Amnesia (from Greek Ἀμνησία) (see spelling differences) is a condition in which memory is disturbed. The causes of amnesia are organic or functional. 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. Amnesia refers to a variety of conditions in which memory is lost or disturbed. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // R00-R99 - Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R09) Symptoms and signs involving the circulatory and respiratory systems (R00) Abnormalities of heart beat (R000) Tachycardia, unspecified (R001) Bradycardia, unspecified (R002) Palpitations (R008) Other and unspecified abnormalities of heart beat (R01) Cardiac murmurs and other... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... The differences in the spellings of British English and American English are as follows: Spelling differences between U.S. usage on one side and British and Commonwealth usage on the other are generally more conspicuous than spelling differences within the Commonwealth. ... In psychology, memory is an organisms ability to store, retain, and subsequently retrieve information. ... In psychoanalytic theory, a defence mechanism is an unconscious way to protect ones personality from unpleasant thoughts which may otherwise cause anxiety. ... Transient global amnesia (TGA), is an anxiety-producing temporary loss of short-term memory. ...

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 hippocampi 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. The hippocampus is structurally located inside the medial temporal lobe of the brain. ...

[edit] Types 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).

• Traumatic amnesia is generally due to a head injury (fall, knock on the head). Traumatic amnesia is often transient, but may be permanent of either anterograde, retrograde, or mixed type. The extent of the period covered by the amnesia is related to the degree of injury and may give an indication of the prognosis for recovery of other functions. Mild trauma, such as a car accident that could result in no more than mild whiplash, might cause the occupant of a car to have no memory of the moments just before the accident due to a brief interruption in the short/long-term memory transfer mechanism.

• Dissociative Amnesia results from a psychological cause as opposed to direct damage to the brain caused by head injury, physical trauma or disease, which is known as organic amnesia. Dissociative Amnesia can include:

• Referring to inability to recall information, usually about stressful or traumatic events in persons' lives, such as a violent attack or rape. The memory is stored in long term memory, but access to it is impaired because of psychological defense mechanisms. Persons retain the capacity to learn new information and there may be some later partial or complete recovery of memory. This contrasts with e.g. anterograde amnesia caused by amnestics such as benzodiazepines or alcohol, where an experience was prevented from being transferred from temporary to permanent memory storage: it will never be recovered, because it was never stored in the first place. Formerly known as "Psychogenic Amnesia"

• Dissociative Fugue (formerly Psychogenic Fugue) is also known as fugue state. It is caused by psychological trauma and is usually temporary, unresolved and therefore may return. The Merck Manual defines it as "one or more episodes of amnesia in which the inability to recall some or all of one's past and either the loss of one's identity or the formation of a new identity occur with sudden, unexpected, purposeful travel away from home" [2]. While popular in fiction, it is extremely rare.

• Posthypnotic amnesia is where events during hypnosis are forgotten, or where past memories are unable to be recalled.

• Lacunar amnesia is the loss of memory about one specific event.

• Childhood amnesia (also known as infantile amnesia) is the common inability to remember events from one's own childhood. Whilst Sigmund Freud attributed this to sexual repression, others have theorised that this may be due to language development or immature parts of the brain. This is often exploited by the use of false memories in child abuse cases.

• Transient Global Amnesia is a well described medical and clinical phenomenon. This form of amnesia is distinct in that abnormalities in the hippocampi can sometimes be visualized using a special form of MRI of the brain known as diffusion-weighted imaging (DWI). Symptoms typically last for less than a day and there is often no clear precipitating factor nor any other neurological deficits. The cause of this syndrome is not clear, hypotheses include transient reduced blood flow, possible seizure or an atypical type of migraine. Patients are typically amnestic of events more than a few minutes in the past, though immediate recall is usually preserved.

• Source amnesia is a memory disorder in which someone can recall certain information, but they do not know where or how they obtained the information.

• Memory distrust syndrome is a term invented by the psychologist Gisli Gudjonsson to describe a situation where someone is unable to trust their own memory.

• Excessive short-term alcohol consumption can cause a blackout phenomenon, with the amnesia being of the anterograde type.

• Long-term alcoholism or malnutrition can cause a type of memory loss known as Korsakoff's syndrome. This is caused by brain damage due to a Vitamin B1 deficiency and will be progressive if alcohol intake and nutrition pattern are not modified. Other neurological problems are likely to be present in combination with this type of Amnesia. Korsakoff's syndrome is also known to be connected with confabulation.

