Jacking in aims for the mass market. The headset is based on raw EEG readings, so is at a very limited level of granularity, but still.

“The exact source of the electrical activity the headset is picking up may not be important, said Dr. Jonathan Wolpaw, chief of the laboratory for nervous system disorders at the Wadsworth Center of the New York State Department of Health in Albany. He uses EEG caps as part of brain-computer interfaces for severely paralyzed people. His systems record brain activity alone, but for a consumer game device, a cap that picks up a mixture of brain and muscle activity may be acceptable.”

http://www.nytimes.com/2008/06/08/technology/08novel.html?_r=1&ref=technology&oref=slogin