Taken from wiki http://en.wikipedia.org/wiki/Amnesia
* Anterograde amnesia
* Traumatic amnesia
*Dissociative Amnesia
*Dissociative Fugue
*Posthypnotic amnesia
*Lacunar amnesia
*Childhood amnesia
*Transient Global Amnesia
*Source amnesia
*Memory distrust syndrome
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.
As you can see there are many types of memory problems, they are mainly due to either problems with encoding into LTM (long term memory) or the retreaval from LTM into the STM (short term memory) for useage. There are afew that I would like to look into further because I feel they have the most potential to produce ideas for a final piece of work. These are
Anterograde Amnesia
Retrograde Amnesia
Memory Distrust Syndrome
The "Blackout Phenomenon" (previously looked at as my first 2nd year project)
First I will look at Anterograde.
From the Wiki page I was able to find a paragraph about the symptoms from this type of amnisia.
In the case that the amnesia is drug-induced, it may be short-lived and patients can recover from it. In the other case, which has been studied extensively since the early 1970s, patients often have damage that is permanent, although some recovery is possible, depending on the nature of the pathophysiology. Usually, there remains some capacity for learning although it may be very elementary. In cases of pure anterograde amnesia, patients have recollections of events prior to the injury but cannot recall day-to-day information or new facts that were presented to them after the injury occurred.
In most cases of anterograde amnesia, patients lose declarative memory, or the recollection of facts, but they retain non-declarative memory, often called procedural memory. For instance, they are able to remember and in some cases learn how to do things such as talking on the phone or riding a bicycle, but they may not remember what they had eaten earlier that day for lunch. In addition, patients have a diminished ability to remember the temporal context in which objects were presented. Certain authors claim that the deficit in temporal context memory is more significant than the deficit in semantic learning ability.
Taken from http://medguides.medicines.org.uk/document.aspx?name=Anterograde%20amnesiaAnterograde amnesia: This is a specific memory difficulty. Patients have good memory of events that happened before the start of their illness, but have difficulty remembering events that have happened since the illness.
I found a case of the type of illness on this site http://www.damninteresting.com/?p=861
It explains how someone live with the illness, their daily experiences and how the illness effects him. Here are little paragraphs I found intresting when reading.
In contrast, anterograde amnesia does not deprive the sufferer of their identity, their past, or their skills; it merely prevents new memories from forming. As a consequence one's final memories are frozen in perpetuity, often accompanied by a constant sensation that one has just awoken from an "unconscious" state which filled the intervening time.
Again we see referances to sleep and this idea of ones identity, I like this idea of freezing. I think this works well with my possiable use of photography when working on my ideas. The text then goes on to explain that from a young age "henry" had seizures every few minuates which left him unconsous. Doctors worked on the mans temproal lobe in order to stop or slow the gap between the seizures.
However the surgeon was distressed to discover that the removal of the hippocampi had stripped Henry of his ability to form new memories.
He is stricken with renewed grief every time he learns of his mother's death. The grief is short-lived, however, as the substance of the news soon slips from the feeble grasp of his "working memory."
Similar cases of anterograde amnesia have appeared over the years, often caused by Korsakoff's Syndrome, a thiamine (vitamin B1) deficiency brought on by chronic alcoholism, malnutrition, eating disorders, or poisoning.
From reading this I have found out that this type of illness is caused by the damaging or removal of the hippocampus which is used to convert STM into LTM. Here is a long but very intesting paragraph taken from the same site again. It tells us that although people with the illness dont seamed to remember events they are able to learn tasks over time, even if the people were experiencing them for the first time. There is also a sketch by "henry or H.M" which shows the actual living space of HM and then his interpritation of the space from his memory (which appently isn't able to encode new memories)
Though anterograde amnesiacs are blocked from storing new information, researchers were astonished to discover that subjects are nonetheless capable of mastering new and complex tasks over time. Subjects who repeatedly practice skills such as backwards writing or guitar-playing can demonstrate measurable improvement, though in each instance the subject believes that he or she is attempting the task for the first time. This insight cast serious doubt upon the long-held belief that all memory is stored in a common mental reservoir. It also demonstrated that procedural memory– the "how to" memory of motor skills– is not governed by the exact same circuitry as episodic memory (autobiographical events) and semantic memory (general knowledge and facts). A diagram of one of Henry M's living spaces, and his depiction of it three years after moving out.Additionally, some patients have experienced the Tetris Effect hours or days after playing the game during experiments; they describe vivid dreams of falling Tetris shapes though they possess no conscious memory of the game's existence.
I enjoyed reading this artical as it had a character and short stories about HM which made it intesting to read. At the end it referances to 'Memento'. An I have learnt about 'reverse chronology' which I knew myself was in the film but not the name. HM was one of the first people scienctists looked a to learn about this form of animisa.
http://www.npr.org/templates/story/story.php?storyId=7584970
An audio clip of HM can be found from research news. It explains the artical as in audio which interviews with HM where scientists ask him questions. It also goes into more depth about the sciences of memories, which I have already looked at.
