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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
Many forms of amnesia fix themselves without being treated. However, there are a few ways to cope with memory loss if that is not the case. One of these ways is cognitive or occupational therapy. In therapy, amnesiacs will develop the memory skills they have and try to regain some they have lost by finding which techniques help retrieve memories or create new retrieval paths. This may also include strategies for organizing information to remember it more easily and for improving understanding of lengthy conversation.
Another coping mechanism is taking advantage of technological assistance, such as a personal digital device to keep track of day-to-day tasks. Reminders can be set up for appointments, when to take medications, birthdays and other important events. Many pictures can also be stored to help amnesiacs remember names of friends, family and co-workers. Notebooks, wall calendars, pill reminders and photographs of people and places are low-tech memory aids that can help as well.
While there are no medications available to treat amnesia, underlying medical conditions can be treated to improve memory. Such conditions include but are not limited to low thyroid function, liver or kidney disease, stroke, depression, bipolar disorder and blood clots in the brain. Wernicke–Korsakoff syndrome involves a lack of thiamin and replacing this vitamin by consuming thiamin-rich foods such as whole-grain cereals, legumes (beans and lentils), nuts, lean pork, and yeast. Treating alcoholism and preventing alcohol and illicit drug use can prevent further damage, but in most cases will not recover lost memory.
Although improvements occur when patients receive certain treatments, there is still no actual cure remedy for amnesia so far. To what extent the patient recovers and how long the amnesia will continue depends on the type and severity of the lesion.
Treatment for confabulation is somewhat dependent on the cause or source, if identifiable. For example, treatment of Wernicke–Korsakoff syndrome involves large doses of vitamin B in order to reverse the thiamine deficiency. If there is no known physiological cause, more general cognitive techniques may be used to treat confabulation. A case study published in 2000 showed that Self-Monitoring Training (SMT) reduced delusional confabulations. Furthermore, improvements were maintained at a three-month follow-up and were found to generalize to everyday settings. Although this treatment seems promising, more rigorous research is necessary to determine the efficacy of SMT in the general confabulation population.
Approaches used to treat those who suffer from anterograde amnesia often use interventions which focus on compensatory techniques, such as beepers, written notes, diaries or through intensive training programs involving the active participation of the individual concerned, along with their supporting network of family and friends.
In this perspective, environmental adaptation techniques are used, such as the compensatory technique education to training (exercise), organizational strategies, visual imagery and verbal labeling. In addition, other techniques are also used in rehabilitation, such as implicit tasks, speech and mnemotechnic methods.
So far, it has been proven that education techniques of compensatory strategies for memory disorders are effective in individuals with minor traumatic brain injuries. In moderately or severely injured individuals, effective interventions are those appealing to external aids, such as reminders in order to facilitate particular knowledge or skill acquisition. Reality orientation techniques are also considered; Their purpose is to enhance orientation using stimulation and repetition of the basic orientation information. These techniques are regularly applied in populations of patients primarily presenting with dementia and head-injured patients.
Treatment for topographical disorientation has been achieved through a case by case basis. Prognosis is largely dependent on the organic cause. Neuropsychological assessment followed by an assessment of unaffected cognitive abilities can be employed in therapy. Treatment for recovering navigational skills require strengthening unaffected navigational strategies to bypass defective ones.
One subsequent human study found no effects of vasopressin on memory. The nonsignificant results were attributed to the study's many potential flaws, particularly its small sample size, the inability of vasopressin to penetrate the blood brain barrier when administered as a nasal spray, inadequate dosing and differences in severity of head injury between the samples. However, Eames et al. (1999) found statistically significant improvements on several tests of memory with the use of a vasopressin nasal spray, with no reported ill effects. Although the degree of improvement was mild, and it could be attributed to numerous other factors of the rehabilitative program, the lack of any ill effects suggests that vasopressin is, at the least, a possible enhancement for a treatment regimen.
