Abstract
A patient who suddenly developed Primary Position Upbeat Nystagmus (PPUN) without any hearing disorder was tested with a series of examinations including ENG.
We describe this patient and review the literature on PPUN. He was a 57-year-old male who showed no nystagmus on the first medical examination, therefore, we ruled out congenital nystagmus. We suspected temporary micro obstruction of the infratentorial circulation, because PPUN occurred suddenly and disappeared gradually. We considered that the main focus was the cerebellar flocculus.
