Motor evoked potential: A reliable and objective measure to document the functional consequences of multiple sclerosis? Relation to disability and MRI

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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 R2 = 0.38). For one clinical measurement the number of spinal cord lesions was also included (adjusted R2 = 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. © 2007 International Federation of Clinical Neurophysiology.
Original languageEnglish
Pages (from-to)1332-1340
JournalClinical neurophysiology
Issue number6
Publication statusPublished - 2007

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