Talking the talk on walking the walk : a 12-item generic walking scale suitable for neurological conditions?

BACKGROUND: The Multiple Sclerosis Walking Scale (MSWS-12) was developed to measure the impact of multiple sclerosis on walking. Many other disabling neurological conditions affect patients' ability to walk, and a generic measure of walking could provide valuable insights into patients' perceptions in clinical trials and epidemiological studies as well as routine clinical practice. OBJECTIVE: To evaluate the clinical usefulness and psychometric properties of the Walking Impact Scale (Walk-12), a modified version of the MSWS-12, in patients with neurological conditions. DESIGN: A prospective, observational study of 120 consecutive patients admitted for rehabilitation. The Walk-12 was used to measure the impact of neurological disability on walking. Traditional psychometric methods (data quality, scaling assumptions, targeting, reliability, validity and responsiveness) were used to assess the Walk-12. Transition questions were used on discharge to measure perception of change. Outcome was also measured using the timed walk test (TWT), Barthel Index (BI) and Functional Independence Measure (FIM). RESULTS: For the total group, missing data were few, scaling assumptions were satisfied, and internal consistency was 0.94. Correlations between the Walk-12 and TWT, BI and FIM motor score were moderate (r=-0.58, -0.26, -0.31). Responsiveness of the Walk-12 was high (effect size=1.12). Relationships between effect size and patients' and physiotherapists' opinion of change in walking demonstrated good concordance. Preliminary subgroup analyses indicate satisfactory psychometric properties across different neurological conditions; however, sample numbers in these analyses are small. CONCLUSIONS: In this sample of neurologically disabled patients the Walk-12 was clinically useful and satisfied standard psychometric criteria. This provides preliminary evidence that it may be suitable as a generic measure of walking ability