Inter-rater reliability of the Swedish modified version of the Postural Assessment Scale for Stroke Patients (SwePASS) in the acute phase after stroke.

Background: Before implementation of the new scale, the Swedish modified version of the Postural Assessment Scale for Stroke Patients (SwePASS), to clinical practice, it is fundamental to analyze its measurement properties.Objective: To examine the inter-rater reliability of the SwePASS in the acute phase after stroke. Methods: Day 3 to day 7 after admission to a stroke unit, 64 persons with stroke were assessed twice, using the SwePASS, by two physiotherapists. Inter-rater reliability was determined using percentage-agreement and the rank-invariant method: relative position, relative concentration, and relative rank variance. Results: The raters showed a percentage agreement of ≥75% in the assessments using the SwePASS. For 9 of the 12 items, the percentage agreement was >80%. For 8 of the 12 items, there was a statistically significant change in position, revealed in relative position values between 0.08 and 0.15. Three items had statistically significant positive relative concentration values between -0.11 and 0.10. Except for a statistically significant negligible relative variance value of 0.01 for the items 1 and 8, there was no relative variance. Conclusions: The SwePASS shows an acceptable inter-rater reliability, albeit with potential for improvement. The reliability can be improved by a consensus how to interpret the scale between the raters prior to implementation in the clinic.