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A hit-and-run accident five years ago left Rob Summers paralyzed from the waist down. Doctors said he would never walk again, but thanks to a new type of therapy, he can now stand on his own.
Summers’ injury disrupted the nerve pathway that normally triggers walking. Researchers implanted an electrical stimulator at the base of the spine that – along with special exercises – allowed his legs to move without input from the brain.
“I stand about an hour a day,” Summers says. “I can move my toes ankles knees, hips all on command.”
He’s also made other meaningful progress – regaining bladder and sexual function. But he’s still wheelchair-bound, and doctors cannot say whether he’ll walk again on his own. But, every day, he remembers the first time he stood up.
“It’s that moment that continues to give me the hope for tomorrow, and the future for this project – and helping out millions of other people in my same situation,” Summer says.
Summers’ therapy is in the experimental stage, and the latest results are published in the journal Lancet. Link -via Geekologie
A brain-machine interface has been developed that has been successfully tested on a patient with Locked-in Syndrome {wiki}. An unnamed 26-year-old man paralyzed for ten years by a brain stem stroke was implanted with electrodes five years ago. Researchers waited as the brain grew around the electrodes.
Three years after implantation, the researchers began testing the brain-machine interface for real-time synthetic speech production. The system is “telemetric” – it requires no wires or connectors passing through the skin, eliminating the risk of infection. Instead, the electrode amplifies and converts neural signals into frequency modulated (FM) radio signals. These signals are wirelessly transmitted across the scalp to two coils, which are attached to the volunteer’s head using a water-soluble paste. The coils act as receiving antenna for the RF signals. The implanted electrode is powered by an induction power supply via a power coil, which is also attached to the head.
The signals are then routed to an electrophysiological recording system that digitizes and sorts them. The sorted spikes, which contain the relevant data, are sent to a neural decoder that runs on a desktop computer. The neural decoder’s output becomes the input to a speech synthesizer, also running on the computer. Finally, the speech synthesizer generates synthetic speech (in the current study, only three vowel sounds were tested). The entire process takes an average of 50 milliseconds.
The tests on the first patient are quite promising.
To confirm that the neurons in the implanted area were able to carry speech information in the form of formant frequency trajectories, the researchers asked the volunteer to attempt to speak in synchrony with a vowel sequence that was presented auditorily. In later experiments, the volunteer received real-time auditory feedback from the speech synthesizer. During 25 sessions over a five-month period, the volunteer significantly improved the thought-to-speech accuracy. His average hit rate increased from 45% to 70% across sessions, reaching a high of 89% in the last session.
Although the current study focused only on producing a small set of vowels, the researchers think that consonant sounds could be achieved with improvements to the system.
Link -via J-Walk Blog
