Very Simple System for Walking-Speed Measurement in Geriatric Patients

Walking speed in geriatric patients is an important index for inferring the patient’s state of health and estimating the success rate of some surgical procedures. Although different solutions for monitoring the gait of a subject exist in scientific literature and on the market, there is a need for a system that is very simple, especially to wear, considering that elderly subjects often have movement difficulties. For this reason, we investigated the possibility of using a standard miniaturized wireless microphone, that can be easily attached to patients’ clothes by means of a clip, as the sole sensing device to be worn by the test subject. A transceiver, a sound card and a PC complete the system, which turns out to be quite simple to be set up and use, thanks to a proper graphic user interface that controls its entire operation. The system essentially tracks the position of the test subject over time by measuring the propagation times of repeated sound pulses from the speaker to the microphone. To avoid hearing discomfort, the frequency of the pulses is chosen at the higher end of the audio spectrum, so that they are essentially undetectable by adults. The measurement range is in excess of 6 m, that is sufficient for the standard 4 m walking-speed test. Tests performed in a laboratory environment have confirmed the effectiveness of the approach we propose.