Evaluating Patient's Understanding of Pain Neurophysiology: Rasch Analysis of the Neurophysiology of Pain Questionnaire.

OBJECTIVE: Educating patients about the neurobiologic basis of their pain experience is an important part of managing patients with pain disorders. The aim of this study was to evaluate the measurement properties of the Neurophysiology of Pain Questionnaire (NPQ) in a population seeking osteopathy treatment for both acute and chronic musculoskeletal pain symptoms.

MATERIALS AND METHODS: Patients attending the Victoria University Osteopathy Clinic for their initial osteopathy consultation were recruited consecutively. Before their consultation patients were invited to complete a health information questionnaire and the NPQ. The measurement properties of the NPQ were evaluated using Rasch analysis.

RESULTS: Two-hundred and ninety-four patients completed the NPQ (female, 51.7%; mean age, 35.5 y). Over two-thirds of these patients presented with a spinal symptoms and 53% of patient presentations were acute. Initial analysis suggested the NPQ responses did not fit the Rasch model. Modifications to the NPQ including removing items and removing person responses, resulted in the development of a 14-item unidimensional version of the NPQ that was free from differential item functioning.

DISCUSSION: The study provides further evidence for the validity of the NPQ total score, derived from a population seeking care for an acute or chronic musculoskeletal pain complaint. The total score is interval-level data and can be used to evaluate changes in pain knowledge before, during, and after pain education interventions. Future studies could utilize this revised version of the NPQ in longitudinal designs and also evaluate pain knowledge changes in conjunction with other objective or subjective pain measures.