Diagnosing Amnesia

[nynaeve_sedai]

I'm writing a fantasy story that involves my main character to have had her memory taken from her (as opposed to actual amnesia). She's been exiled to earth and she remembers only her name. She wakes in a US hospital, bandaged up, and after a conversation with a nurse, the nurse sends for a doctor.

[The actual question...]
If the nurse suspects amnesia, who would he get? Would he call for a psychiatrist? Would it just be whatever doctor is on call? Would a psychiatrist be the one diagnosing amnesia?

I googled this and all I get is "the doctor" :-S I want to know *which* doctor and what the procedure would be - I know from Google that other factors would first have to be ruled out and that there would be brain scans. Is it unlikely that a psychiatrist would be available or even involved? I would suspect that at some point a psychiatrist would be involved if it were found that there were no physical reasons for the amnesia, but at what point?

Thanks :)