The disorder
Clinical features
A patient who gets dizzy at a concert, hears their eyeballs move, and finds their own voice booming in one ear — a constellation odd enough to be diagnostic once you recognise it.
Two clusters, one cause
Symptoms fall into two groups: balance symptoms (dizziness with loud sounds or straining) and hearingsymptoms (hearing one’s own voice and body sounds too loudly). Both come from the same opening. Tap each below.
The vestibular cluster is sound/pressure-induced vertigo and oscillopsia with chronic imbalance; the auditory cluster is autophony, bone-conduction hyperacusis, pulsatile tinnitus and a pseudo-conductive loss.1 Symptom mix varies — some present mainly vestibular, others mainly auditory.
Two clinical pearls. The autophony of SSCD includes bodily sounds (eye movements, footsteps, the pulse) — richer than the voice/breathing autophony of a patulous Eustachian tube. And a patient who reports a conductive hearing problem yet hears a tuning fork on the ankle has supranormal bone conduction — a third window, not middle-ear disease.2
Provoking the signs at the bedside
Because the third window responds to sound and pressure, you can unmask it. The evoked eye movements align with the plane of the superior canal (vertical-torsional). Explore the provocations:
ManoeuvrePresent a loud tone (≈ 110 dB) to the affected ear.
ResponseVertigo and oscillopsia with vertical-torsional nystagmus in the plane of the superior canal — the eyes move as if the canal were excited.
The eye movements are best seen with fixation removed — see how nystagmus is recorded and classified in the Nystagmus and VNG chapters.
Key points
- Vestibular cluster: sound/pressure-induced vertigo and oscillopsia (Tullio, Hennebert), chronic imbalance.
- Auditory cluster: autophony, bone-conduction hyperacusis (hearing eye movements/footsteps/pulse), pulsatile tinnitus.
- Provoked eye movements align with the superior canal’s plane (vertical-torsional).
- Autophony of bodily sounds and supranormal bone conduction point to a third window, not the middle ear.