Anterograde amnesia is a form of amnesia, or memory loss, where new events are not transferred to long-term memory. ... Retrograde amnesia is a form of amnesia where someone will be unable to recall events that occurred before the onset of amnesia. ... This article is about the medical term. ... Episodic memory, or autobiographical memory, a sub-category of declarative memory, is the recollection of events. ... It has been suggested that Explicit_memory be merged into this article or section. ... The temporal lobes are part of the cerebrum. ... The hippocampus is structurally located inside the medial temporal lobe of the brain. ... Head injury is a trauma to the head, that may or may not include injury to the brain (see also brain injury). ... Psychogenic Amnesia is a form of amnesia popularized by popular culture, particularly film. ... Psychogenic Amnesia is a form of amnesia popularized by popular culture, particularly film. ... In the field of psychology, a fugue state is usually defined by the term dissociative fugue. ... The Merck Manual of Diagnosis and Therapy (often referred to simply as The Merck Manual) is one of the worlds most widely used medical textbooks. ... Professor Charcot was well-known for showing, during his lessons at the Salpêtrière hospital, hysterical woman patients – here, his favorite patient, Blanche (Marie) Wittman, supported by Joseph Babiński. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... In psychology, childhood amnesia refers to the inability of people to remember their earliest childhood experiences. ... Sigmund Freud (IPA: ), born Sigismund Schlomo Freud (May 6, 1856 – September 23, 1939), was an Austrian neurologist and psychiatrist who founded the psychoanalytic school of psychology. ... Childrens language development moves from simplicity to complexity. ... For the novel, see False Memory (novel) It has been suggested that Synthetic memory be merged into this article or section. ... Child abuse is the physical, sexual, or emotional maltreatment or neglect of children by parents, guardians, or others. ... Transient global amnesia (TGA), is an anxiety-producing temporary loss of short-term memory. ... Source amnesia is an explicit memory disorder in which someone can recall certain information, but they do not know where or how they obtained it. ... As source amnesia prohibits recollection of the context-specific information surrounding facts in experienced events, there is also the inclusive case of confusion concerning the content or context of events, a highly attributable factor to confabulation in brain disease. ... Gisli Gudjonsson is Professor of Forensic Psychology at the Institute of Psychiatry, Kings College London. ... A blackout is a phenomenon caused by the intake of alcohol in which long term memory creation is impaired. ... Korsakoffs syndrome (Korsakoffs psychosis, amnesic-confabulatory syndrome), is a degenerative brain disorder caused by the lack of thiamine (vitamin B1) in the brain. ... Look up confabulation in Wiktionary, the free dictionary. ...

[edit] 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. Anterograde amnesia features in the movies Memento, Clean Slate, and 50 First Dates, and 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, a character is kidnapped and has amnesia upon returning. The TV show John Doe is based on an amnesiac who mysteriously appears in the middle of a sea. In The Bourne Identity, the main character has retrograde amnesia. In the 1966 motion picture Mr. Buddwing, the protagonist enters an amnesial 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 the Marvel Comics series X-Men, Wolverine, one of the main characters, has retrograde amenesia due to brainwashing. In Season 4 of Smallville, Clark has his memory wiped by a Summerholt patient. Global amnesia is a total loss of the memory. ... Anterograde amnesia is a form of amnesia, or memory loss, where new events are not transferred to long-term memory. ... Memento is a neo-noir–psychological thriller film written and directed by Christopher Nolan, adapted from his brother Jonathans short story Memento Mori. ... Released by MGM in 1994, it stars Dana Carvey and Valeria Golino. ... 50 First Dates is a 2004 romantic comedy starring Adam Sandler and Drew Barrymore and directed by Peter Segal. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... This article does not cite any references or sources. ... For other uses, see 24 (disambiguation). ... Lost is an Emmy Award and Golden Globe-winning American serial drama television series that follows the lives of plane crash survivors on a mysterious tropical island, after a passenger jet flying between Australia and the United States crashes somewhere in the South Pacific. ... This article does not cite any references or sources. ... The Bourne Identity is a 1980 spy fiction thriller by Robert Ludlum about an amnesiac who must discover who he is and why several different groups, including an assassin and the CIA, are trying to kill him. ... Retrograde amnesia is a form of amnesia where someone will be unable to recall events that occurred before the onset of amnesia. ... The Forgotten is a 2004 psychological thriller, directed by Joseph Ruben. ... Marvel Comics is an American comic book line published by Marvel Publishing, Inc. ... The X-Men are a group of comic book superheroes featured in Marvel Comics. ... For other uses, see Wolverine (disambiguation). ... Brainwashing (also known as thought reform or re-education) consists of any systematic effort aimed at instilling certain attitudes and beliefs in a person against his/her will, usually beliefs in conflict with the persons prior beliefs and knowledge. ... It has been suggested that Chloe Sullivan and Lionel Luthor be merged into this article or section. ...

