Reliability of four experimental mechanical pain tests in children

PURPOSE In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT) in healthy children. Furthermore, the aim was also to study the intersession reliability of the following four tests: (1) Total Tenderness Score; (2) PPT; (3) Visual Analog Scale score at suprapressure pain threshold; and (4) area under the curve (stimulus-response functions for pressure versus pain). PARTICIPANTS AND METHODS Twenty-five healthy school children, 8-14 years of age, participated. Test 2, PPT, was repeated three times at 2 minute intervals on the same day to estimate PPT intrasession reliability using Cronbach's alpha. Tests 1-4 were repeated after median 21 (interquartile range 10.5-22) days, and Pearson's correlation coefficient was used to describe the intersession reliability. RESULTS The PPT test was precise and reliable (Cronbach's alpha ≥ 0.92). All tests showed a good to excellent correlation between days (intersessions r = 0.66-0.81). There were no indications of significant systematic differences found in any of the four tests between days. CONCLUSION All tests seemed to be reliable measurements in pain evaluation in healthy children aged 8-14 years. Given the small sample size, this conclusion needs to be confirmed in future studies.