Johannesen Peter T, Lopez-Poveda Enrique A
Unidad de Audición Computacional y Psicoacústica, Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, 37007 Salamanca, Spain.
J Acoust Soc Am. 2010 Jun;127(6):3602-13. doi: 10.1121/1.3377087.
Previous studies have shown a high within-subject correspondence between distortion product otoacoustic emission (DPOAE) input/output (I/O) curves and behaviorally inferred basilar membrane (BM) I/O curves for frequencies above approximately 2 kHz. For lower frequencies, DPOAE I/O curves contained notches and plateaus that did not have a counterpart in corresponding behavioral curves. It was hypothesized that this might improve by using individualized optimal DPOAE primary levels. Here, data from previous studies are re-analyzed to test this hypothesis by comparing behaviorally inferred BM I/O curves and DPOAE I/O curves measured with well-established group-average primary levels and two individualized primary level rules: one optimized to maximize DPOAE levels and one intended for primaries to evoke comparable BM responses at the f(2) cochlear region. Test frequencies were 0.5, 1, and 4 kHz. Behavioral I/O curves were obtained from temporal (forward) masking curves. Results showed high within-subject correspondence between behavioral and DPOAE I/O curves at 4 kHz only, regardless of the primary level rule. Plateaus and notches were equally common in low-frequency DPOAE I/O curves for individualized and group-average DPOAE primary levels at 0.5 and 1 kHz. Results are discussed in terms of the adequacy of DPOAE I/O curves for inferring individual cochlear nonlinearity characteristics.
以往研究表明，对于频率高于约2kHz的情况，畸变产物耳声发射（DPOAE）输入/输出（I/O）曲线与行为学推断的基底膜（BM）I/O曲线之间存在较高的受试者内一致性。对于较低频率，DPOAE I/O曲线包含在相应行为曲线中没有对应物的凹口和平坦段。据推测，通过使用个体化的最佳DPOAE初级水平，这种情况可能会得到改善。在此，对以往研究的数据进行重新分析，通过比较行为学推断的BM I/O曲线与使用既定的组平均初级水平以及两种个体化初级水平规则测量得到的DPOAE I/O曲线来检验这一假设：一种规则是优化以最大化DPOAE水平，另一种规则是使初级刺激在f(2)耳蜗区域诱发可比的BM反应。测试频率为0.5、1和4kHz。行为I/O曲线从时间（前向）掩蔽曲线获得。结果显示，仅在4kHz时，行为学和DPOAE I/O曲线之间存在较高的受试者内一致性，与初级水平规则无关。在0.5和1kHz时，对于个体化和组平均DPOAE初级水平而言，低频DPOAE I/O曲线中的平坦段和凹口同样常见。将根据DPOAE I/O曲线在推断个体耳蜗非线性特征方面的充分性来讨论结果。
