Photograph of the CASIT tactile feedback system courtesy of the UCLA Biomedical Engineering Department.
For patients, limb loss is rarely just about the limb. Body image, sense of health, and life skills all have to be relearned before a patient can return to a sense of wholeness. For lower-limb amputees, re-learning how to walk is oftentimes the central task on the road to recovery. Now, researchers at UCLA’s Center for Advanced Surgical and Interventional Technology (CASIT) are developing a tool that may help leg amputees learn to stand and walk more quickly and easily.
In a report presented at the March 25-26 Haptics Symposium, in Waltham, Massachusetts, a team led by graduate student Steven Wu, presented its early success in developing a sensor-equipped vest that leg amputees are wearing to help them balance while wearing a prosthesis. The vest, which is packed with position sensors and accelerometers, detects the tilt, rotation, and velocity of a wearer’s torso, then inflates sets of 25mm silicone balloons positioned on the ribs, chest, upper back, shoulders, and trapezius muscles to give tactile feedback about where the wearer is leaning. The system includes an optional set of force sensors in the shoe that are worn under the prosthetic foot. The sensors relay information about the foot’s pressure and direction to a cuff worn on the thigh. The cuff contains pneumatic actuators linked to the control system and air tank on the vest. The actuators can inflate the balloons within 60 milliseconds, which IEEE Spectrum quotes co-researcher Martin Culjat, PhD, as saying is the minimum time needed to provide usable real-time feedback to wearers. In the future, the group also hopes to apply the device to patients who struggle with balance due to peripheral neuropathy.
