Association between central sensitivity syndrome and psychophysical factors in patients with masticatory myofascial pain

Purpose: This study explored the relationship between central sensitization symptoms, assessed using the Central Sensitization Inventory (CSI), and psychophysical factors in patients with chronic masticatory myofascial pain (MMP) transitioning from the acute to chronic stages. Methods: In this study, 23 patients with MMP and 22 healthy volunteers were assessed using psychophysical tests, including measurements of pressure pain threshold (PPT) and temporal summation of pain (TSP). Additionally, CSI scores were recorded to evaluate central sensitization symptoms. Results: Patients with chronic MMP showed significantly lower PPT in all masticatory muscles and extratrigeminal areas compared with controls. However, there was no significant correlation between CSI scores and psychophysical test results in patients with MMP. Conclusion: The significant enhancement of TSP in patients with sub- chronic MMP suggests a potential role in the onset of myofascial pain. The main finding suggests that sub-chronic symptom patients show higher CSI scores despite no sensory testing changes, indicating that central sensitization possibly precedes observable symptoms.