[Diagnosis and therapy for benign paroxysmal positional vertigo of the anterior semicircular canal].

OBJECTIVE: To analyse the video-oculographic findings of positional tests and evaluate the efficacy of canalith repositioning procedure (CRP) in patients with paroxysmal positional vertigo ( BPPV) of the anterior semicircular canal (ASC). METHODS: A retrospective study of 31 patients with ASC BPPV. Then the CRP was performed. RESULTS: Twenty-two individuals (70.97%) presented a unilateral positional nystagmus during the Dix-Hallpike test, in 17 individuals had torsional nystagmus component, 5 individuals only had pure positional down beat nystagmus. Nine patients presented bilateral positional nystagmus, 7 individuals had torsional component positional nystagmus, in 2 patients the direction of the torsional component were the same during right and left Dix-Hallpike test, in 4 patients the torsional component were concurrent with positional down beat nystagmus but the direction could not be ascertained clinically, in 2 patients had pure positional down beat nystagmus. Nineteen patients (61.29%) had unilateral lesion, 11 patients had the left ASC BPPV, 8 patients had right ASC BPPV. Eleven patients had with both ASC and PSC BPPV in the ipsilateral. Twenty-one patients (67.74%) were cured, 29 patients (93.55%) were improved, 2 (6.45%) patients were inefficacy. CRP effectively resolved the nystagmus and vertigo in 14 patients (45.16%) when applied only once, The average number of CRP was 1.7 times, there were 5 patients recurrence during the follow-up. CONCLUSIONS: ASC BPPV was not a common condition. The torsional nystagmus component of ASC BPPV might be weak during the Dix-Hallpike test. The positional nystagmus of ASC BPPV was triggered bilaterally. Based on these findings, CRP could be one of the most effective treatment methods for ASC BPPV.