Spanish outlet El Pais has reported that Alonso suffered from memory loss which made him think that it was 1995, with the McLaren driver having no memory of the past 20 years.
When asked by doctors who he was and what he did for a living, El Pais claims that he responded: “I’m Fernando, I drive go karts and I want to be a Formula One driver.”
It has been confirmed that Alonso suffered a concussion in the February 22 crash in which he hit a wall after losing control of his car while going 215km/h.
A statement from McLaren early this week asserted that Alonso was "entirely healthy from neurological and cardiac perspectives", but that he would not race in next weekend's season-opening grand prix in Australia.
However, the crash itself and Alonso's health has been the subject of much discussion, and the latest reports will only add to speculation surrounding the incident.
McLaren have indicated that Alonso should be fit to take part in the second round of the 2015 season in Malaysia in late March, with the 33-year-old set to undergo further precautionary tests next week.