No abstract

Defective pursuit eye movements were recorded by electrooculography (EOG) in 11 of 18 patients (61%) with amyotrophic lateral sclerosis. Pursuit defects consisted of a breakdown of smooth tracking into saccadic motions that were grossly in excess (frequencies and amplitudes) of saccadic interruptions of pursuit in normal subjects. In nine patients, defective pursuits cogwheeling) were obvious by visual inspection as well as by EOG; in two, this abnormality was seen only by EOG. In eight patients, the pursuit defect was the only abnormality of oculomotor function; in three, there were also saccadic defects (optokinetic nystagmus or conjugate gaze) discerned by EOG. Autopsy revealed neuronal degeneration in substantia nigra and demyelination in integral capsule in one patient with the pursuit defect but not in another patient without the defect. The pursuit defect may be a sign of extrapyramidal or supratentorial pyramidal involvement in ALS.

Two patients had palatal myoclonus that disappeared. In one, the palatal myoclonus disappeared completely during all stages of natural sleep only to return again when he awoke, persisting as long as he remained awake. In the other patient, palatal myoclonus was continuous for 2 years, became erratic for 6 months, and then disappeared completely, although she could induce it voluntarily. These cases demonstrate that palatal myoclonus is not always: independent of the sleep-waking cycle, persistent throughout life, and independent of cortical control.

No abstract

No abstract