(b) Horizontal SC canals
| Direction of nystagmus | Intensity of nystagmus | Pathogenetic mechanism | ||
|---|---|---|---|---|
| H-BPPV R | Supine roll test R (+) | Geotropic | More intense | Canalolithiasis |
| Supine roll test L (+) | Geotropic | Less intense | ||
|
| ||||
| H-BPPV R | Supine roll test R (+) | Apogeotropic | Less intense | Cupulolithiasis or canalolithiasis of the short arm of the horizontal SC |
| Supine roll test L (+) | Apogeotropic | More intense | ||
|
| ||||
| H-BPPV L | Supine roll test R (+) | Geotropic | Less intense | Canalolithiasis |
| Supine roll test L (+) | Geotropic | More intense | ||
|
| ||||
| H-BPPV L | Supine roll test R (+) | Apogeotropic | More intense | Cupulolithiasis or canalolithiasis of the short arm of the horizontal |
| Supine roll test L (+) | Apogeotropic | Less intense | ||