Patients who are conscious but almost entirely paralysed could be aided by French research that reads their brain activity to help them communicate.
The condition known as locked-in syndrome has many causes but in most cases it leaves its victims fully conscious but unable to move or speak.
French journalist Jean-Dominique Bauby suffered "locked-in syndrome" when he woke up from a coma caused by a massive stroke to find his mental faculties intact, but body inert.
Despite this he managed to write a memoir entitled The Diving Bell and the Butterfly to give the world a rare glimpse into the internal lives of the locked-in.
The stroke left Mr Bauby able only to blink his left eye and he used this to communicate with an assistant who read out the letters of the alphabet to him.
Probably their brains would be able to react to this, even though they are not able to move
Scientists at France's Institute for Health and Medical Research (Inserm) have come up with a system called OpenVibe to help sufferers of locked in syndrome and to develop understanding of the human brain.
OpenVibe responds directly to the electrical activity of the brain rather than rely on a part of the patient's body that still moves.
"The main application of this technology is to provide some disabled people with a communication aid, especially those who have very severe motor disorders," said Olivier Bertrand from Inserm.
"Using their brain, which is still perfectly functioning, as a way to communicate is a big hope for them getting in touch with the rest of the world," he said.
OpenVibe is based on a grid of letters - the user chooses the letter they want and look at it; the sensors in a cap detect a reaction when the computer selects the right one.
Olivier Bertrand said this tech will allow patients to communicate
"As soon as the letter I've spotted is flashed there is a brain response that tells the computer that this is the one," said OpenVibe researcher Jeremie Mattout.
The computer looks at brain activity to note the column and the row the user is looking at within the grid.
"So by crossing the information of which row and which column have been flashed, he can guess which letter I want," said Mr Mattout.
The process is still slow and painstaking but software that predicts the patient's words could one day speed it up.
Similar technology is also being used at France's digital technology research centre Inria to turn thought into action in the virtual world.
Patients are asked to imagine they are moving their hands, which stimulates the part of the brain that commands such movements.
The OpenVibe system is based on a grid of letters
The brain activity is detected by electrical sensors and the movements are carried out virtually.
OpenVibe could in the future not only help locked-in patients, but also people in a coma.
These patients are often perceived as being beyond reach in terms of communication.
"We always think they are not able to communicate or they are not able to understand what we are telling them," said Mr Bertrand, "but there are some indicators now from neuroscience research that they could have a way to understand our talk".
"Probably their brains would be able to react to this, even though they are not able to move," he added.
Mr Bertrand said that communication between man and machine will continue to improve as scientists further their own understanding of the brain's capabilities.
Neuroscience offers a glimmer of hope for patients cut off from the people nearest to them.