Abstract
Background The Community Balance and Mobility Scale (CB&M) is increasingly used to evaluate walking balance following stroke.
Objective This study applied Rasch analysis to evaluate and refine the CB&M for use in ambulatory community-dwelling adults following stroke.
Methods The CB&M content was linked to task demands and motor skill classifications. Rasch analysis was used to evaluate internal construct validity (structural validity) and refine the CB&M for use with ambulatory community-dwelling adults following stroke. The CB&M data were collected at 3 time points: at discharge from inpatient rehabilitation and at 6 and 12 months postdischarge (N=238). Rasch analysis evaluated scale dimensionality, item and person fit, item response bias, scoring hierarchy, and targeting. Disordered scoring hierarchy was resolved by collapsing scoring categories. Highly correlated and “misfitting” items were removed. Sensitivity to change was evaluated with standardized response means (SRMs) and one-way repeated-measures analysis of variance.
Results The CB&M was primarily linked to closed body transport task demands. Significant item-trait interaction, disordered scoring hierarchies, and multidimensionality were found. Scoring categories were collapsed in 15/19 items, and 5 misfitting items were removed. The resulting stroke-specific 14-item unidimensional CB&M (CB&MStroke) fit Rasch model expectations, with no item response bias, acceptable targeting (13% floor effects and 0% ceiling effects), and moderate-to-strong sensitivity to change at 6 months postdischarge (SRM=0.63; 95% confidence interval=−1.523, −0.142) and 12 months postdischarge (SRM=0.73; 95% confidence interval=−2.318, −0.760).
Limitations Findings are limited to a modest-sized sample of individuals with mild-to-moderate balance impairment following stroke.
Conclusions The CB&MStroke shows promise as a clinical scale for measuring change in walking balance in ambulatory community-dwelling adults poststroke. Future studies are recommended in a larger sample to validate and further refine the scale for use in this clinical population.
Footnotes
Dr Miller planned and executed the analyses. All authors contributed to interpreting the results, writing, and approval of the final manuscript. The authors acknowledge the support of Dr J. Pallant in providing Rasch analysis methodology materials and advice.
The preliminary findings from this research were presented at the Canadian Stroke Congress; October 4–7, 2014; Vancouver, British Columbia, Canada.
The data used for this secondary analysis were obtained from studies supported by a Heart and Stroke Foundation of BC and Yukon grant awarded to Dr Garland (grant number 000227) and a Heart and Stroke Foundation of Ontario grant awarded to Dr Brouwer and Dr Garland (SRA 5974). Dr Miller was supported by a Heart and Stroke Foundation Junior Personnel Research Fellowship, and Dr Pollock was supported by a Canadian Institutes of Health Doctoral Fellowship. Dr Garland and Dr Brouwer are the principal investigators for grant funding of the respective clinical trials providing the data used in this secondary analysis.
This study was a secondary analysis of data from 2 clinical trials. Ethics approval for ClinicalTrials.gov NCT00400712 was obtained from the human research ethics boards at Western University and Queen's University. The Human Research Ethics Board at the University of British Columbia approved both ClinicalTrials.gov NCT00400712 and ClinicalTrials.gov NCT01573585.
- Received July 30, 2015.
- Accepted March 28, 2016.
- © 2016 American Physical Therapy Association
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