Psychometric Properties of the Urdu Translation of Berg Balance Scale in People with Parkinson's Disease.

BACKGROUND

The most common assessment tool used in clinical settings to detect changes in balance performance is the Berg Balance Scale (BBS). Thus, the purpose of this study was to translate the BBS into Urdu and investigate the psychometric properties (acceptability, internal consistency reliability, interrater reliability, construct validity) for individuals with Parkinson's disease (PD).

METHODS

Eighty patients of either gender with idiopathic Parkinson's disease, stages I-III on the modified Hoehn-Yahr (H&Y) scale, with intact cognition according to the Mini Mental Score Examination (MMSE) score (greater than or equal to 24) and independent of transfers, were included in this study. The BBS was translated according to international guidelines based on forward and backward translation processes. The test-retest reliability as well as intra- and inter-observer reliability was assessed by calculating the intra-class correlation coefficient (ICC). The internal consistency of the entire BBS score was assessed by calculating Cronbach's α. The convergent validity was assessed by correlating the scale with the Unified Parkinson Disease Rating Scale (UPDRS) parts II and III and the Activity-specific Balance Confidence Scale (ABCS). The construct validity was assessed using a factor analysis.

RESULTS

The mean age of the subjects was 62.35 ± 5.74 in years (range: 60-87 years). The ICC for intra- and inter-observer reliability was 0.95 ( < 0.0001) and 0.99 ( < 0.001), respectively. Cronbach's α was calculated as 0.81, which showed acceptable internal consistency of the Urdu version of the BBS. The test-retest reliability (ICC) of the Urdu version of the BBS was determined as 0.97 for the total score, and ranged from 0.66-0.95 for individual items. In terms of validity, the Urdu version of the BBS was correlated with the ABCS (in the positive direction) and UPDRS-II and III (in the negative direction) (r = 0.53, < 0.001; r = -0.68, < 0.001, r = -0.78, < 0.0001), respectively.

CONCLUSION

The Urdu version of the BBS is a reliable and valid scale to be used in balance assessment of population diagnosed with PD with excellent psychometric properties.