Sisto Renata, Moleti Arturo
Dipartimento Igiene del Lavoro, ISPESL, Via Fontana Candida, 1, 00040 Monte Porzio Catone, Roma, Italy.
J Acoust Soc Am. 2007 Oct;122(4):2183-90. doi: 10.1121/1.2769981.
Cochlear latency has been evaluated in young adults by time-frequency analysis of transient evoked otoacoustic emissions recorded using the nonlinear acquisition mode at different levels of the click stimulus. Objective, even if model-dependent, estimates of cochlear tuning have been obtained from the otoacoustic latency estimates. Transmission-line cochlear models predict that the transient-evoked otoacoustic emission latency is dependent on the stimulus level, because the bandwidth of the cochlear filter (tuning) depends on the local cochlear excitation level due to nonlinear damping. The results of this study confirm the increase of tuning with increasing frequency and show clearly the decrease of latency and tuning with increasing stimulus level. This decrease is consistent with the expected relation between the slowing down of the traveling wave near the tonotopic place and the cochlear excitation amplitude predicted by cochlear models including nonlinear damping. More specifically, these results support the models in which nonlinear damping consists of a quadratic term and a constant positive term.
通过对使用非线性采集模式在不同强度点击刺激下记录的瞬态诱发耳声发射进行时频分析，对年轻成年人的耳蜗潜伏期进行了评估。即使依赖模型，也已从耳声潜伏期估计中获得了耳蜗调谐的客观估计。传输线耳蜗模型预测，瞬态诱发耳声发射潜伏期取决于刺激强度，因为耳蜗滤波器（调谐）的带宽取决于由于非线性阻尼导致的局部耳蜗兴奋水平。本研究结果证实了调谐随频率增加而增加，并清楚地表明潜伏期和调谐随刺激强度增加而减小。这种减小与耳蜗模型（包括非线性阻尼）预测的在音调定位处附近行波减慢与耳蜗兴奋幅度之间的预期关系一致。更具体地说，这些结果支持非线性阻尼由二次项和恒定正项组成的模型。
