Distortion-product otoacoustic emissions measured using synchronized swept-sines.

Area of Science:

• Audiology
• Bioacoustics
• Otoacoustic Emissions

Background:

• Evoked otoacoustic emissions (OAEs) are crucial for hearing diagnostics.
• Current measurement techniques like Fourier analysis, heterodyne method, and least-square-fitting (LSF) have limitations in speed or computational demand.
• Distortion-product otoacoustic emissions (DPOAEs) are a specific type of OAE used to assess cochlear function.

Purpose of the Study:

• To adapt and validate a swept-sine technique for extracting DPOAEs.
• To introduce and verify the synchronized swept-sines (SSS) method for DPOAE measurement.
• To compare the computational efficiency and accuracy of the SSS technique against established methods like LSF.

Main Methods:

• Utilized a technique for direct emission extraction from intermodulation impulse response, originally proposed for exponential swept-sines.
• Employed adjusted formulas for exponential swept-sines to generate synchronized swept-sines (SSSs) for accurate DPOAE phase extraction.
• Validated the SSS technique using data from a numerical cochlear model and human subject measurements.

Main Results:

• The SSS technique successfully extracted DPOAEs evoked by simultaneous swept-sines.
• Validation showed comparable results to the noise-robust least-square-fitting (LSF) technique.
• The SSS method demonstrated significantly lower computational demands compared to LSF.

Conclusions:

• The synchronized swept-sines (SSS) technique is a viable and efficient method for measuring DPOAEs.
• SSS offers a computationally advantageous alternative for DPOAE extraction, suitable for both modeling and human subject studies.
• This technique enhances the speed and accessibility of high-resolution OAE measurements.