A device developed by researchers at the University of South Florida (USF) may help identify patients with early dementia. Most dementia is not detected until memory loss has already occurred. Symptoms are very subtle and usually overlooked. The RFID transponder evaluates the way people walk. Researchers were looking for unusual walking patterns that might indicate impending Alzheimer's Disease .

An RFID (Radio Frequency Identification Device) tag is a microchip attached to an antenna that sends signals to, and receives signals from, a reader. Each tag has a unique serial number, but can contain other information, such as a patient's name. Tags come in many forms. The ones used in this test were part of a small device the patients wore on their wrist. Signals indicating the patient's movements in three spatial dimensions were captured by receivers in their care facility. The tendency to wander, veer suddenly, or pause frequently can be an indication of cognitive decline.

USF research used ultra-wideband (UWB) chips because they experience less interference than do passive RFID chips, and walls don't impede the signals. The transmitters have a range of 600 feet and allow multiple people to be monitored even in a crowd. The batteries have a life of three years.

To implement this system in a care facility would cost around $7,000 and include 6 tags according to William Kearns, an assistant professor at USF who does research on aging and mental health. The University's next step is to develop software that will automatically detect these warning signs.

A study involving only a small sampling - 20 patients - showed that there was a statistical relationship between those who had abnormal walking patterns and those who had mental test scores that indicated dementia.

Not everyone agrees that the walking test is a good indicator. Robert Green, a codirector for a clinic and research program at Boston University, says Alzheimer's Disease "in its very early stages is not a movement disease". However, dementia comes in many forms, including Parkinson's Disease, which definitely affects coordination. The RFID research may open a path to other health-related applications.