The treatment of horizontal canal positional vertigo: our experience in 66 cases.

Objectives/hypothesis: The horizontal semicircular canal variant of paroxysmal positional vertigo (HSC-PPV) shows three subtype nystagmic patterns: 1) bilateral geotropic nystagmus, 2) bilateral apogeotropic nystagmus that may switch into bilateral geotropic, and 3) bilateral apogeotropic nystagmus that never switches into bilateral geotropic. In recent years, many methods of physical treatment have been proposed for HSC-PPV, yet no standard protocol has been defined. We studied the effects of different methods according to each different form of HSC-PPV after a precise definition of the nystagmic and clinical features.