[Significance of the seated supine positioning nystagmus for the diagnosis of benign paroxysmal positional vertigo].

To observe and assess the significance of seated supine positioning nystagmus (SSPN) in the diagnosis of benign paroxysmal positional vertigo(BPPV).Two hundreds patients who were diagnosed BPPV were tested with the seated supine positioning test(SSPT) to observe SSPN,then were tested Supine roll test(SRT) and Dix-Hallpike test(DHT). According to the result of SRT and DHT,patients were divided into different groups. The positive rate and feature of SSPN in different types of BPPV was analyzed.Among the 200 patients,116 cases(58.0%) of them showed SSPN. Among the 116 cases who were divided to the posterior semicircular canal BPPV(PSC-BPPV) group,72 cases of them showed SSPN. Horizontal semicircular canal BPPV(HSC-BPPV) group were 60 cases,44 cases showed SSPN. Anterior semicircular canal BPPV(ASC-BPPV) group were 4 cases and none of them showed SSPN. The direction of SSPN was a combination of torsional nystagmus with the upper pole of the eyes beating toward the affected side combined with vertical nystagmus beating upward (toward the forehead) typically in the PSC-BPPV group. Canalolithiasis of HSC were 41 cases,and 28 cases showed SSPN,and SSPN was contralesional in 22 cases(78.6%) and ipsilesional in 6 cases. Cupulolithiasis of HSC were 19 cases and 16 cases showed SSPN,and SSPN was ipsilesional in 16 cases.Significance of the seated supine positioning nystagmus in different types of BPPV is different.