Reliability of 2 protocols for assessing pressure pain threshold in healthy young adults

Objective: The purposes of this study were to determine whether there were differences in mean values or reliability for 2 frequently used protocols for pressure pain threshold (PPT) and to calculate how large a difference in PPT is necessary to be 95% confident that a real change has occurred.

Methods: Thirteen participants (8 females) aged 22.3 (±2.3) years from a university community were included. Two testers evaluated participants using 2 protocols, in which PPT was measured 3 times at 8 different body locations. The "cluster protocol" consisted of 3 successive measurements at each location with a 30-second rest between each measurement. The "circuit protocol" consisted of 1 measurement taken at each anatomical location until "the circuit" was complete and then repeated a total of 3 times.

Results: A 2-way analysis of variance did not reveal significant differences between protocols at any body location (P = .46-.98). Intertester reliability was good to excellent for all locations (intraclass correlation coefficient, 0.84-0.96), and limits of agreement ranged from 108 to 223 kPa.

Conclusions: Either the cluster or circuit protocol can be used to measure PPT in clinical or research setting. A difference of 160 kPa is considered sufficient to indicate a real difference between repeated measures of PPT regardless of protocol used for testing.