Functional Connectivity Alterations in Patients with Post-stroke Epilepsy Based on Source-level EEG and Graph Theory

Area of Science:

• Neuroscience
• Clinical Neurology
• Biophysics

Background:

• Epilepsy is a common complication after stroke.
• Understanding the neural mechanisms underlying post-stroke epilepsy (PSE) is crucial for developing targeted treatments.
• Altered functional brain connectivity may underlie the development of PSE.

Purpose of the Study:

• To investigate differences in source-level functional connectivity using electroencephalography (EEG) between stroke patients with and without PSE.
• To identify specific brain network alterations associated with PSE.

Main Methods:

• Source-level EEG analysis was performed on 30 stroke patients with PSE and 35 without PSE during a resting state.
• Brainstorm software was used for source estimation and connectivity matrix generation.
• Graph theoretical analysis was applied using the BRAPH program across different EEG frequency bands (delta, theta, alpha, beta, low gamma, high gamma).

Main Results:

• In the beta and low gamma bands, increased radius and diameter were observed in patients with PSE.
• In the high gamma band, patients with PSE exhibited increased radius, diameter, average eccentricity, and characteristic path length, but decreased average strength, mean clustering coefficient, and transitivity.
• No significant differences in functional connectivity were found in the delta, theta, or alpha bands between the groups.

Conclusions:

• Significant alterations in functional brain connectivity are present in patients with PSE.
• Patients with PSE demonstrate decreased segregation and integration within their brain networks compared to stroke patients without PSE.
• These findings highlight the role of disrupted brain network dynamics in the pathophysiology of PSE.