Home TeleHealth Excerpt: Health-monitoring systems for elderly people living alone

Shigeru Ohta, Hiroshi Nakamoto, Yoshimisu Shinagawa and Toshio Kishimoto

In Japan, one-quarter of the population will soon be older than 65 years as a consequence of the increasing life span and the decreasing birth rate. Consequently, more social services will be needed, such as home help for elderly people living alone. Japan has been a keen developer of monitoring systems for elderly people. Continuous monitoring may be of physical activities, physiological functions or daily habits in order to estimate a health condition.

Monitoring cannot be carried out in the long term if the system disturbs users’ lives or puts them under pressure. Ideally, monitoring systems should be unobtrusive. We therefore have developed a remote health-monitoring system for elderly people living alone. We have monitored the daily health status of elderly people living alone by placing infrared sensors, which sense body temperature, in their homes. The people are monitored without operating any sensor, without wires and without them being aware.

We continuously monitored client’s in-house movements by placing infrared sensors at various points in each house. The infrared sensors could detect the heat (at a wavelength longer than 5 m) radiated from human bodies. Because the sensors were inexpensive, we were able to place them in every appropriate room of the person’s house. The sensors recorded the exact time when someone entered the room. Knowing when and where the previous sensor had been activated, we could calculate the speed and distance moved by the person.

Long-term monitoring showed that the pattern of movements of the people in their houses was reasonably consistent. The in-house movements can be represented in a transition diagram (Fig. 18.3). The person’s location, which is indicated by the sensor number, is plotted against time. The time of meals or sleep can be estimated from this diagram.

It was possible to classify the days as usual or unusual based on:

• Duration of stay in each room
• No-response time interval
• Movement patterns

When the data were out of the expected range or when the trend deviated from the average, the day was categorized as an unusual day. A relationship between health conditions and movement patterns could be inferred in this way. When an unusual pattern was found, our monitoring system informed the family members by telephone or e-mail. If a sudden disease or an accident is suspected, a home help or ambulance should be arranged. The system reduced anxiety for the elderly people and their family members by giving information on health conditions to family members through the Internet.