Non-invasive monitoring of the activities of daily living of elderly people at home--a pilot study of the usage of domestic appliances.

We conducted a feasibility study of a system for non-invasive monitoring of subjects at home. Electrical activity was recorded from room lights and from electrical domestic appliances; this was translated into the probability of physical activity or a particular Activity of Daily Living (ADL). Thirteen volunteer subjects were monitored for a period of 6.4 months (range 3-8). The mean age of the subjects was 80 years and they all lived alone at home; one had moderate Alzheimer's disease. A one-week validation was carried out to ascertain whether the recorded activity actually occurred. The results showed that daily and nocturnal activity could be well differentiated. The probability of having eaten, taken a bath and going to the toilet could be calculated each day. Eating was the most accurately measured ADL; toileting and bathing results were less accurate. The system appears to be a promising component of home telecare.