Use of generic versus region-specific functional status measures on patients with cervical spine disorders

Background and Purpose. Few data exist to support the use of functional status measures on patients with disorders of the cervical spine. This study was designed to compare the construct validity and sensitivity to change of the Neck Disability Index (NDI) and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Subjects and Methods. Patients (N=146) with a variety of disorders of the cervical spine completed the NDI and the SF-36 prior to treatment. Following discharge from treatment, 69 of these patients completed a second NDI and SF-36. Results. There was evidence for the construct validity and sensitivity to change of the NDI and the physical and mental component scores of the SF-36. The ability of the NDI and SF-36 to detect change varied, depending on the construct tested. The SF-36 was superior in some instances, and the NDI was superior in other instances. The NDI appears to measure both mental and physical health-related factors. Conclusion and Discussion. There appears to be substantial overlap between the 2 measures. The use of both measures, therefore, is probably not necessary.