Early detection of cochlear damage is essential to mitigate the long-term effects of hearing loss—especially when the damage is not evident on a standard audiogram. One promising early marker of such subclinical pathology is hearing loss in the extended high frequencies (EHFs), even when thresholds from 250 Hz to 8 kHz remain within normal limits. However, the consequences of EHF loss and its relationship to cochlear integrity at standard frequencies remain poorly understood. The present study investigated whether EHF hearing loss is associated with altered cochlear compression, as estimated by distortion product otoacoustic emission (DPOAE) input/output functions. Sixty young adults (ages 18–30) with clinically normal hearing completed the Noise Exposure Structured Interview and DPOAE testing at 1, 2, 4, and 6 kHz. Cochlear compression metrics—low-level slope, compression slope, and compression threshold—were derived using two-segment piecewise linear modeling. Preliminary results revealed a significant age-related decline in EHF sensitivity, and poorer EHF thresholds were significantly associated with reduced DPOAEs and elevated compression thresholds at 4 and 6 kHz. These findings suggest that early basal cochlear damage may compromise nonlinear cochlear function at lower frequencies. Findings will be discussed in relation to emerging models of early-stage auditory pathology.
Aryal et al. (Wed,) studied this question.