Intra- and inter-rater reliability and validity of a clinical and quantifying test of the sit-to-stand task in Parkinsonian syndromes

Introduction/Background Measuring sit-to-stand (STS) in Parkinson's disease is an important part of the clinical exam, that both reflects Parkinsonian symptom severity and everyday life abilities. However, there is no quantified, specific, reliable measure that can be applied to all patients and tests their maximal performance. The present study aims to evaluate the intra- and inter-rater reliability and validity of Sit-To-Stand-15 (STS15) that measures the maximal number of sit-to-stand movements performed in 15 seconds. Material and method Thirty participants with moderate Parkinson's disease (Hoehn and Yahr 2–3) performed, in the levodopa OFF-state, STS15 with 3 independent raters, on 2 occasions, 1 week apart; raters had to count the number of full sit-to-stand movements completed in 15 seconds. STS15 tests were separated by periods of 15 minutes of rest; the rotation order of the raters was randomized for each patient. Participants were also assessed by MDS-UPDRS part II and III, the 20-meter ambulation test (AT20), the Five Time Sit-To-Stand (FTSTS), the MoCA and the PDQ-8. Intra- and inter-rater reliability were assessed using intraclass correlation coefficients (ICC) and concurrent validity was assessed by Spearman's and Pearson's correlations. Results Preliminary findings show excellent intra- and inter-rater reliability of STS15, with mean ICC > 0.95. Correlations with FTSTS and AT20, were highly significant and present to a lesser degree with the MDS-UPDRS-III score. The other correlations were not significant. The mean duration of the sit-to-stand movement with STS15 was lower than with FTSTS ( P Conclusion STS15 is a reliable and valid test to assess sit-to-stand in moderate Parkinson's disease.