Objective: Depression of motor evoked potentials (MEPs) following transcran
ial magnetic stimulation (TMS) may be a sign of central motor fatigue. As a
pilot study, we have examined whether post-exercise MEP depression can be
compensated by application of sensory stimuli prior to TMS.
Methods: We studied 15 healthy volunteers (aged 21-28 years) who were requi
red to perform an exercise protocol of ankle dorsiflexion until force fell
below 66% of maximum force. MEPs were recorded from the right tibialis ante
rior muscle. Prior to TMS, electrical stimuli were applied to the ipsilater
al sural nerve with an individual interstimulus interval between 50 and 80
ms.
Results: MEP areas decreased after exercise. When a sensory stimulus was ad
ministered MEPs did not change.
Conclusion: We conclude that the effects of central fatigue may be influenc
ed by application of sensory stimuli. (C) 2000 Elsevier Science Ireland Ltd
. All rights reserved.