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

Abstract

Purpose: To compare the clinimetric properties of the de Morton Mobility Index (DEMMI®) and the Elderly Mobility Scale (EMS). Method: A head-to-head comparison of the EMS and DEMMI® with 120 consecutive older acute medical patients. The DEMMI® 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® and EMS, respectively. For the DEMMI®, 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® 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® and EMS. There was no significant difference in responsiveness to change between the DEMMI® and EMS. The EMS was significantly quicker to administer compared to the DEMMI®. Conclusion: The DEMMI® and EMS are both valid measures of mobility for older acute medical patients. The DEMMI® 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.