Reliability and Responsiveness of Patient-Reported Outcome Measures of Neck Disability to Physical Therapy: Comparison of the Copenhagen, Northwick Park, and Neck Bournemouth Questionnaires and the Neck Disability Index

Abstract

ObjectiveThe purpose of this study was to identify the external and internal reliability and responsiveness of the validated patient-reported outcome measures (PROMs) of neck pain to a standardized regimen of physiotherapy administered acutely after mild whiplash injury using the clinically significant improvement components of the Patient Global Impression of Change (PGIC) as the outcome measure. MethodsEighty-six patients with neck pain alone were referred for physiotherapy within 2 weeks of whiplash injury. They completed the Copenhagen, Northwick Park (NP), and Neck Bournemouth (NBQ) questionnaires and the Neck Disability Index (NDI) before starting and after treatment when they also completed the PGIC. Treatment comprised deep soft tissue massage, myofascial releases, muscle energy techniques, joint articulation and manipulation techniques, and a home exercise program. The duration of treatment was between 3 and 6 weeks. A PGIC of 6 or 7 was considered to be clinically significant improvement. ResultsThe external reliability of the PROMs was >0.7 and internal >0.87. All components of the PROMs contributed to the final score except headache in the Copenhagen and upper-limb dysesthesia in the NP. The most reliable questionnaire was the NBQ, which was significantly more responsive than the Copenhagen (P = .008). The NBQ was slightly more responsive than the NDI and NP. The NBQ and NDI were successfully completed more frequently than the NP and Copenhagen. ConclusionThe NP, NDI, and NBQ are all reliable and responsive measures of change after physiotherapy for neck pain after acute whiplash injury.