Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
Adv Exp Med Biol. 2013;787:283-91. doi: 10.1007/978-1-4614-1590-9_32.
Normal-hearing individuals have sharply tuned auditory filters, and consequently their basilar-membrane (BM) impulse responses (IRs) have durations of several ms at frequencies in the range from 0 to 5 kHz. When presenting clicks that are several ms apart, the BM IRs to the individual clicks will overlap in time, giving rise to complex interactions that have not been fully understood in the human cochlea. The perceptual consequences of these BM IR interactions are of interest as lead-lag click pairs are often used to study localization and the precedence effect. The present study aimed at characterizing perceptual consequences of BM IR interactions in individual listeners based on click-evoked otoacoustic emissions (CEOAEs) and auditory brainstem responses (ABRs). Lag suppression, denoting the level difference between the CEOAE or wave-V response amplitude evoked by the first and the second clicks, was observed for inter-click intervals (ICIs) between 1 and 4 ms. Behavioral correlates of lag suppression were obtained for the same individuals by investigating the percept of the lead-lag click pairs presented either monaurally or binaurally. The click pairs were shown to give rise to fusion (i.e., the inability to hear out the second click in a lead-lag click pair), regardless of monaural or binaural presentation. In both cases, the ICI range where the percept was a fused image correlated well with the ICI range for which monaural lag suppression occurred in the CEOAE and ABR (i.e., for ICIs below 4.3 ms). Furthermore, the lag suppression observed in the wave-V amplitudes to binaural stimulation did not show additional contributions to the lag suppression obtained monaurally, suggesting that peripheral lag suppression up to the level of the brainstem is dominant in the perception of the precedence effect.
正常听力个体具有锐化的听觉滤波器，因此他们的基底膜（BM）脉冲响应（IR）在 0 到 5 kHz 范围内的频率下持续数毫秒。当呈现相隔数毫秒的 click 时，单个 click 的 BM IR 会在时间上重叠，从而产生尚未完全理解的复杂相互作用在人类耳蜗中。这些 BM IR 相互作用的感知后果很有趣，因为 lead-lag click 对常用于研究定位和优先效应。本研究旨在基于 click 诱发的耳声发射（CEOAE）和听觉脑干反应（ABR）来描述个体听力者 BM IR 相互作用的感知后果。在 1 到 4 毫秒的间隔内，观察到了第一个和第二个 click 之间的时间延迟抑制，这表示 CEOAE 或波 V 响应幅度的水平差。通过研究单耳或双耳呈现的 lead-lag click 对的感知，获得了延迟抑制的行为相关性。结果表明，无论单耳还是双耳呈现，lead-lag click 对都会产生融合（即无法听到 lead-lag click 对中的第二个 click）。在这两种情况下，感知到融合的 click 对的 ICI 范围与在 CEOAE 和 ABR 中发生单耳延迟抑制的 ICI 范围（即 ICI 低于 4.3 毫秒）非常吻合。此外，双耳刺激下观察到的波 V 幅度的延迟抑制并没有对单耳获得的延迟抑制产生额外贡献，这表明直到脑干水平的外周延迟抑制在优先效应的感知中占主导地位。
