The aetiology of retrograde amnesia.

To date, hypotheses of the ætiology of retrograde amnesia have focused on anatomical effects of traumatic lesions and on the presumed existence of short-term memory. The invariable association of retrograde amnesia with post-traumatic amnesia has been ignored as a clue to the origin of retrograde amnesia. It is suggested here that post-traumatic amnesia, by depriving preceding memories of a large proportion of their associated memories, leads to retrograde amnesia. The hypothesis accounts for the occurrence of retrograde amnesia in so many different situations and allows for the existence of very long retrograde amnesia.