Human experience with canalith repositioning maneuvers.

Three distinct pathological conditions, related to different means by which dense intralabyrinthine particles interfere with the function of a semicircular canal and cause nystagmus and vertigo, are amenable to treatment with repositioning maneuvers. Known as benign paroxysmal positional vertigo and variants, these conditions are better designated collectively by the term "vestibular lithiasis." Each form requires a different treatment strategy of head maneuvers and application of other modalities to restore normal semicircular function and thereby eliminate the positional nystagmus and vertigo. Real-time observation of the nystagmus induced by the particles during the maneuvers can greatly facilitate the repositioning process.