Diagnosing benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo (BPPV) is due to crystalline deposits (otoconia) that are displaced from the utricle and lodge in the posterior semicircular canal. These deposits cause excessive deflection of the sensory organ (cupula) when the head moves in certain directions. Most often BPPV has no obvious trigger, but it can be a complication of head trauma or other conditions that damage the labyrinth (eg vestibular neuritis, Ménière disease). Suspect BPPV when vertigo is triggered by head movement in the vertical (or pitch) plane (eg head extension, lying down) or when rolling over in bed (see Differential diagnosis of vertigo  for the differential diagnosis of vertigo). The diagnosis is confirmed when a Hallpike manoeuvre induces positional nystagmus.