CAN MOTOR RECOVERY IN STROKE PATIENTS BE PREDICTED BY EARLY TRANSCRANIAL MAGNETIC STIMULATION

Background and Purpose We used transcranial magnetic stimulation of th e motor cortex to evaluate the functional state of corticospinal pathw ays innervating the first dorsal interosseous muscle of the hand in 26 patients suffering from a first-ever ischemic stroke in the middle ce rebral artery territory. Methods All patients had complete hand palsy and were tested within the first 24 hours from stroke onset. Patients were also tested clinically with the MRC, Rankin, and National Institu tes of Health (NIH) stroke scales at day 1 and with MRC and NM scales and the Barthel Index at day 14. Electrophysiological testing was repe ated at day 14. Patients were divided into three subgroups according t o the amplitude of the maximal response (motor evoked potential [MEP]) evoked at day 1. Results After 2 weeks, all 6 patients with initial M EPs >5% maximum motor response (M(max)) showed some first dorsal inter osseous muscle motor function recovery, whereas 19 of 20 patients with initially absent or small (<5% M(max)) MEPs were left with complete h and palsy. There were strong positive correlations between MEP amplitu de at day 1 and MRC and Barthel Index scores at day 14. However, measu rement of central motor conduction time proved to be of little prognos tic value. Conclusions We conclude that early-performed transcranial m agnetic stimulation is a valuable prognostic tool for motor recovery f rom stroke and that relatively preserved MEP amplitude shortly after s troke is a better prognostic factor than normal central motor conducti on time.