Background & Aims
Conditioned Pain Modulation (CPM) is crucial to understand pain modulation mechanisms in humans. However, the choice of the different CPM methods, including the types of paradigm, sequential or parallel, remains a subject of debate, particularly concerning their efficacy in elucidating pain modulation dynamics in healthy individuals and those with chronic pain. This study aims to compare these paradigms in healthy individuals and those with chronic myofascial masticatory pain (CMMP), elucidating discrepancies in pain modulation assessment. Addressing the controversy surrounding CPM methods is crucial for refining pain management strategies and advancing our understanding of pain modulation in human subjects.
Methods
This was a cross-sectional study, enrolling a total of 83 volunteers (47 with CMMP and 36 asymptomatic), aged between 18 and 60, irrespective of gender. For CMMP individuals, a diagnosis of myofascial pain was established based on the Diagnostic Criteria for Temporomandibular Disorder (DC/TMD). Primary complaints of pain were required to localize in the masseter and/or temporal muscles (secondary complaints of pain in the pre-auricular area (TMJ) were also considered). Participants in the asymptomatic group were those who reported no pain symptoms and did not meet the DC/TMD criteria for any pain-related Temporomandibular Disorders (TMD).
The study compared 2 methods employing sequential and parallel paradigms (referred to as CPMS and CPMP). The conditioning stimulus (CS) involved immersing the hand in cold water while the Pressure Pain Threshold (PPT) served as the test stimulus (TS). Both groups underwent both CPM protocols, with a time interval between them for comparison purposes.
Results
The sample has a majority of female (73.49%) volunteers, most of them belonged to the CMMP group (39 female individuals). The mean age of the sample was 30.4 years, with a mean pain score according to the Visual Analog Scale (VAS) of 4.62. The Kolmogorov-Smirnov test was employed to assess the normality of quantitative data. Spearman’s correlation test was used to explore the correlation between variables (age, VAS, and percentage of variation), revealing no significant correlations among them. A significance level of 5% (p<0.05) was adopted for all tests. All statistical procedures were conducted using Jamovi version 2.3. To compare between the CMMP and asymptomatic groups and among the different paradigms, CPMS and CPMP, a t-test was performed, indicating no significant differences between them (p= 0.700, p= 0.376, respectively).
Conclusions
This study aimed to scrutinize the efficacy of different paradigms of CPM in elucidating pain modulation mechanisms among individuals with CMMP and asymptomatic individuals. Despite the widespread debate regarding the choice of CPM methods, our findings suggest that neither sequential nor parallel paradigms significantly differ in their ability to modulate pain perception in CMMP individuals. The absence of significant differences between groups and protocols emphasizes the complexity of pain modulation mechanisms and challenges conventional assumptions regarding pain processing. Furthermore, the lack of correlation between demographic variables and pain perception emphasizes the multifactorial nature of pain experience, transcending physiological responses. Further research is needed to unravel the intricacies of pain modulation and refine pain management strategies.
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Presenting Author
Maria Emilia Servin Berden
Poster Authors
Maria Emilia Servin Berden
MSc
Bauru School of Dentistry, University of São Paulo
Lead Author
Tatiana da Fonte
University of São Paulo
Lead Author
Carolina Cunha
Sacred Heart University Center
Lead Author
Samilla Braga
Universidade de São Paulo
Lead Author
Dyanne Medina Flores
Bauru School of Dentistry, Universidade de São Paulo
Lead Author
Marcelo Koishi Ugadin
Bauru School of Dentistry, University of São Paulo
Lead Author
Paulo Conti
University of São Paulo
Lead Author
Topics
- Models: Musculoskeletal