Swept-tone stimulus-frequency otoacoustic emissions: Normative data and methodological considerations.

Area of Science:

• Auditory Neuroscience
• Otoacoustic Emissions Research
• Psychoacoustics

Background:

• Stimulus-frequency otoacoustic emissions (SFOAEs) are reflection-source emissions, often underutilized in audiological assessments.
• Understanding normative SFOAE data is crucial for characterizing typical auditory function and identifying deviations.

Purpose of the Study:

• To present normative SFOAE data from a large group of young adults.
• To characterize typical SFOAE levels, reliability, and phase across a wide frequency range.
• To describe methodological advances enhancing SFOAE measurement efficiency.

Main Methods:

• Measured SFOAEs in 48 young adults across a four-octave frequency range.
• Utilized probe levels from 20 to 60 dB SPL.
• Employed technical innovations including concurrent sweeping, suppressor decontamination, and artifact rejection.

Main Results:

• SFOAE levels peaked in low-to-mid frequencies (∼6-7 dB SPL) with high signal-to-noise ratios (23-34 dB SPL).
• Test-retest reliability was ±4 dB for 90% of data; females showed higher SFOAE levels than males (∼2.5 dB).
• SFOAEs exhibited linear growth at low levels, a compression threshold around 35 dB SPL, and phase accumulation indicating an apical-basal transition near 1.1 kHz.

Conclusions:

• Normative SFOAE data provide a benchmark for auditory function in young adults.
• Methodological improvements enhance the efficiency and reliability of SFOAE measurements.
• SFOAE characteristics, including phase delay, offer insights into cochlear mechanics and tonotopic organization.