About Nystagmus Transformation in a Case of Apogeotropic Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo
Figure 1
(a) Patient with a left LSC-BPPV of the apogeotropic form in sitting position (backward view): the debris is localized in the anterior arm of the canal and is free floating. (b) When the patient moves from the sitting to the supine position, the endolymphatic flow (dashed arrow) causes the debris to move towards the ampulla (thin arrow). Here, acting as a plunger, debris determines an ampullopetal deflection of the cupula (thick arrow), thus triggering a left-beating nystagmus (head arrow).
