A 14-year-old Palmerston North girl who has lost consciousness every three days for almost two years does not know who she is, where she is, or even what her parents look like, every time she wakes up.

"It's like waking up in another world, but you don't know what world you've come from," says Amelia Guest.

Amelia was 12 years old the first time she passed out - she was out cold for 45 minutes.

Two years later, it is still happening and doctors do not know what is wrong, other than a general diagnosis of Functional Neurological Disorder (FND).

Her medical records show lengthy lists of symptoms, including loss of sight and hearing, as well as hallucinations.