Introduction of the Charité Mobility Index (CHARMI) – A Novel Clinical Mobility Assessment for Acute Care Rehabilitation

INTRODUCTION: Mobility is an essential part of a person’s functioning and independence. It encompasses locomotive functions, but also the more basic functions of positioning and transferring. Despite the availability of several mobility-related assessment instruments to date, there is a need for assessment instruments with the specific capability to display the full range of mobilisation. Our aim was to develop and validate a scoring instrument with hierarchical composition where every score value stands for a defined mobility level. PARTICIPANTS AND METHODS: A previously developed and validated pilot instrument was applied to assess patients (n = 113) admitted to an acute rehabilitation programme. Mobility was assessed during admission, subsequently at weekly intervals and at discharge to acquire a detailed status of mobility at multiple time points and individual mobilisation profiles over time. The scoring instrument was then remodelled based on clinical criteria to establish an easy-to-use scoring system with hierarchical composition. Psychometric properties were calculated using an independent sample of 87 consecutive patients. RESULTS: Content validity could be affirmed. The psychometric tests demonstrated excellent convergent validity with the three mobility items of the Barthel Index (r = 0.93), despite an adequately lower correlation with the whole Barthel Index (r = 0.63). Adequate floor and ceiling effects (20%) and a large responsiveness to change (ǀdǀ = 1.7, p < 0.001) between admission and discharge values were demonstrated. Inter-rater reliability was excellent (κ = 0.88). CONCLUSIONS: The Charité Mobility Index (CHARMI) is a promising, easy-to-use hierarchical scoring instrument assessing the full individual spectrum from immobility to unlimited mobility, including positioning, transfer and locomotion items. It allows for monitoring of mobilisation.