Dr Corkin's (the doctor who spent decades studying with HM) paper can be found at this link
http://homepage.mac.com/sanagnos/corkin2002.pdf.
After reading the paper I have found out that the removed size of the hippocampi is related to the servarity of the amnisa. Also memory is encoded with this type of amnisa its problems with its retreaval which causes the problems. People with this problem do not loose there idenity like with other illness's, they have a sence of who they are, due to them being able to remember past events.
Searching the links at the bottom of the page I discovered another story from a broadsheet about an extreme case of amnisa which linked more than one type. http://observer.guardian.co.uk/magazine/story/0,11913,1394684,00.html
Deborah describes it, 'melts like snow, leaving not a trace'
I really enjoyed this idea of the memory being snow, a solid stable object at its current state but eventualy destined to be reduced to water, not a trace of what it once was. I really should think of things like this to show memory, as memories are hard to show for what they are.
How do we know what we are seeing is a memory or reality?
The artical referances to 'Hades' rivers from greek mythology which one of the rivers was forgetfulness and memory.
http://en.wikipedia.org/wiki/Lethe
http://en.wikipedia.org/wiki/Mnemosyne
Dead souls drank from Lethe so they would not remember their past lives when reincarnated. Initiates were encouraged to drink from the river Mnemosyne when they died, instead of Lethe.
further reading of the artical I noticed something which I had overlooked. This was the way that people with this problem of recalling information from LTM recorded there events. Like with the film 50 First Dates the main character keeps a diary of events she wants to remember and how she felt at that time. This is something I could look at further, the methord of recording events, and if changing these would effect how a person would look at the world.
What if you could 'program' a persons idenity by writing their memories for them?
Here is a paragraph from the artical which shows the diary of someone with amnisia.
His diaries show his desperation and also the articulate man he had so recently been. '7.46am: I wake for the first time. 7.47am: This illness has been like death till NOW. All senses work. 8.07am: I AM awake. 8.31am: Now I am really, completely awake. 9.06am: Now I am perfectly, overwhelmingly awake. 9.34am: Now I am superlatively, actually awake.'
This was taken later down it talks about the soul and that the deisease has taken away his soul. This is another thing I could look at although it would largely get confused with death.
Neurologist Oliver Sacks asks in his book The Man Who Mistook His Wife for a Hat, 'What sort of life (if any), what sort of world, what sort of self, can be preserved in a man who has lost the greater part of his memory and, with this, his past, and his moorings in time?' Of a patient with similar symptoms to Clive, he writes: 'One tended to think of him, instinctively, as a spiritual casualty - a lost soul. Was it possible that he had really been "de-souled" by the disease?'
I looked at the tetris effect quickly after reading about HM and found that people with retrograde amnisa dreapt of tetris shapes after playing the game alot. This again links somehow with being able to recall memories inside a dream but not while in a conouse awakened state.
http://en.wikipedia.org/wiki/Tetris_effect
I have just been looking on youtube and found a documentry about Clive Wearing.
Part 1a
Part 1b
Part 2a
Part 2b
Part 2c
Part 2d
There is a newer documenty which I found a 9min clip of on youtube.
So what is Retrograde Amnesia?
Taken from wiki http://en.wikipedia.org/wiki/Retrograde_amnesia
Retrograde amnesia is a form of amnesia where someone will be unable to recall events that occurred before the onset of amnesia.
Retrograde amnesia is caused by trauma that results in brain injury. Critical details of the physical changes in the brain that cause retrograde amnesia are still unknown. Retrograde amnesia is often temporally graded, meaning that remote memories are more easily accessible than events occurring just prior to the trauma.
Both Anterograde Amnesia and Retrograde Amnesia often occur together and the Clive Wearing case is one of the worst examples of this.
A documentry film which aired on channel 4 called 'Unknown White Male' explored how a man woke up on the subway with a headache and had no recolection of himself or his past. He was able to form new memories but everything sentimental to him was gone. He had no idea who he was, no idenity. Here is the youtube clip of the trailer for Unknown White Male.
Taken from http://unknownwhitemale.co.uk/medical/amnesia.php I found this to be intresting in how it is seen to be "convenient" to loose your memory. This makes me think back to the memory pill fiction I found and look at some of the questions and also why it is important for us to keep our memories. I could see it being convenient if the person has a 'bad' life and wanted a fresh start.The site also looks at verious movies which are based around the theme of memory.
It can be very convenient to loose your memory. We all have things in our past that we'd like to forget; most of us, at some time or other, have entertained the fantasy of having a second chance at life, of wiping the slate clean and starting again. We only have someone's word for it that they can't remember who they are, and as extreme amnesia may not have an obvious or identifiable cause and tends not to affect learned skills like language use, car driving, or piano playing, it can often seem implausible even when it's completely genuine.
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