Evaluation of posterior and lateral semicircular canal diagnostic videonystagmography records in patients with benign paroxysmal positional vertigo

None of the provocative maneuvers that are used for the diagnosis of benign paroxysmal positional vertigo (BPPV) induces response in a single semicircular canal alone. Angular changes in position of the head affect position of all semicircular canals relative to the gravity. The aims of this study were to evaluate the videonystagmography (VNG) records of positional tests that are performed for the diagnosis of vertigo and to define the characteristics of nystagmus responses that are detected in both Dix-Hallpike and supine head-roll tests. Records of 7523 patients that have applied to the Department of Otolaryngology at Baskent University Ankara Hospital with the complaint of vertigo between 10.14.2016 and 2.11.2019 were reviewed from the VNG computer database. 2880 recordings (68.1% female; mean age, 53) were found to include results of both Dix-Hallpike and head-roll tests. Graphical results of each of those VNG recordings were printed out and examined. Video images of 148 records that had been detected to have nystagmus on graphical printouts of both Dix-Hallpike and head-roll tests were further analyzed by two independent researchers. Ocular movements were found to be inaccurately represented on VNG tracings and there were significant differences between the video images and graphical printouts especially in terms of nystagmus direction. Analysis of the records that were detected to have nystagmus response in both Dix-Hallpike and head-roll tests revealed that, diagnosis was posterior canal BPPV in 8.8% and lateral canal BPPV in 59.4% (47.7% geotropic [canalolithiasis] and 52.3% apogeotropic [cupulolithiasis] variants). More than one canal was involved in 4.1%, 1 rehabilitation maneuver was performed in 53.3%, and recurrence was observed in 7.4% of those patients. In both geotropic and apogeotropic variants of lateral canal BPPV, nystagmus can be observed during Dix-Hallpike test in addition to head-roll test. In patients with posterior canal BPPV nystagmus can also be detected in head-roll test. In order to reach to a correct diagnosis and apply appropriate treatment in BPPV, Dix-Hallpike test and head-roll test should be completely performed and results of those tests must be interpreted concomitantly.