Significance of Lying-Down Nystagmus in the Lateralization of Lateral Canal Benign Paroxysmal Positional Vertigo / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Lateral canal benign paroxysmal positional vertigo (LC-BPPV) is characterized by horizontal direction changing nystagmus induced by lateral head turning in supine position. According to the Ewald's second law, the direction of head turning that creates stronger response represents the affected side of geotropic nystagmus and the healthy side in apogeotropic nystagmus. However, it may not always be possible to lateralize the involved ear only by comparing the intensity of the nystagmus. We studied the values of lying-down nystagmus (LDN) in the lateralization of LC-BPPV. SUBJECTS AND METHOD: We performed a retrospective study of 54 patients who had been diagnosed as having LC-BPPV in Dizziness Clinic of Seoul National University Bundang Hospital from May 2003 to February 2004. The directions of the nystagmus induced by lying down were compared with those determined by the Ewald's second law. RESULTS: Of the 54 patients, 32 (20 apogeotropic and 12 geotropic) patients showed horizontal nystagmus induced by lying down. The nystagmus was ipsilesional in 16 (80%) apogeotropic and contralesional in 9 (75%) geotropic patients. CONCLUSION: In LC-BPPV, the LDN mostly beats toward the involved ear in the apogeotropic type, and directs to the healthy ear in the geotropic type. The direction of LDN may help lateralizing the involved ear in LC-BPPV

Treatments of Lateral Semicircular Canal BPPV / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Benign paroxysmal positional vertigo (BPPV) is a common vestibular disease. The theories of can-alolthiasis and cupulolithisis of posterior semicircular canal are commonly accepted in BPPV. Recently, not only posterior canal but also lateral canal BPPV were reported. The purposes of this study are to analyze the result of lateral canal BPPV treatment and to introduce effective schedule of reposition maneuvers and follow up. MATERIALS AND METHODS: Sixty two patients who were diagnosed as lateral semicircular canal BPPV were included in this study. Supine head turning test was done and eye movement was documented with videonystagmography. In the canalolithiasis type, barbecue rotation maneuver was performed and in the cupulolithiasis type, cupulolith reposition maneuver was performed. In each type of BPPV, we analyzed the number of treatment until nystagmus was disappeared, recurrence rate and relationship between recurrence and age, sex of patients. RESULTS: Canalolithiasis type was 55% and cupulolithiasis type was 37%. Eight percents of patients showed combined type. All except 2 cases (congenital malformation) were healed by the reposition maneuver. Vertigo recurred in about 30% of patients, and they were retreated with the reposition maneuver. There was no correlation between recurrence and age, sex of patients. CONCLUSION: In lateral semicircular canal BPPV, the reposition maneuver was a effective treatment method. The reposition maneuver was recommended to perform continuously once a day until nystagmus disappeared. Because recurrence rate was about 30%, continuous follow-up was needed.