Jean-Francois Payen, a doctor at the Grenoble hospital that treated Schumacher after his injury in December 2013, said he has visited the Schumacher family at home in Switzerland to track his patient's progress.
"Life after a head injury is punctuated by stages," Payen told RTL radio on Thursday. He predicted a convalescence of one to three years. "We hope, but we have to give him time."
Schumacher was with his 14-year-old son in the French Alps when he fell, hitting the side of his head on a rock, cracking his helmet.