Amnesia Classification and external resources
ICD-10	R41.3
ICD-9	780.9, 780.93
MeSH	D000647

Amnesia (from Greek Ἀμνησία) is a condition in which memory is disturbed. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings R00-R69 - Symptoms and Signs (R00-R09 Circulatory and Respiratory systems ( Abnormalities of Heart beat The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases 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 Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly In Psychology, memory is an organism's ability to store retain and subsequently retrieve information 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. Transient global amnesia (TGA is an anxiety-producing temporary loss of Short-term memory. ^[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. The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United The hippocampus is a part of the Forebrain, located in the medial Temporal lobe. ^[2] 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.

Contents 1 Forms of amnesia 2 Types/causes of amnesia 3 Amnesia in fiction 4 See also 5 References

Forms of amnesia

• In anterograde amnesia, new events contained in the immediate memory are not transferred to the permanent as long-term memory. Anterograde amnesia is a loss of Memory of what happens after the event that caused the Amnesia; it is different from Retrograde amnesia, where memories 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. Retrograde amnesia is a form of Amnesia where someone will be unable to recall events that occurred before the onset of amnesia

The terms are used to categorize patterns of symptoms, rather than to indicate a particular cause or etiology. Etiology (alternatively aetiology, aitiology) is the study of causation. 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. Episodic memory is the Memory of unique personal experiences ( Events Times Places associated Emotions and other conception-based Declarative memory is the aspect of human Memory that stores Facts It is so called because it refers to memories that can be consciously discussed or declared The temporal lobes are parts of the cerebrum that are involved in speech, Memory, and Hearing. The hippocampus is a part of the Forebrain, located in the medial Temporal lobe.

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).

Types/causes of amnesia

Post-traumatic amnesia is generally due to a head injury (e. Post-traumatic amnesia ( PTA) is a state of confusion that occurs immediately following a Traumatic brain injury (TBI in which the injured person is Traumatic brain injury (TBI also called intracranial injury, occurs when Physical trauma injures the Brain. g. a fall, a 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 results 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. The sufferer may also lose knowledge of who people are, they may remember events, but will not remember faces of them.

• 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. Psychogenic amnesia, also known as functional or dissociative amnesia, is a disorder characterized by abnormal memory functioning in the absence of structural Dissociative Amnesia can include:

• Repressed memory is a theory referring to the supposed inability to recall information, usually about stressful or traumatic events in persons' lives, such as a violent attack or rape. Psychogenic amnesia, also known as functional or dissociative amnesia, is a disorder characterized by abnormal memory functioning in the absence of structural Repressed memory is a theoretical concept used to describe a significant Memory, usually of a traumatic nature that has become unavailable for recall also called 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. A fugue state is a state of mind characterized by abandonment of personal Identity, along with the Memories, Personality and other identifying 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. The Merck Manual of Diagnosis and Therapy, often called simply The Merck Manual, is the world's best-selling medical textbook " ^[3] 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. Hypnosis is often thought to be a wakeful state of focused attention and heightened suggestibility with diminished peripheral awareness

• Lacunar amnesia is the loss of memory about one specific event. 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. Childhood Amnesia is the common inability of Adults to remember the earliest years of their 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. Sigmund Freud (ˈziːkmʊnt ˈfʁɔʏt born Sigismund Shlomo Freud (May 6 1856 &ndash September 23 1939 was an Austrian Psychiatrist who founded Language development is a process that starts early in human life when a person begins to acquire Language by learning it as it is spoken and by mimicry

• Transient global amnesia is a well-described medical and clinical phenomenon. Transient global amnesia (TGA is an anxiety-producing temporary loss of Short-term memory. This form of amnesia is distinct in that abnormalities in the hippocampus can sometimes be visualized using a special form of magnetic resonance imaging of the brain known as diffusion-weighted imaging (DWI). The hippocampus is a part of the Forebrain, located in the medial Temporal lobe. Diffusion MRI is a Magnetic resonance imaging (MRI method that produces In vivo images of biological tissues weighted with the local microstructural 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. Source Amnesia is an Explicit memory disorder in which someone can recall certain information but not where or how it was obtained

• 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. 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

• Blackout phenomenon can be caused by excessive short-term alcohol consumption, with the amnesia being of the anterograde type. A blackout is a phenomenon caused by the intake of alcohol in which long term memory creation is impaired

• Korsakoff's syndrome can result from long-term alcoholism or malnutrition. Korsakoff's syndrome or "Korsakov's syndrome" ( Korsakoff's psychosis, amnesic-confabulatory syndrome) is a brain disorder caused by the lack of thiamine It 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. Confabulation, also known as false memory is the confusion of Imagination with Memory, and/or the confusion of true memories with false memories

• Drug-induced amnesia is intentionally caused by injection of an amnesiac drug to help a patient forget surgery or medical procedures, particularly those which are not performed under full anesthesia. Such drugs are also referred to as "premedicants. " Memories of the short time frame in which the procedure was performed are permanently lost; otherwise, memory is not affected.

