Repeatability of pain drawings in a low back pain population

Study Design. This is a prospective test-retest repeatability study. Objective. The primary purpose of this study was to determine the test-retest repeatability, using a variety of scoring methods, of pain drawings in a group of chronic low back pain patients. The intraevaluator repeatability for the methods requiring subjective interpretation was also evaluated. Summary of Background Data. Pain drawings have been used in a variety of applications, including documentation of symptom location, as a tool for diagnosis and as a psychological screening tool. Accordingly, there have been several methods described for interpreting the drawings and several groups have investigated evaluators' abilities to replicate their interpretation; However, there has been less investigation of patients' consistency in completing the drawings. Methods. The intraevaluator repeatability was determined for the two scoring methods requiring subjective interpretation by the evaluator rescoring the drawings 2 weeks after the initial scoring. To determine repeatability, drawings were completed on two occasions by 75 patients. Patients who indicated on a questionnaire that there had been no change in their pain location since their first clinic visit (the day the first drawing was completed) were included in the study. This subgroup consisted of 45 patients who completed pain drawings on two occasions separated by a mean of 244.2 days (range, 26-1197 days). Repeatability was assessed for several scoring methods described in the literature: penalty point system, overall visual inspection, body regions, and a grid method. Results. Patients were consistent in completing the drawings, assessed by the various scoring methods. The worst repeatability values were for some of the sensation types. Discussion. As reported by others, the intraevaluator repeatability was high. The results of this study, finding acceptable repeatability for most scoring methods for pain drawing completed on occasions separated by a relatively long period of time, support that the pain drawing is a stable instrument for use in chronic back pain patients.