Motor evoked potentials as a predictor for upper limb function following acute stroke

ABSTRACT

To record the MEPs in the affected upper limb of hemiplegic patients in order to study its role in the prediction of functional and motor recovery of the upper limb in cases of acute stroke. This study included 30 patients suffering from acute stroke, all of them were subjected to history taking, clinical and neurological examination and clinical assessment scales [initially and after three months of conventional physiotherapy] including Medical Research Council [MRC] scale, Nine Hole Peg test [NHPT] and action research arm test [ARAT]. Also, all patients and controls were subjected to MEPs recording in order to evaluate resting motor threshold, MEP amplitude and central motor conduction Time [CMCT]. The mean of initial MRC scale, NHPT and ARAT was 1.73 +/- 1.17, 4.23 +/- 2.34 and 21.53 +/- 14.42 respectively. As regards MEPs, the mean of resting motor threshold [mamp], MEP amplitude [microv] and CMCT [msec] were 109.57, 0.56 and 11.28 respectively showing a highly significant difference from the control group whose mean values were 73.4, 2.98 and 7 respectively. Patients were divided according to initial CMCT into three groups group I and II [patients with normal and delayed CMCT respectively] and Group III [patients with absent MEP]. On comparing the initial and follow up motor and functional recovery according to the clinical scales [MRC, NHPT and ARAT] in the three patient groups, group I and II exhibited highly significant [P<0.01] higher scores than group III. Correlation study showed a significant negative correlation between CMCT and MRC scale and ARAT, also there was a significant positive correlation between CMCT and NHPT while no significant correlation was found between resting motor threshold or amplitude of MEPs and the follow up clinical scales. Predictive value of CMCT for improvement of different scores [MRC, NHPT and ARAT] was 22, 38 and 36.6% respectively. CMCT of MEPs was the parameter with the highest predictive value to functional improvement of affected upper limb in stroke patients. These data can be helpful for clinicians to plan the program of rehabilitation according to the expected recovery of motor function