Psychometric properties of the short form of the Stroke Impact Scale in German-speaking stroke survivors.

BACKGROUND: The short form of the Stroke Impact Scale (SF-SIS) consists of eight questions and provides an overall index of health-related quality of life after stroke. The goal of the study was the evaluation of construct validity, reliability and responsiveness of the SF-SIS for the use in German-speaking stroke patients in rehabilitation. METHODS: The SF-SIS, the Stroke Impact Scale 2.0 (SIS 2.0), EQ-5D-5L, National Institutes of Health Stroke Scale (NIHSS) and de Morton Mobility Index were assessed in 150 inpatients after stroke, with a second measurement two weeks later for the analyses of responsiveness. In 55 participants, the test-retest-reliability was assessed one week after the first measurement. The study was designed following the recommendations of the COSMIN initiative. RESULTS: The correlations of the SF-SIS with the SIS 2.0 (ρ = 0.90), as well as the EQ-5D-5L (ρ = 0.79) were high, as expected. There was adequate discriminatory ability of the SF-SIS index between patients who were less and more severely affected by stroke, as assessed by the NIHSS. Exploratory factor analysis indicated a two-factor structure of the SF-SIS explaining 59.9% of the total variance, providing better model fit in the confirmatory factor analysis than the one-factorial structure. Analyses of test-retest-reliability showed an intraclass correlation coefficient of 0.88 (95% CI 0.75-0.94). Hypotheses concerning responsiveness were not confirmed due to lower correlations between the assessments change scores. CONCLUSION: Results of this analysis of the SF-SIS's psychometric properties are matching with the validity analysis of the English original version, confirming the high correlations with the Stroke Impact Scale and the EQ-5D-5L. Examination of structural validity did not confirm the presumed unidimensionality of the scale and found evidence of an underlying two-factor solution with a physical and cognitive domain. Sufficient test-retest reliability and internal consistency were found. In addition, this study provides first results for the responsiveness of the German version. Trial registration The study was registered at the German Clinical Trials Register. TRIAL REGISTRATION NUMBER: DRKS00011933, date of registration: 07.04.2017.

Comparison of the de Morton Mobility Index and Hierarchical Assessment of Balance and Mobility in older acute medical patients.

OBJECTIVE: To compare the measurement properties of the de Morton Mobility Index (DEMMI) and the Hierarchical Assessment of Balance and Mobility (HABAM) in an older acute medical inpatient population. DESIGN: Cross-sectional. SUBJECTS: Older acute medical inpatients. METHODS: The DEMMI, HABAM and further assessments were performed after hospital admission. Construct validity was assessed by testing 13 hypotheses on convergent and known-groups validity. Test-retest reliability and minimal detectable change were estimated based on a re-assessment of unchanged patients. Floor and ceiling effects were used to indicate adequacy of scale width. RESULTS: For both the DEMMI and HABAM, 11 (85%) hypotheses regarding construct validity were confirmed (n = 158). Both scales showed strong correlations with other multi-component mobility scales (Spearman's rho 0.75-0.92). Neither floor nor ceiling effects were evident. The intraclass correlation coefficient was 0.98 (95% confidence interval (95% CI) 0.96-0.99) for the DEMMI and 0.99 (95% CI 0.99-0.99) for the HABAM, respectively (n = 30). The minimal detectable change with 90% confidence was 6 points on the 100-point DEMMI scale and 1 point on the 26-point HABAM scale. CONCLUSION: The DEMMI and the HABAM appear to be suitable for measuring mobility in older acute medical patients.