File
MacDermid J.1, Walton D.1
1Western University, Physical Therapy, London, Canada
Background: Measurement of disability in neck pain requires a simple outcome measures that focudes on a single construct. Tools in common use have some common limitations: lack of unidimensionality, complex items and a failure to include patients in item generation.
Purpose: This paper describes the development and validation of a new outcome measure for people with neck disorders.
Methods: Based on review of other neck measures, studies on neck pain and our qualitative interviews with patients we set out to define a simple 10 item scale that would measure disability and be transferable across contexts. Literature review indicated in the NDI items driving was often blank due to lack or relevance, and that items were double-barrelled. Patient interviews indicated upper extremity use was limited by neck pain. Combining new and legacy concepts of neck-related disability led to a final list of ten salient items. These were subject to evaluation using cognitive interviewing. A sample of 30 test-retests were performed; and 60 patients with neck pain completed the ND10 and the NDI or DASH. Construct validity was performed comparing the two scales. Patient preferences and readability were assessed. Statistical analyses included Pearson correlations, ICCs for reliability and effect sizes for responsiveness.
Results: The ND10 was easier to read than the NDI. The correlations were between the ND10 and the DASH were > 0.80; and > 0.70 for the NDI. Cognitive interviews suggested all ND10 items were easily understood. The reliability of the ND10 was ICC.>0.90. No items were left blank; no ceiling or floor effects were observed; and responsiveness to detect change with physical therapy indicated a large effect size.
Conclusion(s): The ND10 is a reliable and valid measure of neck-related disability.
Implications: Physiotherapists may measure neck-related disability separate from pain using this new outcome measure.
Funding acknowledgements: None
Topic: Musculoskeletal: spine
Ethics approval: McMaster University
All authors, affiliations and abstracts have been published as submitted.
