Assessment of Self-Rated Disability, Impairment, and Sincerity of Effort in Whiplash-Associated Disorder

Abstract

Objectives: To review the reliability and comparability of different pain and disability self-report questionnaires as they relate to patients with whiplash-associated disorders [WAD] and to conduct analytic cohort studies of two samples of subjects with respect to impairment and sincerity of effort.

Methods: The Neck Disability Index, Neck Pain Questionnaire, and the Copenhagen Neck Functional Disability Index were reviewed for comparability of pain, impairment, and disability items. Two small clinical samples were assessed with disability and strength tests.

Results: The three instruments for self-rated disability in WAD have numerous similarities in content and format, and have equally good basic psychometric efficacy. The Neck Disability Index has been used in a larger number of reports, and more is known about its psychometric properties, particularly as they apply to the assessments made in research studies.

The two small studies demonstrate that sincerity of effort is an important variable to consider in interpreting both the subjective reports of pain and self-rated disability as well as the objectively obtained measurements of movements and strength in WAD patients.

Conclusions: High quality instruments now exist for the assessment of self-rated disability and, in two cases, self-rated pain in WAD patients. These instruments are suitable for both clinical and research settings in the clinical management of WAD. The Neck Disability Index has been studied more extensively than the other two and is probably the instrument of choice for research settings. The original investigations in this report suggest that the link between subjective reports and objective test performances by WAD patients should be calibrated by an assessment of the patient's sincerity of effort.

KEYWORDS:

• Whiplash
• pain
• assessment
• sincerity
• impairment