Multimodal sensory and motor evoked potentials in a two-year follow-up study of MS patients with relapsing course.

Serial recording of multimodal sensory (pattern reversal visual, brainstem auditory, median and tibial somatosensory) and motor evoked potentials during a 2-year period was performed on a group of 25 patients with relapsing multiple sclerosis. A new, 10-degree evoked potentials abnormality scale was introduced. In contrast to the insignificant common trend of both the mean individual EP latency parameters and the mean expanded disability status scale and evoked potentials abnormality scale to deteriorate the changes in both expanded disability status scale (p less than 0.05) and evoked potentials abnormality scale (p less than 0.01) were significant using a 1-point criterion for change and non-parametric testing. Changes in both scales differed in about 50% of patients; contrary to bidirectional changes in the clinical scale, no improvement in the evoked potential scale was found. The introduction of an evoked potentials abnormality scale based on separate cut-off step-like criteria may increase the robustness of evoked potential changes due to the activity of the disease in longitudinal studies.