What happens in benign paroxysmal positional vertigo?
It is thought that BPPV is caused by one or more tiny solid fragments (debris) that float about in the fluid of the labyrinth. The fragments are made up of calcium carbonate crystals which are thought to have broken off from the inside lining of the vestibule part of the labyrinth. These tiny fragments are called otoconia. These cause no problems if the fragment remains in the vestibule. However, problems occur if a fragment gets into one of the semicircular canals. The posterior canal is the usual one affected. In this situation, when your head is still, the fragment ‘sits’ at the bottom of the posterior canal. But when the head moves in certain directions the fragment gets carried along with the flow of fluid. The fragment brushes along the delicate hairs that line the semicircular canal and this bombards messages down the vestibular nerve. The extra nerve messages sent from the affected ear conflict with the normal messages sent from the other unaffected ear. The brain becomes very
