Amnesia
From Memory Alpha, the free Star Trek reference.
Amnesia is a medical condition in which the patient loses all (or most) of their memories of past events.
In 2372, after his appearance and identity were changed to free him from his dishonor, Kurn (now Rodek) was told by Doctor Julian Bashir that he was suffering from a form of permanent amnesia. (DS9: "Sons of Mogh")
