Rasetshwane Daniel M, Gorga Michael P, Neely Stephen T
IEEE Trans Biomed Eng. 2014 Jan;61(1):64-75. doi: 10.1109/TBME.2013.2276351. Epub 2013 Aug 2.
Because frequency components interact nonlinearly with each other inside the cochlea, the loudness growth of tones is relatively simple in comparison to the loudness growth of complex sounds. The term suppression refers to a reduction in the response growth of one tone in the presence of a second tone. Suppression is a salient feature of normal cochlear processing and contributes to psychophysical masking. Suppression is evident in many measurements of cochlear function in subjects with normal hearing, including distortion-product otoacoustic emissions (DPOAEs). Suppression is also evident, to a lesser extent, in subjects with mild-to-moderate hearing loss. This paper describes a hearing-aid signal-processing strategy that aims to restore both loudness growth and two-tone suppression in hearing-impaired listeners. The prescription of gain for this strategy is based on measurements of loudness by a method known as categorical loudness scaling. The proposed signal-processing strategy reproduces measured DPOAE suppression tuning curves and generalizes to any number of frequency components. The restoration of both normal suppression and normal loudness has the potential to improve hearing-aid performance and user satisfaction.
由于频率成分在耳蜗内会相互非线性作用，因此与复合声音的响度增长相比，纯音的响度增长相对简单。抑制一词是指在第二个纯音存在时，第一个纯音的反应增长有所降低。抑制是正常耳蜗处理过程的一个显著特征，并且会导致心理声学掩蔽。在听力正常受试者的许多耳蜗功能测量中，包括畸变产物耳声发射（DPOAE），抑制现象都很明显。在轻度至中度听力损失的受试者中，抑制现象也在较小程度上明显存在。本文描述了一种助听器信号处理策略，旨在恢复听力受损听众的响度增长和双音抑制。该策略的增益处方基于一种称为分类响度标度法的响度测量。所提出的信号处理策略能够重现测得的DPOAE抑制调谐曲线，并可推广到任意数量的频率成分。恢复正常抑制和正常响度有可能改善助听器性能和用户满意度。
