The Signal Amplifier
Dateline: 12/02/99
In a novel approach, researchers at the University of Alberta in Canada are testing implants that amplify nerve signals traveling along the spinal cord. The current tests involve animals but the researchers hope to have human clinical trials in about two years.
Approximately 80 percent of people with spinal cord injuries don't have complete severing of the cord. In such cases, some residual weak signals continue to be conducted below the point of injury. The researchers believe that by amplifying these signals, coordinated movement of muscles might one day be possible.
Theoretically speaking, since there are complex interactions between the brain and muscles that include feedback loops, once a particular movement process is started by the brain, a signal boosting implant could allow the process to continue via the feedback loops.
Microwires are fed into the spinal chord from the signal boosting implant. Source: New Scientist.
To test the amplification of signal propagation, the researchers installed implants in cats that were attached to the vertebra of the spine. Several wires that protruded from the implant base were fed into the spinal cord itself.
The cats were subdivided into two groups consisting of four unanesthetised cats and four anesthetized cats respectively.
By testing various signals and amplifications, the researchers were successful in getting both cat groups to flex their rear legs and getting the unanesthetised group to support their own weight while raising the rear of their bodies.
The researchers noted that the amplification process appeared to be painless based on the cat's behavior during testing. The cats in the study did not have damaged spinal cords but the researchers believe that the implants can amplify weaker signals in damaged cords.
Human trials are currently being planned with the initial goal of helping paralyzed persons stand and move their legs. If progress is successful, the scientists speculate that walking with a frame may be possible in a few more years. The trials are being planned in conjunction with the Alberta Paraplegic Foundation and the Alberta Heritage Foundation for Medical Research in Canada.
What do you think? How might additional modifications to the signal amplification technique help signal conduction? If the preliminary trials are successful, how long might it take before we see mainstream use? Come on over to the Biology Forum and share your thoughts, opinions, and feelings. 'Til next time...
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