The ocular tilt reaction. A paroxysmal dyskinesia associated with elliptical nystagmus.

The ocular tilt reaction, a synkinesis of ocular torsion, skew deviation, and head tilting, was a paroxysmal disorder in a patient with multiple sclerosis. In this distinctive pattern of eye and head motion, the 12 o'clock corneal meridians of both eyes are rotated conjugately in the direction of the lower skewed eye and the head is inclined laterally in the same direction. Paroxysmal activation of brain stem otolithic vestibular projections is proposed responsible for the dyskinesia. Coincident attacks of vertical and horizontal low amplitude pendular oscillation of the eyes produced elliptical nystagmus. This ocular motor disorder was treated effectively with carbamazepine.