A Belt for Better Balance

Veterans with balance disorders will soon have the chance to try on an unusual fashion accessory: a vibrating belt. Using what's called vibrotactile feedback, the "balance belt" warns wearers with vibrating pulses when they are about to tip too far in any direction. This month, the Veterans Administration will begin a 4 to 6 week pilot study to test three of these belts.

A variety of research groups are now studying haptics technologies, which employ users' sense of touch, to help physical therapy patients. Some devices, such as this treadmill-like machine, actually push people into the required positions, in this case to build the muscle strength required for walking. Others are more subtle--like this theoretical device that could use small electrical currents, basically "noise" to the sensory system, to improve touch and also balance.

The balance belt falls somewhere in-between; it doesn't physically keep wearers from falling, but provides perceptible vibrating cues when the wearer seems liable to fall.

The belt's developer, Conrad Wall, a professor of otology and laryngology at Harvard Medical School, first imagined a balance vest. In early tests he had those with balance disorders stand on a platform while researchers "made life difficult for them." When the platform moved, the patients stumbled. But Wall says his vibrating vest changed that: "They put the device on and they didn't fall over anymore. It was pretty dramatic, actually." 

IEEE Spectrum described a much different balance vest in April. Instead of vibrations, pneumatic actuators inflate portions of that vest to warn wearers of an impending stumble. In that article, creators of the inflating vest argue that users might get used to and ignore vibrations--especially given long term feedback, as would be necessary for amputees, for example.

Wall imagines that his device will be worn temporarily, to help users train their muscles as part of physical therapy "homework" exercises, but he hasn't ruled out the possibility of giving the belts to patients with longer term balance problems.

The current version of the device comes from a collaboration with Draper Laboratory in Cambridge, MA, which helped him to turn a "cumbersome research device", a vest with 48 vibration points, called tactors, into a belt with 4 tactors, orchestrated with a microprocessor. He imagines that in the future, if this pilot test is successful, a mass-produced, single-user device might cost about $1,000. 

Image: Draper Laboratory