  A rare genetic condition, PIEZO2 loss of function (LOF) is characterized by
absence of proprioception and light touch, which makes functional tasks (e.g.,
walking, manipulation) difficult. There are no pharmacological treatments or
assistive technologies available for individuals with PIEZO2-LOF. We propose a
sensory substitution device that communicates proprioceptive feedback via
detectable haptic stimuli. We created a wearable prototype that maps
measurements of elbow movement to deep pressure applied to the forearm. The
prototype applies up to 18 N, includes an embedded force sensor, and is
programmable to allow for various angle-to-pressure mappings. Future work
includes comparing proprioceptive acuity and movement ability with and without
the device in healthy and PIEZO2-LOF individuals, developing low-profile
devices using soft robotics, providing sensory substitution for multiple joints
simultaneously, and encoding additional aspects of joint dynamics.
