Table 1.

Nystagmus characteristics defining the different subtypes of BPPV ^{[3, 11]}

Nystagmus characteristics	Subtypes of BPPV
	Canalolithiasis	Cupulolithiasis
Posterior SCC	Upbeat nystagmus with rotatory component beating toward the ground (geotropic) during Dix-Hallpike testing. Ipsilateral affection.	As for canalolithiasis but without latency and also persistent nystagmus > 1 min.
Lateral SCC	Geotropic horizontal nystagmus during supine roll test in both positions with the highest frequency observed on the affected side.	Apogeotropic horizontal nystagmus during supine roll test in both positions with the highest frequency observed on the nonaffected side.
Anterior SCC	Downbeat nystagmus with rotatory component beating away from the ground (apogeotropic) during Dix-Hallpike testing. Contralateral affection.	As for canalolithiasis but without latency and also persistent nystagmus > 1 min.

SCC: semicircular canal.