"It is neither a good nor a bad sign that there has been no communication on the progress of the recovery process," said the newsmagazine Focus.
"The waking-up can take days, weeks and even months, depending on how quickly the body breaks down the anaesthetic."
Some well-known F1 figures, however, interpreted the news about the beginning of the waking-up process as a positive sign.
"No one from a distance can assess the situation," Mercedes chairman Niki Lauda told the Swiss newspaper Blick, "but I am happy that at last there is a positive message."
Red Bull team owner Dietrich Mateschitz agreed: "I can only hope that this is good news."