How Thought-Controlled Wheelchairs Work

NASA's Subvocal Speech Research

NASA i­s developing subvocal control for potential use by astronauts. Astronauts on spacewalks or in the International Space Station work in noisy environments doing jobs that often don't leave their hands free to control computer systems. Voice-recognition programs don't work well in these situations because all the background noise makes voice commands difficult to interpret. NASA hopes the use of subvocal signals will circumvent this problem.

While NASA's system could also be extremely beneficial for disabled people, it has other applications in mind, including the ability to speak silently on a cell phone and uses in military or security operations where speaking out loud would be disruptive.

NASA's subvocal system requires two sensors attached to the user's neck, and the system has to be trained to recognize a particular user's subvocal speech patterns. It takes about an hour of work to train six to 10 words, and the system as of 2006 was limited to 25 words and 38 phonemes [source: TFOT].

In an early experiment, NASA's system achieved higher than 90 percent accuracy after "training" the software. The system controlled a Web browser and did a Google search for the term "NASA" [source: NASA].


When Will They Be Available?

You won't find thought-controlled wheelchairs or other devices at your local electronics store -- yet. Ambient has a way for potential users to contact the company, but no pricing or availability information was forthcoming (Ambient didn't respond to requests for information).

In an interview with the Web site "The Future of Things," Dr. Chuck Jorgensen, chief scientist for neuroengineering at NASA Ames Research Center, claimed that commercial applications of subvocal control technology were two to four years in the future [source: TFOT].

To learn more about thought-controlled wheelchairs and subvocal speech, check out the links below.

Related HowStuffWorks Articles

More Great Links


  • Ambient. "Technology."
  • Gennuth, Iddo. "Speaking Without Saying a Word." The Future of Things, Oct. 12, 2006.
  • Hawking, Stephen. "The Computer."
  • LabVIEW:
  • NASA. "Subvocal Speech Demo."
  • The CompactRIO:
  • Tobii Technologies. "Eye control for accessibility."