on developing a targeted muscle rein-nervation (TMR) procedure to restore natural touch sensations. The TMR procedure’s modular sensor systems, which measure a mere 5 × 5 millimeters and contain 100 electrodes for recording nerve signals and stimulating nerve fibers, are now entering a commercial transition phase.

Harshbarger says that keeping these different projects synchronized and focused on a modular design philosophy required constant communication. “Most people, including myself, believed that coordination of these various research groups and their principal investigators would be like herding cats,” he says. “In reality, however, I was surprised and exceptionally proud of how the team focused on the common goals and mission of the project.” Another researcher working in this area is Fredrik Sebelius, coordinator of the SmartHand project and a professor in the department of measurement technology and industrial electrical engineering at Lund University. The SmartHand project, spanning multiple research facilities at several universities across Europe, paralleled DARPA’s Revolutionizing Prosthetics program in its ambitiousness, but focused exclusively on replicating the capabilities of the human hand. The goal for Sebelius and other researchers working in the project was to create an elec-tromyography-controlled robotic hand that could deliver feedback to the user by stimulating what Sebelius calls the sensoric phantom map.

Sebelius describes the sensoric phantom map as a well-organized region of the brain that can be stimulated through nerves in the arm to produce feelings in a missing hand. The idea might appear to be straightforward, but the implementation is far from simple. Sebelius and his team developed and refined their approach to phantom maps by using functional magnetic resonance imaging and a modular neural interface designed to be attached to an arm’s nerve bundles. “The sensors on the hand prosthesis deliver tactile information to the subject’s phantom map via actuators and, voila, the subject experiences sensation from the missing fingers,” he says.

The SmartHand project reached the
proof-of-concept stage, but Sebelius
says much work needs to be done be-
fore the technology can move out of
the lab. The main challenges, he says,
are biocompatibility and signal loss.
As for the SmartHand prosthesis it-
self, Sebelius says the project will need
more funding to make it ready for com-
mercialization. “The robotic hand was
only intended for research groups,” he
says. “It has not undergone produc-
tion development.” Still, Sebelius notes
the research that led to the creation of
the hand made it possible to achieve
crucial advances for ongoing work in
nerve-signal recognition and process-
ing.

a myoelectric prothesis created by researchers in the smarthand project at Lund university.