Counterdrifting of the eyes: additional findings and hypothesis.

Electro-oculograms for monitoring eye movements and eye positions were performed in patients having a prolonged episode of acute peripheral vestibulopathy. During the course of such illness counterdrifting eye movements have been observed. Counterdrifting is defined as slow eye movements which develop in the direction opposite to the primary drift (i.e. the slow phase of spontaneous nystagmus), that occur when lateral gaze is attempted in the dark at eye positions on the side ipsilateral to the vestibulopathy. Counterdrifting appears always to be accompanied or followed by some recovery of labyrinthine function on the side of vestibular failure, and in 2 patients it was associated with so-called recovery nystagmus. It has not been observed after vestibular neurectomy. The hypothesis is put forward that counterdrifting could be an oculomotor phenomenon--centripetal drifting--similar to that underlying Alexander's modification of acute vestibular spontaneous nystagmus.