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Piloting a wheelchair with the power of the mind

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  • Piloting a wheelchair with the power of the mind

    Piloting a wheelchair with the power of the mind

    Recent successful tests of neural prosthetics bring the devices closer to widespread use.
    By Emily Singer

    Paralyzed patients dream of the day when they can once again move their limbs. That dream is making its way to becoming a reality, thanks to a neural implant created by John Donoghue and colleagues at Brown University and Cyberkinetics Neurotechnology Systems.

    In 2004, Matthew Nagle, who is paralyzed due to a spinal-cord injury, became the first person to test the device, which translated his brain activity into action (see "Implanting Hope," March 2005, and "Brain Chips Give Paralyzed Patients New Powers"). Nagle's experience with the prosthetic was exciting but very preliminary: he could move a cursor on a computer screen and make rough movements with a robotic arm. Now Donoghue and team are pushing ahead with their quest to develop a commercially available product by testing the device in two new patients, one with a neurodegenerative disease and the other suffering the effects of a stroke.

    With spinal-cord injuries and some types of stroke and neurodegenerative disease, the information-relay system between the brain and muscles is disrupted. The Cyberkinetics device consists of a tiny chip containing 100 electrodes that record signals from hundreds of neurons in the motor cortex. A computer algorithm then translates this complex pattern of activity into a signal used to control a computer cursor, robotic arm, and, maybe eventually, the patient's own limb.

    The researchers have now tested the device in two new patients, one with ALS, a progressive neurodegenerative disease, and the other with brain-stem stroke, a particularly devastating type of stroke that paralyzes the body but leaves the mind intact. The scientists presented their latest results at the Society for Neurosciences conference this week in Atlanta, GA. At the conference, Donoghue, founder of Cyberkinetics and a neuroscientist at Brown, and Leigh Hochberg, a neurologist at MGH who works with the patients studied, talked with Technology Review about the latest developments in neural prosthetics and their plans for the future.

    Technology Review: Who are your two newest patients?

    Leigh Hochberg: One patient is a 53-year-old woman who had a brain-stem stroke nine years ago. She has no use of her hands or legs and can't speak, but she can move her head and usually uses a button on her wheelchair to communicate. The other patient is a 37-year-old man with advanced ALS. He can't speak or move his arms or legs.

    TR: Are the new patients testing a new, improved device, or is it the same one used in Matthew Nagle's trial?

    John Donoghue: The device is the same, but we're using a new filter [a piece of software that decodes neural signals and transmits the command to a user interface, e.g., a computer]. Now it's possible to get quite a good level of control. Patients can move the cursor much more cleanly, and they can point to a target and click on it, just like you would with a mouse.

    LH: The new filter does a much better job of stabilizing the cursor. The patients imagine moving their wrist to move the cursor and squeezing their hand to click on a target. Once you have the capacity to move a cursor in two dimensions and point and click, you can imagine a very powerful tool. Patients could control any computer-based device. For example, we could use the same point-and-click concept with a typing board.

    We're also working with a company called Rolltalk, which has developed a powerful interface. It was built for people who use eye-based controls [devices that convert directed eye movements into specific commands], but we're adapting it for brain control. One patient has already used it to control the movement of a wheelchair.

    I did see this on TV the other day, pretty amazing. Rolltalk is a company from here and now Cyberkinetics (Cyberkinetics also have other things like the Andara OFS platform in the pipeline for both acute and chronic SCI) wants to do more collaboration with Rolltalk for this product over here as well.,