Doctor performing the Dix-Hallpike test for the diagnosis of benign paroxysmal positional vertigo (BPPV) on a 72 year old female patient. 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. The patient, with their head turned to one side, is moved from sitting to lying down with their head slightly off the table and supported by the doctor. The patient will remain like this for a couple of minutes while the doctor observes the patient's eyes and asks if there are any symptoms of dizziness. The test is performed with the head turned to both sides. 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.