[Disorders of eye movement in amyotrophic lateral sclerosis--report of 2 patients]

Amyotrophic lateral sclerosis (ALS), a neurodegenerative disorder of unknown origin, was thought to spare the extraocular muscles. Extraocular involvement has recently been reported to occur in the late stages of ALS following respiratory insufficiency.

We report on two patients with ALS who were referred for screening of oculomotor impairment in ALS. Orthoptic examination in a 64-year-old woman with peripheral ALS revealed retraction of the upper eye lids as well as impaired abduction and upgaze in both eyes, developing prior to respiratory insufficiency. A 50-year-old man with bulbar ALS was found to have bilateral impairment of upgaze as well as a negative Bell's phenomenon. Horizontal pursuit was interrupted by compensatory saccades, vertical fixating saccades were slightly hypometric. These oculomotor changes were also seen prior to respiratory insufficiency.

These findings provide further evidence of early oculomotor involvement in ALS, e.g. prior to respiratory failure and prior than previously suspected. Oculomotor impairment may occur in both the peripheral and the bulbar type of ALS.