Schulte Alina, Marozeau Jeremy, Kral Andrej, Innes-Brown Hamish
Department of Experimental Otology of the Clinics of Otolaryngology, Institute for AudioNeuroTechnology (VIANNA), Hannover Medical School, Hannover, Germany.
Eriksholm Research Center, Oticon A/S, Snekkersten, Denmark.
Sci Rep. 2025 Jul 12;15(1):25202. doi: 10.1038/s41598-025-07718-8.
Combined auditory and tactile stimuli have been found to enhance speech-in-noise perception both in individuals with normal hearing and in those with hearing loss. While behavioral benefits of audio-tactile enhancements in speech understanding have been repeatedly demonstrated, the impact of vibrotactile cues on cortical auditory speech processing remains unknown. Using functional near-infrared spectroscopy (fNIRS) with a dense montage setup, we first identified a region-of-interest highly sensitive to auditory-only speech-in-quiet. In the same region, we then assessed the change in activity ('audio-tactile gains') when presenting speech-in-noise together with a single-channel vibratory signal to the fingertip, congruent with the speech envelope's rate of change. In data from 21 participants with normal hearing, audio-tactile speech elicited on average 20% greater hemodynamic oxygenation changes than auditory-only speech-in-noise within bilateral middle and superior temporal gyri. However, audio-tactile gains did not exceed the sum of the unisensory responses, providing no conclusive evidence of true multisensory integration. Our results support a metamodal theory for the processing of temporal speech features in the middle and superior temporal gyri, providing the first evidence of audio-tactile speech processing in auditory areas using fNIRS. Top-down modulations from somatosensory areas or attention networks likely contributed to the observed audio-tactile gains through temporal entrainment with the speech envelope's rate of change. Further research is needed to understand the neural responses in concordance with their behavioral relevance for speech perception, offering future directions for developing tactile aids for individuals with hearing impairments.
研究发现，听觉和触觉刺激相结合能够增强听力正常者和听力损失者在噪声环境下的言语感知能力。虽然听觉-触觉增强对言语理解的行为益处已得到反复证实，但振动触觉线索对皮质听觉言语处理的影响仍不明确。我们使用密集蒙太奇设置的功能性近红外光谱技术（fNIRS），首先确定了一个对仅听觉安静言语高度敏感的感兴趣区域。然后，在同一区域，我们评估了在向指尖呈现噪声言语并伴有单通道振动信号时（该信号与言语包络的变化率一致）活动的变化（“听觉-触觉增益”）。在21名听力正常参与者的数据中，双侧颞中回和颞上回内，听觉-触觉言语引发的血液动力学氧合变化平均比仅听觉噪声言语大20%。然而，听觉-触觉增益并未超过单感觉反应的总和，没有提供真正多感觉整合的确凿证据。我们的研究结果支持了颞中回和颞上回中言语时间特征处理的元模态理论，首次提供了使用fNIRS在听觉区域进行听觉-触觉言语处理的证据。来自体感区域或注意力网络的自上而下调制可能通过与言语包络变化率的时间同步，促成了观察到的听觉-触觉增益。需要进一步研究以了解与言语感知行为相关性一致的神经反应，为开发听力障碍者的触觉辅助设备提供未来方向。
