Moore Brian C J
All India Institute of Speech and Hearing, Manasagangothri, Mysore, India.
J Acoust Soc Am. 2007 Jul;122(1):542-53. doi: 10.1121/1.2722055.
Regions in the cochlea with no (or very few) functioning inner hair cells and/or neurons are called "dead regions" (DRs). The recognition of high-pass filtered nonsense syllables was measured as a function of filter cutoff frequency for hearing-impaired people with and without low-frequency (apical) cochlear DRs. The diagnosis of any DR was made using the TEN(HL) test, and psychophysical tuning curves were used to define the edge frequency (f(e)) more precisely. Stimuli were amplified differently for each ear, using the "Cambridge formula." For subjects with low-frequency hearing loss but without DRs, scores were high (about 78%) for low cutoff frequencies, remained approximately constant for cutoff frequencies up to 862 Hz, and then worsened with increasing cutoff frequency. For subjects with low-frequency DRs, performance was typically poor for the lowest cutoff frequency (100 Hz), improved as the cutoff frequency was increased to about 0.57f(e), and worsened with further increases. These results indicate that people with low-frequency DRs are able to make effective use of frequency components that fall in the range 0.57f(e) to f(e), but that frequency components below 0.57f(e) have deleterious effects. The results have implications for the fitting of hearing aids to people with low-frequency DRs.
耳蜗中没有（或极少）功能正常的内毛细胞和/或神经元的区域被称为“死区”（DRs）。针对有无低频（顶端）耳蜗死区的听力受损者，测量了对高通滤波无意义音节的识别能力与滤波器截止频率的函数关系。使用TEN(HL)测试对任何死区进行诊断，并使用心理物理调谐曲线更精确地定义边缘频率（f(e)）。使用“剑桥公式”对每只耳朵的刺激进行不同程度的放大。对于低频听力损失但无死区的受试者，低截止频率时得分较高（约78%），截止频率高达862Hz时得分大致保持不变，然后随着截止频率增加而变差。对于有低频死区的受试者，最低截止频率（100Hz）时表现通常较差，随着截止频率增加到约0.57f(e)表现有所改善，进一步增加则变差。这些结果表明，有低频死区的人能够有效利用落在0.57f(e)至f(e)范围内的频率成分，但低于0.57f(e)的频率成分有有害影响。这些结果对为有低频死区的人 fitting助听器具有启示意义。 （注：“fitting”在这里可能是“适配”之类的意思，原词可能有误，推测应该是“fitting of hearing aids”即“助听器适配” ）
