Others leverage our increasing understanding of the brain to envision direct control of a prosthetic limb. Jan Scheuermann is one of the first people to try it out, after a neurodegenerative disease called spinocerebellar degeneration left her unable to move her arms and legs.
Scheuermann entered a trial at the University of Pittsburgh and underwent surgery to have sensors installed in her brain. The goal: to control a prosthetic arm with her thoughts.
After some training, Scheuermann showed she could control the arm by just thinking about moving it, feeding herself for the first time in nearly a decade.
As for Downs, he became an expert at maneuvering the DEKA arm through a complicated tap dance that gives him nimble control.
"The ability to take care of yourself is so crucial," Downs said. "Combing your hair, brushing your teeth, getting dressed; all of those are what you need as a human being to have your dignity."