Oxenham Andrew J, Bacon Sid P
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
Ear Hear. 2003 Oct;24(5):352-66. doi: 10.1097/01.AUD.0000090470.73934.78.
This article provides a review of recent developments in our understanding of how cochlear nonlinearity affects sound perception and how a loss of the nonlinearity associated with cochlear hearing impairment changes the way sounds are perceived. The response of the healthy mammalian basilar membrane (BM) to sound is sharply tuned, highly nonlinear, and compressive. Damage to the outer hair cells (OHCs) results in changes to all three attributes: in the case of total OHC loss, the response of the BM becomes broadly tuned and linear. Many of the differences in auditory perception and performance between normal-hearing and hearing-impaired listeners can be explained in terms of these changes in BM response. Effects that can be accounted for in this way include poorer audiometric thresholds, loudness recruitment, reduced frequency selectivity, and changes in apparent temporal processing. All these effects can influence the ability of hearing-impaired listeners to perceive speech, especially in complex acoustic backgrounds. A number of behavioral methods have been proposed to estimate cochlear nonlinearity in individual listeners. By separating the effects of cochlear nonlinearity from other aspects of hearing impairment, such methods may contribute towards identifying the different physiological mechanisms responsible for hearing loss in individual patients. This in turn may lead to more accurate diagnoses and more effective hearing-aid fitting for individual patients. A remaining challenge is to devise a behavioral measure that is sufficiently accurate and efficient to be used in a clinical setting.
本文综述了我们对耳蜗非线性如何影响声音感知，以及与耳蜗听力损失相关的非线性丧失如何改变声音感知方式的最新认识进展。健康哺乳动物的基底膜（BM）对声音的反应具有尖锐调谐、高度非线性和压缩性。外毛细胞（OHC）受损会导致这三个属性发生变化：在OHC完全丧失的情况下，BM的反应变得调谐宽泛且呈线性。正常听力和听力受损听众在听觉感知和表现上的许多差异都可以用BM反应的这些变化来解释。以这种方式可以解释的影响包括听力阈值较差、响度重振、频率选择性降低以及明显的时间处理变化。所有这些影响都会影响听力受损听众感知语音的能力，尤其是在复杂声学背景下。已经提出了一些行为方法来估计个体听众的耳蜗非线性。通过将耳蜗非线性的影响与听力损失的其他方面分开，这些方法可能有助于识别个体患者听力损失的不同生理机制。这反过来可能会为个体患者带来更准确的诊断和更有效的助听器适配。一个尚存的挑战是设计一种行为测量方法，该方法要足够准确和高效，以便在临床环境中使用。
