Released in 2000, ‘Memento’ was a psychological thriller film, directed by Christopher Nolan, starring Guy Pearce as Leonard Shelby, a man with anterograde amnesia, which impaired his ability in storing new memory from recent events. Other examples of anterograde amnesia in popular culture include Dory from ‘Finding Nemo’ and Lucy from ‘50 First Dates’.
The two main features of amnesia are:
- Anterograde amnesia: Impaired ability to learn new information following the onset of amnesia
- Retrograde amnesia: Impaired ability to recall past events and previously familiar information
Anterograde and retrograde amnesia can occur simultaneously in the same patient. The memory loss doesn’t affect a person’s intelligence, general knowledge, awareness, attention span, judgement, personality or identity. People with amnestic syndrome usually can understand written and spoken words and can learn skills such as bike riding or piano playing. They may also understand that they have a memory disorder.
An amnestic syndrome caused by brain injury or damage is known as neurological amnesia. Possible causes of neurological amnesia include stroke, lack of adequate oxygen in the brain, long-term alcohol abuse leading to thiamin (vitamin B-1) deficiency, tumors in the areas of the brain that control memory and degenerative diseases such as Alzheimer’s Disease.
Head injuries, such as those sustained in car accidents, can lead to confusion and problems remembering new information, especially in the early stages of recovery - but usually don’t cause severe amnesia.
Another rare type of amnesia, called psychogenic or dissociative amnesia, sterns from emotional shock or trauma, such as being the victim of a violent crime. In this disorder, a person may lose personal memories and autobiographical information, usually just for a brief time.