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.