What causes benign paroxysmal positional vertigo (BPPV)?

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What causes benign paroxysmal positional vertigo (BPPV)?

BPPV develops when calcium carbonate crystals, which are known as otoconia, shift into and become trapped within the semicircular canals (one of the vestibular organs of the inner ear that control balance). The otoconia make up a normal part of the structure of the utricle, a vestibular organ next to the semicircular canals. (See illustration.)

In the utricle, the otoconia may be loosened because of injury, infection, or age. They land in a sac – the utricle – where they are naturally dissolved. As a person’s head position changes, the otoconia begin to roll around and push on the tiny hair-like processes (cilia) within the semicircular canals. Those cilia help to transmit information about balance to the brain. Vertigo develops when the cilia are stimulated by the rolling otoconia.

Movements that can bring about an episode of BPPV include:

  • Rolling over or sitting up in bed;
  • Bending the head forward to look down, or;
  • Tipping the head backward.

In most people, only a single ear is affected by BPPV, although both ears may be involved on occasion.

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