During the past several years, there has been a significant amount of research conducted on brain/computer interfaces. I have written about several programs that are seeking to enable computers and mechanical systems to be controlled by thought alone.
The latest development comes from a report at Kurzweil.com. Studies are being done that allow thoughts to be communicated from brain to brain. Essentially, the person at the sending site thinks of moving their hand or their foot. The brain activity (EEG) those thoughts generate is translated into binary code and sent via internet to a person at the receiving site, where the code is transmitted to the receiver via transcranial magnetic stimulation (TMS).
Could this be a technology that would enable communication with comatose or non-responsive patients?