Response to Chronic Multicanalicular BPPV as a Possible Cause of Mal de Débarquement Syndrome Dear Editor,We would like to thank Dr. Tjell for his interest in our article “Treatment options in Mal d’Embarquement Syndrome: A scoping review.” Thank you for the opportunity to respond to the issues raised.The consideration brought forward is that chronic multicanalicular benign paroxysmal positional vertigo (mc-BPPV) can present with similar symptoms to mal de débarquement (MDDS) and may contribute to the development of an MDDS diagnosis. Specifically, the symptoms of superior semicircular canal canalithiasis, which may be more common in mc-BPPV, are indicated as a possible confounding variable as symptoms can present similarly (). Although overlap in symptoms can occur, it is critical to mention that in the diagnostic criteria codified in 2020 by the international classification of vestibular disorders, previous passive motion exposure must be present in addition to improvement of symptoms in passive motion (such as in a car) (). There are also specific criteria when considering anterior/superior semicircular canal BPPV, with common findings including a down beating positioning nystagmus, with a torsional component clockwise for the left canal and counterclockwise for the right canal (). We do concede that mc-BPPV can present with a complicated and variable nystagmus pattern, and chronic canalithiasis/cupulolithiasis may lead to persistent disequilibrium and may require additional balance therapy and other maneuvers. There are multiple vertiginous pathologies that can result in motion-modulated oscillatory vertigo that are not related to passive motion, and as such, it is important to review this risk factor with patients where other symptoms do overlap. For example, horizontal cupulolithiasis with a persistently loaded cupula can often present as a “floating sensation,” which may mimic oscillatory/rocking vertigo, and utricular and saccular dysfunction can result in postural instability and rocking/swaying vertigo (). Vestibular migraine and persistent postural-perceptual dizziness are both more recognized etiologies of motion modulated oscillatory vertigo, and vestibular migraine has been implicated in changes of endolymphatic density, leading to an atypical positional nystagmus (). These two pathologies can be differentiated from MDDS in that patients with persistent postural-perceptual dizziness often worsen with passive motion exposure and those with vestibular migraine have strong migraine history and are more often episodic (). In addition, neither have an onset triggered by passive motion. In conclusion, yes, it is true that chronic or multiple canal BPPV can lead to a nonrotary vertigo and present with similar features to MDDS, but at this point, we cannot say that chronic BPPV causes MDDS in keeping with the consensus diagnostic criteria proposed previously (). Corin Kinkhabwala, MD, Habib G. Rizk, MD, MSc, Department of Otolaryngology Head and Neck Surgery Medical University of South Carolina Charleston, South Carolina
