Downbeat nystagmus during eye closure.

Two patients with dizzy spells demonstrated downbeat nystagmus during eye closure. The eye movements were examined by simultaneous horizontal and vertical electro-oculography. As the eyeballs were depressed to the midline position during eye closure, downbeat nystagmus appeared. There were no remarkable neurological findings in either patient. The pathophysiology of this nystagmus remains to be defined.