双向滤波法去除瞬态诱发耳声发射检测中的刺激伪迹

在瞬态诱发耳声发射信号检测中,去除刺激伪迹最传统的方法是“引出的非线性响应”法。但因其赖以成立的假设条件无法精确成立,会造成明显刺激伪迹残留,限制了对与刺激伪迹有重叠的短潜伏期高频耳蜗响应的检测。窗函数法和小波变换方法可在一定程度上减少刺激伪迹残留,但仍未解决对高频响应的检测问题。本文提出了双向滤波法去除刺激伪迹,避免了滤波时刺激伪迹影响后传的趋势。物理模拟实验及106例瞬态诱发耳声发射信号实测结果表明:与现有方法相比,该方法可进一步减少刺激伪迹残留,拓展不受刺激伪迹污染的信号区间;并能检测出潜伏期更短、强度更大的高频瞬态诱发耳声发射信号。同时,该方法简便易行,便于在实时检测系统中实现。

Stimulus artifact reduction by bidirectional filtering in transient evoked otoacoustic emissions recording

In the detection of transient evoked otoacoustic emissions (TEOAEs), the commonly used stimulus artifact reduction scheme is Derived NonLinear Response (DNLR). But obvious stimulus artifact will be left if only DNLR is used because the assumptions DNLR based on are not precisely met. The residual stimulus artifact inhibits the examination of high frequency cochlear responses with short latencies. Time window and wavelet based methods were applied to suppress the large residual component of stimulus artifact left after DNLR. Whereas these two methods are still not able to solve the difficulty of high frequency TEOAEs extraction, although they improve artifact reduction. To solve these problems, we propose an artifact reduction technique bidirectional filtering that avoids the leakage of artifact to the subsequent signals while filtering. Physical simulation and 106 clinical TEOAEs detection tests with bidirectional filtering showed that the proposed method is much more effective in reducing stimulus artifact than time window and wavelet based methods, as it not only expands the time region of TEOAEs uncontaminated by stimulus artifact but also detects out more TEOAEs with higher frequencies and shorter latencies. Moreover, it can be easily implemented in a real-time TEOAEs detection system.