School of Speech, Language, and Hearing Sciences, San Diego State University, CA.
National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR.
J Speech Lang Hear Res. 2023 Aug 3;66(8):2950-2966. doi: 10.1044/2023_JSLHR-23-00013. Epub 2023 Jul 19.
Distortion product otoacoustic emissions (DPOAEs) provide an objective assessment of cochlear function and are used for serial ototoxicity monitoring in pediatric cancer patients. DPOAEs are modeled as having distortion (near ) and reflection (near 2-) component sources, and developmental changes are observed in these components' relative strengths in infants compared with adults. However, little is known about source component strengths in childhood or at extended high frequencies (EHFs; > 8 kHz). Thus, the purpose of this study was to describe the effects of age and stimulus frequency on DPOAE components in children.
DPOAEs were collected with varied frequency ratios (/ = 1.1-1.25) for a wide range of frequencies (2-16 kHz) in 39 younger (3-6 years) and 41 older (10-12 years) children with constant levels (L/L) of 65/50 dB SPL. A depth-compensated simulator sound pressure level method of calibration was employed. A time waveform representation of the results across various ratios was created to estimate peak pressures and latencies of each DPOAE component.
Estimated peak pressures of DPOAE components revealed the greatest differences in DPOAE sources between children occurring at the highest frequencies tested, where the peak pressure of both components was largest for younger compared with older children. Latency differences between the children were only noted at higher frequencies for the distortion component.
These results suggest that DPOAE levels decrease with age and reflection emissions are vulnerable to cochlear change. This work guides optimization of protocols for pediatric ototoxicity monitoring, whereby including EHF otoacoustic emissions is clearly warranted and choosing to isolate DPOAE sources may prove beneficial.
畸变产物耳声发射（DPOAE）可提供耳蜗功能的客观评估，并用于儿科癌症患者的连续耳毒性监测。DPOAE 被建模为具有失真（近）和反射（近 2-）分量源，并且在婴儿与成人相比，这些分量的相对强度在发育过程中会发生变化。然而，对于儿童或扩展高频（EHF；>8kHz），源分量强度知之甚少。因此，本研究的目的是描述年龄和刺激频率对儿童 DPOAE 分量的影响。
在 39 名年龄较小（3-6 岁）和 41 名年龄较大（10-12 岁）的儿童中，使用变化的频率比（/=1.1-1.25）收集 DPOAE，频率范围很广（2-16kHz），恒定水平（L/L）为 65/50dB SPL。采用深度补偿模拟器声压级方法进行校准。创建了各种比率的结果的时间波形表示，以估计每个 DPOAE 分量的峰值压力和潜伏期。
DPOAE 分量的估计峰值压力显示了儿童之间 DPOAE 源之间的最大差异，这些差异发生在测试的最高频率，其中两个分量的峰值压力对于年幼的儿童而言最大。仅在较高频率下才注意到儿童之间的潜伏期差异，对于失真分量而言。
这些结果表明，DPOAE 水平随年龄降低，反射发射易受耳蜗变化影响。这项工作指导了儿科耳毒性监测协议的优化，其中包括 EHF 耳声发射显然是有必要的，并且选择分离 DPOAE 源可能是有益的。