Amnesia can result from a side-effect of prescription or non-prescription drugs. Both substance use and alcohol can cause both long-term and short-term memory loss, resulting in blackouts.
The most commonly used group of prescription drugs which can produce amnesia are benzodiazepines, especially if combined with alcohol, however, in limited quantities, triazolam (Halcion) is not associated with amnesia or memory impairment.
When someone is suffering from RA, their memory cannot be recovered from simply being told personal experiences and their identity. This is called reminder effect or reminder treatment. The reminder effect consists of re-exposing the patient to past personal information, which cannot reverse RA. Thus, reminding the patient details of their life has no scientific bearings on recovering memory. Fortunately, memory can be and usually is recovered due to spontaneous recovery and plasticity.
Early research pointed to vasopressin as a potential treatment for improving the memory of patients living with post-traumatic amnesia (PTA). Lysine vasopressin, a modified form of the vasopressin molecule, had positive effects on memory when administered by injection to patients with amnesia resulting from traumatic brain injury and Korsakoff's syndrome. Subsequent animal studies with rats found similar results, particularly in aversion and avoidance learning tasks. Rats lacking adequate vasopressin, either due to genetic defect or hypophysectomy (surgical removal of the pituitary gland), exhibited significant improvements in memory and learning functions when exogenous vasopressin was administered. Particularly encouraging was the finding that a short treatment period produced long-lasting improvements, in both humans and rats. However, the animal models of PTA are highly limited, as the dimension of self-awareness and orientation is almost impossible to model adequately. PTA in animals, especially rats, is often observed post-trauma (commonly post-surgery), but it is often only measured in terms of impaired learning or unusual behavior.
Confabulations can also be detected using a free recall task, such as a self-narrative task. Participants are asked to recall stories (semantic or autobiographical) that are highly familiar to them. The stories recalled are encoded for errors that could be classified as distortions in memory. Distortions could include falsifying true story elements or including details from a completely different story. Errors such as these would be indicative of confabulations.
It was once assumed that anyone suffering from Korsakoff's syndrome would eventually need full-time care. This is still often the case, but rehabilitation can help regain some, albeit often limited, level of independence. Treatment involves the replacement or supplementation of thiamine by intravenous (IV) or intramuscular (IM) injection, together with proper nutrition and hydration. However, the amnesia and brain damage caused by the disease does not always respond to thiamine replacement therapy. In some cases, drug therapy is recommended. Treatment of the patient typically requires taking thiamine orally for 3 to 12 months, though only about 20 percent of cases are reversible. If treatment is successful, improvement will become apparent within two years, although recovery is slow and often incomplete.
As an immediate form of treatment, a pairing of IV or IM thiamine with a high concentration of B-complex vitamins can be administered three times daily for period of 2–3 days. In most cases, an effective response from patients will be observed. A dose of 1 gram of thiamine can also be administered to achieve a clinical response. In patients who are seriously malnourished, the sudden availability of glucose without proper bodily levels of thiamine to metabolize is thought to cause damage to cells. Thus, the administration of thiamine along with an intravenous form of glucose is often good practice.
Treatment for the memory aspect of Korsakoff's syndrome can also include domain-specific learning, which when used for rehabilitation is called the method of vanishing cues. Such treatments aim to use patients' intact memory processes as the basis for rehabilitation. Patients who used the method of vanishing cues in therapy were found to learn and retain information more easily.
People diagnosed with Korsakoff's are reported to have a normal life expectancy, presuming that they abstain from alcohol and follow a balanced diet. Empirical research has suggested that good health practices have beneficial effects in Korsakoff's syndrome.
Clinically induced RA has been achieved using different forms of electrical induction.
- Electroconvulsive therapy (ECT), used as a depression therapy, can cause impairments in memory. Tests show that information of days and weeks before the ECT can be permanently lost. The results of this study also show that severity of RA is more extreme in cases of bilateral ECT rather than unilateral ECT. Impairments can also be more intense if ECT is administered repetitively (sine wave simulation) as opposed to a single pulse (brief-pulse stimulation).
