dissociation between these performance and mental effort measures underlines the importance of including measurements of pupil dilation as an independent index of mental effort during speech processing in different types of noisy environments and at different intelligibility levels.
最近的研究表明，瞳孔扩张（一种衡量心理努力程度的指标，即认知处理负荷）对言语可懂度的差异敏感。本研究通过考察掩蔽类型和年龄对言语接受阈（SRT）和心理努力的影响，扩展了这一结果。
在年轻和中年成年人中，当他们执行 SRT 任务时，测量了瞳孔扩张，在该任务中，以固定噪声、波动噪声或与单个说话者掩蔽器一起呈现口语句子。掩蔽器的水平被调整为实现 50%或 84%的句子可懂度。
结果表明，与固定噪声相比，波动噪声和单个说话者掩蔽器的 SRT 更好，这与先前研究的结果一致。反映心理努力的瞳孔最大扩张在单个干扰说话者条件下比其他掩蔽器条件下更大。值得注意的是，与阈值相反，在波动噪声和固定噪声之间没有观察到最大扩张的差异。这种效应独立于可懂度水平和年龄。
为了保持相似的可懂度水平，参与者在存在单个说话者掩蔽器以及另外两种掩蔽器的情况下，需要更多的心理努力来进行言语感知。这表明来自单个说话者掩蔽器的言语信息存在附加干扰效应。这些性能和心理努力测量之间的分离强调了在不同类型的噪声环境和不同的可懂度水平下，将瞳孔扩张作为言语处理过程中心理努力的独立指标进行测量的重要性。
