Papsin B C, Abel S M, Nedzelski J M
Department of Otolaryngology, University of Toronto, Canada.
Laryngoscope. 1994 Sep;104(9):1092-8. doi: 10.1288/00005537-199409000-00008.
Frequency selectivity was compared in subjects with hearing loss due to acoustic neuroma and cochlear pathology, and normal listeners. A particular interest was the role of probe tone parameters on the shape of the tuning curve. Psychophysical tuning curves (PTCs) were measured for each of two equal energy 2000-Hz probe tones (10 dB SL/300 msec and 17 dB SL/60 msec), using simultaneous 1/3-octave narrow-band noise maskers centered at 1, 1.25, 1.6, 2.5, 3.15, and 4 kHz. The results showed that the critical masker levels obtained for impaired listeners were significantly greater than those from normal subjects. The slope of the low-frequency limb of the PTC was steeper for normal compared to hearing-impaired listeners but there was no difference due to site of lesion. In all three groups, the critical masker levels obtained with the short probe were significantly greater than those for the long probe, negating the hypothesis that equal energy probes would yield the same outcomes. Tuning in listeners with hearing loss was highly correlated with audiometric threshold but not with tumor size, width of the internal auditory canal, or tumor location within the cerebellopontine angle. The main conclusion was that cochlear and retrocochlear hearing loss are similar with respect to their effect on frequency selectivity.
对因听神经瘤和耳蜗病变导致听力损失的受试者以及正常听力者的频率选择性进行了比较。特别感兴趣的是探测音参数对调谐曲线形状的作用。使用以1、1.25、1.6、2.5、3.15和4 kHz为中心的同时1/3倍频程窄带噪声掩蔽器，对两个等能量的2000 Hz探测音（10 dB SL/300毫秒和17 dB SL/60毫秒）分别测量心理物理调谐曲线（PTC）。结果表明，听力受损受试者获得的临界掩蔽水平明显高于正常受试者。与听力受损的受试者相比，正常受试者的PTC低频段斜率更陡，但病变部位没有差异。在所有三组中，短探测音获得的临界掩蔽水平明显高于长探测音，这否定了等能量探测音会产生相同结果的假设。听力损失受试者的调谐与听力阈值高度相关，但与肿瘤大小、内耳道宽度或小脑脑桥角内的肿瘤位置无关。主要结论是，耳蜗性和蜗后性听力损失对频率选择性的影响相似。
