The Scale for Retropulsion: Internal consistency, reliability and construct validity.

Background Retropulsion is an impairment of body orientation against gravity in the sagittal plane. In a Delphi study, the Scale for Retropulsion (SRP) was developed with a high level of expert agreement. Objective To assess the clinimetric properties of the German SRP in patients with neurological disorders. Methods The SRP was applied to 70 hospitalized patients with neurological disorders (stroke, critical illness neuropathy and/or myopathy, Parkinson syndromes). Internal consistency was determined with the Cronbach ɑ. Test-retest and interrater reliabilities were evaluated with the weighted kappa, intraclass correlation coefficient (ICC), and Bland-Altman plots. The construct validity was evaluated with Spearman correlation. Results The median (interquartile range) SRP score was 5 (3-8) and ranged from 0 to 22 (total scale range: 0 to 24). The SRP had excellent internal consistency (Cronbach ɑ = 0.875) and good to excellent test-retest reliability (weighted kappa = 0.957, ICC = 0.957) and interrater reliability (weighted kappa = 0.837, ICC = 0.837). Analysis of construct validity resulted in good correlations with other clinical balance scales (rSp > 0.80), and fair to moderate correlations with posturographic measures (rSp = 0.27-0.56) and the subjective postural vertical error in the sagittal plane (rSp = -0.325, p = 0.012) as well as the range in the frontal plane (rSp = 0.359, p=0.007). The SRP discriminated between patients classified with and without retropulsion by an independent clinical expert (p Conclusion The SRP provides a valid and reliable bedside test to quantify retropulsion in individuals with neurological disorders.