Physiological measures of therapeutic response to interferon beta-1a treatment in remitting-relapsing MS.

Abstract Objective : This pilot study was designed to determine the effects of interferon beta-1a (IFNB) therapy (Avonex ® ) on cortically evoked motor potentials (MEPs) during resting and fatigued states in individuals with multiple sclerosis (MS). Methods : Eight women with relapsing–remitting MS (mean age 36) and mean Expanded Disability Status Scale (EDSS) score of 3.1 were evaluated before and after 3, 6, and 12 months of IFNB therapy. At each test period, MEPs were recorded at rest and following a fatigue paradigm (3 min maximal contraction). Effects of IFNB on neurological and functional (7.7 m walk and 10 s finger tapping) status and fatigue were also examined. Results : Recovery from post-exercise depression of MEP amplitudes (PED) was 41, 43, and 43.5% faster at 3, 6, and 12 months, respectively, compared to baseline ( P P Conclusions : Results indicate that IFNB therapy may improve the rate of recovery from central fatigue. Significance : Transcranial magnetic stimulation (TMS) may have promise as an objective physiological tool to evaluate disease activity and treatment responses in MS.