Psychometric performance of a generic walking scale (Walk-12G) in multiple sclerosis and Parkinson’s disease
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Walking difficulties are common in neurological and other disorders, as well as among the elderly. There is a need for reliable and valid instruments for measuring walking difficulties in everyday life since existing gait tests are clinician rated and focus on situation specific capacity. The Walk-12G was adapted from the 12-item multiple sclerosis walking scale as a generic patient-reported rating scale for walking difficulties in everyday life. The aim of this study is to examine the psychometric properties of the Walk-12G in people with multiple sclerosis (MS) and Parkinson’s disease (PD). The Walk-12G was translated into Swedish and evaluated qualitatively among 25 people with and without various neurological and other conditions. Postal survey (MS, n = 199; PD, n = 189) and clinical (PD, n = 36) data were used to test its psychometric properties. Respondents considered the Walk-12G relevant and easy to use. Mean completion time was 3.5 min. Data completeness was good (<5% missing item responses) and tests of scaling assumptions supported summing item scores to a total score (corrected item-total correlations >0.6). Coefficient alpha and test–retest reliabilities were >0.9, and standard errors of measurement were 2.3–2.8. Construct validity was supported by correlations in accordance with a priori expectations. Results are similar to those with previous Walk-12G versions, indicating that scale adaptation was successful. Data suggest that the Walk-12G meets rating scale criteria for clinical trials, making it a valuable complement to available gait tests. Further studies involving other samples and application of modern psychometric methods are warranted to examine the scale in more detail.
KeywordsMultiple sclerosis Outcome assessment Parkinson’s disease Psychometrics Walking
The authors wish to thank the respondents, interviewees, translators and lay people for their cooperation. We are also grateful to Martina Eliasson, Jan Reimer, Klas Wictorin, Gun Jadbäck, Lars Forsgren, Mona Edström and Birgitta Wikström for assistance with data collection and sampling. The study was supported by the Swedish Research Council, the Swedish Parkinson Foundation, the Swedish Parkinson Academy, the Skane County Council Research and Development Foundation, and the Faculty of Medicine at Lund University. MHN was in part supported by the Swedish Council for Working Life and Social Research, within the context of the Centre for Ageing and Supportive Environments (CASE), Lund University, Sweden.
Conflict of interest
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