Researchers say a Belgian man who stunned the world last year by apparently communicating after 23 years in a coma cannot in fact do so.
Claims that Rom Houben - who was seriously injured in a car crash in 1983 - could communicate, swept around the world last November.
However the doctor who believed that Mr Houben was communicating through a facilitator now says the method does not work, the BBC reports.
Dr Steven Laureys, a neurologist at Liege University Hospital in Belgium, told the BBC that a series of tests on a group of coma patients, including Mr Houben, had concluded that the method was after all false. The results of the study were presented in London on Friday.
Dr Laureys had earlier established that Mr Houben was more conscious than doctors had previously thought - and that is still thought to be the case.
After more than two decades in a coma, Rom Houben was filmed apparently tapping out messages on a special touchpad keyboard with the help of his speech therapist.
By holding Mr Houben's forearm and finger, the therapist was said to feel sufficient pressure to direct her to the correct keys on the keyboard.