More than 5 million Americans have Alzheimer’s with approximately half in the disease’s early stages. Early diagnosis means many patients still have years of independent living before they will be reduced to dependency on others. At some point, most will begin wandering and this requires more intense supervision to keep them safe.

Many states are adopting “Silver Alerts” programs that notify the public when an Alzheimer’s patient wanders off. Some families opt for higher-tech options — from simple radio-wave beacons to GPS technology.

In development now is a Web-based mapping service. With a system as small as many netbooks, families can buy a transmitter and then choose a monthly monitoring plan to help them keep their family member safe.