Investigation of Motor Evoked Potential and Cortical Silent Period in Migraine Patients

Rationale and Background:

Migraine is a neurological disorder that significantly impairs individual quality of life and imposes substantial economic burdens on healthcare systems worldwide. Although its pathophysiology is not fully understood, recent research suggests that migraine is associated not only with vascular changes but also with alterations at neurological and cortical levels (Goadsby et al., 2017). Evidence increasingly indicates enhanced excitability and disrupted inhibitory mechanisms in central nervous system regions, including the motor cortex (Coppola et al., 2007).

Transcranial Magnetic Stimulation (TMS) is a non-invasive and reliable neurophysiological technique that stimulates the motor cortex and records muscle responses. Parameters obtained through TMS, such as Motor Evoked Potential (MEP) and Cortical Silent Period (CSP), are used to assess cortical excitability and inhibitory control, respectively (Chen et al., 1999). CSP is particularly useful for evaluating GABA-B-mediated inhibitory mechanisms. The hypothesis that migraine patients exhibit reduced cortical inhibition can be directly tested using CSP measurements.

Previous studies have reported shortened CSP durations and increased MEP amplitudes in migraine patients, suggesting cortical hyperexcitability (Brighina et al., 2002; Afra et al., 1998). However, these findings are inconsistent, and how they vary across migraine subtypes (with aura vs. without aura) remains unclear. Therefore, this study aims to characterize cortical physiological changes in migraine using objective and quantitative measures, filling gaps in the literature and contributing to clinical evaluations. Additionally, the relationship of these parameters with clinical features such as migraine type, duration, and attack frequency will be investigated to lay the groundwork for individualized neurophysiological profiling.

Primary and Secondary Objectives: