Reliability and validity of the Persian translation of Berg Balance Scale in Parkinson disease

Purpose Parkinson disease (PD) is one of the common causes of imbalance, and the balance assessment is necessary for treatment and rehabilitation of these patients. The Berg Balance Scale (BBS) has been the main instrument used to evaluate balance impairment. The purpose of this study is to investigate reliability and validity of the Persian translation of BBS in Parkinson disease. Methods One hundred PD patients (with mean age of 56.8 +/- 15.13 years) were included. Interrater reliability was measured with the Kappa statistics and interclass correlation coefficients. Results The mean values of the BBS scored by the two evaluators were 47/85 +/- 11/09 and 48/03 +/- 10/90, respectively. The mean of Kappa coefficient between two examiners was 0.76, which was between 0.38 and 0.93 for various items. The total score recorded by both examiners, interclass correlation coefficient, was 0.99, which is excellent. Cronbach's alpha for Iranian version of BBS was 0.92, which shows the excellent reliability of the questionnaire (0.62-0.9 for all items). Conclusion The Persian version of the BBS has excellent interrater reliability and internal consistency for the assessment of PD patients.