Brain-machine interfaces (BMI) could someday help people with severe paralysis move their limbs, walk, and use a computer.
A brain-computer interface (BCI), sometimes called a direct neural interface or a brain-machine interface, is a direct communication pathway between a human or animal brain (or brain cell culture) and an external device. (Wikipedia,2008)
Paralysis is caused by a break in the neural pathway between the cognitive part of the brain, where the intention to make a movement is generated, and the muscles that do the moving. So an artificial system that senses the neural signals generated in the brain, analyzes what the brain is trying to do, and then moves the limbs mechanically can bypass the roadblock in the pathway and restore normal functioning.
An artificial system senses and analyzes neural signals, and then translates those signals into movement. This method has two problems challenging to solve:
1. Acquiring signals, the design of the actual physical interface that taps into the brain’s neural signals. Poking electrodes into the brain is a surgical procedure that risks infection as well as injury. The ideal would be to sense the signals noninvasively, through electrodes placed on the scalp. Such an approach can yield poor signal-to-noise ratio. Another avenue of research involves experimentation with an electrocorticographic method that positions a small electrode array on the cerebral cortex, yielding signals that suffer a lot less attenuation than EEG signals while manifesting a higher signal-to-noise ratio.
2. Minimizing power consumption. Using as little power as possible to minimize the heating of tissue and to prolong battery life is another important goal. One possible approach is minimizing the bandwidth occupied by the data being transmitted from the implanted device to the outside world.
In my opinion as research continues in the field of BMI more techniques will evolve that will make this approach easy enough to implement and support thus giving hope to many people.
MICHAEL J. RIEZENMAN (2008). Melding Mind and Machine. Available at: http://www.theinstitute.ieee.org/portal/site/tionline/menuitem.130a3558587d56e8fb2275875bac26c8/index.jsp?&pName=institute_level1_article&TheCat=2201&article=tionline/legacy/inst2008/jun08/featuretechnology.xml&
Wikipedia (2008). Brain-computer interface. Available at: http://en.wikipedia.org/wiki/Brain-computer_interface