Primary Position Spontaneous Vertical Nystagmus; Pathophysiology and Review of the Literature

-Upbeat Nystagmus, Downbeat Nystagmus, and Alternating Vertical Nystagmus Treated by the Authors-

Abstract

In their study of the literature, the authors found 41 cases of primary position upbeat nystagmus (PPUN) and over 250 of primary position downbeat nystagmus (PPDN). We have treated 2 patients with PPUN due to chronic alcoholism and malnutrition, and one with PPDN. There are two types of PPUN, brainstem type and cerebellar type, as with PPDN. The characteristics of the nystagmus are described.
A study of the lesion due to chronic alcoholism suggests that spontaneous vertical nystagmus in which the direction changes during convergence or in the course of the disease is specific for this disorder.