Atypical BPPV an often confusing entity: Review of literature

Abstract

Benign Paroxysmal Positional Vertigo (BPPV) is not an uncommon disorder involving the vestibular system which is associated with recurrent attacks of vertigo and nystagmus and aggravated by positional change of head. As per the “Barany Society diagnostic criteria for BPPV” it includes vertigo or dizziness associated with change in position along with positional nystagmus, and if these features are absent we classify them as atypical BPPV. Lately, various forms of atypical BPPV have emerged, including cases with no nystagmus in typical positions, intense short lasting nystagmus in different head positions. The phenomenon of "canal switch," where otolith from one semicircular canal shifts into another, has been proposed to explain the occurrence of paradoxical nystagmus. This review aims to provide a comprehensive overview of the possible origins of eye movements in all three semicircular canals and explore the different forms of atypical BPPV, contributing to a deeper understanding of this enigmatic condition.