Matthew Nagle | Medical volunteer, 27

Matthew Nagle, 27, who volunteered for a groundbreaking treatment for the paralyzed that allowed him to use his brain signals to work a computer, died Monday in Brockton, Mass.

He died at Good Samaritan Medical Center after falling into a coma on July 17; he was diagnosed with sepsis, an infection of the blood. He lived at New England Sinai Hospital & Rehabilitation Center in Stoughton.

Mr. Nagle was paralyzed from the shoulders down in July 2001 after he was stabbed in the neck while trying to help friends in a brawl. He was left unable to breathe without a ventilator and barely able to talk after scar tissue grew over his vocal cords.

Nicholas Cirignano, who stabbed Mr. Nagle, is serving a 10-year sentence. The Norfolk County District Attorney's Office says Mr. Nagle's death is being treated as a homicide.

In 2004, Mr. Nagle volunteered for a Brown University experiment with a device called BrainGate, which used a tiny sensor implanted in his head to read his electrical brain signals. The signals were read by computer software that allowed him to move a computer cursor.

The BrainGate chip was later removed, and electrodes were implanted to stimulate the diaphragm, allowing Mr. Nagle to breathe without a ventilator and control his wheelchair with his breath. - AP