Amnesia is a state of mind in which the person tends to suffer from partial or complete memory loss. There are varying types and degrees of amnesia that take place during old age. Talking about the amnesia symptoms, the persons suffering from this mental disorder forget words and names.
There is a distinctive uncommon form of amnesia in which the memory loss occurs to such an extent that the patient even forgets his own identity, as in his name, age, and family background. It is a stage in which the person fails to recollect anything of the past.
source : iloveindia.com