Department of Communication Sciences and Disorders, The University of Texas Rio Grande Valley, Edinburg, Texas, USA.
MAA Institute of Speech & Hearing, Hyderabad, India.
Ear Hear. 2022 May/Jun;43(3):822-835. doi: 10.1097/AUD.0000000000001140.
Humans can hear up to 20 kHz. Emerging evidence suggests that hearing in the extended high frequencies (EHFs; >8 kHz) contributes to speech perception in noise. The objective of the present study was to describe the features of EHF hearing impairment in young adults with normal standard audiograms (0.25-8 kHz). Specifically, the study goals were to: (1) characterize the EHF hearing impairment and identify potential risk factors; (2) elucidate the age-related changes in EHF hearing; (3) determine the effect of EHF hearing impairment on speech-in-noise recognition; and (4) examine the extent to which EHF hearing impairment influences cochlear functioning in the standard frequencies.
Hearing thresholds at standard frequencies and EHFs (10, 12.5, 14, and 16 kHz), and speech recognition thresholds (SRTs) using digit triplets in multi-talker babble were measured in both ears from 222 participants (19-38 years; n = 444 ears) with normal audiograms (≤20 dB HL at standard frequencies). Test-retest measurement of hearing thresholds was obtained in a subset of 50 participants (100 ears), and clinical distortion product otoacoustic emissions (f2 frequency = 2, 3, 4, and 5 kHz) were recorded in 49 participants (98 ears).
Forty-two of 222 participants had EHF hearing impairment (>20 dB HL for at least one EHF in either ear). Only seven individuals with EHF impairment had significant case history and/or listening-in-noise complaints. A breakpoint in the threshold-age function was observed for the EHFs for males but not for females. Linear mixed models revealed a significant effect of age, pure-tone averages for speech frequencies (0.5, 1, 2, and 4 kHz), and EHFs and group (NH versus EHF hearing impairment) independent of each other on the SRTs. Individuals with EHF hearing impairment had less measurable emissions and when present, had a lower magnitude of otoacoustic emissions relative to NH controls. There was no difference in hearing thresholds, SRTs, or otoacoustic emissions between earphone users and nonusers.
The hearing thresholds for the EHFs exhibit signs of early auditory aging. Age-related deterioration in auditory function can be observed in the third decade of human life. A breakpoint in the threshold-age function suggests that rapid aging processes are operational at a relatively younger age (21 years) for males. The audibility of EHFs contributes to speech-in-noise recognition. EHF hearing impairment independent of age and speech frequencies can affect speech-in-noise recognition. Reduced distortion product otoacoustic emissions in the standard frequencies may suggest preclinical cochlear degeneration in individuals with EHF hearing impairment.
人类的听觉频率最高可达 20 kHz。新出现的证据表明，在扩展高频（EHF；>8 kHz）范围内的听力有助于噪声中的言语感知。本研究的目的是描述高频听力障碍在具有正常标准听力图（0.25-8 kHz）的年轻成年人中的特征。具体而言，本研究的目标是：（1）描述 EHF 听力障碍并确定潜在的危险因素；（2）阐明 EHF 听力的年龄相关性变化；（3）确定 EHF 听力障碍对噪声中言语识别的影响；（4）检查 EHF 听力障碍对标准频率下耳蜗功能的影响程度。
对 222 名参与者（19-38 岁；n=444 耳）的标准频率（0.25-8 kHz）和 EHF（10、12.5、14 和 16 kHz）的听力阈值和多说话者噪声中的数字三音识别阈值（SRT）进行了测量，这些参与者均具有正常听力图（标准频率下的听力阈值≤20 dB HL）。在 50 名参与者（100 耳）中获得了听力阈值的重复测量，并且在 49 名参与者（98 耳）中记录了临床失真产物耳声发射（f2 频率=2、3、4 和 5 kHz）。
在 222 名参与者中，有 42 名存在 EHF 听力障碍（在一只或两只耳朵中至少有一个 EHF 的听力阈值>20 dB HL）。仅有 7 名存在 EHF 损伤的个体具有显著的病例史和/或噪声下的听力抱怨。对于男性，EHF 听力阈值与年龄之间存在明显的拐点，而对于女性则没有。线性混合模型显示，年龄、言语频率（0.5、1、2 和 4 kHz）的纯音平均值以及 EHF 和组（NH 与 EHF 听力障碍）对 SRT 有显著影响，且彼此之间没有相互影响。EHF 听力障碍的个体具有较少可测量的耳声发射，而且当存在耳声发射时，其耳声发射的幅度低于 NH 对照组。耳机使用者和非使用者之间的听力阈值、SRT 或耳声发射没有差异。
EHF 的听力阈值表现出早期听觉老化的迹象。在人类生命的第三个十年中，可以观察到听觉功能的年龄相关性恶化。阈值-年龄函数的拐点表明，对于男性来说，相对年轻（21 岁）就存在快速老化过程。EHF 的可听度有助于噪声中的言语识别。EHF 听力障碍独立于年龄和言语频率，可能会影响噪声中的言语识别。EHF 听力障碍个体的标准频率下的失真产物耳声发射减少可能表明耳蜗存在临床前退化。
