Predictive Validity of the Postural Assessment Scale for Stroke (PASS) to Classify the Functionality in Stroke Patients: A Retrospective Study

The analysis of the predictive validity of a scale allows us to establish objectives in rehabilitation and to make decisions in the clinical setting. The objective of this study was to determine the validity of the Postural Assessment Scale for Stroke (PASS) to predict functionality at each stage of recovery in stroke patients. Methods: A retrospective study was carried out collecting data from patients admitted to a neurorehabilitation hospital. All patients having suffered a stroke less than two months before hospital admission were included in the study. The balance was measured with the PASS scale and the functionality with the Functional Independence Measure (FIM) scale. Simple linear regressions were performed to model the relationship between the PASS and FIM scores in the acute, subacute and chronic stages (6 and 12 months), as well as between the PASS scores at admission and the FIM values in the chronic stage. Results: The PASS scale showed a good predictive validity (R2 values from 0.54 to 0.87; β values from 1.99 to 2.62; p < 0.001) for FIM scores at acute, subacute and chronic stages, with lower goodness-of-fit for PASS scores at admission and FIM scores at 12 months (R2 = 0.383; β = 1.61 (0.96−2.26); p < 0.001). Cut-off points in the PASS scale to predict high functional level were 17.5 for the acute stage and 16.5 for the subacute and chronic stages. A score of 8.5 on the PASS scale measured in the acute phase predicted a high functional level at 12 months. Conclusion: The PASS scale is a useful tool to classify the functionality of stroke patients in the acute, subacute and chronic phases. The PASS score upon admission into the hospital can predict the functionality of the stroke patients after 12 months. However, future studies should be carried out to corroborate our findings with larger sample sizes.