Moore B C, Vickers D A, Glasberg B R, Baer T
Department of Experimental Psychology, University of Cambridge, England.
Br J Audiol. 1997 Aug;31(4):227-45. doi: 10.3109/03005369709076796.
Simulations of hearing impairment were presented to the normal ears of subjects with moderate to severe unilateral cochlear hearing loss. The intelligibility of speech in quiet and in background sounds was compared with that obtained for the impaired ears using unprocessed stimuli. The results of loudness matches between the two ears were used to tailor a simulation of threshold elevation combined with loudness recruitment individually for each subject. This was assessed either alone, or in combination with a simulation of reduced frequency selectivity, performed by spectral smearing. Finally, we included a simulation of 'dead' regions in the cochlea, where there are assumed to be no functioning inner hair cells and/or neurones, by band-stop filtering over the frequency range corresponding to the dead region. Performance for the impaired ears was markedly worse than for the normal ears using the simulation of threshold elevation and loudness recruitment. The addition of the simulation of reduced frequency selectivity caused performance to worsen, but it remained above that for the impaired ears. The additional simulation of a dead region had little effect, except for one subject, for whom it produced performance comparable to that for the impaired ear in quiet but not when background sounds were present. It is suggested that the relatively poor results for the impaired ears may be caused partly by a form of 'neglect' which is specific to subjects with unilateral or asymmetric loss. This idea was supported by results obtained using bilaterally hearing-impaired subjects, which were markedly better than for the impaired ears of the unilaterally hearing-impaired subjects, and comparable to those for the normal ears listening to the combined simulation of threshold elevation, loudness recruitment and reduced frequency selectivity.
对患有中度至重度单侧耳蜗性听力损失的受试者的正常耳朵进行了听力损伤模拟。将安静环境和背景声音中的言语可懂度与使用未处理刺激时患耳的言语可懂度进行了比较。利用双耳之间响度匹配的结果，为每个受试者单独定制阈值升高与响度重振相结合的模拟。这一模拟单独进行评估，或与通过频谱模糊进行的频率选择性降低模拟相结合进行评估。最后，我们通过在对应于死区的频率范围内进行带阻滤波，对耳蜗中的“死”区进行了模拟，在这些区域假定没有功能正常的内毛细胞和/或神经元。使用阈值升高和响度重振模拟时，患耳的表现明显比正常耳朵差。增加频率选择性降低的模拟会使表现变差，但仍高于患耳的表现。除了一名受试者外，死区的额外模拟几乎没有影响，对于该受试者，在安静环境中其表现与患耳相当，但在有背景声音时则不然。有人认为，患耳相对较差的结果可能部分是由一种“忽视”形式导致的，这种形式是单侧或不对称听力损失受试者所特有的。使用双侧听力受损受试者获得的结果支持了这一观点，这些结果明显优于单侧听力受损受试者的患耳，并且与正常耳朵在听阈值升高、响度重振和频率选择性降低综合模拟时的结果相当。
