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Updated: Jul 16, 2026
Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation
Published on: February 23, 2020
Motor evoked potential: a reliable and objective measure to document the functional consequences of multiple
N F Kalkers1, R L M Strijers, M M S Jasperse
1Department of Neurology, VU University Medical Center, De Boelelaan 1117, Amsterdam, The Netherlands.
Objective:
In an attempt to analyze whether MEP can serve as a valid measure for evaluating neurological dysfunction in multiple sclerosis (MS), we related MEP to clinical and MRI measures.
Methods:
Transcranial magnetic stimulation was applied in 52 MS patients to determine the central motor conduction time (CMCT) to the extremities. We calculated Z-scores for each CMCT (Zcmct) corrected for height. All patients underwent two clinical measurements and a MRI scan, of which T1 and T2 brain lesion volumes, brain volume, spinal cord volume and the number of T2 spinal cord lesions were derived.
Results:
The clinical measurements correlated significantly with various Zcmct (Spearman correlation coefficients ranged from 0.29 to 0.53; p<0.05). The number of spinal cord lesions, brain T1 and T2 lesion volume and spinal cord volume correlated with various Zcmct (r=0.31-0.53; p<0.05). Linear regression analysis revealed that the clinical measurements were explained by Zcmct left leg and T1 lesion volume (adjusted R(2)=0.38). For one clinical measurement the number of spinal cord lesions was also included (adjusted R(2)=0.43).
Conclusion:
We found a relation between MEP, brain and spinal cord MRI measures, and two clinical measures. Moreover, a model for explaining disability in MS revealed that MEP measures provide information in addition to MRI measures.
Significance:
This study suggests that MEP is a measure that might adequately reflect pathology and neurological dysfunction in MS.
