Motor recovery following stroke: a transcranial magnetic stimulation study.
OBJECTIVE
To verify the usefulness of early recording of motor evoked potentials (MEPs) in predicting motor outcome after stroke and to investigate the neural mechanisms underlying functional recovery following stroke.


METHODS
We performed a comparative analysis of the behaviour of motor responses evoked by transcranial magnetic stimulation (TMS) of the ipsilateral and contralateral motor cortex in the affected and unaffected thenar muscles of 21 consecutive patients with acute stroke.


RESULTS
According to the behaviour of MEPs in the affected muscles, patients could be divided into 3 groups: (a) 10 subjects with absent responses to TMS of both the damaged and undamaged hemisphere, whose motor recovery was poor and related to the size of MEPs on the normal side; (b) 5 subjects with larger MEPs upon TMS of the ipsilateral (undamaged) than of the contralateral (damaged) cortex, whose good recovery possibly resulted from the emergence of ipsilateral pathways; (c) 6 subjects with larger MEPs in the affected than in the unaffected muscles, whose good recovery was possibly subserved by alternative circuits taking over cortical deafferentation.


CONCLUSIONS
Early MEP recording in acute stroke provides useful information on the clinical prognosis and the different mechanisms of motor recovery.
Trompetto
C
C
Department of Neurological Sciences and Vision, University of Genoa, Via de Toni 5, I-16132, Genoa, Italy.
Assini
A
A
Buccolieri
A
A
Marchese
R
R
Abbruzzese
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000503:physiopathology; D020521:Stroke / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation