Visually evoked responses in multiple sclerosis.

Visually evoked cerebral responses (VERs) from the occipital and central areas were compared between 50 patients with multiple sclerosis and 50 control subjects. The average peak latencies of four occipital components (OII-OV) and two central ones (CIV and CV) were significantly delayed. In no instance was the amplitude significantly different. Routine EEGs were either entirely normal (16) or showed only minor findings (10) in 26 patients. Of this group, nine showed abnormal VERs. Seventeen patients had clinical symptoms or signs which pointed to spinal cord involvement only; nonetheless, eight in this group had abnormal responses. Inasmuch as changes in visually evoked potentials are not directly dependent upon the presence of a demonstrable field defect, the technique may be useful in detecting otherwise occult cerebral lesions.