Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
J Acoust Soc Am. 2019 Aug;146(2):1189. doi: 10.1121/1.5121423.
Separating sound sources in acoustic environments relies on making ongoing, highly accurate spectro-temporal comparisons. However, listeners with hearing impairment may have varying quality of temporal encoding within or across ears, which may limit the listeners' ability to make spectro-temporal comparisons between places-of-stimulation. In this study in normal hearing listeners, depth of amplitude modulation (AM) for sinusoidally amplitude modulated (SAM) tones was manipulated in an effort to reduce the coding of periodicity in the auditory nerve. The ability to judge differences in AM rates was studied for stimuli presented to different cochlear places-of-stimulation, within- or across-ears. It was hypothesized that if temporal encoding was poorer for one tone in a pair, then sensitivity to differences in AM rate of the pair would decrease. Results indicated that when the depth of AM was reduced from 50% to 20% for one SAM tone in a pair, sensitivity to differences in AM rate decreased. Sensitivity was greatest for AM rates near 90 Hz and depended upon the places-of-stimulation being compared. These results suggest that degraded temporal representations in the auditory nerve for one place-of-stimulation could lead to deficits comparing that temporal information with other places-of-stimulation.
在声环境中分离声源依赖于持续进行、高度准确的谱时比较。然而，听力受损的听众在一个或两个耳朵内的时间编码质量可能存在差异，这可能限制了听众在刺激位置之间进行谱时比较的能力。在这项正常听力听众的研究中，正弦幅度调制 (SAM) 音调的幅度调制 (AM) 深度被操纵，以努力减少听觉神经中周期性的编码。研究了在不同的耳蜗刺激位置、同一耳或对侧耳内呈现刺激时，对 AM 率差异的判断能力。假设如果一对音调中的一个音调的时间编码较差，则对该对 AM 率差异的敏感性会降低。结果表明，当一对 SAM 音调中的一个音调的 AM 深度从 50%降低到 20%时，对 AM 率差异的敏感性降低。当 AM 率接近 90 Hz 时，敏感性最大，并且取决于要比较的刺激位置。这些结果表明，一个刺激位置的听觉神经中时间表示的恶化可能导致与其他刺激位置比较该时间信息的缺陷。
