Re: Questions About Locked-in Syndrome
Locked-in syndrome usually follows a stroke(although severe Guillain-Barre can do it too). It damages or destroys the ability of the person to move from the mid-face area on down. They also cannot move their eyes to the left and right. They can't speak or swallow, breathe or move their limbs. However, the brain functions and consciousness remains intact. They sleep and wake like everyone else and can only communicate through eye movements.
We had neighbors with a child who could not speak due to cerebral palsy and I know with time, the computer was adjusted to pick up entire words that he used regularly instead of each letter. He'd blink at a letter and it would bring up a list of his commonly used words and then he could choose the word he wanted. In some cases, it would just go to a certain word and then he could cancel that word and chose another. It depends of the ability of the user and the speed and sophistication of the computer.
Stephen Hawking's problem is different. He has chronic ALS....very rare. ALS usually kills in 2-5 years by causing paralysis of all the muscles, starting with the voice and vocal cords. He cannot speak but does have some movement, including movement in his face...he can smile. In Locked-in syndrome, everything is paralyzed except the up and down movement of the eyes and the ability to open and close the eyelids. If you broke your neck at the base of your skull...the highest you can go....you'd have movement of the face and mouth, eyes and scalp muscles. Because this happens in the brain, it affects the cranial nerves too and renders you paralyzed basically from the eyes down.
If you've ever seen someone who's had a stroke on one side of the brain, the often have one side of the face that droops and they drool out that same side of the mouth. They may not be able to open and close the eyelid on that side either. Same process but the stroke occurs on both sides of the brain and gives you the same thing but on both sides instead of just one.
Hope this helps you to better understand this most agonizing of brain injuries. For more info on the computers they use for eye blink communication, try doing some searching for agencies that provide computers for people with severe cerebral palsy who cannot speak or have controlled use of their hands. It pioneered with them.