An article in the November 2008 issue of IEEE Spectrum Online describes how Guitar Hero is being used to help "train" artificial arms for amputees. It's part of the Revolutionizing Prosthetics (RP) 2009 project, sponsored by the U.S. Defense Advanced Research Projects Agency (DARPA). One of the RP 2009 project's goals is that:
[i]n four years, DSO [the Defense Services Office] will deliver a prosthetic for clinical trials that has function almost identical to a natural limb in terms of motor control and dexterity, sensory feedback (including proprioception), weight, and environmental resilience. The four-year device will be directly controlled by neural signals.
The project has already pioneered a surgery whereby the nerves that used to control the amputee's arm are routed into the chest and affixed with electrodes. These electrodes "read" muscle activation signals (electromyography, or EMG)and translate them into movement for the artificial limb. So far, the procedure has enabled a prosthetic arm to move with six degrees of freedom, but getting fingers to move is much harder. As the IEEE article states:
To establish a clear link between mind and machine, the software that translates between EMG signals and the mechanical arm must be trained to understand what the different muscle signals mean. Pattern-recognition algorithms have to be trained by correlating input signal patterns (from muscle contractions) with the intended outputs (opening the mechanical index finger).
That's where Guitar Hero comes in.
After rewiring the game's controls for one-handed play and for using muscle contractions rather than button-presses for its control scheme, the researchers tested it with non-amputee volunteers. Then they brought it to Duke University and PhD candidate Jon Kuniholm, an Iraq veteran who lost his right hand. He also founded the Open Prosthetics Project, which aims to make open source prosthetic arm technology. The Applied Physics Laboratory at Johns Hopkins University, which designed the special interface for Guitar Hero, is working on making their prosthetic arm hardware and interface software open source.