Comparison of Techniques for Evaluation of Deep Pain Sensitivity in the Craniofacial Region

Aims: To determine whether a new palpometer and manual palpation can detect site-to-site differences in human craniofacial pain sensitivity in a similar pattern to that of an electronic pressure algometer and subsequently to compare between-session and within-session variability of palpometer and manual palpation. Methods: Sixteen volunteers participated. Experiment 1 was carried out in two sessions. In session 1, pressure pain thresholds (PPT) were determined with a pressure algometer at nine craniofacial sites. Manual palpation and the palpometer were then applied to all sites, and subjects scored perceived pressure/pain on a 0 to 100 numerical rating scale (NRS). Mean scores were compared using analysis of variance (ANOVA). Ten of the volunteers were recalled for a second session and the same protocol was carried out except for assessment of PPTs to establish between-session variability. In experiment 2, three craniofacial sites were examined using the palpometer and manual palpation. Both techniques were repeated 10 times at each site and coefficient of variation (CV) was compared to determine withinsession variability. Results: There were no significant differences in NRS scores evoked by manual palpation or palpometer at any test site between repeated sessions. The CV varied between techniques, with lower within-session variability for the palpometer compared with manual palpation (P = .03). Conclusion: The palpometer and manual palpation could detect differences in craniofacial sensitivity in healthy subjects, with no significant differences between repeated sessions. All techniques showed the highest sensitivity at the retromandibular site and the lowest at the temporalis muscle site. The palpometer had lower within-session variability compared with manual palpation. Keywords: algometer, numerical rating scale, palpation, palpometer, temporomandibular disorders