Conductive hearing loss without middle ear disease
A 44-year-old yoga instructor presents with 2 years of right-sided autophony and a sensation of pressure in the right ear during sustained yoga postures. She hears her own footsteps and the sound of her chewing inside the right ear. She has a mild hearing loss on the right confirmed at a recent screening, with an audiogram showing a low-frequency conductive component. Otoscopy is normal. Tympanogram is type A. She had myringotomy tubes placed twice (no benefit), and her general ENT has been considering ossicular reconstruction.
A 44-year-old yoga instructor presents with 2 years of right-sided autophony and a sensation of pressure in the right ear during sustained yoga postures. She hears her own footsteps and the sound of her chewing inside the right ear. She has a mild hearing loss on the right confirmed at a recent screening, with an audiogram showing a low-frequency conductive component. Otoscopy is normal. Tympanogram is type A. She had myringotomy tubes placed twice (no benefit), and her general ENT has been considering ossicular reconstruction.
Which finding most strongly argues AGAINST a middle-ear cause of her conductive hearing loss?
You ask the patient to perform a Valsalva maneuver against pinched nostrils. Within 2 seconds, she develops vertigo and a slow drift of both eyes downward and toward the LEFT, with corrective saccades to the right (Hennebert sign on the right). Tragal pressure on the right ear produces the same response. You play a 110 dB tone through earphones to the right ear: she develops vertigo and the same eye drift (Tullio phenomenon).
Both Hennebert and Tullio responses on the right side. Which VEMP pattern would you expect?
Superior semicircular canal dehiscence (right) presenting as 'conductive' hearing loss
- 1.SCD classically presents in adults aged 30-60. The third-window effect produces three distinct manifestations: (1) sound- and pressure-induced vertigo; (2) autophony with bone-conducted sounds (footsteps, voice, chewing); (3) a low-frequency 'pseudoconductive' hearing loss with supernormal bone conduction.
- 2.Patients with SCD are frequently misdiagnosed as having otosclerosis. Stapes surgery in undiagnosed SCD does not improve hearing and may worsen vestibular symptoms — making accurate preoperative diagnosis critical.
- 3.Diagnostic workup combines (a) high-resolution temporal bone CT with reformats in Pöschl and Stenvers planes — direct visualization of bone dehiscence; (b) VEMPs — lowered cVEMP thresholds, elevated oVEMP amplitudes; (c) audiogram — supernormal bone thresholds at low frequencies.
- 4.Imaging caveat: radiographic dehiscence is found in ~1-2% of asymptomatic temporal bone CTs. Diagnosis requires symptoms + signs + imaging concordance, not imaging alone.
- 5.Surgical options: middle fossa craniotomy for canal plugging or resurfacing, or transmastoid approach. Reserved for disabling symptoms because of small risks to ipsilateral hearing.