Journal of the Korean Balance Society  2006;5(2):299-306

Bilateral Inversion of Initial Nystagmus in Benign Paroxysmal Positional Vertigo of Horizontal Canal.

Myung Whan SUH 1 ; Sang Wook KIM ; Min Hyun PARK ; Ji Soo KIM ; Ja Won KOO

Affiliations

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Keywords

Positional vertigo; Semicircular canal; Diagnosis; Nystagmus

Country

Republic of Korea

Language

Korean

Abstract

Horizontal canal benign paroxysmal positional vertigo (HC-BPPV) is characterized by direction-changing nystagmus of the horizontal component induced by lateral head turning in supine position. Yet, some patients with HC-BPPV show nystagmus inversion during head turning to one side. And, mostly, the nystagmus started in a geotropic direction and the inversion was observed only when the head is turned to the lesion side. Reversal of the clot movement in the canal and sensory adaptation were suggested as the hypothesis for such finding. However, bilateral inversion of geotropic nystagmus into apogeotropic nystagmus in HC-BPPV has seldom been described before. In this paper, the authors presented the characteristic features and progression during reposition of a patient with bilateral nystagmus inversion and speculated its mechanisms.