Rare Inner Ear Disorder May Have Struck All Three Balance Canals at Once

A case report published in Frontiers in Audiology and Otology describes what the authors say may be the first documented instance of the rare “light cupula phenomenon” affecting all three semicircular canals in a single inner ear. The patient, a 55-year-old soldier in Ljubljana, Slovenia, experienced violent, position-dependent vertigo: dizziness eased lying flat but returned when sitting upright. Clinicians observed nystagmus that changed horizontal direction with head orientation and showed a persistent downward-beating component when he sat up. The light cupula phenomenon is characterized by positional nystagmus that appears rapidly, does not fatigue, and lacks the delay typical of benign paroxysmal positional vertigo. The authors explain it using the idea that a cupula with lower density than surrounding endolymph becomes continuously deflected by gravity, disappearing only at a specific “null plane” head angle.