Distortion product otoacoustic emissions stimulated through bone conduction

Objective: To demonstrate the viability of bone conduction as a novel method for stimulation of distortion product otoacoustic emissions (DPOAEs). Design: DPOAEs were recorded from a single ear of 23 normally hearing adults using bone and air conduction for the delivery of stimulus tones. Exploration of the input-output function was performed by varying stimulus frequency and magnitude. Results: Bone-stimulated emissions demonstrated similar characteristics to those obtained through standard air transmission techniques. Characteristic nonlinear DPOAE growth was found as the magnitude of the higher frequency stimulus tone, L-2, was increased monotonically with other parameters fixed. Bilateral stimulation due to using bone conduction did not saturate the mechanisms of emission suppression. Emission magnitude was not altered substantially by occlusion of the ear canal. Conclusion: Bone conduction can be used successfully to elicit DPOAEs. Absolute comparison of air-and bone-stimulated DPOAEs was difficult because of imprecise calibration of the bone conductors for each individual and particular placement. Properties unique to bone conduction, such as simultaneous bilateral stimulation and reduction of stimulus magnitude in the ear canal, may make bone conduction attractive for clinical measurement of DPOAEs.