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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)
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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.
In psychiatry, confabulation (verb: confabulate) is a disturbance of memory, defined as the production of fabricated, distorted, or misinterpreted memories about oneself or the world, without the conscious intention to deceive. People who confabulate present incorrect memories ranging from "subtle alterations to bizarre fabrications", and are generally very confident about their recollections, despite contradictory evidence.
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.
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.
Source amnesia is not a rare phenomenon – everybody experiences it on a near daily basis as, for much of our knowledge, it is important to remember the knowledge itself, rather than its source. However, there are extreme examples of source amnesia caused by a variety of factors.
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.
Reduplicative paramnesia is the delusional belief that a place or location has been duplicated, existing in two or more places simultaneously, or that it has been 'relocated' to another site. It is one of the delusional misidentification syndromes and, although rare, is most commonly associated with acquired brain injury, particularly simultaneous damage to the right cerebral hemisphere and to both frontal lobes.
The term "reduplicative paramnesia" was first used in 1903 by psychiatrist Arnold Pick to describe a condition in a patient with suspected Alzheimer's disease who insisted that she had been moved from Pick's city clinic to one she claimed looked identical but was in a familiar suburb. To explain the discrepancy she further claimed that Pick and the medical staff worked at both locations.
In retrospect, however, the phenomenon has been found to have been first reported by the Swiss naturalist Charles Bonnet in 1788, who described a woman who also had what would now be called Cotard delusion. Henry Head and Paterson and Zangwill later reported on soldiers who had the delusional belief that their hospital was located in their home town, although in these cases traumatic brain injury seemed to be the most likely cause.
It wasn't until 1976 that serious consideration was given to the disorder, when three cases were reported by Benson and colleagues. Benson not only described striking reduplication syndromes in his patients, but also attempted to explain the phenomena in terms of the neurocognitive deficits also present in the patients. This was one of the first attempts to give a neuropsychological explanation for the disorder.
As described, Korsakoff 's syndrome usually follows or accompanies Wernicke's encephalopathy. If treated quickly, it may be possible to prevent the development of Korsakoff's syndrome with thiamine treatments. This treatment is not guaranteed to be effective and the thiamine needs to be administered adequately in both dose and duration. A study on Wernicke-Korsakoff's syndrome showed that with consistent thiamine treatment there were noticeable improvements in mental status after only 2–3 weeks of therapy. Thus, there is hope that with treatment Wernicke's encephalopathy will not necessarily progress to WKS.
In order to reduce the risk of developing WKS it is important to limit the intake of alcohol or drink in order to ensure that proper nutrition needs are met. A healthy diet is imperative for proper nutrition which, in combination with thiamine supplements, may reduce the chance of developing WKS. This prevention method may specifically help heavy drinkers who refuse to or are unable to quit.
The most effective method of preventing Korsakoff's syndrome is to avoid B vitamin/thiamine deficiency. In Western nations, the most common causes of such a deficiency are alcoholism and eating disorders. Because these are behavioral-induced causes, Korsakoff's syndrome is essentially considered a preventable disease. Thus, fortifying foods with thiamine, or requiring companies that sell alcoholic beverages to supplement them with B vitamins in general or thiamine in particular, could avert many cases of Korsakoff's Syndrome.
The onset of Wernicke's encephalopathy is considered a medical emergency, and thus thiamine administration should be initiated immediately when the disease is suspected. Prompt administration of thiamine to patients with Wernicke's encephalopathy can prevent the disorder from developing into Wernicke–Korsakoff syndrome, or reduce its severity. Treatment can also reduce the progression of the deficits caused by WKS, but will not completely reverse existing deficits. WKS will continue to be present, at least partially, in 80% of patients. Patients suffering from WE should be given a minimum dose of 500 mg of thiamine hydrochloride, delivered by infusion over a 30-minute period for two to three days. If no response is seen then treatment should be discontinued but for those patients that do respond, treatment should be continued with a 250 mg dose delivered intravenously or intramuscularly for three to five days unless the patient stops improving. Such prompt administration of thiamine may be a life-saving measure. Banana bags, a bag of intravenous fluids containing vitamins and minerals, is one means of treatment.
Memory disorders are the result of damage to neuroanatomical structures that hinders the storage, retention and recollection of memories. Memory disorders can be progressive, including Alzheimer's disease, or they can be immediate including disorders resulting from head injury.
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.
Normal aging, although not responsible for causing memory disorders, is associated with a decline in cognitive and neural systems including memory (long-term and working memory). Many factors such as genetics and neural degeneration have a part in causing memory disorders. In order to diagnose Alzheimer's disease and dementia early, researchers are trying to find biological markers that can predict these diseases in younger adults. One such marker is a beta-amyloid deposit which is a protein that deposits on the brain as we age. Although 20-33% of healthy elderly adults have these deposits, they are increased in elderly with diagnosed Alzheimer's disease and dementia.
Additionally, traumatic brain injury, TBI, is increasingly being linked as a factor in early-onset Alzheimer's disease.