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. Global amnesia is a total loss of the memory It is an extremely rare form of Amnesia, and is often a defense mechanism of the brain after a traumatic event occurs

• In The Bourne Identity (both the book and the movie), main character Jason Bourne has retrograde amnesia. The Bourne Identity is a 1980 Spy fiction thriller novel by Robert Ludlum about a retrograde amnesiac who must discover who he is and The Bourne Identity is a 2002 Spy film loosely based on Robert Ludlum 's novel of the same name. Retrograde amnesia is a form of Amnesia where someone will be unable to recall events that occurred before the onset of amnesia
• In the Marvel Comics series X-Men, Wolverine, one of the main characters, has retrograde amenesia due to brainwashing. Marvel Comics is an American comic book company owned by Marvel Publishing Inc The X-Men is a team of fictional Superhero characters in Comic books published by Marvel Comics. Brainwashing (also known as Thought reform or as Re-education) consists of any effort aimed at instilling certain attitudes and Beliefs
• Anterograde amnesia features in the movies:
  • Memento
  • Clean Slate
  • Finding Nemo
  • 50 First Dates
• Lacunar amnesia features in the movie Eternal Sunshine of the Spotless Mind. Anterograde amnesia is a loss of Memory of what happens after the event that caused the Amnesia; it is different from Retrograde amnesia, where memories Memento is a Psychological thriller Film written and directed by Christopher Nolan, adapted from his brother Jonathan 's short Clean Slate is a film released by MGM in 1994 It stars Dana Carvey and Valeria Golino. Finding Nemo is a 2003 computer-animated American Family film. 50 First Dates is a 2004 Romantic comedy starring Adam Sandler and Drew Barrymore and directed by Peter Segal. Lacunar amnesia is the loss of Memory about one specific event Eternal Sunshine of the Spotless Mind is a 2004 American drama and Romantic comedy by French director Michel
• In the first season of 24, a prominent character has dissociative amnesia. 24 is an Emmy and Golden Globe award-winning American action Drama Television series.
• In the first season of Lost, Claire Littleton is kidnapped and has amnesia upon returning. Lost is an Emmy and Golden Globe award-winning American serial drama television series. Claire Littleton is a Fictional character on the ABC television series Lost, played by Australian actress Emilie de Ravin
• In season two of MacGyver, a narrow escape from a gang of international terrorists leaves Mac without his memories but with his ingenuity intact. MacGyver is an American Adventure Television series, produced in the United States and Canada, about the laid-back
• The TV show John Doe is based on an amnesiac who mysteriously appears in the middle of a sea. John Doe is an American Television series that aired on The Fox Network during the 2002–2003 TV season
• In the TV show Heroes, one of the characters nicknamed The Haitian, can cause various degrees of amnesia to others with his powers. Heroes is an American Science fiction television drama series created by Tim Kring, which premiered on NBC on September The Haitian is a Fictional character on the NBC television series Heroes, portrayed by Haitian actor Jimmy Jean-Louis. 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. Peter Petrelli, portrayed by Milo Ventimiglia, is a Fictional character on the NBC Science fiction drama series Heroes " Four Months Later " is the first episode of the second season of the NBC Science fiction drama series Heroes. New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world
• 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. The Forgotten is a 2004 American Psychological thriller Film, directed by Joseph Ruben and starring

