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

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.