A Vibrotactile Feedback Device for Balance Rehabilitation in the EksoGT™ Robotic Exoskeleton

Robotic exoskeletons have been used in physical therapy clinics for several years to help individuals with neurological impairments stand and walk. Exoskeletons, including EksoGT™, are used as rehabilitation tools to assist in gait re-training for those with the potential to restore some walking function. For patients with impaired proprioceptive systems, the exoskeleton can compensate for impaired sensory signals, thereby assisting in balance and gait training; however, not much information is provided to the patients in real-time about their balance. In this paper, we present a haptic device that can provide real-time balance feedback during standing in an EksoGT™. Sensory information is conveyed via a vibrotactile belt worn around the chest. Three subjects with spinal cord injuries (SCI) and eight able-bodied subjects were recruited to test the prototype and evaluate the efficacy of the additional biofeedback in balance training. Results show reduced postural sway in quiet standing tasks among both groups when vibrotactile feedback was enabled. Additional vibrotactile cues also assisted in guiding the subjects towards the target positions and kept the subjects within a safe region of standing balance. All subjects found the additional sensory feedback intuitive and they could control their postures actively. This preliminary study has demonstrated the potential therapeutic/in-home application of the additional haptic feedback in improving balance control for SCI patients.