Computers obey brain waves of paralyzed

Some scientists envision taking the use of brain signals way beyond what’s been done so far.

John Donoghue, chair of Brown University’s neuroscience department and chief science officer of Cyberkinetics Neurotechnology Systems Inc. of Foxborough, Mass., talks about giving disabled people use of their arms and legs someday by using brain signals to drive their muscles.

Eventually, paralyzed people might even wear lightweight mechanical arms and legs that fit over their own limbs and would enable them to walk and reach for things, says Miguel Nicolelis of Duke University, who calls such devices “wearable robots.” Nicolelis has done robot-arm work in monkeys and hopes to start studies in severely paralyzed people this year.

And Dr. Philip Kennedy of Neural Signals Inc. in Atlanta, who has tested brain sensors in seven locked-in patients since 1996, ponders the notion of helping such people speak someday. That would require planting electrodes in speech areas of the brain to give people control over 30 or so speech sounds, which would be produced by a synthesizer.

“It’s not an insurmountable problem,” Kennedy says.

That would be a huge jump from today’s brain-controlled programs that can spell out words, but only a few letters per minute. The paralyzed patients near Stuttgart use such a program.

But even a relatively slow spelling device could make a huge difference to people with no good alternative to communicate, says Dr. Terry D. Heiman-Patterson. She is working with Wolpaw’s laboratory in a project with her Lou Gehrig’s disease patients at Drexel University.

That disease, formally called amyotrophic lateral sclerosis or ALS, gradually robs people of their ability to use their muscles. Eventually their breathing muscles stop working, and late-stage patients have to decide whether to go on a ventilator to stay alive.

“One of the reasons people choose to die over live is that they can no longer communicate,” Heiman-Patterson said. “If we can unlock the ability to communicate with others...we may be able to change some of the choices people are making.”

Even for people who can blink or direct their gaze to send signals, it may take 20 laborious minutes to ask to be taken to the bathroom or be turned over, she said “The difficulty becomes so great just to do that,” she said, “that people say, ’I can’t deal with this any more.”’

Streaks of control
I do relax. In fact, it turns out I’m pretty good at making my mind go blank.

I imagine my brain is a chunk of cold white marble and resolutely refuse to think anything else for the four seconds the little red box takes to cross the screen. More often than not, it seems, the box sinks and hits the lower target.

Making that box rise, however, is a problem. Chopin works for a while, then seems to abandon me. I add an imagined jerk of my left wrist, which initially yanks the box to the top of the screen, but then loses its effectiveness too. Next I imagine both hands tickling the bottom of that danged box. Doesn’t work.

Scooping up a hard-hit ground ball and throwing to first ... directing a Sousa march in the gazebo of a town square ... whacking a golf ball ... clawing at a dirt wall. (From Chopin to Sousa to clawing in dirt. Has it come to this?)

None of these works very well over my first few days of training, and my overall accuracy hasn’t improved a lot either. I’m surprised when Wolpaw’s colleague Dennis McFarland suggests a new strategy for the lower target: Imagine moving my feet. I thought the chunk-of-marble strategy was working well. But I tried his suggestion.

Gangbusters! Over the next three minutes I hit four out of every five targets overall, a startling improvement. The following run, I hit three out of every four, still gratifying. But my accuracy nosedives to around random-chance levels on the two runs after that. Before long, I go back to chunk-of-marble.

Eventually, I settle on the thought of waggling a baseball bat around for the upper target, and it seems to work pretty well. Between that and chunk-of-marble, I find myself enjoying occasional streaks of control, hitting two-thirds of the targets and sometimes much better.

I can’t stay in the groove as long as I’d like. Usually, under my uncertain command, the red box flits across the screen like a butterfly buffeted by a summer breeze, its destination in doubt until the last instant.

But not when I’m at my best. I can make it glide upward like a party balloon or even jump like I’d punted it. And when I aim at the lower target, the box bumps its way downward, sometimes even dropping and running like a fumbled nickel.

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