Pulsed Radiofrequency Analgesia Alters EEG Spatiotemporal Dynamics: A Microstate-Based Exploratory Study.

INTRODUCTION

Pulsed radiofrequency (PRF) is a well-established neuromodulation technique widely used for managing neuropathic pain. Lumbosacral radicular pain, a common neuropathic condition, is often refractory to conventional treatments. Although dorsal root ganglion (DRG) PRF has emerged as a promising intervention, its therapeutic efficacy is often limited and variable, likely due to an incomplete understanding of its mechanisms. To elucidate the neural mechanisms underlying DRG PRF analgesia, this study characterized treatment-induced alterations in microstate spatiotemporal dynamics and examined their correlation with pain intensity, thereby assessing their potential as neurophysiological markers.

METHODS

We recorded high-density electroencephalograms (EEG) in healthy controls and patients before and after DRG PRF treatment. Topographic differences were assessed using topographic analysis of variance (TANOVA). Microstate temporal parameters (duration, occurrence, coverage) and transition probabilities were analyzed. Pearson correlation analysis was performed between transition probabilities and visual analogue scale (VAS) scores.

RESULTS

TANOVA revealed significant differences in microstate topographies among the three groups (p = 0.033), primarily attributed to microstates C and E. Although we found no significant differences in global temporal parameters or transition probabilities, our exploratory analysis revealed a reduction in the transition probability from microstate D to E (Delta TM D to E) in patients before DRG PRF treatment compared to healthy controls (p = 0.016, uncorrected). Notably, this reduction showed a trend toward normalization after treatment. Furthermore, we observed a significant negative correlation between Delta TM D to E and VAS scores (r = -0.459, p = 0.008).

CONCLUSION

DRG PRF alleviates neuropathic pain by normalizing interactions between large-scale brain networks, as evidenced by topographic reorganizations and trends toward normalized transition dynamics. The sensitivity of microstate metrics to these changes supports their potential as neurophysiological markers for assessing both pain-related brain dysfunction and treatment response.

TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov with the following number: ChiCTR2500104921.