1 Department of Experimental Surgery, McGill University, Montreal, QC, Canada.
2 Department of Clinical Research, Shriners Hospitals for Children-Canada, Montreal, QC, Canada.
3 Department of Health, Kinesiology, & Applied Physiology, Concordia University, Montreal, QC, Canada.
4 Faculty of Medicine, McGill University, Montreal, QC, Canada.
5 Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
6 Montreal General Hospital, McGill University Health Centre, Montreal, QC, Canada.
7 School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada.
8 Department of Anesthesia, McGill University, Montreal, QC, Canada.
9 Research Institute-McGill University Health Centre, Montreal, QC, Canada.
10 Alan Edwards Research Center for Pain, McGill University, Montreal, QC, Canada.

Introduction: The pathophysiology of pediatric musculoskeletal (MSK) pain is unclear, contributing to persistent challenges to its management.

Objectives: This study hypothesizes that children and adolescents with chronic MSK pain (CPs) will show differences in electroencephalography (EEG) features at rest and during thermal pain modalities when compared with age-matched controls.

Methods: One hundred forty-two CP patients and 45 age-matched healthy controls (HCs) underwent a standardized thermal tonic heat and cold stimulations, while a 21-electrode headset collected EEG data. Cohorts were compared with respect to their EEG features of spectral power, peak frequency, permutation entropy, weight phase-lag index, directed phase-lag index, and node degree at 4 frequency bands, namely, delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz), at rest and during the thermal conditions.

Results: At rest, CPs showed increased global delta (P = 0.0493) and beta (P = 0.0002) power in comparison with HCs. These findings provide further impetus for the investigation and prevention of long-lasting developmental sequalae of early life chronic pain processes. Although no cohort differences in pain intensity scores were found during the thermal pain modalities, CPs and HCs showed significant difference in changes in EEG spectral power, peak frequency, permutation entropy, and network functional connectivity at specific frequency bands (P < 0.05) during the tonic heat and cold stimulations.

Conclusion: This suggests that EEG can characterize subtle differences in heat and cold pain sensitivity in CPs. The complementation of EEG and evoked pain in the clinical assessment of pediatric chronic MSK pain can better detect underlying pain mechanisms and changes in pain sensitivity.