How tetraplegic subject utilizes brain-machine interfaces to manipulate prosthetic arm, and regain and restore significant limb functionality

Researchers implanted two 96-channel intracortical microelectrodes into the motor cortex of an individual with tetraplegia using multi-modality image guidance. Six months of BMI training were conducted with the goal being for the subject to control an anthropomorphic prosthetic limb with 10 degrees-of-freedom (3D translation, 3D orientation and 4D hand posture). Clinical measures of upper-limb function were used to assess the participant subject's ability to use the prosthetic limb. The results of this study, 10 degree-of-freedom neuroprosthetic control by an individual with tetraplegia, will be presented by Elizabeth C. Tyler-Kabara, MD, PhD, FAANS, on Tuesday, April 30. Co-authors are Jennifer Collinger, PhD; Brian Wodlinger, PhD; John Downey, BS; Wei Wang, PhD; Douglas Weber, PhD; Angus McMorland, PhD; Meel Velliste, PhD; Michael Boninger, MD; and Andrew Schwartz, PhD.

The subject in this study demonstrated the ability to move the prosthetic device freely in the three-dimensional (3D) workspace after just two days of training. Following 13 weeks of training and interaction, 7 degree-of-freedom movements were regularly performed, including 3D translation, 3D orientation and one-dimensional grasping. The researchers noted that performance of target-based reaching tasks improved over time in terms of success rate, completion time and path efficiency.

After six months, the subject exercised robust 10 degree-of freedom movements routinely in 3D translation, 3D orientation and fourth-dimension hand posture. The participant in the study also could use the prosthetic limb to perform a variety of skillful and coordinated reach and grasp movements, which resulted in in clinically significant gains in tests of upper-limb function. Researchers concluded that this study suggests that a person with chronic tetraplegia can perform consistent, natural, complex movements with an anthropomorphic robotic arm to regain clinically significant limb function.