Brain implants allow man, paralyzed, to move objects

With the aid of electrodes implanted in his brain, a man paralyzed from the neck down was able to perform certain everyday activities – move a computer cursor, open e-mail, turn on a TV set – by imagining them.

The patient, whose spinal cord was injured when an attacker stabbed him in the neck, was even able to open and close a prosthetic hand, his thoughts translated into action by a custom-built computer.

For now, the patient must be tethered to a cart loaded with electronics.

The system was developed by scientists at Brown University, who say it is just a few years away from commercial use.

The results, reported in today’s issue of the journal Nature, offer hope that thousands of people with injured spinal cords could someday regain significant function by bypassing the injury.

The team expects that, eventually, patients will have a wireless device implanted in the brain that sends signals not only to computers but also to parts of their own bodies.

The efforts of the Brown University team included researchers in Chicago and Massachusetts.

After implanting electrodes in the brain of Matthew Nagle, the 25-year-old stabbing victim, scientists discovered that the neurons associated with moving his arms and hands could still generate electrical signals – a surprising find, three years after the attack.

They ran wires through his skull to BrainGate, an electronic device that filtered out the noise and learned to interpret the signals.

When connected to a computer, Nagle was able to play the video game “Pong,” and he also drew a circle using a computer drawing program.

“I just imagined moving the cursor,” he said from his room in a Massachusetts rehab hospital.

University of Pittsburgh neurobiologist Andrew Schwartz, who was not part of this study but has done similar work in monkeys, said the success in human patients was a good start.

It is “still far from being a useful device,” he said.

John Donoghue, senior author of the new article and chief scientific officer of Cyberkinetics Neurotechnology Systems Inc., the company that makes BrainGate, acknowledged there is room for improvement.

But the technology has improved since his team wrote the Nature article, he said.

Nagle sometimes moved the cursor in a wobbly fashion and overshot his target on the computer screen.

Subsequent patients have performed much better because researchers have refined the computer algorithm, Donoghue said.

Translating the signal is difficult because millions of neurons are associated with moving the arm, whereas the hair-thin electrodes only pick up signals from dozens.

The goal is to make a wireless device that could be fully implanted so the patient would not have to be wired to a computer – much like with cochlear implants, the devices that can help deaf people perceive sound.

One hitch is that the array of electrodes implanted in Nagle’s brain seems to have suffered a short-circuit toward the end of the 14-month experiment.

The breakdown was not caused by any adverse reaction in the brain itself, Donoghue said.

“The barriers to this seem more technological, but surmountable, rather than anything biological,” he said. “I’m very encouraged.”

While the current work involves moving computer cursors and prosthetic devices, the researchers hope someday to transmit electrical signals from the brain to a patient’s real hands and arms.

Nagle’s parents were somewhat apprehensive about the brain implant, but he was determined to press forward.

The electrodes were removed after the experiment, so he no longer can bypass his crippling injury with BrainGate.

But Nagle’s participation was not just about bettering his own condition, he said.

“I knew it would give a lot of people hope,” Nagle said.