How much change is true change? The minimum detectable change of the Berg Balance Scale in elderly people.

Abstract

OBJECTIVE: To determine the minimum detectable change at 95% confidence for the Berg Balance Scale in a group of elderly people, undergoing physiotherapy rehabilitation. DESIGN: Multi-centre, test-retest design. SUBJECTS: Cross-sectional sample of convenience of people over 65 years (n = 118) without a previous history of stroke, Parkinson's disease or recent hip arthroplasty. RATERS: Physiotherapists working with elderly people, drawn from the Physiotherapy Research into Older People group, ranging in experience from newly qualified to 39 years qualified. METHODS: Each participant was assessed using the Berg Balance Scale and again within 48 hours by the same physiotherapist. The minimum detectable change at 95% was established. RESULTS: A change of 4 points is needed to be 95% confident that true change has occurred if a patient scores within 45-56 initially, 5 points if they score within 35-44, 7 points if they score within 25-34 and, finally, 5 points if their initial score is within 0-24 on the Berg Balance Scale. CONCLUSION: A clinician with a working knowledge of these minimum detectable change values can be up to 95% confident that a true change or not a true change in a patients' functional balance has occurred and can therefore alter their interventions accordingly to ensure quality, focused rehabilitation.