Open AccessHorizontal semicircular canal jam: Two new cases and possible mechanisms
Author(s) -
Schubert Michael C.,
Helminski Janet,
Zee David S.,
Cristiano Elisabetta,
Gian Antonio,
Tortoriello Giuseppe,
Marcelli Vincenzo
Publication year - 2020
Publication title -
laryngoscope investigative otolaryngology
Language(s) - English
Resource type - Journals
ISSN - 2378-8038
DOI - 10.1002/lio2.352
Subject(s) - benign paroxysmal positional vertigo , semicircular canal , medicine , supine position , nystagmus , posterior semicircular canal , vestibular system , vertigo , audiology , surgery
Benign paroxysmal positional vertigo (BPPV) of the horizontal semicircular canal (hSCC) can present with otoconia blocking its lumen (canalith jam), with signs and symptoms that make it difficult to distinguish from central nervous system pathology. Objective Here we report two cases of canalith jam affecting the hSCC and offer a theoretical mechanism based on known vestibular neurophysiology. Methods We use video‐oculography to document the canalith jam and show the moment the otoconia loosen. Results Canalith jam is a rare form of BPPV remedied with repositioning maneuvers. Conclusion Clinicians should consider canalith jam as a mechanism for BPPV when the nystagmus is (a) Direction fixed with fixation removed and during positional testing; (b) Velocity dependent on supine head position; (c) Converts to geotropic directional changing nystagmus.