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The patient who hears her own eyeballs

A 38-year-old woman with autophony, sound-induced vertigo, and a peculiar audiogram.

The case

A 38-year-old graphic designer presents with a 6-month history of progressively troublesome aural symptoms. She describes hearing her own voice booming inside her head, hearing her footsteps loudly, and — most distinctively — hearing her own eyeballs move when she shifts her gaze laterally.

She has also noticed transient dizziness when blowing her nose hard or lifting heavy weights at the gym, and occasionally feels unsteady when a loud truck passes her.

On examination, her ear canals and tympanic membranes are normal. Tuning fork testing shows the Weber lateralising to the right ear; Rinne is positive bilaterally. There is no spontaneous nystagmus. Fistula testing with tragal pressure produces a brief downbeat-torsional nystagmus and a sensation of vertigo.

Her audiogram is shown below.

Investigations

Right-ear low-frequency conductive pattern-100204060801001201252505001k2k4k8kHearing level (dB HL)Frequency (Hz)normal limit (25 dB)Right air (O)Left air (X)Right bone (<)Left bone (>)
Fig. Right ear: low-frequency air-conduction loss with supranormal bone-conduction thresholds (−5 to −10 dB at 250–500 Hz). The air-bone gap is in the low frequencies. Acoustic reflexes (not shown) were intact bilaterally. Left ear is normal.

Question

What is the single most likely diagnosis?

Teaching point

Supranormal bone-conduction thresholds in the low frequencies are the single most specific audiometric finding in SCDS — they reflect the third window's enhancement of bone-conducted vibration transfer. The clinical scenario (autophony + sound/pressure-induced vertigo) plus the audiogram should prompt CT in Pöschl plane before any consideration of stapes surgery. Patients with apparent otosclerosis who fail tympanometric or acoustic-reflex testing deserve re-imaging for SCDS — there are well-documented cases of unnecessary stapedectomy in patients with unrecognised superior canal dehiscence.

References

  1. [1]Minor LB, Solomon D, Zinreich JS, Zee DS. Sound- and/or pressure-induced vertigo due to bone dehiscence of the superior semicircular canal. Archives of Otolaryngology–Head and Neck Surgery 1998;124(3):249–258. doi:10.1001/archotol.124.3.249
  2. [2]Ward BK, van de Berg R, van Rompaey V, Bisdorff A, Hullar TE, Welgampola MS, Carey JP. Superior semicircular canal dehiscence syndrome: diagnostic criteria. Consensus document of the committee for the classification of vestibular disorders of the Bárány Society. Journal of Vestibular Research 2021;31(3):131–141. doi:10.3233/VES-200004
  3. [3]Minor LB. Clinical manifestations of superior semicircular canal dehiscence. Laryngoscope 2005;115(10):1717–1727. doi:10.1097/01.mlg.0000178324.55729.b7
Related moduleSuperior Canal Dehiscence Syndrome →