Pattern visual evoked responses in multiple sclerosis.

The latency of the first major positive component of the visual evoked response to pattern reversal was measured from a midoccipital electrode for each eye in 30 patients with a definite diagnosis of multiple sclerosis (MS). Their latencies were compared with those of a group of 18 normal subjects and 18 patients with other neurological diseases. Of 26 MS patients with a measurable response, 77% gave values that were outside the ranges of the two control groups.