Doctor performing the Epley manoeuvre on a 72 year old female patient to treat benign paroxysmal positional vertigo (BPPV). BPPV is the most common form of vertigo, a balance disorder that creates the illusion for the patient that they or their surroundings are spinning. BPPV is caused when tiny calcium crystals (otoconia) in the inner ear become loosened and move from their usual position to the semicircular canals. There they disturb the tiny hair-like structures that transmit information about balance to the brain. The Epley manoeuvre involves a series of head movements that aim to move the otoconia out of the semicircular canals.