Comparison of the pattern and diffuse-light visual evoked responses in definite multiple sclerosis.

We prospectively studied 100 patients with "definite" multiple sclerosis to determine which of three methods of stimulation most consistently had results that disclosed abnormalities in the visual evoked response when they were compared with those from normal controls. The three methods were diffuse flashes of light, intermittent reversing pattern, and constant luminous but reversing pattern. The most sensitive indicator of abnormality of the visual evoked response was the latency of the major occipital positive peak. Virtually no difference was evident between the results from the two methods of pattern stimulation. Of only slightly less sensitivity was the latency of the major positive peak with diffuse-light stimulation, and this showed a prolonged latency in a greater number of patients when visual acuity was poor. Abnormalities of latency of the first negative peak and of amplitude were not related to the clinical expression of the multiple sclerosis, whether relapsing, progressive, or relapsing and progressive.