Häusler R, Colburn S, Marr E
Acta Otolaryngol Suppl. 1983;400:1-62. doi: 10.3109/00016488309105590.
In order to get a systematic picture of how various hearing impairments and neurologic disorders may affect sound localization, psychophysical spatial- and lateralization-discrimination measurements were performed on 140 subjects, including 69 with different types of hearing impairments, 32 with neurological diseases, and 39 with normal hearing. The quantities measured were: in the freefield, the horizontal minimum audible angle (MAA) at eight reference azimuths around the head and the vertical MAA straight ahead; with headphones, the just-noticeable difference (JND) in interaural time delay and the JND in interaural intensity difference. The standard stimulus was broadband (0.25-10 kHz), pulsed (1-sec), noise presented at a suprathreshold level for both ears (65-100 dB SPL). The results show that there exist characteristic impairments of sound localization in the different types of hearing impairments tested. On a general level, the results are consistent with the concept that the localization of sound relies on a decision made by the central auditory system based on a number of cues present in the acoustic signal at the two ears. The cues tested in our study are: 1) the interaural time difference, 2) the interaural intensity difference, and 3) the spectrum of the received signal at each ear. At a more specific level, the sound localization impairments found in conductive hearing losses are interpreted as bone-conduction effects, the results found in sensorineural hearing losses are interpreted as consequences of impaired or preserved spectral processing, the results in neurinomas are interpreted as impaired signal transmission in the auditory nerves, and the results of subjects with central involvements suggest that separate processors exist at some level in the central auditory system for the different localization cues. Finally, comments are made about the practical clinical significance of sound localization tests in the audiological and neurological evaluation of patients.
为了系统了解各种听力障碍和神经疾病如何影响声音定位，对140名受试者进行了心理物理学空间辨别和侧向化辨别测量，其中包括69名患有不同类型听力障碍的受试者、32名患有神经疾病的受试者以及39名听力正常的受试者。测量的量包括：在自由声场中，头部周围八个参考方位的水平最小可听角（MAA）以及正前方的垂直MAA；使用耳机时，双耳间时间延迟的刚可察觉差异（JND）和双耳间强度差异的JND。标准刺激是宽带（0.25 - 10 kHz）、脉冲式（1秒）、双耳阈上水平（65 - 100 dB SPL）呈现的噪声。结果表明，在所测试的不同类型听力障碍中存在声音定位的特征性损害。总体而言，结果与声音定位依赖于中枢听觉系统根据双耳声信号中存在的多种线索做出决策的概念一致。我们研究中测试的线索有：1）双耳间时间差，2）双耳间强度差，3）每只耳朵接收到的信号频谱。在更具体的层面上，传导性听力损失中发现的声音定位损害被解释为骨传导效应，感音神经性听力损失的结果被解释为频谱处理受损或保留的后果，神经瘤的结果被解释为听神经中信号传输受损，而有中枢受累受试者的结果表明，中枢听觉系统在某些层面上存在针对不同定位线索的独立处理器。最后，对声音定位测试在患者听力和神经评估中的实际临床意义进行了评论。
