Exciting new experimental technology is letting some paralyzed patients perform physical actions without moving a muscle. Using a neuromotor prosthesis system called BrainGate Neural Interface System, two men paralyzed from the neck down learned to control a computer cursor simply by thinking about it, according to a recent report in Nature. One of the men also learned to perform various other tasks, such as playing a simple video game, changing the channel and volume on a TV, opening e-mail, and moving a prosthetic hand. However, because of current technologic limitations, these abilities diminished over time.
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The BrainGate system includes a small sensor containing 100 tiny electrodes. The sensor is implanted on the surface of the brain's motor cortex, which controls voluntary muscle movement. The electrodes pick up signals from neurons (neural spikes) and transmit them to a titanium pedestal that protrudes about 1 inch above the patient's scalp. A cable then carries the signals to external equipment that interprets them and generates actions.
After the sensor and pedestal are implanted, a patient learns to control a computer cursor by imagining his hand moving the mouse. Researchers study data from the sensor to convert patterns of neural spikes into commands. They say because of individual differences, the training process is unique to each patient.
While promising, the experimental therapy is a long way from practical application. For more information on the BrainGate Neural Interface System, visit the manufacturer's Web site at http://www.cyberkineticsinc.com.
Neuronal ensemble control of prosthetic devices by a human with tetraplegia, Nature, LR Hochberg, et al., July 13, 2006.