While that's always a possibility with such an injury, only time will and Hartstein warns that patience is the key when dealing with head trauma such as Schumacher's.
"The guys quoted in the online article I saw have taken care of patients like Michael," he wrote on his blog. "They have not, however, examined Michael, reviewed his scans, etc.
"Because their titles imply that these men are consummate professionals, I've no doubt that they made clear that they were speculating as to possible outcomes. Because that is what they are doing.
"I think that we need to look at this speculation rather like the arrival time estimates of your satnav," he explained. "Their initial estimate is based on some assumptions and statistics. Obviously, as you get closer and closer to the destination the estimate gets better and better."
No matter the outcome, the 58-year-old warned that things certainly wouldn't return to normal after and many years of 'painstaking' work lies ahead.
"It is highly unlikely that when Michael and his family are finished with hospitals, finished with rehab centers, he will be the same Michael we had known until that Sunday.
"Once again, patience, long painstaking work by all concerned, and just maybe our thoughts, best wishes and prayers will be needed. Long periods with no news are perfectly normal, and will remain so. We will likely enter a chronic phase, punctuated by (hopefully) several steps forward and (hopefully) many fewer backward."
01/16/14 Doctors fear that Michael Schumacher may remain in a coma for the rest of his life.
The F1 racing champion suffered a serious head injury following a skiing accident while on holiday at the French resort of Meribel on December 29.
He was treated by medical teams in Grenoble and has been in an artificially induced coma for 18 days.
German weekly newspaper Bild newspaper reported that his condition is so severe that there are currently no plans to wake him.
According to German magazine Focus, medical experts have stated that patients placed in comas are usually brought out of them after one to two weeks.
Neurosurgeon Andreas Zieger of the University Clinic for neurosurgery in Oldenburg told the publication: "There may have been complications. We should not speculate here. Ultimately, we are talking about life and death. A coma can in theory be maintained for a lifetime. It won't hurt the human brain."
Professor Zieger added: "Brain injuries are among the most complicated injuries that can happen to the human body.
"Predictions about how long a person might be in a coma or potential complications are seldom reliable."
Cologne neurological expert Professor Gereon Fink fears that the extended duration of the coma indicates serious damage in the brain and that his condition remains critical.
"If the injuries are so severe that it would harm the patient, he is kept longer in the medically induced coma," said professor Fink.
"Depending on where bleeding has taken place can lead to unilateral paralysis, speech disorders or personality changes."
Schumacher's wife Corinna and his two children are maintaining a constant vigil by his bedside. Fans and sports stars have sent messages of support to Schumacher and his family. IB Times