Comparison of Two Mechanical Rotation Chairs With Diagnostics of Benign Paroxysmal Positional Vertigo.

Overview

This study aims to investigate whether the diagnosis of benign paroxysmal positional vertigo (BPPV) is equally good with two different mechanical rotation chairs (MRCs) (TRV rotary chair and the Rotundum rotary chair). In the study, two different diagnostic criteria will be used (the international Bárány criteria and the American Academy of Otolaryngology-Head and Neck surgery (AAO-HNS) criteria) with both MRCs. Patients with BPPV experience brief attacks of positional vertigo. Typically, this vertigo is provoked by changes in head position relative to gravity, e.g. laying down or turning to the side from the supine position. Previous studies on the use of MRCs have shown that MRCs offer very precise and accurate BPPV diagnostics. With MRCs it is possible to determine 1) laterality (left/right), 2) specific location (specific semicircular canal), and 3) BPPV subtype (canalolithiasis/cupulolithiasis). Treatment-wise, these MRCs have also shown to be very efficient with treatment success rates being above ninety percent. The two MRCs used in this study do not offer the exact same features (e.g. design, portability, fixed positions, and the possibility of adding kinetic energy). To the knowledge of the authors, no studies exist on direct comparison of separate MRCs. The Rotundum rotary chair, which is also the newest of the two MRCs included, has so far not been included in many studies. However, the hypothesis of the current study is that the Rotundum rotary chair and the TRV rotation chair are equally good in terms of BPPV diagnostics.

The primary aim is to investigate whether diagnostics of benign paroxysmal positional vertigo (BPPV) is equally good with two different MRCs, using both the international Bárány Society criteria and the American AAO-HNS criteria with both MRCs. Whether or not these two MRCs may be considered equally good will be evaluated based on the number of identified BPPV cases with each MRC as well as laterality (right/left), semicircular canal location (anterior/posterior/lateral) and subtype of BPPV (canalithiasis/cupulolithiasis). The participants in this study are patients with a typical BPPV history that have been referred to a University Hospital based tertiary dizziness outpatient clinic. The following mechanical rotation chairs will be used: * TRV® rotary chair (Interacoustics©, Middelfart, Danmark). * Rotundum® rotary chair (balcare GmbH©, Küsnacht, Schweiz). With MRC testing, advanced videonystagmography (VNG) glasses are used to visualize, monitor, and register eye movements. With the TRV chair, VF405® (Interacoustics©, Middelfart, Denmark) will be used with the software Micromedical VisualEyes™ (version 3.1.0.203, Interacoustics©, Middelfart, Denmark). With the Rotundum chair, the ICS Impulse® (Natus Inc©, Middleton, WA, USA) will be used with the software OTOsuite (4.88®, Natus Inc©, Middleton, WA, USA). The same diagnostic procedure will be performed with each MRC. This includes the supine position, bilateral supine roll tests (SRTs), bilateral Dix-Hallpike tests, and, if lateral canal BPPV is ambigious, the bow and lean test. Initial MRC will be randomized. For each participant, the following data will be collected: * Age * Gender * Type and duration of symptoms * Description of nystagmus (direction, duration, a-SPV, latency) * Subjective vertigo during tests * Description of BPPV (laterality, semicircular canal localization, subtype) Sample size assessment Data will be analyzed using Cohen's Kappa. A dropout rate of 10 percent and a power of 90 percent is expected.