Department of Otolaryngology-Head and Neck Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan; Nissay Hospital, 6-3-8 Itachibori Nishi-ku, Osaka 550-0012, Japan.
Department of Otolaryngology-Head and Neck Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
Neurosci Lett. 2014 Jan 24;559:117-21. doi: 10.1016/j.neulet.2013.11.048. Epub 2013 Dec 4.
Speech-modulated bone-conducted ultrasound (BCU) can transmit speech sounds for some profoundly deaf individuals. Hearing aids using BCU are considered to be a novel hearing system for such individuals. In our previous study, the speech discrimination for speech-modulated BCU was objectively confirmed using a magnetoencephalography. Moreover, in our previous behavioral study, prosodic information for speech-modulated BCU could also be discriminated in the normal hearing. However, the prosodic discrimination for speech-modulated BCU has not objectively been studied. In order to evaluate the prosodic discrimination for speech-modulated BCU, mismatch fields (MMFs) elicited by prosodic and segmental change were measured for speech-modulated BCU and air-conducted speech. Ten Japanese participants with normal hearing took part in this study. Stimuli re-synthesized from the speech of a native Japanese female adult were used. Standard stimulus was /itta/ with a flat pitch pattern, and two deviant stimuli were /itta?/ with a rising pitch pattern and /itte/ with a flat pitch pattern. All and nine participants elicited the prominent MMF elicited by the prosodic and segmental change for the speech-modulated BCU, respectively. The moment of MMF components for speech-modulated BCU was significantly smaller than those for air-conducted speech, while no difference in the MMF latency elicited by the prosodic and segmental change were observed between both stimulus conditions. Comparing the MMFs elicited by prosodic and segmental change, no significant differences were observed for both stimulus conditions. Thus, it is suggested that the prosodic change can be discriminate to the same degree as segmental change even for speech-modulated BCU. However, discrimination capability for speech-modulated BCU is slightly inferior to that for air-conducted speech.
语音调制骨导超声（BCU）可将语音信号传输给一些深度聋患者。使用 BCU 的助听器被认为是这些患者的一种新型听力系统。在我们之前的研究中，使用脑磁图客观地证实了语音调制 BCU 的语音辨别能力。此外，在我们之前的行为研究中，也可以在正常听力中辨别语音调制 BCU 的韵律信息。然而，语音调制 BCU 的韵律辨别能力尚未得到客观研究。为了评估语音调制 BCU 的韵律辨别能力，测量了语音调制 BCU 和空气传导语音中韵律和音段变化引起的失匹配场（MMF）。10 名听力正常的日本参与者参加了这项研究。使用来自日本成年女性语音的再合成刺激。标准刺激为/itta/，具有平坦的音高模式，两个偏差刺激为/itta?/，具有上升的音高模式和/itte/，具有平坦的音高模式。所有参与者和 9 名参与者分别诱发出语音调制 BCU 和空气传导语音的韵律和音段变化引起的显著 MMF。语音调制 BCU 的 MMF 成分的时刻明显小于空气传导语音，而在两种刺激条件下，韵律和音段变化引起的 MMF 潜伏期没有差异。比较韵律和音段变化引起的 MMF，两种刺激条件均无显著差异。因此，即使对于语音调制 BCU，也可以以相同的程度辨别韵律变化。然而，语音调制 BCU 的辨别能力略逊于空气传导语音。
