Psychometric Properties of Pressure Pain Thresholds Measured in 2 Positions for Adults With and Without Neck-Shoulder Pain and Tenderness

Objective: The purpose of this study was to determine the psychometric properties of pressure pain threshold (PPT) testing in adults with and without neck-shoulder pain and tenderness and to compare the differences in PPT measurements between the seated and prone positions. Methods: Thirty asymptomatic adults and 30 symptomatic patients with intermittent neck-shoulder pain and tenderness completed the study. A pressure algometer was used to assess PPTs at specific points on the middle deltoid, levator scapulae, and upper trapezius muscles of the dominant side of the asymptomatic individuals and the painful side of the patients. Four trials were performed on each muscle in both the seated and prone positions. To determine between-day reliability, a subset of the participants returned to repeat the testing. Results: The intraclass correlation coefficients showed good to excellent within-session reliability and fair to excellent between-day reliability of PPT measurements in both the seated and prone positions for both groups. There were significant differences between groups for all muscles in both positions (P <.05) except for the upper trapezius muscle in the prone position. In addition, significant differences were found between the 2 testing positions for the middle deltoid and upper trapezius muscles in the symptomatic group and for the middle deltoid muscle in the asymptomatic group. Conclusion: The results of the study suggest that PPT testing could be useful for distinguishing individuals with and without neck-shoulder pain and tenderness. Further, the patient's position should be considered when testing PPT, specifically at the middle deltoid or upper trapezius muscles.