In a chat with Reuters, Kehm confirmed again that recovery for Schumacher will take a long time.
"We need a long time. It's going to be a long time and a hard fight," Kehm told Reuters.
"He is making progress appropriate to the severity of the situation," she added.
The seven-time F1 champion suffered severe head injuries from a skiing accident in the French Alps in December 2013. After coming out of an induced coma in June he went home in September to be treated by doctors in the surroundings he knows.
Philippe Streiff, another former F1 driver, told Le Parisien on Sunday, that Schumacher "had yet to recover the power of speech" but was "nevertheless starting to recognize those close to him".
Streiff claims to be a close friend of the driver and got the information from Corinne, Schumacher's wife, and his surgeon Gerard Saillant.
But Kehm said that the claims were nonsense saying: "I cannot confirm that (report).
"I can only confirm that I do not know where Mr. Streiff has his information from because he has no contact with us and he never has," she added.