Causes

Often, there's no known cause for BPPV. This is called idiopathic BPPV.

When there is a known cause, BPPV is often associated with a minor to severe blow to your head. Less common causes of BPPV include disorders that damage your inner ear or, rarely, damage that occurs during ear surgery or long periods positioned on your back, such as in a dentist chair. BPPV also has been associated with migraines.

The ear's role

Inside your ear is a tiny organ called the vestibular labyrinth. It includes three loop-shaped structures (semicircular canals) that contain fluid and fine, hairlike sensors that monitor your head's rotation.

Other structures (otolith organs) in your ear monitor your head's movements — up and down, right and left, back and forth — and your head's position related to gravity. These otolith organs contain crystals that make you sensitive to gravity.

For many reasons, these crystals can become dislodged. When they become dislodged, they can move into one of the semicircular canals — especially while you're lying down. This causes the semicircular canal to become sensitive to head position changes it would normally not respond to, which is what makes you feel dizzy.