Matthew Nagle, 27, medical volunteer

BROCKTON, Mass. (AP) — Matthew Nagle, 27, who volunteered for a groundbreaking treatment for the paralysis that forced him to use his brain signals to work a computer, died July 23 in Good Samaritan Medical Center in Brockton.

Mr. Nagle fell into a coma on July 17 and was diagnosed with sepsis, an infection of the blood.

He lived at New England Sinai Hospital and 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 at an Independence Day celebration in Weymouth, Mass. He was left unable to breathe without a ventilator and nearly unable to talk after scar tissue grew over his vocal cords.

Nicholas Cirignano, who stabbed Mr. Nagle, is serving a 10-year prison sentence.

The Norfolk County (Mass.) 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 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, which allowed Mr. Nagle to breathe without a ventilator and control his wheelchair with his breath.

Patrick Nagle said his son volunteered for the treatments because he wanted to do his part to help the paralyzed.

Mr. Nagle was born in Cambridge, Mass., and grew up in Weymouth.