TOWARDS ELECTRICALLY EVOKED OTOACOUSTIC EMISSIONS IN HUMANS

Current objective diagnostics of hearing, such as otoacoustic emissions, electrocochleography, auditory brainstem responses, steady-state responses, and cortical responses, rely on acoustic stimulation. These techniques struggle to accurately assess low-frequency cochlear mechanics and hearing loss below 500 Hz because of poor signal-to-noise ratios (Alamanda and Hohman, 2025). This leads to a risk of misdiagnosis, for example in newborns with residual low-frequency hearing who may receive cochlear implants that compromise their remaining function. The aim of this study is to investigate neurosensory mechanisms of low-frequency hearing using electrically evoked otoacoustic emissions, which offer targeted hair-cell-specific measurements without acoustic artifacts. As hair cells can be excited through electrophonic stimulation, which modulates their membrane potential, using electrical stimulation can provide insights of the fundamental mechanism behind hair-cell activation. The findings can provide knowledge on the cause and reason of residual hearing, while also offering the opportunity for developing new diagnostic tools for low-frequency hearing. In this study, we developed and validated a new experimental setup for examining low-frequency residual hearing by first recording conventional acoustic OAEs. Pilot measurements in normal hearing listeners further demonstrated that the electric stimulation delivered through this setup elicits auditory sensations and the results indicate electrically evoked otoacoustic emissions.