Subclinical conductive hearing loss significantly reduces otoacoustic emission amplitude: Implications for test performance

Distortion product otoacoustic emissions (DPOAEs) are a time-efficient, non-invasive means of assessing the integrity of active inner ear mechanics. Unfortunately, the presence of even relatively minor conductive hearing loss (CHL) has been suggested to reduce the clinical utility of DPOAEs significantly. The primary aims of this study were to systematically evaluate the impact of CHL on DPOAE amplitude and to determine if ear-specific primary tone level manipulations can be used to mitigate CHL impact and recover DPOAE measurability. For 30 young adults (57 ears) with normal hearing, DPOAEs were obtained for f2 = 1–6 kHz. Observed DPOAE amplitudes were used to generate ear- and frequency-specific models with the primary tone levels, L1 and L2, as inputs and predicted DPOAE amplitude, LDP, as output. These models were then used to simulate the effect of CHL (0–15 dB), as well as L1 manipulations (0–15 dB), on DPOAE measurability. Mean LDP for every CHL condition was significantly different from that for all other conditions (p =