The Belgian patient Rom Houben who was wrongly diagnosed as comatose for 23 years cannot communicate by computer, his neurologist Steven Laureys told AFP Saturday.
Laureys of Liege university, who recently presented a study on the method known as "facilitated communication", concluded that it "did not work in the majority of cases".
Facilitated communication involves holding the hand of paralysed but conscious patients above a computer keyboard as a medical assistant taps the relevant letters when they observe any minute pressure.
The study by the medical team led by Laureys was based on three Belgian patients considered in a comatose state, including Houben.
In the end, just one out of the three patients was able to reply to questions using this assisted mode of communication.
Houben, now 46, was involved in a road accident in 1983 and had been wrongly diagnosed as comatose for 23 years when he was actually paralysed but conscious, as medical examinations led by Laureys discovered in 2006.
Since, Houben's family tried various methods of communication and brought his case to media attention last November.
Several supposed declarations made by the former engineering student were subsequently published in the press.
However, "from the start", Laureys cautioned, "I had said one must wait for scientific confirmation. But it is hard sometimes for the media to reflect a complex reality."