- Electroconvulsive shock (ECS): The research in this field has been advanced by using animals as subjects. Researchers induce RA in rats, for example, by giving daily ECS treatments. This is done to further understand RA.
Individual therapy may be best suited to treat the individual's delusions. Persistence is needed in establishing a therapeutic empathy without validating the patient’s delusional system or overtly confronting the system. Cognitive techniques that include reality testing and reframing can be used. Antipsychotics and other therapeutic drugs have been used with relative success.
When there is damage to just one side of the MTL, there is opportunity for normal functioning or near-normal function for memories. Neuroplasticity describes the ability of the cortex to remap when necessary. Remapping can occur in cases like the one above, and, with time, the patient can recover and become more skilled at remembering. A case report describing a patient who had two lobectomies – in the first, doctors removed part of her right MTL first because of seizures originating from the region, and later her left because she developed a tumor – demonstrates this. This case is unique because it is the only one in which both sides of the MTL were removed at different times. The authors observed that the patient was able to recover some ability to learn when she had only one MTL, but observed the deterioration of function when both sides of the MTL were afflicted. The reorganization of brain function for epileptic patients has not been investigated much, but imaging results show that it is likely.
The DSM-IV-TR states that the fugue may have a duration from days to months, and recovery is usually rapid. However, some cases may be refractory. An individual usually has only one episode.
Memory distrust syndrome is a condition coined by Gísli Guðjónsson and James MacKeith in 1982, in which an individual doubts the accuracy of their memory concerning the content and context of events of which they have experienced. Since the individual does not trust their own memory, they will commonly depend on outside sources of information rather than using their ability for recollection. Some believe that this may be a defense or coping mechanism to a preexisting faulty memory state such as Alzheimer's disease, amnesia, or possibly dementia.
The condition is generally considered to be related to source amnesia, which involves the inability to recall the basis for factual knowledge. The main difference between the two is that source amnesia is a lack of knowing the basis of knowledge, whereas memory distrust syndrome is a lack of believing the knowledge that exists. The fact that an individual lacks the trust in their own memory implies that the individual would have a reason or belief that would prevent them from the trust that most of us have in our recollections. Cases concerning memory distrust syndrome have led to documented false confessions in court cases.
The verbal fluency test is a widely and commonly used test to assess for frontal lobe dysfunction in patients.
- Procedure:
Participants are asked to generate words beginning with letters that had previously been introduced to them (e.g.: generate a word beginning with 'A' or 'R'). They are given three 1-min trials (one trial per letter). The goal is to say as many different words possible that begin with the given letter.
- Results:
The Verbal fluency test can assess for damage in the prefrontal lobes, which has been associated with patients suffering from source amnesia. Patients with frontal lobe disorder have trouble putting verbal items into a proper sequential order, monitor personal behaviors as well as a deficient judgment in recency. All of these behaviors are required for the proper recall of the source of a memory.
Source amnesia is the inability to remember where, when or how previously learned information has been acquired, while retaining the factual knowledge. This branch of amnesia is associated with the malfunctioning of one's explicit memory. It is likely that the disconnect between having the knowledge and remembering the context in which the knowledge was acquired is due to a dissociation between semantic and episodic memory – an individual retains the semantic knowledge (the fact), but lacks the episodic knowledge to indicate the context in which the knowledge was gained.
Memory representations reflect the encoding processes during acquisition. Different types of acquisition processes (e.g.: reading, thinking, listening) and different types of events (e.g.: newspaper, thoughts, conversation) will produce mental depictions that perceptually differ from one another in the brain, making it harder to retrieve where information was learned when placed in a different context of retrieval. Source monitoring involves a systematic process of slow and deliberate thought of where information was originally learned. Source monitoring can be improved by using more retrieval cues, discovering and noting relations and extended reasoning.
The main symptom of memory distrust syndrome is the lack of belief in one's own memory, however this comes with the side effect of using outside sources for information. The individual may have their own memory, but will readily change it depending on chosen outside sources. The memories that they have may be correct, but due to their distrust they will still alter their belief of what is true if contrary information is suggested.
