Motor Control Of Individual Digits Of A Robotic Hand Using Only Signals Recorded From The Peripheral Nerves
Jonathan Cheng, MD1, Edward W. Keefer, PhD2, Qi Zhao, PhD3, Zhi Yang, PhD3.
1University of Texas Southwestern Medical Center, Dallas, TX, USA, 2Nerves Incorporated, Dallas, TX, USA, 3University of Minnesota, Minneapolis, MN, USA.
PURPOSE: Despite advances in artificial sensory feedback and EMG-based motor control, robotic hand "dexterity" remains elusive due to the inability to provide reliable individual digit motor control. We previously demonstrated functionally-relevant tactile and proprioceptive sensory feedback using fascicle-specific targeting of longitudinal intrafascicular electrodes (FAST-LIFE interfaces) implanted in the residual nerves of the amputated upper limb. Here we describe advances in motor control obtained by combining FAST-LIFE interfacing with peripheral nerve-specific motor control technology developed by our group.
METHODS: Oversight by the UTSW IRB. 6 patient trials were performed, duration 3 - 15 months. Amputation level: 3 partial hand (FAST-LIFE interfaces in motor/sensory fascicles of ulnar nerve); 3 transradial (FAST-LIFE interfaces in motor/sensory fascicles of median + ulnar nerves).
RESULTS: We demonstrated individual digit control of a robotic hand prosthesis using: 1) FAST-LIFE interfacing, 2) hardware for recording peripheral nerve signals, 3) machine learning decoding of motor intent, and 4) portable controllers for individual digit actuation. Details of decoding accuracy, task matching trials, and individual digit control will be discussed. The study culminated in a "take-home" trial.
CONCLUSIONS: Individual digit control of a robotic hand prosthesis can be accomplished using only signals derived from FAST-LIFE implants placed in the residual nerves of the amputated upper limb. Our novel motor control strategy holds promise for robotic hand control in higher level amputations, where conventional EMG sensors are ineffective due to total absence of the forearm muscles.
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