Mehr M A, Turner C W, Parkinson A
Department of Speech Pathology and Audiology, University of Iowa, Iowa City 52242, USA.
J Acoust Soc Am. 2001 Jan;109(1):359-66. doi: 10.1121/1.1322021.
The purpose of this study was to develop and validate a method of estimating the relative "weight" that a multichannel cochlear implant user places on individual channels, indicating its contribution to overall speech recognition. The correlational method as applied to speech recognition was used both with normal-hearing listeners and with cochlear implant users fitted with six-channel speech processors. Speech was divided into frequency bands corresponding to the bands of the processor and a randomly chosen level of corresponding filtered noise was added to each channel on each trial. Channels in which the signal-to-noise ratio was more highly correlated with performance have higher weights, and conversely, channels in which the correlations were smaller have lower weights. Normal-hearing listeners showed approximately equal weights across frequency bands. In contrast, cochlear implant users showed unequal weighting across bands, and varied from individual to individual with some channels apparently not contributing significantly to speech recognition. To validate these channel weights, individual channels were removed and speech recognition in quiet was tested. A strong correlation was found between the relative weight of the channel removed and the decrease in speech recognition, thus providing support for use of the correlational method for cochlear implant users.
本研究的目的是开发并验证一种方法，用于估计多通道人工耳蜗使用者赋予各个通道的相对“权重”，以此表明该通道对整体语音识别的贡献。将相关方法应用于语音识别，该方法既用于听力正常的听众，也用于配备六通道语音处理器的人工耳蜗使用者。语音被划分为与处理器频段相对应的频带，并且在每次试验中，为每个通道添加随机选择的相应滤波噪声水平。信噪比与表现相关性更高的通道具有更高的权重，反之，相关性较小的通道具有较低的权重。听力正常的听众在各个频带上的权重大致相等。相比之下，人工耳蜗使用者在各频段上的权重并不相等，且因人而异，有些通道显然对语音识别的贡献不大。为了验证这些通道权重，去除各个通道并测试安静环境下的语音识别。发现去除通道的相对权重与语音识别下降之间存在很强的相关性，从而为人工耳蜗使用者使用相关方法提供了支持。
