Sabin Andrew T, Souza Pamela E
1Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA.
Trends Amplif. 2013 Jun;17(2):94-107. doi: 10.1177/1084713813495981.
Most hearing aid prescriptions focus on the optimization of a metric derived from the long-term average spectrum of speech, and do not consider how the prescribed values might distort the temporal envelope shape. A growing body of evidence suggests that such distortions can lead to systematic errors in speech perception, and therefore hearing aid prescriptions might benefit by including preservation of the temporal envelope shape in their rationale. To begin to explore this possibility, we designed a genetic algorithm (GA) to find the multiband compression settings that preserve the shape of the original temporal envelope while placing that envelope in the listener's audiometric dynamic range. The resulting prescription had a low compression threshold, short attack and release times, and a combination of compression ratio and gain that placed the output signal within the listener's audiometric dynamic range. Initial behavioral tests of individuals with impaired hearing revealed no difference in speech-in-noise perception between the GA and the NAL-NL2 prescription. However, gap detection performance was superior with the GA in comparison to NAL-NL2. Overall, this work is a proof of concept that consideration of temporal envelope distortions can be incorporated into hearing aid prescriptions.
大多数助听器处方专注于优化从语音的长期平均频谱得出的一个指标，而没有考虑规定的值可能如何扭曲时间包络形状。越来越多的证据表明，这种扭曲会导致语音感知中的系统性误差，因此助听器处方若在其原理中纳入对时间包络形状的保留可能会有益处。为了开始探索这种可能性，我们设计了一种遗传算法（GA）来找到多频段压缩设置，该设置能保留原始时间包络的形状，同时将该包络置于听者的听力动态范围内。所得处方具有低压缩阈值、短启动和释放时间，以及将输出信号置于听者听力动态范围内的压缩比和增益组合。对听力受损个体的初步行为测试表明，GA处方和NAL-NL2处方在噪声环境下的语音感知方面没有差异。然而，与NAL-NL2相比，GA在间隙检测性能方面更优。总体而言，这项工作证明了一个概念，即对时间包络失真的考虑可以纳入助听器处方中。
