Investigating the Mini-BESTest's construct validity in elderly with Parkinson's disease.

OBJECTIVES: The Mini-BESTest consists of items relevant to balance deficiencies among people with Parkinson's disease (PwPD). However, the Mini-BESTest's construct validity has been sparsely evaluated in this population. We therefore aimed to investigate the hypotheses that the Mini-BESTest results would be worse among: (i) PwPD compared to healthy controls; (ii) PwPD with moderate compared to mild motor severity; (iii) PwPD with a history of recurrent compared to non-recurrent falls. Moreover, the relationship between the Mini-BESTest and tests of similar and different constructs was expected to be moderate to strong and poor, respectively.

MATERIALS AND METHODS: One hundred and five PwPD with mild-to-moderate motor severity and 47 healthy controls were included. PwPD were divided into subgroups based on motor severity and fall history. Main outcome measures were the Mini-BESTest, the timed up and go (TUG), and the original Unified Parkinson's Disease Rating Scale, part II (Activities of Daily Living). Independent t-tests and Spearman's rho were used for the analyses.

RESULTS: The Mini-BESTest results were worse among PwPD compared to controls (P<.001), and among people with moderate motor severity compared to those with mild severity (P<.001). However, no differences were found between recurrent and non-recurrent fallers (P=.096). Spearman's rho showed moderate (ρ=-.470) and poor correlations (ρ=-.211) for convergent (TUG) and divergent validity (UPDRS, part II), respectively.

CONCLUSIONS: Overall, the Mini-BESTest appears to adequately measure dynamic balance among PwPD with mild-to-moderate severity, although it was unable to distinguish between recurrent and non-recurrent fallers.