[Nystagmus characteristics of the horizontal semicircular canal light cupula]

Objective:To analyze the nystagmus characteristics of 9 patients with horizontal semicircular canal light cupula.Method:Patients who visited the department of otolaryngology of Shanghai sixth people's hospital from September 2017 to December 2017 with a typical history of positional vertigo and roll test evoked horizontal geotropic direction changing nystagmus that lasted more than one minute were enrolled in the study.Nystagmus was monitored using the videonystagmoscopy (VNG), and parameters of nystagmus,including latency, duration and the intensity of nystagmus were analyzed. Barbecue maneuvers were tried for all patients and no other treatment was performed.Result:Nine patients were enrolled,DixHallpike test had no nystagmus, Roll test showed a persistent geotropic DCPN, the recorded average duration of nystagmus was (64.2±13.7)s (longer actually), and averaged latency was (5.3±4.7)s.In some cases, positional nystagmus increased rapidly in intensity and then declined slowly as seen in patients with canalolithiasis. Immediate effectiveness is 0 after barbecue maneuver,but 4 patients recovered within one week,2 patients improved within 1 week,and recovered within 2 weeks, 1 patient transferred into posterior semicircular canal BPPV, and 2 cases had not been followed up.Conclusion:Nystagmus of horizontal canal light cupula has a latency of several seconds,with a crescendodecrescendo pattern of intensity.Barbecue maneuver may be not effective in resolving nystagmus,but the prognosis is good for those patients.