BRAIN POWER: Brain waves recorded using noninvasive EEG can be mathematically decoded into meaningful information about human movements.
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Our bodies are wired to move, and damaged wiring is often impossible to repair. Strokes and spinal cord injuries can quickly disconnect parts of the brain that initiate movement with the nerves and muscles that execute it, and neurodegenerative disorders such as Parkinson's disease and amyotrophic lateral sclerosis (ALS) draw the process out to the same effect. Scientists have been looking for a way to bypass damaged nerves by directly connecting the brain to an assistive device—like a robotic limb—through brain-computer interface (BCI) technology. Now, researchers have demonstrated the ability to nonintrusively record neural signals outside the skull and decode them into information that could be used to move a prosthetic.
Past efforts at a BCI to animate an artificial limb involved electrodes inserted directly into the brain. The surgery required to implant the probes and the possibility that implants might not stay in place made this approach risky.
The alternative—recording neural signals from outside the brain—has its own set of challenges. "It has been thought for quite some time that it wasn't possible to extract information about human movement using electroencephalography," or EEG, says neuroscientist and electrical engineer Jose Contreras-Vidal. In trying to record the brain's electrical activity off the scalp, he adds, "people assumed that the signal-to-noise ratio and the information content of these signals were limited."
Evidently, that is not the case. In the March issue of The Journal of Neuroscience, Contreras-Vidal and his team from the bioengineering and kinesiology departments at the University of Maryland, College Park, show that the noisy brain waves recorded using noninvasive EEG can be mathematically decoded into meaningful information about complex human movements. "This means we can use a noninvasive method to develop the next generation of brain–computer interface machines," Contreras-Vidal says. "It can expand considerably the range of clinical and rehabilitative applications."
Instead of undergoing brain surgery, users would wear an electrode-covered head cap that records the electric impulses from neurons—the only mess involved is the clear gel applied to the head to enhance conduction. Some patients have already used the caps to communicate via word processors. (The recognition of a letter flashing on a screen signals the word processor to choose that letter.) The next step is to put the decoded movement information to work. "We hope to show that a person with a stroke or an amputee would be able to control an assistive device," Contreras-Vidal says. He already has healthy volunteers testing two different setups: One has them moving a computer cursor on a screen; the other has them controlling an artificial hand.
Contreras-Vidal also hopes to integrate sensory feedback into the system to optimize the user's control over the device. "In all the studies so far people have used visual feedback to close the loop between the user and the machine," he says. "We think it's important to use other types of feedback, too, because vision is a slow signal" compared with the sensory signal a person would get from an intact limb.
Whether such a system would work for patients with longstanding nerve damage is unknown. Such patients haven't activated their movement-generating neurons or received the related sensory feedback for many years and could generate abnormal brain wave–based movement information. "We're starting to look at patient populations to answer that question," Contreras-Vidal says, naming stroke patients and below-elbow amputees as the first test subjects. "We know the brain is highly redundant, so we think that even if there's a deletion in the brain, we might be able to decode from another place. One advantage to using electroencephalography is access to the whole brain, not just a specific area."
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12 Comments
Add Commentseems wonderful, but needs long way to go
Reply | Report Abuse | Link to thisIf brain waves can be transmitted and received outside the skull doesn't this also affirm the possibility of "ESP" as just an extension of the communications between a brain that's a good receiver and a subject that is a good transmitter? - Howard Sobel, WUGNET
Reply | Report Abuse | Link to thishsobel - That would be analogous to an RFI receiver that could remotely detect not just the transmissions of a PC's WIFI connection, but its memory chips, identifying the bits
Reply | Report Abuse | Link to thisrepresenting an image stored somewhere within. The sensitivity and decoding required would be many orders of magnitude greater than what's described here, not to mention many additional difficulties that would have to be overcome. Not likely to provide remote viewing capabilities anytime soon, either.
This is a potentially useful discovery in that it creates a huge drop in the cost of neural feedback integration and signal decompilation.
Reply | Report Abuse | Link to thisIf only our peripheral nerves weren't so well shielded.
In the near futur, maybe the Psycoframe weapon can be realized.
Reply | Report Abuse | Link to thisJust like a description of the GUNDAM Japanese animation, science not only brings evolution for human but also devastation.
How does this relate to the Emotiv Systems game controlling cap Scientific American described in article.cfm?id=head-games-video-controller-brain back in April of 2008? Is that one a weaker version, or does it really work at all? Oh, and hsobel, if you are right, we should test for ESP by shaving peoples heads, applying clear gel, and pressing them together to improve the signal.
Reply | Report Abuse | Link to thisOh, PLEASE post that on Youtube!
Reply | Report Abuse | Link to thisI didn’t notice it in the article, but it might be reasonable to expect that motor command signals might have higher amplitude than, for example, some abstract reasoning process, as they must be communicated to peripheral limbs. This could explain why they are detectable (due to their local external signal to noise ratio).
Reply | Report Abuse | Link to thisAs a non-scientist, my question is; if we can detect and track the tiny signals coming from Voyager which is about 10 million miles away, why can't we detect signals coming from our own brain neurons?
Reply | Report Abuse | Link to thisdonburg - As a non-scientist, one answer is mentioned in the article: signal to noise ratio. When in a crowded room full of people talking, the person you want to understand must talk loud enough for you to filter out the sound of other conversations.
Reply | Report Abuse | Link to thisVoyager's communications have much different characteristics that surrounding electromagnetic signals from the space around it. Likewise, these researchers have to separate the signals (I think neuronal electron emissions) associated with movement from all the others detected by the external electrodes.
I saw a very similar thing on the TV show - beyond 2000, in the mid 80's. Except it was a (sport like) head band, which looked much cooler. It controlled computer games like table tennis and pacman, it was also able to steer, accelerate and brake an electric wheelchair. This is over 30 years ago, other technology has seemed to have boomed since that time, while this seems to be the same, it's looks even bulkier than older models. That said, BCI tech is an awsome endevour, keep plugging away at it. So I can directly interface with future technology, can't wait!
Reply | Report Abuse | Link to thisIt seems that Darpa is only now achieving control of a prosthetic device with implants. The monkey is doing it so we know it's possible. The locked-in with implants are working onscreen to move a device via well placed control points such as a rider would on her horse. Although implants are better; until, for instance, nanotechnology can distribute implants over a wide area, the dense array EEG offers many, maybe more, possibilities. I think the BCI parade is concerning itself far too much with exhibitions of mind power when instead it should be seeing to the learning of the machine.
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