For example, a person has a memory of a house and recalls it to be white. Then, a trusted family member begins talking with them and suggests that it was red instead. The afflicted individual will then believe the house was red despite their recollection of it being white. It is unknown if the person's memory of the house is permanently altered; however, they will say that the house was red regardless of the memory's condition.
Also, this does not necessarily allow for confabulatory memory fabrication. Currently it is not believed that an afflicted individual will readily believe an outside source on a memory of which the person is not involved, such as a randomly shared story. This further suggests that memory distrust syndrome solely alters the individual's currently retrievable memories, and not randomized information.
A false memory is the psychological phenomenon where a person recalls something that did not happen. False memory is often considered in legal cases regarding childhood sexual abuse. This phenomenon was initially investigated by psychological pioneers Pierre Janet and Sigmund Freud. Freud wrote "The Aetiology of Hysteria", where he discussed repressed memories of childhood sexual trauma in their relation to hysteria. Elizabeth Loftus has, since her debuting research project in 1974, been a lead researcher in memory recovery and false memories. False memory syndrome recognizes false memory as a prevalent part of one's life in which it affects the person's mentality and day-to-day life. False memory syndrome differs from false memory in that the syndrome is heavily influential in the orientation of a person's life, while false memory can occur without this significant effect. The syndrome takes effect because the person believes the influential memory to be true. However, its research is controversial and the syndrome is excluded from identification as a mental disorder and, therefore, is also excluded from the "Diagnostic and Statistical Manual of Mental Disorders". False memory is an important part of psychological research because of the ties it has to a large number of mental disorders, such as PTSD.
Amnesia is a deficit in memory caused by brain damage, disease, or psychological trauma. Amnesia can also be caused temporarily by the use of various sedatives and hypnotic drugs. The memory can be either wholly or partially lost due to the extent of damage that was caused. There are two main types of amnesia: retrograde amnesia and anterograde amnesia. Retrograde amnesia is the inability to retrieve information that was acquired before a particular date, usually the date of an accident or operation. In some cases the memory loss can extend back decades, while in others the person may lose only a few months of memory. Anterograde amnesia is the inability to transfer new information from the short-term store into the long-term store. People with this type of amnesia cannot remember things for long periods of time. These two types are not mutually exclusive; both can occur simultaneously.
Case studies also show that amnesia is typically associated with damage to the medial temporal lobe. In addition, specific areas of the hippocampus (the CA1 region) are involved with memory. Research has also shown that when areas of the diencephalon are damaged, amnesia can occur. Recent studies have shown a correlation between deficiency of RbAp48 protein and memory loss. Scientists were able to find that mice with damaged memory have a lower level of RbAp48 protein compared to normal, healthy mice. In people suffering with amnesia, the ability to recall "immediate information" is still retained, and they may still be able to form new memories. However, a severe reduction in the ability to learn new material and retrieve old information can be observed. Patients can learn new procedural knowledge. In addition, priming (both perceptual and conceptual) can assist amnesiacs in the learning of fresh non-declarative knowledge. Amnesic patients also retain substantial intellectual, linguistic, and social skill despite profound impairments in the ability to recall specific information encountered in prior learning episodes. The term is ; .
Before delirium treatment, the cause must be established. Medication such as antipsychotics or benzodiazepines can help reduce the symptoms for some cases. For alcohol or malnourished cases, vitamin B supplements are recommended and for extreme cases, life-support can be used.
Fragmentation of memory is a memory disorder in when an individual is unable to associate the context of the memories to their autobiographical (episodic) memory. The explicit facts and details of the events may be known to the person (semantic memory). However, the facts of the events retrieve none of the effective and somatic elements of the experience. Therefore, the emotional and personal content of the memories can't be associated with the rest of the memory. Fragmentation of memory can occur for relatively recent events as well.
