Thinking Out Loud; December 2004; Scientific American Mind; by Nicola Neumann and Niels Birbaumer; 6 Page(s)

Consider the plight of Hans-Peter Salzmann. The 49-year-old former lawyer is confined to a wheelchair and cannot eat or breathe on his own. For the past 15 years he has been suffering from amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig's disease, an incurable degenerative disease of the nerve cells that breaks down the entire voluntary motor system. To spell out words, Salzmann blinks his left eye to choose letters from a printed list on a board, a tedious process that requires an experienced interpreter. Sometimes his eyelid is too weak to make the selections. Ultimately, people with ALS, brain stem stroke or other illnesses may lose all ability to move--becoming a functioning mind "locked in" an immobile body.

Now technologies called brain-computer interfaces, which read aspects of brain activity and react to them, are offering patients such as Salzmann ways to continue to express themselves despite their disabilities. The systems enable a person to use his mind to guide cursors on a screen for communication. Someday they may lead to mental command of environmental-control devices in a home, "smart" wheelchairs and prosthetics.