Department of Speech, Language and Hearing Sciences, 1846Boston University, Boston, MA, United States.
Department of Biomedical Engineering, 1846Boston University, Boston, MA, United States.
Trends Hear. 2022 Jan-Dec;26:23312165221095357. doi: 10.1177/23312165221095357.
While many studies have reported a loss of sensitivity to interaural time differences (ITDs) carried in the fine structure of low-frequency signals for listeners with hearing loss, relatively few data are available on the perception of ITDs carried in the envelope of high-frequency signals in this population. The relevant studies found stronger effects of hearing loss at high frequencies than at low frequencies in most cases, but small subject numbers and several confounding effects prevented strong conclusions from being drawn. In the present study, we revisited this question while addressing some of the issues identified in previous studies. Participants were ten young adults with normal hearing (NH) and twenty adults with sensorineural hearing impairment (HI) spanning a range of ages. ITD discrimination thresholds were measured for octave-band-wide "rustle" stimuli centered at 500 Hz or 4000 Hz, which were presented at 20 or 40 dB sensation level. Broadband rustle stimuli and 500-Hz pure-tone stimuli were also tested. Thresholds were poorer on average for the HI group than the NH group. The ITD deficit, relative to the NH group, was similar at low and high frequencies for most HI participants. For a small number of participants, however, the deficit was strongly frequency-dependent. These results provide new insights into the binaural perception of complex sounds and may inform binaural models that incorporate effects of hearing loss.
虽然许多研究报告称，听力损失患者对低频信号精细结构中携带的两耳时间差（ITD）的敏感性降低，但关于高频信号包络中携带的 ITD 的感知，相关数据相对较少。在大多数情况下，相关研究发现高频听力损失的影响比低频更强，但由于受试者数量较少和多种混杂因素，无法得出强有力的结论。在本研究中，我们在解决之前研究中发现的一些问题的同时，重新研究了这个问题。参与者包括 10 名听力正常的年轻人（NH）和 20 名年龄不等的感音神经性听力障碍成年人（HI）。我们测量了以 500Hz 或 4000Hz 为中心的 8 倍频带宽“沙沙”声刺激的 ITD 辨别阈值，这些刺激在 20 或 40dB 感觉水平下呈现。还测试了宽带“沙沙”声刺激和 500Hz 纯音刺激。平均而言，HI 组的阈值比 NH 组差。对于大多数 HI 参与者，相对于 NH 组，低频和高频的 ITD 缺陷相似。然而，对于少数参与者，缺陷强烈依赖于频率。这些结果为复杂声音的双耳感知提供了新的见解，并可能为包含听力损失影响的双耳模型提供信息。
