Alex Zanardi's son says there are "encouraging signs" after the former F1 driver left hospital this week.

The former Lotus and Williams driver's month-long sedation for severe head and facial injuries is now over and he has been moved to a rehabilitation clinic.

But his son Niccolo told Corriere della Sera that his father remains unconscious for now, even though the signs are "encouraging".

"He will make it, I am sure," said the 21-year-old. "He will do it again this time and one day we will talk about it. He will talk to me and to my children. I am hopeful, as is my mother."

However, Niccolo Zanardi also admitted there remain concerns about his father's eyesight.

"That is not the most important thing now. What matters the most is knowing whether he can communicate with us again. We have a long way to go," he said.

"We are happy because his recovery has been much faster than we expected, but we shouldn't be surprised because we're talking about Dad.

"The energy of that man is incredible. He is unusually strong.

"Without going into details, he is a little better and he is beginning to recover. There is no more threat to his life, and this is already saying a lot.

"I repeat: the rehabilitation will take a long time," Zanardi jr added.