"We must imagine a person very different from the one we remember on the track, with a very altered and deteriorated organic, muscular and skeletal structure. All as a result of the brain trauma he suffered," the doctor revealed.
In December, Schumacher's personal doctor revealed details over the treatment the motorsport legend has been receiving.
Kean-Francois Payen, who was the first to confirm Schumacher had come out of his coma five years ago, told German publication In Touch "There is a one-to-three year plan for the regeneration period.
"I still visit him occasionally and talk to the family about any progress I see."
Professor Philippe Menasché also confirmed to the German publication that Schumacher received heart and vascular surgery at the Paris Georges Pompidou Hospital.
"There he was subjected to cell therapy.
"But it was clear from the outset that no miracles would happen to him during therapy."
Schumacher has been treated at home in a mansion in Switzerland since September 2014.