[Changes in pattern evoked visual potentials in multiple sclerosis in respect to development of illness].

In 43 patients (28 female, 15 male) with a definitive diagnosis of disseminated sclerosis visual evoked potentials were tested several times with pattern stimulation. The average duration of the disease was 7 years before the first pattern evoked potential. The latency of the evoked potential, estimated from the first positive peak, was in the pathological range in 30 patients in the first investigation, whereas in 38 patients there was a delayed latency in the last measurement. There was an average period of 1.5 years between the first and last investigation. In 20 cases the evoked potentials showed a continuous delay in the latency. Two patients maintained the original pathological values and in 7 cases the control results were below that of the first investigation. In 9 cases it was not possible to show a definite result because of the marked fluctuation in the values. 5 times in the entire investigation was a pathological result absent. There was a clear correlation between both the duration of the disease and the presence of a delayed latency, and the frequency of episodes and a pathological latency.