What is retrograde amnesia?

According to the Mayo Clinic, retrograde amnesia is the decreased ability to remember events that happened in the past and information that was previously familiar. Retrograde amnesia is distinct from anterograde amnesia, which is the decreased ability to remember new events or information after amnesia is diagnosed.

According to Elaine de Guise of McGill University Health Centre, retrograde amnesia can affect a person's memories of events that occurred years, months, days or minutes before the onset of brain damage or a traumatic life event, which is referred to as post-traumatic amnesia. Those with retrograde amnesia find the oldest memories the most difficult to recall.