[The exploration on optimization of two alternatives between roll test and Dix-Hallpike test in benign paroxysmal positional vertigo].

To analyze the objective characteristics of roll test and Dix-Hallpike test in benign paroxysmal positional vertigo(BPPV)patients, discussing the premier solution of positional test. A total of 230 patients with BPPV, whereas 170 posterior semicircular canal canalithiasis (PSC-Can) BPPV and 60 horizontal semicircular canal canalithiasis (HSC-Can) BPPV were involved respectively. The induced nystagmus in roll test and Dix-Hallpike test was recorded by video nystagmuo graph (VNG), and the direction, intensity and time characteristics of nystagmus were compared in various BPPV.SPSS19.0 software was used for statistical analysis. Vertically upward nystagmus was induced by hanging in 170 PSC-Can Dix-Hallpike test, and the nystagmus reversed and turned weaker when the subjects came to sit. The intensity of nystagmus at turning to lesion side by hanging and sitting were (30.3±14.1)°/s and (12.6±7.5)°/s respectively, the difference was statistically significant (=20.153, <0.05). However, no nystagmus was induced in PSC-Can roll test. Horizontal nystagmus in the same direction with turning was induced in 60 HSC-Can roll test. The intensity of nystagmus at turning to lesion side and normal side was (42.0±18.0)°/s and (20.3±8.7)°/s respectively, the difference was statistically significant (=12.731, <0.05). Furthermore, horizontal nystagmus in the same direction with turning was induced in 57 HSC-Can Dix-Hallpike. The coherence was 95% with the results of roll test. Dix-Hallpike test can not only be used to diagnose PSC-Can, but also induce nystagmus in HSC-Can effectively. Whereas the roll test only show significance in diagnosing HSC-Can. To avoid uncomfortable stimulation to patients as much as possible, we suggest to use Dix-Hallpike test at first, and to judge whether using roll test based on the result of the horizontal nystagmus.