TABLE 2

Observed nystagmus patterns based on semicircular canal involvement

Provocative maneuverNystagmus directionAffected canal
Dix-HallpikeTo the affected side and upPosterior
Dix-HallpikeTo the affected side and downAnterior
Supine roll, right ear down
Supine roll, left ear down
Right (geotropic)
Left (geotropic)
Horizontal. The head-turn direction eliciting stronger nystagmus indicates the affected horizontal canal
Supine roll, right ear down
Supine roll, left ear down
Left (apogeotropic)
Right (apogeotropic)
Horizontal. The head-turn direction eliciting weaker nystagmus indicates the affected horizontal canal