What is post traumatic amnesia?
Even after a fairly minor head injury there will be a time after the head injured person has apparently woken up, which he / she will, later be unable to remember.
This time can range from a few seconds or minutes to days, weeks or months.
During this period he may answer or ask questions, he may walk around, have a meal or do other apparently awake things, but because he or she is completely unable to remember them later, we know that he or she was obviously not actually awake. Post traumatic amnesia is basically the time between the injury and the resumption of normal continuous memory.