Evoked potentials predict the clinical changes in a multiple sclerosis drug study

Abstract

Visual, brainstem auditory, and median nerve somatosensory evoked potential (EP) tests were performed annually during a 3-year, double-blind, placebo-controlled study of azathioprine with or without steroids in chronic progressive MS. Treatment-related visual and somatosensory EP changes became statistically different 1 year before corresponding differences were seen in the Standard Neurological Examination scores. The statistical significance of EP changes was substantially greater than seen for changes in other clinical scales. The degree of significance was increased by using EP latency values, rather than simple criteria for change. EPs are sensitive, objective measurements useful in MS therapeutic trials.

Clemastine fumarate as a remyelinating therapy for multiple sclerosis (ReBUILD): a randomised, controlled, double-blind, crossover trial

“…Furthermore, the sustained clinical response in the first epoch provides evidence that the observed improvement was not due to a transient effect of medication on electrical conductance but rather reflects a persistent structural change induced by treatment. Previous studies (NCT02040298) 35 suggested that drugs that target the immune system or paranodal potassium channels might reduce VEP latency.…”

Clinical, Radiological and Electrophysiological Comparison of Immunomodulatory Therapies in Multiple Sclerosis

“…In our study, VEP abnormality was the most commonly encountered defect. EPs have been used to investigate the natural progression of diseases and the efficacies of treatment methods (20,21,22,23,24,25). While some studies reported weak or no correlation between clinical and EP changes, some studies reported moderate correlations (20,21,22,25).…”

“…In a study performed during the period before the wide usage of immunomodulatory drugs, it was proposed that azathioprine causes changes in VEP and SEP one year before any clinical changes in chronic progressive MS. In another study where the effects of methylprednisolone were investigated, a relationship between the changes in disability and EP scores was suggested (24,26).…”

Serial evoked potentials in multiple sclerosis bouts. Relation to steroid treatment

“…Stable patients are electrophysiologically stable [9,24], whereas progression of disability seems to be associated with a progressive increase in latency [9,30]; no or poor correlations can be found with clinical symptoms [1,2,12,24]. In a long-term followup of chronic progressive azathioprine-methylprednisolone-treated MS patients, Nuwer et al [20] were able to find a correlation between latency changes and clinical outcome. A significant improvement in central conduction time and clinical course after HDMP therapy has been found in acute MS patients [25], although no significant short-term EP changes were detected in steroidtreated MS patients [6,7,28), thus questioning the usefulness of EPs in monitoring disease activity in therapeutic trials [1,2].…”

“…The diagnostic value of Evoked Potentials (EPs) in Multiple Sclerosis (MS) is well known [5,8,11,17,22], but their usefulness in disease monitoring is controversial [1,2,16,20]. Steroids are widely used in the treatment of MS exacerbations, but is still uncertain if their mechanisms of action are mainly antiedemic [14], antiinflammatory [6] or something else [3,29].…”