air-bone gap
Difference between air conduction and bone conduction thresholds, indicating conductive hearing loss component.
Full Definition
The air-bone gap represents the mathematical difference between air conduction and bone conduction hearing thresholds at each frequency, measured in decibels. A gap of 10 dB or greater suggests conductive hearing loss, where sound transmission through the outer or middle ear is impaired while inner ear function remains normal. Larger gaps indicate more severe conductive components. This measurement is crucial for determining candidacy for medical treatment, surgical intervention, or appropriate hearing aid technology. Mixed hearing losses show both air-bone gaps and elevated bone conduction thresholds.
Usage
Usage note: Always hyphenated; express as 'X dB air-bone gap' rather than 'air-bone gap of X dB' in clinical writing.
In Context
- "The 40 dB air-bone gap at 500 Hz suggests significant middle ear pathology requiring ENT referral." — Audiological assessment report
- "Post-surgical results showed closure of the air-bone gap to within 10 dB." — Follow-up examination notes