Department of Computational Linguistics, University of Zurich, Zurich, Switzerland.
Department of Comparative Language Science, University of Zurich, Zurich, Switzerland; Center for Neuroscience Zurich, University and ETH of Zurich, Zurich, Switzerland; University Research Priority Program (URPP) Dynamics of Healthy Aging, University of Zurich, Zurich, Switzerland; Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland; Cognitive Psychology Unit, Alpen-Adria University, Klagenfurt, Austria.
Cortex. 2022 Jun;151:133-146. doi: 10.1016/j.cortex.2022.02.017. Epub 2022 Mar 19.
The alignment between low-frequency activity in the brain and slow acoustic modulations in the speech signal depicts a core principle in present theories of speech perception-a process referred to as 'neural speech tracking'. While most older adults, particularly those with highly prevalent age-related hearing loss, have difficulties with speech perception and comprehension, the impact of hearing loss on neural speech tracking is still unclear. In this study we investigated the effects of pure-tone hearing loss and different types of background noise on the neural tracking response in a large sample of older adults (N = 101). Furthermore, we examined whether the neural tracking response was predictive for speech comprehension. For this purpose, we obtained scalp EEG from our participants who had varying degrees of pure-tone hearing loss (7.5-59.6 dB HL for .5-8 kHz pure tones) while they listened to sentences in quiet, pink and multi-talker babble noise. Speech tracking was quantified by computing the cross-correlation between the EEG signal and the amplitude envelope of the sentences heard. A higher degree of pure-tone hearing loss was associated with greater neural speech tracking (i.e., greater cross-correlation). Additionally, neural speech tracking showed a positive association with speech comprehension. This relationship was modulated by the degree of pure-tone hearing loss with hearing-impaired participants benefitting more from greater neural speech tracking. Our results highlight the potential of neural speech tracking as an objective measure of speech comprehension and as a possible target mechanism for clinical interventions such as neurofeedback. Furthermore, the interaction between speech tracking and pure-tone hearing loss suggests a compensatory mechanism by which the hearing-impaired rely more on slow amplitude modulations in the speech signal.
大脑低频活动与言语信号中的慢声调制之间的一致性描绘了言语感知理论中的一个核心原则——即“神经言语跟踪”。虽然大多数老年人，尤其是那些有普遍存在的与年龄相关的听力损失的老年人，在言语感知和理解方面存在困难，但听力损失对神经言语跟踪的影响仍不清楚。在这项研究中，我们调查了纯音听力损失和不同类型的背景噪声对大样本老年人（N=101）的神经跟踪反应的影响。此外，我们还研究了神经跟踪反应是否可以预测言语理解能力。为此，我们从听力损失程度不同（0.5-8kHz 纯音为 7.5-59.6dBHL）的参与者那里获得了头皮 EEG，他们在安静、粉红噪声和多说话者噪声环境中听句子。通过计算参与者听到的句子的 EEG 信号和幅度包络之间的互相关来量化言语跟踪。较高的纯音听力损失程度与更大的神经言语跟踪（即更高的互相关）相关。此外，神经言语跟踪与言语理解呈正相关。这种关系受到纯音听力损失程度的调节，听力受损的参与者从更大的神经言语跟踪中受益更多。我们的结果突出了神经言语跟踪作为言语理解的客观测量指标的潜力，以及作为神经反馈等临床干预的潜在目标机制的潜力。此外，言语跟踪和纯音听力损失之间的相互作用表明，听力受损者更多地依赖言语信号中的慢幅度调制，这是一种补偿机制。
