Clinical Audiology 2 Exam 1 Practice

Distortion-product OAEs reflect outer hair cell function in the cochlea. They’re typically present even when hearing is mildly impaired because enough outer hair cell activity remains to generate the emissions. When the sensorineural loss becomes substantial, around 50–60 dB HL, outer hair cells are sufficiently damaged that these emissions can no longer be detected, so DPOAEs disappear. That’s why the threshold for absent DPOAEs is about 50–60 dB HL.

The other thresholds would imply DPOAEs stop earlier or later than what is commonly observed; they can still be present up into the mild-to-moderate range and tend to vanish as the loss reaches around 50–60 dB HL, not as low as 20 or 30–40 dB HL, nor only at very high losses like 70–80 dB HL.