"Michael's condition remains critical but stable. We would like to clearly stress that any information regarding Michael's health not coming from the doctors treating him or from his management must be treated as invalid and pure speculation," Schumacher's agent, Sabine Kehm, said in a statement.
Kehm added that Schumacher's "helmet camera was voluntarily given to the investigating authorities by the family".
Kehm made the comments after former Formula One driver Philippe Streiff, a friend of Schumacher's, told Sky TV he had been told by surgeon and friend, Gerard Saillant, who is at the Grenoble hospital, that the German's life was "out of danger".
The retired motor racing great slammed his head on a rock while skiing off-piste on Sunday morning.
He has been in an induced coma for six days since being transferred to a Grenoble hospital, where he has undergone two operations.
Schumacher, who turned 45 on Friday, is the most successful Formula One driver of all time with a record 91 race victories.