A head-to-head comparison of the de Morton Mobility Index (DEMMI) and Elderly Mobility Scale (EMS) in an older acute medical population

Purpose: To compare the clinimetric properties of the de Morton Mobility Index (DEMMI (R)) and the Elderly Mobility Scale (EMS). Method: A head-to-head comparison of the EMS and DEMMI (R) with 120 consecutive older acute medical patients. The DEMMI (R) and EMS were administered within 48 h of hospital admission and discharge. Results: At admission, 6% and 15% of participants scored the lowest scale score for the DEMMI (R) and EMS, respectively. For the DEMMI (R), 17% of participants scored within the minimal detectable change of the lowest scale score compared to 20% for the EMS at admission. At hospital discharge, DEMMI (R) scores were normally distributed and the EMS had a ceiling effect. Similar evidence of convergent, discriminant and known groups validity were obtained for the DEMMI (R) and EMS. There was no significant difference in responsiveness to change between the DEMMI (R) and EMS. The EMS was significantly quicker to administer compared to the DEMMI (R). Conclusion: The DEMMI (R) and EMS are both valid measures of mobility for older acute medical patients. The DEMMI (R) has a broader scale width than the EMS with interval level measurement and therefore provides a more accurate method for measuring and monitoring changes in mobility for older acute medical patients.