CENTRAL FATIGUE ASSESSED BY TRANSCRANIAL MAGNETIC STIMULATION

Central fatigue is a subjective phenomenon which can be examined using transcranial magnetic stimulation (TMS). To assess central fatigue, w e compared TMS and peripheral electrical stimulations in patients with central nervous system (CNS) lesions and controls before and after an exhaustive task. The recovery times of motor evoked potential (MEP) a mplitudes were significantly prolonged in the patient group whereas th e recovery of F waves and compound muscle action potentials showed no significant changes. The results indicate that fatigue cannot be attri buted either to intramuscular processes or to reduced spinal excitabil ity, but reflects a supraspinal, probably cortical phenomenon. The mea surement of MEP recovery times proved to be a simple and objective too l for the assessment of fatigue and for the differentiation between he althy controls and patients with CNS lesions. (C) 1996 John Wiley & So ns, Inc.