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. Anastasia is an animated feature film produced and directed by Don Bluth and Gary Goldman at Fox Animation Studios, and was released on November 14, 1997 by Twentieth Century Fox. ...

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, a second concussion would have catastrophic consequences, a phenomenon known as Second Impact Syndrome. 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. A sitcom or situation comedy is a genre of comedy performance originally devised for radio but today typically found on television. ... Concussion, or mild traumatic brain injury (MTBI), is the most common and least serious type of traumatic brain injury. ... Mysterious Skin is California filmmaker Gregg Arakis eighth film. ... Gene Wolfe (born May 7, 1931, New York, New York) is an American science fiction and fantasy writer. ...

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 Noir, a girl named Kirika Yuumura loses her memory because the memories she had were too traumatic for her. Likewise, in both Madlax and Sukisyo, the main characters experienced amnesia because their pasts involve betraying someone dear to them. In all three of these cases, the characters went into an advanced state of shock once they gain their memories back; they adapted to their pasts in a homicidal fashion. In Loveless, the main character has no memories of the first ten or so years of his life, but 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. Though about a third of the way into the series, the characters Raito (or Light) and Misa in Death Note lose all memories of having been serial killers. This is actually a major improvement in their personalities and actions, as one might expect. There are countless other examples of this. Original run October 13, 1999 – January 19, 2000 No. ... Noir ), is a 26-episode anime television series produced in 2001 by the Bee Train animation studio and was licensed for American distribution by ADV Films. ... MADLAX ) is a 26-episode anime television series that was produced by the Bee Train animation studio. ... Suki na Mono wa Suki Dakara Shōganai! ), also known as Sukisho! is a light novel that has since expanded into a BL-anime-style video game, an anime series and OVA. The title translates into English as I like what I like, so it can`t be helped, or... Loveless is also a Manga and Anime series. ... Utawarerumono ) is the title of a fictional series mainly concerning wars and battles set in a primitive time. ... Spirited Away, originally known in Japan as Sen to Chihiro no Kamikakushi ), is an Academy Award winning 2001 film by the Japanese anime studio Studio Ghibli, written and directed by famed animator Hayao Miyazaki. ... Serialized in Weekly Shonen Jump Arena Komik Original run December 2003 – May 2006 No. ...

[edit] See also

• Betrayal Trauma
• Clive Wearing
• Emotion and memory
• False memory
• HM (patient)
• Mr. Nobody
• Doug Bruce

Betrayal, as a form of deception or dismissal of prior presumptions, is the breaking or violation of a presumptive social contract (trust, or confidence) that produces moral and psychological conflict within a relationship amongst individuals, between organizations or between individuals and organizations. ... Clive Wearing (born 1938) is a British musicologist, conductor, and keyboardist suffering from an acute and long lasting case of anterograde amnesia. ... Emotion can have a powerful impact on memory. ... For the novel, see False Memory (novel) It has been suggested that Synthetic memory be merged into this article or section. ... HM (also known as H.M. and Henry M., born 1926 in Connecticut) is an anonymous memory impaired patient who has been widely studied since the late 1950s and has been very important in the development of theories that explain the link between brain function and memory, and in the... Sywald Skeid (born Ciprian Skeid [1], and also known by various other names, including Philip Staufen, Georges Lecuit, Keith Ryan, Mike Jones, and Mr. ... Doug Bruce is the subject of Rupert Murrays 2006 documentary Unknown White Male. Bruce claims to suffer from amnesia. ...

[edit] References