Michael Schumacher, the seven-time Formula 1 world champion, suffered a serious skiing accident in 2013 that has left him in critical condition. Reports indicate that he cannot speak but can communicate with his eyes.

According to Italian newspaper Corriere della Serra, Schumacher cries when he hears the familiar voices of his wife and children.

The retired F1 driver, who turned 36 on January 3, is continuing his recovery after the accident. He spent his birthday with his wife, son and daughter at their home by Lake Geneva, and has been there since leaving hospital in September. Schumacher's wife Corinna has said he is now in a process of recovery.

According to the Daily Times, "Sometimes a tear rolls down Michael's face. He cries when he hears the voice of his children or his wife." The paper indicated that Schumacher is capable of demonstrating emotion through tears.

Schumacher spent nine months in an induced coma after he hit his head on a rock while skiing with his son Mick in the French Alps on December 29, 2013. He suffered severe head injuries and had two brain operations at a hospital in Greenoble before being moved to hospital in Lausanne last June.

A separate report in the magazine Autosprint said Schumacher was able to sit up.

"The good news is that Michael is not stuck in a bed. When not undergoing physical therapy to avoid muscle atrophy, he sits in a chair in front of the windows of his villa, overlooking on one side the snowy peaks of the Swiss Alps, and on the other the shores of Lake Geneva," said Alberto Sabbatini of Autosprint.

The former sportsman's manager, Sabine Kehm, said last week that her client faces a "hard fight" to recover from the serious head injuries that he suffered.