Limiting spectral resolution in speech for listeners with sensorineural hearing loss.
Limiting spectral resolution in speech for listeners with sensorineural hearing loss.
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DOI：
10.1044/jslhr.4204.773
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发表时间：
1999-08
期刊：
影响因子：
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通讯作者：
C. Turner;Siu-Ling Chi;Sarah Flock
中科院分区：
文献类型：
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作者：
C. Turner;Siu-Ling Chi;Sarah Flock
在听力正常的听者和中度感音神经性听力损失的听者中，辅音识别被测量为语音刺激的频谱分辨率的函数。以前的工作(Turner，Souza和Forget，1995)已经表明，当语言被处理成只有一个光谱分辨率的通道时，感音神经性听力损失的听者可以识别辅音，而听力正常的听者也可以识别辅音。目前实验中测试的假设是，当语言被限制在少数光谱通道时，正常听力和听力受损的听众都会继续表现出类似的表现。随着刺激呈现出更精细的光谱分辨率，而听力受损的听众的光谱分辨率低于正常水平成为一个限制因素，可以预测听力受损的听众的表现将变得比正常听力的听众更差。之前对轻中度听力损失听众的频率分辨率能力的研究表明，这些听众的关键带宽比听力正常的听众大三到四倍。在本实验中，语音刺激被处理成具有1、2、4或8个通道的光谱信息。单声道语音条件的结果与之前的研究一致，因为两组听者的表现相似。然而，听力受损的听者在所有其他条件下的表现都比正常听者差，包括双声道语音条件。这些结果似乎与最初的假设相矛盾，因为中度感音神经性听力损失的听众预计至少有2个频道的频率分辨率。一种可能性是，听力受损的听众的频率分辨率可能比之前估计的要差得多；然而，随后的过滤语音实验并不支持这一解释。目前的结果确实表明，尽管听力损失的听者能够以正常的方式使用单个通道的时间包络信息，但当被给予机会合并多个通道的信息时，他们表现出不足的性能。
Consonant recognition was measured as a function of the degree of spectral resolution of the speech stimulus in normally hearing listeners and listeners with moderate sensorineural hearing loss. Previous work (Turner, Souza, and Forget, 1995) has shown that listeners with sensorineural hearing loss could recognize consonants as well as listeners with normal hearing when speech was processed to have only one channel of spectral resolution. The hypothesis tested in the present experiment was that when speech was limited to a small number of spectral channels, both normally hearing and hearing-impaired listeners would continue to perform similarly. As the stimuli were presented with finer degrees of spectral resolution, and the poorer-than-normal spectral resolving abilities of the hearing-impaired listeners became a limiting factor, one would predict that the performance of the hearing-impaired listeners would then become poorer than the normally hearing listeners. Previous research on the frequency-resolution abilities of listeners with mild-to-moderate hearing loss suggests that these listeners have critical bandwidths three to four times larger than do listeners with normal hearing. In the present experiment, speech stimuli were processed to have 1, 2, 4, or 8 channels of spectral information. Results for the 1-channel speech condition were consistent with the previous study in that both groups of listeners performed similarly. However, the hearing-impaired listeners performed more poorly than the normally hearing listeners for all other conditions, including the 2-channel speech condition. These results would appear to contradict the original hypothesis, in that listeners with moderate sensorineural hearing loss would be expected to have at least 2 channels of frequency resolution. One possibility is that the frequency resolution of hearing-impaired listeners may be much poorer than previously estimated; however, a subsequent filtered speech experiment did not support this explanation. The present results do indicate that although listeners with hearing loss are able to use the temporal-envelope information of a single channel in a normal fashion, when given the opportunity to combine information across more than one channel, they show deficient performance.