Rasch validation of the German version of the Prosthesis Embodiment Scale for lower limb amputees and proposal of a revised version.

PURPOSE: To perform a detailed psychometric Rasch analysis of the Prosthesis Embodiment Scale (PEmbS) administered in adults with lower limb amputation (LLA). METHODS: A convenience sample of German-speaking adults with LLA (n = 150), recruited from German state agencies' databases, was asked to complete the PEmbS, a 10-item patient-reported scale assessing prosthesis embodiment. RESULTS: The local dependency between two items was resolved by keeping for the global score only the lower score of these two items (#9 and #10). Collapsing the seven response categories to four (two expressing disagreement and two agreement) eliminated disordered thresholds. After that, the PEmbS demonstrated unidimensionality, acceptable item fit, and good reliability indices. A keyform plot was created to transform raw scores into linear measures of prosthesis embodiment, making it possible to compare the individual's item responses with those expected by the Rasch model, and to manage missing responses. CONCLUSIONS: The PEmbS is useful for assessing prosthesis embodiment in people with LLA, both for research and clinical purposes. We propose a revised version of the PEmbS for lower limb amputees; its appropriateness in other LLA contexts requires further investigation.

Prosthesis embodiment has been empirically related to positive clinical outcomes in limb amputees.The Prosthesis Embodiment Scale (PEmbS) is a patient-reported scale that has been recently recommended for use in research on prosthesis embodiment.Rasch analysis showed that the revised version of the German PEmbS is a psychometrically sound instrument for the assessment of prosthesis embodiment in lower limb amputees.The PEmbS thus also allows reliable and valid diagnosis of prosthesis embodiment in clinical and rehabilitation contexts.

Rasch validation of the German translation of the Prosthetic Limb Users Survey of Mobility short forms in people with lower limb amputation.

BACKGROUND: Prostheses are a primary rehabilitative intervention for people after lower limb amputation. To appropriately measure the effectiveness of prosthetic interventions, valid and reliable measures of prosthetic mobility are required. The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a promising instrument for measuring prosthesis users' mobility. However, German translations of the PLUS-M short forms have not yet been validated. OBJECTIVES: Rasch validation of the German translation of the PLUS-M short forms in people with lower limb amputation. STUDY DESIGN: This study is based on a cross-sectional survey of prosthesis-using lower limb amputees from a nation-wide cohort. METHODS: PLUS-M data (the 7-item and the 12-item shortforms; PLUS-M-7 and PLUS-M-12, respectively) from 194 lower limb prosthesis users were subjected to Rasch analysis, an advanced statistical method for assessing if the measurement properties of a questionnaire comply with a wide spectrum of psychometric requirements. RESULTS: Analysis showed appropriate rating scale functioning, good internal construct validity (item fit), unidimensionality, and good targeting of the PLUS-M-7 and PLUS-M-12 short forms. Moreover, the greater conditional measurement precision of PLUS-M-12 (regarding higher test information and lower standard error of mobility estimates) was quantified. CONCLUSIONS: Rasch analysis of the German translation of both PLUS-M short forms showed good psychometric qualities. In addition, our study showed that test scores from the PLUS-M-12 are more accurate. Therefore, the PLUS-M-12 is recommended for individual-level clinical applications (e.g., classification or change assessment).