Seventeen patients diagnosed as being in a persistent vegetative state - some for as long as four years - were in fact aware of themselves and their surroundings and could communicate with carers, according to a study.
The extent of misdiagnosis revealed in this first detailed study of PVS, has profound legal and ethical implications.
It raises the possibility that some patients, for whom tube feeding or vital treatment was withdrawn at the request of their family with court approval, were not, in fact, in a vegetative state. And scores of other patients in non-specialist centres, diagnosed as PVS, may be acutely aware of what is going on, but are being cared for as if they were not, and given no opportunity to communicate. There are between 1,000 and 1,500 PVS patients in Britain.
In the light of the findings, Dr Keith Andrews, author of the study and a world authority on vegetative state, is urging doctors to refer any patient in this condition to a specialist team before making any application to discontinue feeding.
PVS is used to describe patients with severe brain damage who spend time awake and asleep; who show no meaningful response to things around them and whose movements and reactions are reflex. They can breathe on their own but most have to be fed through a tube.
Doctors at the Royal Hospital for Neuro-disability in London, Britain's only specialist centre for vegetative state, studied 40 patients referred there since 1992 from hospitals where they were diagnosed as PVS;17 (about 43 per cent) were found to be misdiagnosed, some after just a few days' assessment.
According to a report in tomorrow's British Medical Journal, all 17 patients could communicate by pressing a buzzer or pointing with their eyes to make simple choices. Eight could spell out letters to relatives.
Two-thirds of the patients knew where they were and had a sense of time. Three-quarters were able to learn new information, such as the names of staff, and two-thirds could process information such as simple arithmetic.
Dr Andrews, director of medical services at the hospital, said one of the principal findings was that vegetative state - he wants persistent or permanent to be dropped from the title - is very difficult to diagnose. "It cannot be made by even the most experienced specialist from a bedside assessment," he said.
Two-thirds of the misdiagnosed patients were found to be blind and had been thought to be unaware because they did not track objects with their eyes or blink when threatened. All had very limited movement so communication was difficult without special equipment.
The misdiagnosed patients remain severely physically and mentally disabled. However, the majority had stated very strongly that they wanted to live, Dr Andrews said, and described their quality of life as good. "Quality of life is something I say I have, not something that someone else tells me I have got."
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies