The purpose of this study was to compare the treatment effectiveness of three different methods for posterior semicircular canal benign paroxysmal positional vertigo. The included methods are Modified Epley maneuver, Semont maneuver and Sham maneuver.

This study was a prospective, double blinded, randomized, multicenter clinical trial. The enrolled posterior semicircular canal benign paroxysmal positional vertigo patients were randomized to one of the three treatment regimens when they are diagnosed with the Dix-Hallpike test. An then the patient was treated with one of the three maneuvers. After 20 minutes, the patient was examined with the Dix-Hallpike test again. The resolution of nystagmus and symptoms were checked. When the nystagmus was sustained, the same treatment was applied once again. And after 20 minutes, the patient was examined with the Dix-Hallpike test too. 1 day after and 7 days after, the patient was re-examined with the Dix-Hallpike test.

Inclusion Criteria:

• a symptom of positional vertigo
• rotational and upbeating nystagmus in Dix-Hallpike test
• the nystagmus should be disappear within 60 seconds
• no spontaneous nystagmus

Exclusion Criteria:

• ages under 18 years
• suspicious or verified a central nervous system lesion
• traumatic vertigo patients
• other otologic disease(acute/chronic otitis media, otosclerosis, etc)
• other vestibular disease(vestibular neuronitis, Meniere's disease, etc)
• congenital nystagmus patients
• the patients with spinal disease
• the patients with the limitation of cervical movement