We conducted a study to validate the French version of the Copenhagen Neck Functional Disability Scale (CNFDS).

We used the CNFDS on data generated by a previous randomized controlled trial comparing pulsed electromagnetic field therapy (PEMFT), spa therapy, and standard therapy in patients with neck pain. Patients were recruited locally and examined by a physician who was unaware of the treatment group and independent from the trial. Treatment efficacy was evaluated based on a visual analog scale (VAS) for pain, the short-form-36 quality-of-life instrument (SF36), payments by public healthcare insurance, and overall assessments by the patients and physicians. Efficacy was evaluated at baseline, at treatment completion, and after 3 and 6 months. In addition, the patients completed the CNFDS at these time points.

CNFDS scores were normally distributed. CNFDS scores and their variations correlated well with the other efficacy criteria. CNFDS scores were less sensitive to change than the VAS pain scores and more sensitive to change than the other efficacy criteria.

The CNFDS holds promise as a tool for evaluating neck pain. Score reproducibility needs to be studied. The CNFDS can be added to the other instruments that have been translated in recent years to serve as tools for clinical research. However, the ease of completion of the CNFDS is consistent with use in clinical practice.