Reliability of the Community Balance and Mobility Scale (CB&M) in high-functioning school-aged children and adolescents who have an acquired brain injury

Primary objective: To examine inter-rater, intra-rater and test-re-test reliability of the Community Balance and Mobility Scale (CB&M) and compare reliability in live vs videotape rating contexts for children with acquired brain injury (ABI). Research design: Repeated measures design. Methods and procedures: Seven physiotherapists (PTs) were trained as assessors. The primary assessor administered and scored baseline CB&M while the second assessor observed and scored independently (inter-rater reliability). Re-assessment occurred 3-10 days later by primary assessor (test-re-test reliability). Assessments were videotaped. Main outcomes and results: There were 32 participants with ABI ( mean age = 14 years 1 month (SD = 2 years 1 month)). Baseline mean scores were 67.4% (18.2) and 66.7% (18.3) for primary and second assessor, respectively. Primary assessors' re-test mean score was 69.3%. Inter-rater reliability ICC was 0.93 (95% confidence interval (CI) = 0.87-0.97). Test-re-test ICC was 0.90 ( 95% CI = 0.81-0.95) and Bland-Altman plot indicated greatest test-re-test differences for mid-range CB&M scores. Minimum detectable change (MDC90) was 13.5% points. Conclusions: The CB&M showed excellent reliability in youth. Reliability was comparable for live and videotape rating approaches, meaning that the easier and less expensive live-rating can be recommended. Future work should focus on evaluation of responsiveness to change in rehabilitation centre and community intervention contexts.