TY - JOUR A1 - Maritz, R. A1 - Tennant, A. A1 - Fellinghauer, C. A1 - Stucki, G. A1 - Prodinger, Birgit T1 - The Extended Barthel Index (EBI) can Be Reported as a Unidimensional Interval-Scaled Metric – A Psychometric Study JF - Physikalische Medizin, Rehabilitationsmedizin, Kurortmedizin N2 - Background: The Extended Barthel Index (EBI), consisting of the original Barthel Index plus 6 cognitive items, provides a tool to monitor patients’ outcomes in rehabilitation. Whether the EBI provides a unidimensional metric, thus can be reported as a valid sum-score, remains to be examined. Objective: To examine whether the EBI can be reported as unidimensional interval-scaled metric for neurological and musculoskeletal rehabilitation. Methods: Rasch analysis of a calibration sample of 800 cases from neurological or musculoskeletal rehabilitation in 2016 in Switzerland. Results: In the baseline analysis no fit to the Rasch Model was achieved. When accommodating local dependencies with a testlet approach satisfactory fit to the Rasch Model was achieved, and an interval scale transformation table was created. Conclusion: The results support the reporting of adapted EBI total scores for both rehabilitation groups by applying the interval scaled transformation table presented in this study. N2 - Hintergrund: Der Erweiterte Barthel Index (EBI), der den Barthel Index um 6 kognitive Items ergänzt, ist ein Assessmentinstrument für die Rehabilitation. Ob der EBI eine eindimensionale Metrik liefert und somit als valider Gesamtscore berichtet werden kann, ist unklar. Ziel: Untersuchung ob der EBI für die neurologische und muskuloskelettale Rehabilitation als eindimensionale intervallskalierte Metrik berichtet werden kann. Methode: Rasch-Analyse einer Stichprobe von 800 neurologischen und muskuloskelettalen Rehapatienten aus der Schweiz. Ergebnisse: In der Basisanalyse wurde keine Übereinstimmung mit den Annahmen des Rasch-Modells erreicht. Nachdem lokale Item-Abhängigkeiten mit 2 Testlets angepasst wurden, wurde die Übereinstimmung erreicht und eine intervallskalierte Transformationstabelle erstellt. Konklusion: Die Ergebnisse unterstützen die Verwendung eines angepassten EBI Gesamtscores für beide Rehabilitationsgruppen unter Anwendung der intervallskalierten Transformationstabelle. KW - activities of daily living KW - assessment instruments KW - outcome assessment KW - rehabilitation KW - Rasch model KW - quality management Y1 - 2019 UR - https://doi.org/10.1055/a-0820-4642 VL - 29 IS - 04 SP - 224 EP - 232 ER - TY - JOUR A1 - Maritz, R. A1 - Tennant, A. A1 - Fellinghauer, C. A1 - Stucki, G. A1 - Prodinger, Birgit T1 - The Functional Independence Measure 18-item version can be reported as a unidimensional interval-scaled metric: Internal construct validity revisited JF - Journal of Rehabilitation Medicine N2 - Abstract Objective: Since the 1990s the Functional Independence Measure (FIM™) was believed to measure 2 different constructs, represented by its motor and cognitive subscales. The practice of reporting FIM™ total scores, together with recent developments in the understanding of the influence of locally dependent items on fit to the Rasch model, raises the question of whether the FIM™ 18-item version can be reported as a unidimensional interval-scaled metric. Design: Rasch analysis of the FIM™ using testlet approaches to accommodate local response dependency. Patients: A calibration sample containing 946 cases of data from 11,103 patients undergoing neurological or musculoskeletal rehabilitation in Switzerland in 2016. Results: Baseline analysis and the traditional testlet approach showed no fit with the Rasch model. When items were grouped into 2 testlets, fit to the Rasch model was achieved, indicating unidimensionality across all 18 items. A transformation table to convert FIM™ raw ordinal scores to the corresponding Rasch interval scaled values was created. Conclusion: This study provides evidence that FIM™ total scores represent a unidimensional set of items, supporting their use in clinical practice and outcome reporting when applying the respective transformation table. This provides a basis for standardized reporting of functioning. Lay Abstract The aim of this study was to look in detail at the FIM™, an assessment tool often used for patients undergoing rehabilitation. Some users report the FIM™ as 2 scores: one related to motor tasks, the other to cognitive tasks; others recommend reporting it as a single score including both motor and cognitive tasks. This study explored whether it is statistically meaningful to sum all the points into a single FIM™ total score. The results support the current practice of summing the points into a single total score for patients undergoing musculo-skeletal and neurological rehabilitation. The results also allowed an interval scale to be derived from the FIM™, enabling a broad range of calculations to be made using the FIM™ score, such as calculating the change in FIM™ outcomes from the time a patient is admitted to a rehabilitation clinic until their discharge. KW - Functional Independence Measure Y1 - 2019 UR - https://doi.org/10.2340/16501977-2525 VL - 51 IS - 3 SP - 193 EP - 200 ER -