Exploratory EEG correlates of sensory and affective pain dimensions in patients with chronic widespread pain.

Introduction: Chronic widespread pain (CWP) is a debilitating condition characterized by persistent pain, yet objective biomarkers based on electroencephalography (EEG) remain elusive. This exploratory study aimed to identify neurophysiological correlations related to the sensory and affective dimensions of CWP using resting-state EEG data analyzed with exact low-resolution electromagnetic tomography (eLORETA). Methods: We analyzed data from 20 CWP patients and 22 healthy controls, calculating current source density (CSD) and functional connectivity (FC) in key brain networks and correlating them with pain scores from the numerical rating scale and short-form McGill Pain Questionnaire. Results: While no significant CSD or FC differences emerged between the groups, analysis within the CWP group yielded two preliminary associations. First, current pain intensity was negatively correlated with CSD values in the γ bands of the precuneus/posterior cingulate cortex (PCC) (r = -0.743). Second, the affective pain component was positively correlated with δ band FC between the anterior cingulate cortex (ACC) and the right anterior insula (r = 0.647). Discussion: These results suggest that EEG-derived neurophysiological correlations can offer insights into individual differences in the CWP experience. The findings in the precuneus/PCC may reflect exploratory correlations associated with sensory pain intensity, while the salience network connectivity may be linked to the affective dimension of pain. Future research with larger, homogeneous samples and longitudinal designs is needed to evaluate the potential clinical relevance of these electrophysiological correlations.