Increased post-exercise facilitation of motor evoked potentials in multiple sclerosis.

OBJECTIVES

To study post-exercise facilitation following a non-fatigue exercise in a homogenous group of multiple sclerosis (MS) patients with complaints of muscle fatigue.

METHODS

In 15 MS patients and matched controls motor evoked potentials (MEP) were recorded from the biceps brachii muscle at time delays of 0.5-30s after an isometric contraction with a torque of 50% of maximal voluntary contraction (MVC) maintained for 2-6s. In addition, MEP was recorded after isometric torque of 25, 50, and 100% of MVC maintained for 6s.

RESULTS

Isometric non-fatigue contraction induced significant post-exercise increase in MEP amplitude in MS patients compared with controls being most pronounced after a contraction for 6s. The post-exercise increase in MEP lasted for longer than 30s in MS patients.

CONCLUSIONS

Post-exercise increase of MEP amplitude following a non-fatigue exercise was significant in MS patients with complaints of muscle fatigue compared with healthy subjects.