Efficacy of the "bow and lean test" for the management of horizontal canal benign paroxysmal positional vertigo.

OBJECTIVES/HYPOTHESIS: Horizontal semicircular canal (HSC) benign paroxysmal positional vertigo (BPPV) has been reported to have a poorer prognosis than posterior semicircular canal BPPV. Incorrect determination of the affected ear appears to be one of the causes of poorer outcome. The aim of this study was to assess the efficacy of the "bow and lean test" (BLT) for proper determination of the affected ear followed by preferable treatment outcomes of HSC-BPPV.

STUDY DESIGN: A prospective study.

METHODS: The 211 patients (225 cases) with HSC-BPPV were sequentially classified into two groups by hospital visiting time and diagnostic methods. The head roll test (HRT) group (61 cases) was treated with canalith repositioning procedure (CRP) on the basis of the results of HRT alone between 2001 and 2004. The BLT group (164 cases) was treated based on the results of both BLT and HRT from 2005 to 2008.

RESULTS: The remission rates after two sessions of CRPs in the BLT group and the HRT group were 83.1% and 67.4% (P = .041), respectively, for the canalolithiasis type and 74.7% and 61.1% (P = .250), respectively, for the cupulolithiasis type. In the BLT group, 76.8% had bowing and/or leaning nystagmus; 35.7% of them (45 of 126 cases) benefited from BLT with regard to determining the affected ears because HRT was unable to provide the definitive affected ears (17 cases) or showed different localization between two methods (28 cases).

CONCLUSIONS: BLT is a useful method to improve the remission rates of HSC-BPPV, giving more corrective information regarding affected ears than the HRT alone.