Formula One fans gathered outside the Grenoble hospital Friday, on Michael Schumaher’s 45th birthday. (Charles Platiau / Reuters)

Michael Schumacher remains in a medically induced coma, his condition unchanged as he recovers from traumatic brain injuries he suffered in a skiing accident Dec. 29.

The accident, which occurred as he skiied through a rock-strewn off-piste area between two groomed runs at the French resort of Meribel, is under investigation and Der Spiegel reported over the weekend (via that Albertville authorities are looking at video from the helmet camera he was wearing as well as expecting to take a look at video taken by another skier. That skier, a man from Essen, was filming his girlfriend with his smartphone and may have caught Schumacher’s accident.

Schumacher’s helmet, which cracked from the impact of his head against a rock, carried a miniature camera with a 170-degree wide angle lens, but it is not yet clear whether it captured the accident. Authorities plan to reveal the results of their investigation Wednesday.

Schumacher, the most successful driver in Formula One history, turned 45 Friday and doctors at the Grenoble hospital in which he is being treated are offering no more of the updates that came daily early last week. He has undergone two procedures in which neurosurgeons have relieved intercranial pressure and removed blood clots on the brain.

“The clinical state of Michael Schumacher is stable as he’s under permanent care and treatment,” it said in a statement (via Reuters). ”However, the medical team in charge stresses that it continues to assess his situation as critical.” It added, “The privacy of the statement demands that we are not going into details of his treatment, and this is why we do not plan any press conferences, nor give out written press releases, anymore for the time being.”