Decreased postexercise facilitation of motor evoked potentials in patients with CFS or depression

We studied the effects of exercise on motor evoked potentials
(MEPs) elicited by transcranial magnetic stimulation (TMS) in
18 normal (control) subjects, 12 patients with chronic
fatigue syndrome, and 10 depressed patients. Subjects
performed repeated sets of isometric exercise of the extensor
carpi radialis muscle until they were unable to maintain half
maximal force. MEPs were recorded before and after each
exercise set and for up to 30 minutes after the last set. The
mean amplitude of MEPs recorded from the resting muscle
immediately after each exercise set was 218% of the mean
pre-exercise MEP amplitude in normal subjects, 126% in
chronic fatigue patients, and 155% in depressed patients,
indicating postexercise MEP facilitation in all three groups.
The increases in the patient groups, however, were
significantly lower than normal. The mean amplitudes of MEPs
recorded within the first few minutes after the last exercise
sets in all three groups were approximately half their mean
pre-exercise MEP amplitudes. This postexercise MEP depression
was similar in all groups. We conclude that postexercise
cortical excitability is significantly reduced in patients
with chronic fatigue syndrome and in depressed patients
compared with that of normal subjects.

Samii A,Wassermann E,Ikoma K,Mercuri B,George MS,O'Fallon A,Dale JK,
Straus S, Hallett M

1 Star2 Stars3 Stars4 Stars5 Stars (44 votes, average: 3.05 out of 5)

Leave a Reply