In DPOAE (distortion product otoacoustic emissions) testing, the emission frequency most commonly measured to assess outer hair cell function is generated at which frequency relative to the two primary tones f1 and f2?
- A f1 + f2
- B f2 - f1
- C 2f1 - f2 ✓
- D 3f1 - 2f2
Explanation
In DPOAE testing, two primary tones f1 and f2 (with f2/f1 ratio of approximately 1.2) are delivered to the ear. The basilar membrane's nonlinear properties (driven by outer hair cell electromotility/prestin activity) generate intermodulation distortion products. The most prominent and clinically used distortion product is at the cubic difference tone frequency 2f1 - f2 (e.g., if f1 = 1 kHz and f2 = 1.2 kHz, the DPOAE is at 0.8 kHz). This emission is absent or reduced when outer hair cells are damaged (as in NIHL, ototoxicity, or cochlear hearing loss > 30–40 dB), making DPOAEs a sensitive objective test of cochlear (outer hair cell) integrity.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.