The case of Rom Houben, thought to have been in a coma for 23 years, but apparently conscious all the time, raises a horrifying prospect: how can you cope being trapped in your body, aware of everything but unable to communicate with the outside world?
Mike Cubiss can vividly remember the tiles on the kitchen floor and how cold they felt.
He was waiting for the ambulance, afraid he might die, but unable to move or say goodbye to his wife.
On an ordinary day in 2002, as he prepared to take his three sons to school, and his wife got ready for work, Mike collapsed. The aftermath was locked-in syndrome.
Public awareness of the condition today is largely a result of The Diving Bell and the Butterfly, a book by French magazine editor Jean-Dominique Bauby, later turned into a film.
The syndrome is typically caused by a lesion in the pons, effectively the part of the brain stem that acts as a bridge between brain and body. The most common cause is a stroke.
In its "classical form" those with the syndrome are almost completely paralysed and sometimes only able to move their eyes up and down, or to blink. They cannot move but they are fully conscious.
"It has nightmarish qualities, robbed of all function and trapped in a body in which you can't communicate," says Dr Mark Delargy, director of the brain injury programme at the National Rehabilitation Hospital in Dublin.
"Another aspect is that it is often diagnosed at a very late interval. The person could be in hospital, considered to be in a coma state or vegetative state [and] it's only discovered some months after the person has been surviving, that they are actually not in a vegetative state.
"It's often family members who believe that their nearest and dearest have some intellect. They are not believed for a while. Eventually someone spots what the family have seen."
In Rom Houben's case, his mother always believed he could communicate. And the idea that the family may establish a line of communication first is familiar to Lorna Elwick who became partially locked-in in 1993, when she was 40.
"I had a particularly bad headache at work one day," says Lorna, communicating via a special computer. "The ache was centred round the lower part of my head, at the back, and my neck. I also couldn't speak. Over three days I went three times to both my GP and A&E. Neither had any ideas, I wasn't scanned but just given strong painkillers.
"By the third day I couldn't even swallow. A&E finally agreed to take me in on the third evening, but the following morning I completely collapsed. They diagnosed brain-stem infarction and locked-in syndrome."
It was her brother, a policeman familiar with communicating by using presses of a walkie-talkie button, who found that Lorna could communicate.
"He said he was going to ask me some questions, which I should blink once for no and three times for yes. In 15 minutes he had established that I was cognitively ok.
"The consultant said it meant nothing and told my husband that I'd probably die. Gradually the medical staff - beginning with auxiliaries and ending with consultant - began communicating like that with me."
Many doctors would know to test consciousness by looking for eye movements, says Adam Zeman, professor of cognitive and behavioural neurology at Exeter's Peninsula Medical School.
"The trouble is that you may lose even those movements and still be aware. It becomes much more difficult to diagnose. It is very nightmarish but very, very rare."
Even for those where a line of communication is established using eye movements, it is a painstaking process.
"Often the individual has a lot of eye problems - eye watering, they can't blink, grit gets into their eyes. The eye becomes very sore," says Dr Delargy.
"Eye movements fatigue very rapidly. It gives a sense of pressure on the communicator to be clever about the questions.
"It's the equivalent of a mobile phone with a dying battery."
How can the locked-in patient maintain the will to live? Studies of patients suggest that while the layman imagines it a fate worse than death, the vast majority of those who are locked-in want to be alive, despite their predicament.
It's something that Mike Cubiss attests to: "I now feel that this is better than being dead. I accept it. I do not allow myself to dwell on it as that would be too depressing.
"I am surrounded by my family and can see my sons grow up, though I can't put much input into that, which makes me very sad."
Dr Delargy knows that most people immediately assume the locked-in person is in a state of mental torment, but they are in a battle where there is no choice but to carry on.
"The person has been in a state for so long that they have worked out how to cope with this. They have lived with the situation day by day until an appropriate person finds out.
"Not everyone is on anti-depressants. They choose not to be. People who are in locked-in syndrome say it isn't great but it is better than being dead."
Complete recovery is rare, but patients can make improvements. Lorna no longer considers herself locked-in. She can mouth words to those who can lipread, she has some use of her right finger and has learned to swallow food.
She remains angry about the standard of medical treatment she had before and immediately after she became locked-in. And life is still very hard.
"When I was first ill, I was very upbeat. Now I get fed-up more often especially as I am forced to stay in bed more or my bum hurts.
"What helps most is the fact that I had more than my fair share of emotional lability [a symptom of brain-stem damage that can cause uncontrollable laughter] and found humour in so many things - some people cry or get angry but, although I did cry and get very angry, predominantly I laughed quite uncontrollably and still do.
