The effect of labyrinthectomy on flash-induced nystagmus (FIN).

After bilateral labyrinthectomy the maximum slow phase velocity of flash-induced nystagmus (FIN) was diminished; the flash induced after-nystagmus was always absent. Unilateral labyrinthectomy resulted in a weaker FIN response on stimulation of both eyes, but the best response was seen after contralateral stimulation. These findings are discussed in relation to reported effects of labyrinthectomy on OKN, "central nystagmus" and vestibular nuclear discharge activity.