The clinical spectrum of internuclear ophthalmoplegia in multiple sclerosis.

The eye movements of 100 patients with multiple sclerosis were examined clinically, including a saccade test. Thirty-four cases of internuclear ophthalmoplegia were found, of which 14 were bilateral and 20 were unilateral. Only three patients had full restriction of adduction, whereas 16 had no restriction at all. A continuous dissociated nystagmus was present in one patient only, while in 15 just a few beats of the abducting eye could be observed. In ten cases both restriction of adduction and dissociated nystagmus were lacking, and the diagnosis could only be made with the saccade test, which in all 34 patients showed a clearly visible disjunction of horizontal saccades. In 15 cases, infrared oculography was performed, which in all cases confirmed the clinical findings, and which in some cases disclosed an additional subclinical internuclear ophthalmoplegia on the opposite side.