"The fact that my husband stayed around, plus all my family also helped. Also, I have much more control now that I'm home."
In terms of practical coping, the locked-in patient has all the same challenges as any paralysed person. They must be moved to avoid bed sores, carers must be aware that certain postures can become uncomfortable for them, and a host of other concerns.
But communication is key. Patients use everything from an e-tran board, where their gaze is interpreted by a carer, to eyegaze computers, to devices operated by tiny body movements.
At the point where blinking or upwards eye movement is all they can manage, carers will read out a reorganised alphabet with yes/no answers to communicate.
And all the time, there is the knowledge for the doctors, carers, and family that the patient is often desperate to communicate something vital.
Dr Delargy recalls one severely locked-in male patient was transferred from a bed to a chair every day for about four hours so he could enjoy a change of scenery. It was two years before it was established that he became uncomfortable after about an hour in the chair.
In a life that was a tissue of problems and discomforts, carers and doctors had been unable to ascertain this particular problem.
"It is exquisitely gut-wrenching," says Dr Delargy.
"Once you get the answer no to the question 'are you comfortable?', it can take another 10 questions."
And of course the issue of coping is not just for those who are locked-in, but also those around them, as Lorna attests.
"My family accepted me almost straightaway. Most friends were obviously so traumatised, they disappeared after the first few months. I was disgusted and angry with them."
Here is a selection of your comments.
I'm so glad the public are being made aware of locked-in syndrome. Fifteen years ago, after a car accident, I was only able to communicate by blinking and using the alphabet. Family and friends became very adept at talking this way with me. Now I can whisper, I have enough movement to use an electric chair and to use a computer. I have a good life, I run my own home, I've brought up my daughter and son. All with the support of family, friends and personal assistants. Of course I have low times, who doesn't. But I'm very glad to be alive and I try to get the most I can out of life.
Often when out I'm aware of the strong reaction to me from people, specially when I open my mouth to talk. I feel my communication difficulties almost frightens people. I've often been told people won't talk to me because they're frightened of upsetting me if they don't understand me. Who's upset?! At the end of the day what's really needed, besides support from family and friends is the right care support and understanding from service providers (enabling us to take our roles back within family and social circles) adequate medical care for both during and after a trauma. So that those of us living with the effect of or the aftermath of locked-in syndrome, are able to pull back some control over our lives.
With the public more aware that it doesn't have to be the end of life to be locked-in. It will hopefully mean that this awareness will help those who are or have been locked-in, get on with living.
Beth Vossler, New Ash Green, Kent
This is a living hell for the patient and truly awful for family and friends. My sister suffered an attack of Guillain-Barre syndrome when she was a fully fit 32-year-old. She was left paralysed to her eyes, on a life support machine, and in constant, agonizing pain. Discovering she was in pain was easy, but working out the location and cause could take hours. Thankfully, a year on she is recovering some feelings and movement, but she may never fully recover.
I am profoundly respectful of those who have the strength to remain upbeat despite an horribly debilitating condition. The ability to communicate one's desires should be taken into account when being alive is NOT better. We are granted the choice to end the suffering of a beloved pet, and it seems that people should be given the same respect and choice. Following a massive stroke, my mother was essentially locked in for three years. The only communication that she had was through tears, and I know what her request would have been. It seems that the communication technology might provide a compelling reason for euthanasia at the patient's request.
Nancy Mullins, Jacksonville, Florida USA
I visited my uncle on the Monday and he died on the Friday but between those dates he was in a coma. However when I first visited him and said it is "Pat's daughter" this glow slowly went up his face till all his face was aglow and then it immediately went back to normal. So I am sure he heard. There was no other response after that.
Pat Bailey, Blackpool
I would want to die instantly. In fact, my mother and I already have a mutual pact regarding this situation. Losing my freedom in every sense of the word would be the worst thing imaginable to me.
Frank Wallace, Glasgow, Scotland
I have so much respect for the way those suffering from this illness manage to cope. Five years ago I suffered from bilateral facial paralysis. Unable to move any part of my face, no blinking, and just about managing to make noise with my mouth in a way that people could understand I felt so trapped within myself & if I could have cried I'm sure I would have done for most of the time I was ill. Luckily for me, I made an almost full recovery, just can't quite open my mouth as wide as I used to or smile the same and one eye gets very small when I'm tired or ill or even if it's very windy. But by comparison, being able to communicate in some form and being able to at least get up & walk around and even have people communicate with me, my problems were minor and I feel so much for those who are 'Locked-in', but their determination to stay positive is a real inspiration!
Paul Savill, London