This was done a few years ago in a different way: you wear an electronic collar which eavesdrops on the nerves running to your vocal chords. These signals are then decoded into words. Finally, some words, like "forward", are interpreted as intentions to move. The system is called the Audeo.

Official site: http://www.theaudeo.com/
Video: http://www.youtube.com/watch?v=iyQv61899HE
Article: http://zone.ni.com/devzone/cda/tut/p/id/6130