Lowery Kristy J, Plyler Patrick N
Department of Audiology and Speech Pathology, University of Tennessee, Knoxville 37996-0740, USA.
J Am Acad Audiol. 2007 Sep;18(8):641-52. doi: 10.3766/jaaa.18.8.2.
The effects of low-frequency expansion on the objective and subjective evaluation of four channel in-the-ear hearing instruments was investigated. Three expansion settings were programmed in each device: expansion off, expansion restricted to channel one, and expansion restricted to channels one and two. Objective evaluations were conducted in quiet (Connected Speech Test) and in noise (Hearing in Noise Test) with speech levels fixed at 40 dB SPL. Subjectively, each participant rated expansion satisfaction in quiet and listening to low-level speech in a sound-treated room then indicated the expansion condition preferred overall. Listeners performed significantly better in quiet and in noise for the Off and Channel 1 conditions than the Channels 1 and 2 condition; however, performance was similar between the Off and Channel 1 conditions. Expansion effects on listener satisfaction ratings depended on the listening environment. Overall, listeners preferred expansion in Channel 1 to expansion in Channels 1 and 2; however, preference was not significantly different between the Channel 1 and Off conditions. Results indicate restricting expansion to 1000 Hz overcomes speech-recognition deficits observed with expansion active across a broader spectrum without significantly reducing subjective benefit or preference.
研究了低频扩展对四通道入耳式助听器客观和主观评估的影响。在每个设备中设置了三种扩展设置：关闭扩展、仅对通道一进行扩展以及对通道一和通道二进行扩展。在安静环境（连接语音测试）和噪声环境（噪声中听力测试）中进行客观评估，语音水平固定为40 dB SPL。在主观方面，每位参与者在安静环境中以及在经过声学处理的房间里聆听低水平语音时对扩展满意度进行评分，然后指出总体上更喜欢的扩展条件。在安静和噪声环境中，对于关闭扩展和通道一条件，聆听者的表现明显优于通道一和通道二条件；然而，关闭扩展和通道一条件之间的表现相似。扩展对聆听者满意度评分的影响取决于聆听环境。总体而言，聆听者更喜欢通道一的扩展，而不是通道一和通道二的扩展；然而，通道一和关闭扩展条件之间的偏好没有显著差异。结果表明，将扩展限制在1000 Hz可以克服在更宽频谱上激活扩展时观察到的语音识别缺陷，而不会显著降低主观益处或偏好。
