Correlation between clinical assessment and force plate measurement of postural control after stroke

Objectives: To explore the correlation between clinical assessment and force plate measurement of postural control after stroke when selected balance tasks are performed under similar spatial and temporal conditions, and to examine the inter-rater agreement of assessment of weight distribution during quiet stance in subjects with stroke. Design: A descriptive and correlational study. Methods: Clinical assessment of postural control using Berg Balance Scale, video recording for rating of weight distribution, and force plate measurement with the Vifor-system, were performed in 20 subjects with stroke. Results: Mean velocity of displacement of the centre of pressure in the anterior-posterior direction correlated moderately with scores from the Berg Balance Scale items "maintaining a position" in the whole sample (r(s) = -0.50, p < 0.05) as well as in a subgroup of subjects with stroke with submaximal Berg Balance Scale scores (r(s) = -0.62, p < 0.05). Moderate correlation was found between ratings of each of 3 physiotherapists and centre of pressure's mean position in the frontal plane on the force plate, while the inter-rater agreement was poor. Conclusion: Clinical assessment of postural control and weight distribution showed moderate correlation with force plate measurement when the assessments were performed under similar conditions. The data suggest that the reliability of observational postural analysis needs to be improved.