A Cross-Sectional Comparative Study of Quantitative Electroencephalogram Characteristics According to the Presence or Absence of Central Neuropathic Pain After Stroke: Study Protocol

Background: Central post-stroke pain (CPSP) is a representative central neuropathic pain syndrome caused by lesions of the thalamus or spinothalamic tract. Current diagnostic approaches rely on subjective symptom reporting. Quantitative electroencephalography (qEEG) has gained attention as a noninvasive neurophysiological biomarker with the potential to overcome these limitations.Methods: A total of 50 stroke patients will be recruited at a single center and allocated into either a CPSP group (<i>n</i> = 25) or a control group without central neuropathic pain (<i>n</i> = 25). Using a 2-channel frontal EEG device (Fp1-Fp2), resting-state EEG will be recorded for 5 minutes under both eyes-open and eyes-closed conditions, followed by a 2-minute EEG acquisition during cold stimulation. After artifact removal, frontal asymmetry indices, the delta-to-alpha ratio, and the delta-theta to beta-alpha ratio will be computed. These qEEG parameters will be compared between groups alongside clinical variables including the Neuropathic Pain Symptom Inventory, Patient Health Questionnaire-9, and relevant medical history.Conclusion: This study seeks to identify distinctive qEEG features such as increased slow-wave activity and altered frontal asymmetry in patients with CPSP, thereby providing foundational evidence for establishing qEEG as an objective tool for early diagnosis and standardized assessment of CPSP. Although the single-center design and the limited spatial resolution of the 2-channel EEG system represent inherent constraints, this study protocol is expected to serve as an essential basis for future multi-channel qEEG investigations, machine learningbased analyses, and individualized intervention assessments in CPSP research.