[The nystagmus characteristics of two positions of the horizontal semicircular canal cupulolithiasis].

To analyze the characteristics of nystagmus of horizontal semicircular canal cupulolithiasis(HSC-Cup) in Roll test and Dix-Hallpike test. Between December 2016 and December 2017, a total of 164 patients with BPPV from Tianjin First Center Hospital, 124 HSC-Can BPPV and 40 HSC-Cup BPPV, were involved.The induced nystagmus in Roll test and Dix-Hallpike test were recorded by video-nystagmograph(VNG), whose direction and intensity characteristics were compared in various BPPV. HSC-Can patients were induced a horizontal nystagmus with Roll test, the nystagmus intensity of the disease and healthy side were (41.3±20.1)°/s (mean standard deviation)and(21.9±9.4)°/s respectively, the difference was statistically significant (=6.709, <0.05). HSC-Cup patients were induced a horizontal nystagmus that was opposite to the direction of the Roll test, the nystagmus intensity of the disease and the healthy side were (12.9±6.4)°/s and(29.1±9.3)°/s respectively, with significant difference (=9.066, <0.05). Among 124 cases of HSC-Can patients, 120 cases of horizontal nystagmus were recorded in the left and right sides of the Dix-Hallpike test in the same direction as the turning direction, the horizontal nystagmus intensity of the disease and the healthy sides were (15.1±10.0)°/s and(9.4±7.4)°/s respectively, the difference was statistically significant (=2.365, <0.05). And 40 cases of HSC-Cup patients were recorded at the head of the Dix-Hallpike test in the opposite direction to the horizontal eye earthquake.The horizontal nystagmus intensity of the disease and the healthy side were (5.3±2.8)°/s and(13.9±4.4)°/s respectively, the difference was statistically significant (=10.579, <0.05). Characteristic horizontal nystagmus can be induced by HSC-Cup in both roll test and Dix-Hallpike test. Preliminary localization of Dix-Hallpike Test can also be used for HSC-Cup.