Table 1

 Comparison of benign paroxysmal positional nystagmus (BPPN) and central positional nystagmus (CPN)

BPPNCPN
Latent period2–45 seconds0 seconds
AdaptationWithin 30 secondsPersisting
FatigabilityDisappears on repetitionPersists
VertigoPresent, sometimes severeUsually absent, or very mild
Direction of nystagmusTorsional and geotropicAny
IncidenceCommonRare