The news follows more than a 150-day coma for the former Ferrari and Mercedes driver, following his skiing fall just after Christmas.
But Kehm told Italy's La Gazzetta dello Sport: "I have never spoken with these journalists, and we have not issued any statement about Michael's health condition."
However, some believe the speculation about Schumacher's condition is only being fuelled by the complete lack of official information from his family and management.
Roger Benoit, a respected and long-serving member of the F1 corps, wrote in Blick newspaper: "Slowly, everybody is really worried.
"Grenoble and the family have been silent for weeks. Why?"
Also critical of the Schumacher camp's media strategy is Gary Hartstein, the former F1 doctor.
He fears the worst.
"I can conceive of no possible reason that Michael's entourage, understandably extremely protective of his and their privacy, would not tell his fans if significantly good things have happened," Hartstein wrote on his blog.
He said that, almost six months into a coma of Schumacher's magnitude, "only a tiny, tiny fraction" of patients ever regain consciousness.
Dr Hartstein added: "I'm quite afraid, and virtually certain, we will never have any good news about Michael. At this point, I rather dread seeing that the family has put out a press release."