• 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. Destination Moon ( Objectif Lune) is the sixteenth of The Adventures of Tintin, a series of classic comic-strip albums written and illustrated The Adventures of Tintin (Les Aventures de Tintin is a series of Comic strips created by Belgian artist Hergé, the pen name of Georges Remi Professor Cuthbert Calculus ( Professeur Tryphon Tournesol, literally Professor Tryphonius Sunflower or Tryphonius Litmus Paper) is a Fictional
• 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 Academy Award nominated American animated feature Musical film produced and directed by Don Bluth and
• 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. Samantha Who? is an American Emmy -winning television sitcom which premiered on October 15 2007 on ABC.
• Dissociative Amnesia plays a critical role in the novel Mysterious Skin and movie of the same name. Mysterious Skin is a 2004 film directed by California Filmmaker Gregg Araki.
• 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. 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. is a Japanese animated Television series created by director Kazuyoshi Katayama and designer Keiichi Sato for Sunrise Studios
  • 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. is a Japanese animated Television series directed by Koichi Mashimo and written by Ryoe Tsukimura. is a 26-episode Japanese Anime Television series produced in 2004 by the Bee Train animation studio Kirika Yuumura (夕叢霧香 Yūmura Kirika) is one of the two Protagonists in the 26-episode Anime series Noir created by Bee Train Madlax (マドラックス Madorakkusu) is one of the two Protagonists of the 26-episode Anime Television series Madlax is one of the two protagonists of the 26-episode Anime Television series Madlax produced in 2004 by the Bee Train
  • In Sukisyo, the main characters experienced amnesia because their pasts involve betraying someone dear to them. also known as Sukisho! or Sukisyo! is a Light novel that has since expanded into a BL - anime-style Video game, an Anime
  • In Loveless, the main character has no memories of the first ten or so years of his life and never regains them. Loveless is a Shōnen-ai fantasy Manga by Yun Kouga. It is currently serialized in the monthly magazine Monthly Comic Zero
  • In Utawarerumono the main character has no memory before the series begins. is the title of a series about a fictional world in the style of feudal Japan He does not exactly get them back, save for in short bursts, showing several past homicides. These endeavors, with time, become accepted.
  • In Mobile Suit Gundam Wing, Trowa Barton, pilot of XXXG-01H Gundam Heavyarms suffers from amnesia for a brief period after he destroys his gundam during a fight against a deranged Quatre Winner who was piloting and under the influence of XXXG-00W0 Wing Gundam Zero at the time. Mobile Suit Gundam Wing, known in Japan as, was an anime series in the Mecha genre and is one of the alternate universe Gundam series is one of the five leading characters from the Anime Mobile Suit Gundam Wing. XXXG-01H Gundam Heavyarms (also referred to as Gundam Zero-Three) is one of the five fictional Gundam mobile suits appearing in the Mobile Suit Gundam Wing a Fictional character, is one of the central characters in the Anime series Mobile Suit Gundam Wing and its various spinoffs The XXXG-00W0 Wing Gundam Zero (commonly abbreviated as either Wing Zero or simply Zero) is one of the fictional Gundam mobile suits appearing in the Mobile
  • In Spirited Away, the character Haku forgot everything about his life as a river spirit, along with his name, which restricted his freedom. is a 2001 film by the Japanese Anime studio Studio Ghibli, written and directed by famed animator Hayao Miyazaki.
• In the Japanese Drama, Hana Yori Dango (Boys Over Flowers), the main character, Domyouji, has amnesia in the second season. is a Japanese Shōjo manga series by Yoko Kamio. It was serialized in the bi-weekly anthology magazine Margaret, which is aimed at high-school-age
• In the RPG Knights of the Old Republic global amnesia fits prominently into a midgame plot twist. A role-playing game ( RPG; often roleplaying game) is a Game in which the participants assume the roles of Fictional characters. Global amnesia is a total loss of the memory It is an extremely rare form of Amnesia, and is often a defense mechanism of the brain after a traumatic event occurs
• In Mario & Luigi: Superstar Saga, Bowser gets amnesia. Mario & Luigi Superstar Saga, known in Japan as, is a role-playing game developed by AlphaDream and published by Nintendo for the Game
• 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. Video Games See also [[List of games featuring Sonic the Hedgehog]] Nearly all games in the series feature a teenage hedgehog named "Sonic the Hedgehog" is a character from the ''Sonic the Hedgehog'' series, an artificially created life form
• 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. Regarding Henry is a 1991 film directed by Mike Nichols, starring Harrison Ford and Annette Bening. Harrison Ford (born July 13, 1942) is an Academy Award - and BAFTA -nominated as well as Golden Globe -winning American
• 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. NetHack is a single-player Roguelike computer game originally released in 1987.
• In the Nintendo DS game The World Ends With You, the character Neku forgets all information about himself besides his name. The World Ends with You, released in Japan as, is an Action role-playing game developed by Square Enix 's Kingdom Hearts After completing the first week of the game, Neku will regain his memory, but will still be missing the memory of how he died.

In movies and television, particularly sitcoms and soap operas, it is often depicted that a second hit to the head (similar to the first one) cures the amnesia. A soap opera is an ongoing episodic work of Fiction, usually broadcast on Television or Radio. 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. Cognition is a concept used in different ways by different disciplines but is generally accepted to mean the process of awareness or thought Cerebral edema (cerebral oedema in British English) is an excess accumulation of water in the intracellular and/or extracellular spaces of the Brain. Second-impact syndrome ( SIS) is an extremely rare condition in which the brain swells rapidly and catastrophically after a person suffers a second Concussion before

See also

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

References

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