Diagnosis of Single- or Multiple-Canal Benign Paroxysmal Positional Vertigo according to the Type of Nystagmus
Figure 6
Stimulation of the right anterior semicircular canal during the right Dix-Hallpike maneuver (c). On (a,b), the semicircular canals of the left and right ears, respectively, are shown. When otoconia is present in the ipsilateral (right) anterior canal (b), the head rotates orthogonally to the plane of the affected anterior canal. However, due to the almost vertical orientation of the its ampullary segment, displacement of otoconia is induced as well and the test will be positive, although the provoked pressure against the cupula and the corresponding symptoms are expected to be less pronounced.
