Review Article

Diagnosis of Single- or Multiple-Canal Benign Paroxysmal Positional Vertigo according to the Type of Nystagmus

Figure 3

Mechanism of cupulolithiasis of BPPV of the horizontal semicircular canal, when the left ear is affected (the involved left horizontal canal is colored black). (a) Patient in supine position with debris adherent to the cupula of the left horizontal canal. (b) When rotating the head towards the affected side, the cupula will undergo an ampullofugal (inhibitory) deflection, triggering an apogeotropic horizontal nystagmus. (c) When rotating the head towards the healthy side, the cupula will undergo in ampullopetal (stimulatory) deflection, triggering a more intense apogeotropic nystagmus.
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(a)
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(b)
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(c)