Correlation between disability and transcranial magnetic stimulation abnormalities in patients with multiple...

Area of Science:

• Neuroscience
• Neurology
• Clinical Electrophysiology

Background:

• Multiple sclerosis (MS) is a central nervous system inflammatory demyelinating disorder.
• Current diagnostic and monitoring methods for MS lack established surrogate markers for disease progression.
• Assessing subclinical pyramidal tract dysfunction is crucial for understanding MS evolution.

Purpose of the Study:

• To evaluate motor evoked potentials (MEP) using transcranial magnetic stimulation (TMS) in multiple sclerosis patients.
• To investigate the correlation between TMS-derived MEP abnormalities and clinical disability.
• To explore the utility of TMS in patients with and without apparent pyramidal tract dysfunction.

Main Methods:

• 131 clinically definite MS patients were enrolled.
• Motor evoked potentials (MEP) were recorded following transcranial magnetic stimulation (TMS).
• Abnormalities included absent MEP, decreased amplitude, prolonged latency, and abnormal central motor conduction time (CMCT).

Main Results:

• 83% of patients showed abnormal MEP amplitude, 52% had MEP latency abnormalities, and 49% exhibited CMCT abnormalities.
• Abnormalities in CMCT, latency, and amplitude were significantly correlated with Expanded Disability Status Scale (EDSS) scores (p<0.001).
• TMS-EP findings demonstrated a strong correlation with disability, even in patients with subclinical presentations.

Conclusions:

• Transcranial magnetic stimulation-evoked potentials (TMS-EP) are a valuable tool for assessing MS patients.
• TMS-EP abnormalities correlate significantly with disability in MS.
• These electrophysiological findings may aid in predicting disability progression in MS, including subclinical cases.