How does "repositioning for vertigo" work?

Very simple: You can see a demonstration under: http://youtu.Be/pa6t-bpg494. There are sequential movement of the head into 4 positions; one should stay in each position for at least 30 seconds.

Floating crystals: Benign positional vertigo (bppv) is caused by a crystal from the inner ear floating loosely in the inner ear fluid, triggering vertigo. The epley maneuver seeks to reposition the floating crystal into a place in the inner ear that does not trigger dizziness.