J Korean Neurol Assoc.  1989 Dec;7(2):266-275.

Motor Evoked Potential in Normal and Ischemic Stroke Patients

• Hwang YM
• Jung B

Abstract

Motor evoked potentials (MEP) were elicited with transcranial cortical stimulation using a magnetic coil in 33 normal subjects and 12 ischemic stroke patients with variable degree of motor weakness. Significant side effects or pain were not encountered. Normal thenar and tibialis anterior (TA) MEP latency measured 20.9+1.4msec and 29.3+1.9msec respectively. Thenar latency correlated with arm length more than height and TA latency correlated with height. The variability of MEP amplitude was great but thenar MEP amplitude exceeded 11% of the maximum thenar M wave. Thenar and TA MEP were evoked in all uninvolved site of ischemic stroke patients to contralateral cortical stimulation. No potentials were noted in involved site of 6 among 12 patients studied thenar MEP and 5 among 7 patients studied TA MEP and their motor powers were lower than those with elicited MEP. All involved site with motor power grade 2 or less in arm and grade 3 or less in leg elicited no potential. These findings suggest that the MEP is very sensitive to ischemic injury.

MeSH Terms

Arm
Evoked Potentials, Motor*
Humans
Leg
Stroke*