An ambulatory system for physical activity monitoring in elderly

A new method of physical activity monitoring is presented, which is able to detect body postures (sitting, standing and lying) and walking period in the elderly from only one kinematic sensor attached to the chest. Wavelet analysis in conjunction with a simple kinematics model was used to recognize different postural transitions and walking periods during daily physical activity. The method was tested on 11 elderly subjects (all community walkers) in a gait laboratory where an optical motion system (Vicon) was used as reference. A close correspondence was found between the two systems. The efficiency of the system for ambulatory monitoring outside of the laboratory was tested on 3 old subjects. High sensitivity (>90%) was obtained for the classification of usual physical activities.