PARIS, France - Doctors treating seven-times Formula One world champion Michael Schumacher will begin lowering his sedation level to start the process of waking him up, his agent said on Thursday. (Jan 30).Schumacher has been in an artificial coma in a hospital in the eastern French city of Grenoble for more than four weeks following an accident in late December when he slammed his head on a rock while skiing off-piste in the resort of Meribel.'MAY TAKE A LONG TIME'Schumacher's agent, Sabine Kehm, said in a statement: "Michael's sedation is being reduced to allow the start of the waking-up process, which may take a long time." The drugs used to keep Schumacher, 45, unconscious have begun to be reduced, though it may be some time yet before he comes to, Kehm said in a statement.She said: "For the protection of the family, it was originally agreed by the interested parties to communicate this information only once this process was consolidated. Please note that no further updates will be given."PRIVACY NEEDEDThe spokeswoman asked the media to respect the privacy of Schumacher's family and to not disturb the doctors treating him.Surgeons said he suffered bleeding and bruising in his brain and a scan showed "widespread lesions". It was unknown in what state he would be if the waking process is successful.Experts said it was rare to keep a patient in an artificial coma for more than three weeks. In accidents of a similar severity, patients often had a disability after their emergence from coma, the experts noted.Schumacher dominated Formula 1 for much of his racing career before his retirement in 2012.He won the F1 title seven times, more than any other driver, and notched up 91 victories between 1994 and 2004. Stay with Wheels24 for the 2014 F1 season – fresh reports every day.