The patients put some additional limitations on the approach. For instance, several objected to cameras as being too obtrusive. The team considered placing microphones throughout the environment, but in the end they rejected this for the initial study, in part because elderly people sometimes speak too softly to be easily understood.

Instead, they use more creative sensors such as a pressure-sensitive bed pad and sensors on the doors of refrigerators and ovens to monitor the patient's eating habits. The Kinotex pad, made by Tactex Controls Inc., goes on the mattress under the sheet, so that you cannot see it. "If you press your hand onto the bedspread, it will create a low resolution image of your hand," Dean Goubran says.

This sensor alone can tell monitoring medical personnel whether the individual is having a good night's sleep or is tossing (a side effect of some medicines), how often he gets up to use the bathroom in the night (a possible indication of diabetes), whether he has trouble getting out of bed, even whether he is losing weight.

A tendency to press harder on the bed with one hand than the other can indicate the beginnings of a hip problem, for instance, that one day might cause the patient to fall and end up in hospital. By recognizing the problem early, the monitors can contact the individual's doctor or a son or daughter to get treatment before the problem becomes severe.

On the technology side, the issues focus on data handling and interpretation. And while for purposes of the experiment an apartment has been set up in the hospital, the plan is eventually to install sensors in seniors' homes throughout the region and use high-speed Internet connections to send the data to a central monitoring location. "These sensors create a loss of data," Dean Goubran says. "We had to decide what data to analyze close to the sensors, and what to send over the network. And we had to figure out how to make sense out of all that data."