The patient-specific functional scale: Validation of its use in persons with neck dysfunction

Self-report measures of disability are being used more frequently to assess patients' outcomes in clinical practice. This study examines the reliability, validity, and sensitivity to change of the Patient-Specific Functional Scale when applied to persons with neck dysfunction. The Patient-Specific Functional Scale and Neck Disability Index were applied at the initial visit, within 72 hours of the initial visit, and following 1-4 weeks of treatment in 31 patients with cervical dysfunction. At the time of the initial visit, the clinician made an estimate of patients' prognoses on a five-point scale. This estimate served as an a priori construct for change: patients with better ratings would change more. The results demonstrate excellent reliability (R = .92), validity (r = .73-83 compared with the Neck Disability Index, and r = .52-.64 compared with the prognosis rating), and sensitivity to change (r = .79-.83 compared with Neck Disability Index change scores, and r = .46-.53 compared with the prognosis rating). No difference was found between the Patient-Specific Functional Scale and Neck Disability Index in their ability to detect change over time. The results of this study are consistent with previous investigations which have concluded that the Patient-Specific Functional Scale is an efficient and valid measure for assessing disability and change in disability in persons with low back pain and knee dysfunction.