The 45-year-old was on Monday transferred from Grenoble university hospital, where he had been a coma since his accident last December, to a rehabilitation clinic in Lausanne after he suffered brain injuries in his French skiing accident.
Sabine Kehm, his manager, said he was no longer in the artificial coma that the driver had been placed in since early January and would begin the “long process” of rehabilitation, but Dr Erich Riederer, who has extensive experience of coma patients had words of caution, report Swiss press.
In a question and answer interview, the neurologist stated that his waking from a coma after half a year was “incredibly positive” and probably due to intense daily physical therapy but added some sobering realities.
The six months in a coma will have left the seven-time F1 champion “skeletal” and Dr Riederer believes that it will be a success for him to sit up unaided inside three months.
A full recovery remains unlikely, with seemingly simple tasks such as forming a sentence set to prove difficult.
“To form complete sentences, should be difficult - he will learn individual words,” added Dr Riederer.
Schumacher, 45, won a record 91 Grand Prix victories before retiring in 2006. He made a brief comeback with Mercedes but finally stopped racing last year.
Riederer prognoses follows that of other doctors who voiced grave concerns and doubts about the chances of Michael Schumacher making a full recovery despite his management team revealing he is “no longer in a coma”.