Restoring Moderate to Severe Loss of Upper Extremity Function Post-stroke with a Neuromotor Prosthesis: A Case Report

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<h3>Research Objectives</h3> To study the effect of a wearable, powered exoskeleton orthosis controlled by a brain-computer interface (BCI) on upper extremity function in a single participant with moderate to severe hemiparesis. <h3>Design</h3> Single subject design with pretest, mid, and posttest. <h3>Setting</h3> Home and outpatient. <h3>Participants</h3> Participant was a 41-year old right-hand-dominant male with moderate to severe (Fugl-meyer upper extremity [FM-UE] 33/66) left-sided hemiparesis due to a stroke that occurred 18 months prior, with left homonymous hemianopsia, left hemi-neglect, left central VII nerve palsy, and spasticity in the weakened left upper extremity. The stroke lesioned the right lentiform nucleus and adjacent white matter. <h3>Interventions</h3> Brain implants were surgically placed within the right precentral gyrus region of the cortex, representing the left hand. The 12-week intervention consisted of neuromotor prosthesis training with BCI controlling the powered exoskeleton and biofeedback for controlling a game cursor; physical therapy once/week; occupational therapy twice/week. <h3>Main Outcome Measures</h3> Action Research Arm Test (ARAT), FM-UE, Motor Activity Log (MAL) domains of Amount of Use (AOU) and Quality of Movement (QOM) <h3>Results</h3> ARAT scores with the powered exoskeleton were greater with BCI (change: 10-point, 18%) than with myoelectric control (change: 5-points, 9%). Upper extremity outcomes exceeded the minimal clinically important difference thresholds for FM-UE (change: 8-point, 21%), MAL-AOU (change: 18.5-points, 12%), and MAL-QOM (Change: 17-point, 11%). <h3>Conclusions</h3> The results indicate promising outcomes of the neuromotor prosthesis on upper extremity function for a single participant with potential for future research with implanted systems combined with therapy. <h3>Author(s) Disclosures</h3> Drs. Serruya and Napoli are inventors on a US provisional patent application that has been filed by Thomas Jefferson University on the software methods used in this study to map neural activity into orthosis control.