What causes my sudden dizziness when I move?

On call

Q. For the past few months, I get dizzy when I turn my head quickly or bend over. What could cause this?

A. You most likely have a bothersome, but not serious, condition called benign paroxysmal positional vertigo. The symptoms are brought on by head movement. They can be quite mild, with just a few seconds of a spinning or off-balance sensation when the head moves a certain way, but some people experience severe dizziness, along with nausea and possible falling.