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Huang M.1, Pang M.Y.C.1
1Hong Kong Polytechnic University, Department of Rehabilitation Sciences, Hong Kong, Hong Kong
Background: Balance Evaluation Systems Test (BESTest) is a comprehensive balance measurement that assesses six subsystems of balance control (i.e., biomechanical constrains, stability limits/verticality, anticipatory postural responses, postural responses, sensory orientation, and stability in gait). The Brief-Balance Evaluation Systems Test (Brief-BESTest) is a shortened version of the original BESTest. However, its psychometric properties remained unknown among people with stroke.
Purpose: This study aimed to examine the floor and ceiling effects, reliability and validity of the Brief-BESTest in individuals with chronic stroke.
Methods: This was an observational study with repeated measurements involving 57 people with chronic stroke [mean (SD) age: 59.2 (7.3) years] and 27 controls [mean (SD) age: 56.7 (7.7 years)]. Ceiling and floor effects were determined by examining the distribution of scores. Intrarater reliability was evaluated by repeating the Brief-BESTest on the same participants within the same day by the same rater, and the interrater reliability was established according to the scores provided by two independent raters in the same session. Concurrent, convergent, discriminant validity was assessed by correlating Brief-BESTest scores with other balance measures (Berg Balance Scale, Postural Assessment Scale for Stroke Patients), motor impairment measures (Fugl-Meyer Motor Assessment, Chedoke-McMaster Stroke Assessment) and measures that evaluated other characteristics (Montreal Cognitive Assessment, Geriatric Depression Scale) in the stroke group, respectively. For known-groups validity, receiver operating characteristics curve analysis was used to test whether the Brief-BESTest scores could effectively delineate the balance ability between the stroke and control groups, and between individuals with stroke who required assistive device for mobility and those who did not.
Results: No significant floor and ceiling effects were found, as the proportion of individuals who attained the bottom 10% and top 10% of the possible Brief-BESTest score range was less than 20%. Good intra-rater [ICC(2,1)=0.974] and inter-rater [ICC(2,1)=0.980] reliability and internal consistency (Cronbach´s alpha=0.820) were found. The minimal detectable change at 95% confidence level (MDC95) was 2 points. The Brief-BESTest demonstrated high correlations (rho=0.55-0.91, p 0.001) with other balance and motor impairment measures, but no correlation with Montreal Cognitive Assessment and Geriatric Depression Scale (rho=-0.15, p>0.05) or low correlation (rho=0.44, p=0.002) with measures that evaluated other constructs. A cutoff score of 18 and 14 best separated the stroke group from controls (area under curve: 0.942), and those individuals with stroke who required assistive device for outdoor mobility from those who did not (area under curve: 0.810), respectively.
Conclusion(s): The Brief-BESTest has good psychometric properties when administered to individuals with chronic stroke.
Implications: The Brief-BESTest would be a useful tool with good psychometric properties to evaluate balance ability in individuals with chronic stroke. The MDC (95) value (2 points) established would provide reference for clinicians to determine whether the intervention has induced a real improvement in balance in their clients with stroke, and for researchers to more accurately interpret the changes in Brief-BESTest score in future studies. The cutoff score of 14 may be useful in guiding the prescription of assistive device for individuals with stroke.
Funding acknowledgements: Meizhen HUANG is supported by the Hong Kong Polytechnic University Research Studentship as a full-time Ph.D. student.
Topic: Neurology: stroke
Ethics approval: This study was approved by the Human Subjects Ethics Subcommittee of the Hong Kong Polytechnic University.
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