The impaired person usually suffers from physical damage to or underdevelopment of the hippocampus. This may be due to a genetic disorder or be the result of trauma, such as post-traumatic stress disorder. Brain dysfunction often has other related consequences, such as oversensitivity to some stimuli, impulsiveness, lack of direction in life, occasional aggressiveness, a distorted perception of oneself, and impaired ability to empathize with others, which is usually masked.
False memory syndrome (FMS) describes a condition in which a person's identity and relationships are affected by memories that are factually incorrect but that they strongly believe. Peter J. Freyd originated the term, which the False Memory Syndrome Foundation (FMSF) subsequently popularized. The term is not recognized as a psychiatric illness in any of the medical manuals, such as the ICD-10 or the DSM-5; however, the principle that memories can be altered by outside influences is overwhelmingly accepted by scientists.
False memories may be the result of recovered memory therapy, a term also defined by the FMSF in the early 1990s, which describes a range of therapy methods that are prone to creating confabulations. Some of the influential figures in the genesis of the theory are forensic psychologist Ralph Underwager, psychologist Elizabeth Loftus, and sociologist Richard Ofshe.
Amnesia is desirable during surgery, since a general anaesthetic should also give the person amnesia for the operation. Sedatives such as benzodiazepines, which are commonly used for anxiety disorders, can reduce the encoding of new memories, particularly in high doses (for example, prior to surgery in order for a person not to recall the surgery). Amnesiac drugs can be used to induce a coma for a child breathing using mechanical ventilation, or to help reduce intracranial pressure after head trauma.
Researchers are currently experimenting with drugs which induce amnesia in order to improve understanding of human memory, and develop better drugs to treat psychiatric disorders and memory related disorders. People with Alzheimer's disease and other forms of dementia are likely to benefit. By understanding the ways in which amnesia-inducing drugs interact with the brain, researchers hope to better understand the ways in which neurotransmitters aid in the formation of memory. By stimulating rather than depressing these neurotransmitters, memory may improve.
The use of a drug to erase traumatic or unwanted memories used to be referred to as "science fiction." Holmes et al. (2010) commented that the media misrepresented two recent studies as research on "erasing" traumatic memories, but showed the fear response associated with stressful memory could be greatly reduced whilst the factual memory of the trauma remained intact. Similarly, Brunet et al. (2008) found that the people with chronic Posttraumatic Stress Disorder who were treated with propranolol for a single day had a reduced response to existing trauma while retaining memory of the trauma. In the process of remembering, the memory needs to be restored in the brain. By introducing an amnesia-inducing drug during this process, the memory can be disrupted. While the memory remains intact, the emotional reaction is dampened, making the memory less overwhelming. Researchers believe this drug will help patients with post-traumatic stress disorder be able to better process the trauma without reliving the trauma emotionally. This has raised legal/ethical concerns should drugs be found to have altered the memory of traumatic events that occur in victims of crimes (e.g. rape), and whether it is therapeutically desirable to do so.
Childhood amnesia, also called infantile amnesia, is the inability of adults to retrieve episodic memories which are memories of specific events (times, places, associated emotions, and other contextual who, what, when, and where) before the age of 2–4 years, as well as the period before age 10 of which adults retain fewer memories than might otherwise be expected given the passage of time. The development of a cognitive self is also thought by some to have an effect on encoding and storing early memories. Some research has demonstrated that children can remember events from the age of 1, but that these memories may decline as children get older.
Most psychologists differ in defining the offset of childhood amnesia. Some define it as the age from which a first memory can be retrieved. This is usually at the age of 3 or 4, but it can range from 2 to 8 years. Changes in encoding, storage and retrieval of memories during early childhood are all important when considering childhood amnesia. Some other research shows differences between gender and culture, which is implicated in the development of language. Childhood amnesia is particularly important to consider in regard to false memories and the development of the brain in early years. Proposed explanations of childhood amnesia are Freud's trauma theory, neurological development, development of the cognitive self, emotion and language.