Effect of aging on horizontal smooth pursuit.

Quantitative infrared oculographic study of horizontal pursuit in young and elderly normal subjects showed significantly lower smooth pursuit velocities in the elderly when tracking triangular waveform targets of 20 degrees amplitude at velocities of 10 degrees/sec and over. Latencies for initiation of smooth eye movements were significantly prolonged in older subjects. The reduced velocity responses of the pursuit system indicate that the diagnosis of abnormal pursuit must be qualified by the age of the patient. Smooth pursuit is an age-dependent motor system.

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.