Amnesia
| Amnesia | |
|---|---|
| Specialty | Psychiatry, neurology  |
Amnesia (from Greek Ἀμνησία) is a condition in which memory is disturbed. The causes of amnesia are organic or functional. In simple terms it is the loss of memory. Organic causes include damage to the brain, through trauma or disease, or use of certain (generally sedative) drugs. Functional causes are psychological factors, such as defense mechanisms. Hysterical post-traumatic amnesia is an example of this. Amnesia may also be spontaneous, in the case of transient global amnesia[1]. This global type of amnesia is more common in middle-aged to elderly people, particularly males, and usually lasts less than 24 hours.
Another effect of amnesia is the inability to imagine the future. A recent study published online in the Proceedings of the National Academy of Sciences shows that amnesiacs with damaged hippocampus cannot imagine the future[1]. This is because when a normal human being imagines the future, they use their past experiences to construct a possible scenario. For example, a person who would try to imagine what would happen at a party that would occur in the near future would use their past experience at parties to help construct the event in the future.
Forms of amnesia
- In anterograde amnesia, new events contained in the immediate memory are not transferred to the permanent as long-term memory. The sufferer will not be able to remember anything that occurs after the onset of this type of amnesia for more than a brief period following the event.
- Retrograde amnesia is the inability to recall some memory or memories of the past, beyond ordinary forgetfulness.
- The terms are used to categorize patterns of symptoms, rather than to indicate a particular cause or etiology. Both categories of amnesia can occur together in the same patient, and commonly result from drug effects or damage to the brain regions most closely associated with episodic/declarative memory: the medial temporal lobes and especially the hippocampus.
- An example of mixed retrograde and anterograde amnesia may be a motorcyclist unable to recall driving his motorbike prior to his head injury (retrograde amnesia), nor can he recall the hospital ward where he is told he had conversations with family over the next two days (anterograde amnesia).
Amnesia in fiction
Amnesia is prevalent in many works of fiction. Global amnesia is a common motif in fiction despite being extraordinarily rare in reality.
- In The Bourne Identity (both the book and the movie), main character Jason Bourne has retrograde amnesia.
- In the Marvel Comics series X-Men, Wolverine, one of the main characters, has retrograde amenesia due to brainwashing.
- Anterograde amnesia features in the movies:
- Lacunar amnesia features in the movie Eternal Sunshine of the Spotless Mind.
- In the first season of 24, a prominent character has dissociative amnesia.
- In the first season of Lost, Claire Littleton is kidnapped and has amnesia upon returning.
- In season two of MacGyver, a narrow escape from a gang of international terrorists leaves Mac without his memories but with his ingenuity intact.
- The TV show John Doe is based on an amnesiac who mysteriously appears in the middle of a sea.
- In the TV show Heroes, one of the characters nicknamed The Haitian, can cause various degrees of amnesia to others with his powers. His most notable victim is one of the main characters, Peter Petrelli, who, in the season 2 premiere, finds himself in a crate that travelled from New York to Ireland with no memory about how he got there or who he is.
- In the 1966 motion picture Mr. Buddwing, the protagonist enters a fugue state in response to distress in his marital relationship.
- In the 2004 film The Forgotten, adults struggle with memory loss about the existence of their children, who have been abducted for alien/government experiments.
- In Season 4 of Smallville, Clark Kent has his memory wiped by a Summerholt patient.
- In Destination Moon, a part of Adventures of Tintin, Professor Calculus, for a brief period of time suffers from total amnesia, putting the project in trouble since only he knows how to make moon-rocket.
- In Century Fox's animated film, Anastasia (1997), Anya suffers from amnesia as a result of having her head hit when trying to climb on train to escape to Paris with her grandmother as a young girl, and cannot recall the first eight years of her life.
- The American sitcom Samantha Who? (2007- ) begins with the main character having suffered retrograde amnesia as the result of an auto accident and the show revolves around events that made her remember her life before the accident.
- Dissociative Amnesia plays a critical role in the novel Mysterious Skin and movie of the same name.
- Author Gene Wolfe addresses amnesia in the series Soldier of the Mist, where the main character Latro is injured during battle, causing relatively long term (24 hour) anterograde amnesia.
- In Japanese anime, amnesia is a common theme:
- The Big O is largely based on the premise of an entire city having lost their memory forty years prior.
- In both Noir and Madlax , the main characters Kirika Yuumura, Madlax and Margaret Burton lose their memory because the memories they had were too traumatic for them.
- In Sukisyo, the main characters experienced amnesia because their pasts involve betraying someone dear to them.
- In Loveless, the main character has no memories of the first ten or so years of his life and never regains them.
- In Utawarerumono the main character has no memory before the series begins. He does not exactly get them back, save for in short bursts, showing several past homicides. These endeavors, with time, become accepted.
- In Spirited Away, the character Haku forgot everything about his life as a river spirit, along with his name, which restricted his freedom.
- In the Japanese Drama, Hana Yori Dango (Boys Over Flowers), the main character, Domyouji, has amnesia in the second season.
- In the RPG Knights of the Old Republic global amnesia fits prominently into a midgame plot twist.
- In Mario & Luigi: Superstar Saga, Bowser gets amnesia.
- In the Sonic the Hedgehog series, Shadow the Hedgehog suffered for a time from amnesia after being found alive in a stasis, having no memory of his past.
- In the film Regarding Henry, Harrison Ford's character Henry Turner suffers from severe retrograde amnesia, and must relearn everything about his life, including basic motor functions.
- In the computer game NetHack, if the player's character reads a scroll of amnesia, the character forgets the layout of the current dungeon level, as well as possibly the layouts of other dungeon levels and even object identifications that have been made.
In movies and television, particularly sitcoms, it is often depicted that a second hit to the head (similar to the first one) cures the amnesia. In reality, however, repeat concussions may cause cumulative deficits including cognitive problems, and in extremely rare cases may even cause deadly swelling of the brain associated with second-impact syndrome.
See also
- Betrayal Trauma
- Clive Wearing
- Emotion and memory
- False memory
- HM (patient)
- Mr. Nobody
- Doug Bruce
- KC (patient)