使用行为学和耳声发射测量方法进行的压迫估计
Compression estimates using behavioral and otoacoustic emission measures.
作者信息
Williams Erica J, Bacon Sid P
机构信息
Psychoacoustics Laboratory, Department of Speech and Hearing Science, Arizona State University, P.O. Box 870102, Tempe, AZ 85287-0102, USA.
出版信息
Hear Res. 2005 Mar;201(1-2):44-54. doi: 10.1016/j.heares.2004.10.006.
Cochlear compression in normal-hearing listeners was estimated at octave frequencies from 250 to 4000 Hz using a forward-masking paradigm. Temporal masking curves (TMCs) for a 10-dB SL signal were obtained with two maskers -- one equal in frequency to the signal and another an octave below the signal. The ratio of the slope of the off-frequency function to that of the mid-level portion of the on-frequency function was computed as an estimate of the amount of compression at each frequency. Compression was less frequency selective at low frequencies, so an average of the off-frequency slopes at high frequencies (1000, 2000, and 4000 Hz) was used in computing the ratio for each signal frequency. Results indicated strong compression (approximately 0.15-0.30) at all frequencies using the averaged off-frequency slopes, indicating little difference in compression across frequencies. Distortion product otoacoustic emission (DPOAE) input-output (I-O) functions were obtained for each subject at 1000, 2000, and 4000 Hz. The slopes of the DPOAE I-O functions and the psychophysical growth rates were similar to one another, reinforcing the assumption that the forward-masking procedure is providing an estimate of cochlear compression, at least at frequencies from 1000 to 4000 Hz.
使用前掩蔽范式,在250至4000Hz的倍频程频率上估计正常听力受试者的耳蜗压缩。用两个掩蔽音获得10dB SL信号的时间掩蔽曲线(TMC)——一个掩蔽音的频率与信号相等,另一个掩蔽音的频率比信号低一个倍频程。计算偏离频率函数的斜率与频率匹配部分的中间电平部分的斜率之比,作为每个频率处压缩量的估计值。低频时压缩的频率选择性较低,因此在计算每个信号频率的比率时,使用高频(1000、2000和4000Hz)处偏离频率斜率的平均值。结果表明,使用平均偏离频率斜率时,所有频率处均存在强烈压缩(约0.15 - 0.30),表明不同频率的压缩差异不大。为每个受试者在1000、2000和4000Hz处获得畸变产物耳声发射(DPOAE)输入 - 输出(I - O)函数。DPOAE I - O函数的斜率与心理物理增长率相似,这进一步支持了前掩蔽程序至少在1000至4000Hz频率上提供耳蜗压缩估计的假设。