Davies-Venn Evelyn, Souza Pamela, Brennan Marc, Stecker G Christopher
Department of Speech and Hearing Sciences, University of Washington, Seattle, Washington 98105-6246, USA.
Ear Hear. 2009 Oct;30(5):494-504. doi: 10.1097/AUD.0b013e3181aec5bc.
This study examined the effects of multichannel wide-dynamic range compression (WDRC) amplification and stimulus audibility on consonant recognition and error patterns.
Listeners had either severe or mild to moderate sensorineural hearing loss. Each listener was monaurally fit with a wearable hearing aid using typical clinical procedures, frequency-gain parameters, and a hybrid of clinically prescribed compression ratios for desired sensation level () and NAL-NL (). Consonant-vowel nonsense syllables were presented in soundfield at multiple input levels (50, 65, 80 dB SPL). Test conditions were four-channel fast-acting WDRC amplification and a control compression limiting (CL) amplification condition. Listeners identified the stimulus heard from choices presented on an on-screen display. A between-subject repeated measures design was used to evaluate consonant recognition and consonant confusion patterns.
Fast-acting WDRC provided a considerable audibility advantage at 50 dB SPL, especially for listeners with severe hearing loss. Listeners with mild to moderate hearing loss received less audibility improvement from the fast-acting WDRC amplification, for conversational and high level speech, when compared with listeners with severe hearing loss. Analysis of WDRC benefit scores revealed that listeners had slightly lower scores with fast-acting WDRC amplification (relative to CL) when WDRC provided minimal improvement in audibility. The negative effect was greater for listeners with mild to moderate hearing loss compared with their counterparts with severe hearing loss.
All listeners, but particularly the severe loss group, benefited from fast-acting WDRC amplification for low-level speech. For conversational and higher speech levels (i.e., when WDRC does not confer a significant audibility advantage), fast-acting WDRC amplification seems to slightly degrade performance. Listeners' consonant confusion patterns suggest that this negative effect may be partly due to fast-acting WDRC-induced distortions, which alter specific consonant features. In support of this view, audibility accounted for a greater percentage of the variance in listeners' performance with CL amplification compared with fast-acting WDRC amplification.
本研究探讨多通道宽动态范围压缩（WDRC）放大及刺激声可听度对辅音识别及错误模式的影响。
受试者为重度或轻至中度感音神经性听力损失患者。采用典型临床程序、频率增益参数以及临床规定的压缩比混合方案，为每位受试者单耳佩戴一款可穿戴式助听器，以实现所需的感觉级（）和NAL-NL（）。在声场中以多个输入声级（50、65、80 dB SPL）呈现辅音-元音无意义音节。测试条件为四通道快速起效WDRC放大和对照压缩限制（CL）放大条件。受试者从屏幕上显示的选项中识别所听到的刺激声。采用受试者间重复测量设计来评估辅音识别及辅音混淆模式。
快速起效WDRC在50 dB SPL时提供了显著的可听度优势，尤其对于重度听力损失患者。与重度听力损失患者相比，轻至中度听力损失患者在快速起效WDRC放大条件下，对于对话和高声级言语，可听度改善较少。对WDRC益处得分的分析表明，当WDRC在可听度方面改善甚微时，受试者在快速起效WDRC放大条件下（相对于CL）得分略低。与重度听力损失患者相比，轻至中度听力损失患者的负面影响更大。
所有受试者，尤其是重度听力损失组，在低水平言语时受益于快速起效WDRC放大。对于对话和较高声级言语（即当WDRC未赋予显著可听度优势时），快速起效WDRC放大似乎会略微降低表现。受试者的辅音混淆模式表明，这种负面影响可能部分归因于快速起效WDRC引起的失真，其改变了特定的辅音特征。支持这一观点的是，与快速起效WDRC放大相比，可听度在CL放大条件下占受试者表现方差的百分比更大。
