Low Frequency Air-Bone Gap in Meniere's Disease: Relationship With Magnetic Resonance Imaging Features of Endolymphatic Hydrops.
Irumee Pai, Steve Connor
PMID 35583512WHAT IT FOUND
Low-frequency air-bone gaps in Meniere's disease are strongly linked to endolymph touching the stapes footplate on MRI.
The gap often disappears later, so a normal audiogram does not rule out this structural change.
Key findings
01Air-bone gaps at low frequencies were significantly associated with endolymphatic space contacting the oval window (VESCO) on MRI, but not with the overall grade of vestibular endolymphatic hydrops.
02VESCO had high sensitivity (90%) and negative predictive value (94%) for detecting low-frequency air-bone gaps, but low specificity (60%) and positive predictive value (47%).
03All but one patient with an air-bone gap had a subsequent audiogram where the gap was no longer present, suggesting the finding is fluctuating.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study was small, with only 35 patients, and only 10 had the condition of interest (LFABG+). The patients were selected from those referred for MRI, which typically occurs when invasive therapy is being considered, so the findings may not apply to all Meniere's patients, especially those with milder or stable disease. The study could not account for fluctuations in air-bone gaps over time because repeat MRI scans were not performed. Other causes of conductive hearing loss (like otosclerosis) were only excluded by CT in a small subset of patients (4 out of 10 in the LFABG+ group), although normal otoscopy and tympanometry were present in all. The definition of air-bone gap varied across previous studies, making direct comparison with other literature difficult.
Declared interests
No conflicts of interest or funding sources were explicitly stated in the provided text.
The easy way to misread this
Do not assume that the presence of a low-frequency air-bone gap indicates a middle ear problem requiring surgical intervention or medical treatment for otitis media. The study shows this gap is a marker of inner ear endolymphatic hydrops contacting the stapes, and it often resolves spontaneously, meaning it is not a permanent conductive defect.