Physiological measures of therapeutic response to interferon beta-1a treatment in remitting-relapsing MS.
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 < 0.05). Percent reduction of MEP amplitude was significantly less at 6 months (P < 0.05) The majority of subjects (5/8 at 3 months; 6/8 at 6 and 12 months) reported decreased physical fatigue. Functional improvements were observed for walk and finger tapping scores after 3 months of IFNB treatment. MEP latencies were unchanged over the course of the intervention.


CONCLUSIONS
Results indicate that IFNB therapy may improve the rate of recovery from central fatigue.


CONCLUSIONS
Transcranial magnetic stimulation (TMS) may have promise as an objective physiological tool to evaluate disease activity and treatment responses in MS.
White
Andrea T
AT
Departments of Exercise and Sport Science and Neurology, University of Utah, 250 S. 1850 E., Rm 241, Salt Lake City, UT 84112, USA. andrea.white@health.utah.edu
Petajan
Jack H
JH
D000328:Adult; D004185:Disability Evaluation; D004574:Electromagnetic Fields; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D005385:Fingers / Q000502:physiology; D006801:Humans; D000068556:Interferon beta-1a; D016899:Interferon-beta / Q000627:therapeutic use*; D015225:Magnetoencephalography; D009044:Motor Cortex / Q000187:drug effects / Q000503:physiopathology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000188:drug therapy* / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D012146:Rest / Q000502:physiology; D016138:Walking / Q000502:physiology
D016899:Interferon-beta; D000068556:Interferon beta-1a