Ambulatory monitoring of mobility-related activities: the initial phase of the development of an activity monitor

Summary: Long-term ambulatory monitoring of mobility-related activities is a method of collecting data that overcomes some of the shortcomings of most other methods in rehabilitation. The aim of the first phase project is the development of a user- and patient-friendly instrument that enables distinguishing between a Set of selected mobility-related activities in a reliable and valid manner. Accelerometers appear to be the most appropriate sensors to use. In this study a first set of mobili tyrelated activities is formulated. The configuration of sensors and the analytical algorithms, which form the starting point for subsequent investigations, are determined. The set of selected activities consists of lying, sitting, standing, walking, walkin g up- and down stairs and cycling. The study demonstrates that the optimal configuration consists of 3 accelerometers, 2 on the trunk and 1 on the upper leg. With this configuration of sensors and using relatively simple analytical algorithms it is possib le to distinguish the activities mentioned. It appears that the detection of static activities is less complex than the detection of dynamic activities. The reliability and validity of the instrument will be investigated in the next phase of the project. (Eur j phys med rehabil 1995;5: 2-7)