Li Bei, Hou Limin, Xu Li, Wang Hui, Yang Guang, Yin Shankai, Feng Yanmei
Department of Otolaryngology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
College of Communication and Information Engineering, Shanghai University, Shanghai 200000, China.
Hear Res. 2015 Aug;326:66-74. doi: 10.1016/j.heares.2015.04.004. Epub 2015 Apr 25.
The present study examined the effects of steep high-frequency sensorineural hearing loss (SHF-SNHL) on speech recognition using acoustic temporal fine structure (TFS) in the low-frequency region where the absolute thresholds appeared to be normal. In total, 28 participants with SHF-SNHL were assigned to 3 groups according to the cut-off frequency (1, 2, and 4 kHz, respectively) of their pure-tone absolute thresholds. Fourteen age-matched normal-hearing (NH) individuals were enrolled as controls. For each Mandarin sentence, the acoustic TFS in 10 frequency bands (each 3-ERB wide) was extracted using the Hilbert transform and was further lowpass filtered at 1, 2, and 4 kHz. Speech recognition scores were compared among the NH and 1-, 2-, and 4-kHz SHF-SNHL groups using stimuli with varying bandwidths. Results showed that speech recognition with the same TFS-speech stimulus bandwidth differed significantly in groups and filtering conditions. Sentence recognition in quiet conditions was better than that in noise. Compared with the NH participants, nearly all the SHF-SNHL participants showed significantly poorer sentence recognition within their frequency regions with "normal hearing" (defined clinically by normal absolute thresholds) in both quiet and noisy conditions. These may result from disrupted auditory nerve function in the "normal hearing" low-frequency regions.
本研究使用绝对阈值似乎正常的低频区域的声学时间精细结构（TFS），考察了陡降型高频感音神经性听力损失（SHF-SNHL）对言语识别的影响。共有28名SHF-SNHL参与者根据其纯音绝对阈值的截止频率（分别为1、2和4kHz）被分为3组。招募了14名年龄匹配的听力正常（NH）个体作为对照。对于每个汉语句子，使用希尔伯特变换提取10个频带（每个频带宽3倍等效矩形带宽）中的声学TFS，并在1、2和4kHz处进一步进行低通滤波。使用不同带宽的刺激，比较NH组以及1kHz、2kHz和4kHz SHF-SNHL组的言语识别分数。结果表明，在不同组和滤波条件下，相同TFS言语刺激带宽的言语识别存在显著差异。安静条件下的句子识别优于噪声条件下的。与NH参与者相比，几乎所有SHF-SNHL参与者在安静和噪声条件下，在其具有“正常听力”（临床上由正常绝对阈值定义）的频率区域内，句子识别都显著较差。这些可能是由于“正常听力”低频区域的听神经功能受损所致。
