I thought I was soooo cool when I started using Dragon Naturally Speaking to respond to emails a few years back. Then I realized that because I spent so much time proof reading for homonyms, it was faster to just type. Little did I know….
There are two choices. One is the patented Neurotrophic Electrode, whereby the electrode tip is implanted 5mm under the surface of the brain and the outer end is attached to amplifiers and FM transmitters located on the skull, under the scalp. No wires or batteries are used. Power is provided by a power induction system similar to your toothbrush holder that charges the toothbrush overnight. This implantation requires major surgery lasting about 10 hours. The neural signals are transmitted to and processed by a computer to activate a switch or drive a cursor and hence provide communication.
The other option is to implant a patented conductive skull screw that does not enter the brain. It records from local field potentials over the surface of the cortex, rather like a very precise EEG (electroencephalogram). These signals can be used to activate a switch and hence provide communication.
These two technologies are available from Neural Signals, Inc., and if I understand correctly, make use of a neurotrophic electrode to recognize neural signals within a very narrow target area.
An alternative called BrainGate is offered by Cyberkinetics who have recently implanted a device that connects up with 100 neurons in the brain. Though clearly in its very early stages, the idea is that disabled individuals (followed, I assume, by augmentation freaks) can “think” their email. The device already allows a young man to talk and turn his head while changing the TV channel with his brain. Where do I sign up?