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Horizontal semicircular canal jam: Two new cases and possible mechanisms
Michael C Schubert1,2, Janet Helminski3, David S Zee1,4,5,6
1Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology - Head and Neck Surgery The Johns Hopkins University School of Medicine Baltimore Maryland.
Laryngoscope Investigative Otolaryngology
|March 5, 2020
Summary
Canalith jam, a rare cause of benign paroxysmal positional vertigo (BPPV) in the horizontal semicircular canal, can mimic central nervous system disorders. This condition is effectively treated with repositioning maneuvers.
Area of Science:
- Vestibular Neurophysiology
- Otolaryngology
- Neurology
Background:
- Benign paroxysmal positional vertigo (BPPV) affecting the horizontal semicircular canal (hSCC) can manifest as a canalith jam.
- This presentation can mimic central nervous system pathology, complicating diagnosis.
Purpose of the Study:
- To report two cases of hSCC canalith jam.
- To propose a theoretical mechanism for this condition based on vestibular neurophysiology.
Main Methods:
- Utilized video-oculography to document the canalith jam.
- Recorded the precise moment otoconia dislodged, resolving the jam.
Main Results:
- Canalith jam is a rare variant of BPPV.
- Repositioning maneuvers successfully treated the reported cases.
Conclusions:
- Clinicians should consider canalith jam in BPPV cases exhibiting specific nystagmus patterns.
- Key diagnostic indicators include direction-fixed nystagmus (without fixation), velocity dependence in supine position, and conversion to geotropic nystagmus.
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