Center for Hearing Research, Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.
J Acoust Soc Am. 2018 May;143(5):2994. doi: 10.1121/1.5038274.
Loudness depends on both the intensity and spectrum of a sound. Listeners with normal hearing perceive a broadband sound as being louder than an equal-level narrowband sound because loudness grows nonlinearly with level and is then summed across frequency bands. This difference in loudness as a function of bandwidth is reduced in listeners with sensorineural hearing loss (SNHL). Suppression, the reduction in the cochlear response to one sound by the simultaneous presentation of another sound, is also reduced in listeners with SNHL. Hearing-aid gain that is based on loudness measurements with pure tones may fail to restore normal loudness growth for broadband sounds. This study investigated whether hearing-aid amplification that mimics suppression can improve loudness summation for listeners with SNHL. Estimates of loudness summation were obtained using measurements of categorical loudness scaling (CLS). Stimuli were bandpass-filtered noises centered at 2 kHz with bandwidths in the range of 0.1-6.4 kHz. Gain was selected to restore normal loudness based on CLS measurements with pure tones. Gain that accounts for both compression and suppression resulted in better restoration of loudness summation, compared to compression alone. However, restoration was imperfect, suggesting that additional refinements to the signal processing and gain-prescription algorithms are needed.
响度既取决于声音的强度又取决于其频谱。听力正常的听众会感觉到宽带声音比等电平窄带声音更响，因为响度随强度呈非线性增长，然后在频带间求和。在感音神经性听力损失（SNHL）患者中，这种带宽函数的响度差异减小。抑制是指同时呈现另一个声音时对一个声音的耳蜗反应的减少，在 SNHL 患者中也会减少。基于纯音响度测量的助听器增益可能无法恢复宽带声音的正常响度增长。本研究调查了模仿抑制的助听器放大是否可以改善 SNHL 患者的响度总和。使用类别响度标度（CLS）的测量来获得响度总和的估计。刺激为中心频率在 2 kHz 的带通噪声，带宽范围为 0.1-6.4 kHz。增益是根据纯音 CLS 测量来选择的，以恢复正常的响度。与仅压缩相比，同时考虑压缩和抑制的增益可更好地恢复响度总和。但是，恢复并不完美，这表明需要对信号处理和增益处方算法进行进一步改进。