One study examined dementia severity in elderly schizophrenic patients diagnosed with Alzheimer's disease and dementia versus elderly schizophrenic patients without any neurodegenerative disorders. In most cases, if schizophrenia is diagnosed, Alzheimer's disease or some form of dementia in varying levels of severity is also diagnosed. It was found that increased hippocampal neurofibrillary tangles and higher neuritic plaque density (in the superior temporal gyrus, orbitofrontal gyrus, and the inferior parietal cortex) were associated with increased severity of dementia. Along with these biological factors, when the patient also had the apolipoprotein E (ApoE4) allele (a known genetic risk factor for Alzheimer's disease), the neuritic plaques increased although the hippocampal neurofibrillary tangles did not. It showed an increased genetic susceptibility to more severe dementia with Alzheimer's disease than without the genetic marker.
As seen in the examples above, although memory does degenerate with age, it is not always classified as a memory disorder. The difference in memory between normal aging and a memory disorder is the amount of beta-amyloid deposits, hippocampal neurofibrillary tangles, or neuritic plaques in the cortex. If there is an increased amount, memory connections become blocked, memory functions decrease much more than what is normal for that age and a memory disorder is diagnosed.
The cholinergic hypothesis of geriatric memory dysfunction is an older hypothesis that was considered before beta-amyloid deposits, neurofibrillary tangles, or neuritic plaques. It states that by blocking the cholinergic mechanisms in control subjects you can examine the relationship between cholinergic dysfunction and normal aging and memory disorders because this system when dysfunctional creates memory deficits.
There is no cure for individuals with DES, but there are therapies to help them cope with their symptoms. DES can affect a number of functions in the brain and vary from person to person. Because of this variance, it is suggested that the most successful therapy would include multiple methods. Researchers suggest that a number of factors in the executive functioning need to be improved, including self-awareness, goal setting, planning, self-initiation, self-monitoring, self-inhibition, flexibility, and strategic behaviour.
One method for individuals to improve in these areas is to help them plan and carry out actions and intentions through a series of goals and sub-goals. To accomplish this, therapists teach patients a three-step model called the General Planning Approach. The first step is Information and Awareness, in which the patients are taught about their own problems and shown how this affects their lives. The patients are then taught to monitor their executive functions and begin to evaluate them. The second stage, Goal Setting and Planning, consists of patients making specific goals, as well as devising a plan to accomplish them. For example, patients may decide they will have lunch with a friend (their goal). They are taught to write down which friend it may be, where they are going for lunch, what time they are going, how they will get there, etc. (sub-goals). They are also taught to make sure the steps go in the correct order. The final stage, named Initiation, Execution, and Regulation, requires patients to implement their goals in their everyday lives. Initiation can be taught through normal routines. The first step can cue the patient to go to the next step in their plan. Execution and regulation are put into action with reminders of how to proceed if something goes wrong in the behavioural script. This treatment method has resulted in improved daily executive functioning, however no improvements were seen on formal executive functioning tests.
Since planning is needed in many activities, different techniques have been used to improve this deficit in patients with DES. Autobiographical memories can be used to help direct future behaviour. You can draw on past experiences to know what to do in the future. For example, when you want to take a bus, you know from past experience that you have to walk to the bus stop, have the exact amount of change, put the change in the slot, and then you can go find a seat. Patients with DES seem to not be able to use this autobiographical memory as well as a normal person. Training for DES patients asks them to think of a specific time when they did an activity previously. They are then instructed to think about how they accomplished this activity. An example includes "how would you plan a holiday". Patients are taught to think of specific times they went on a holiday and then to think how they may have planned these holidays. By drawing on past experiences patients were better able to make good decisions and plans.
Cognitive Analytic Therapy (CAT) has also been used to help those with DES. Because individuals with this syndrome have trouble integrating information into their actions it is often suggested that they have programmed reminders delivered to a cell phone or pager. This helps them remember how they should behave and discontinue inappropriate actions. Another method of reminding is to have patients write a letter to themselves. They can then read the letter whenever they need to. To help patients remember how to behave, they may also create a diagram. The diagram helps organize their thoughts and shows the patient how they can change their behaviour in everyday situations.
The use of auditory stimuli has been examined in the treatment of DES. The presentation of auditory stimuli causes an interruption in current activity, which appears to aid in preventing "goal neglect" by increasing the patients' ability to monitor time and focus on goals. Given such stimuli, subjects no longer performed below their age group average IQ.
Dysexecutive syndrome (DES) consists of a group of symptoms, usually resulting from brain damage, that fall into cognitive, behavioural and emotional categories and tend to occur together. The term was introduced by Alan Baddeley to describe a common pattern of dysfunction in executive functions, such as planning, abstract thinking, flexibility and behavioural control. It is thought to be Baddeley's hypothesized working memory system and the central executive that are the hypothetical systems impaired in DES. The syndrome was once known as frontal lobe syndrome, however dysexecutive syndrome is preferred because it emphasizes the functional pattern of deficits (the symptoms) over the location of the syndrome in the frontal lobe, which is often not the only area affected.
Classification code in ICD-10 - F07
Anton–Babinski syndrome, also known as visual anosognosia, is a rare symptom of brain damage occurring in the occipital lobe. Those who suffer from it are "cortically blind", but affirm, often quite adamantly and in the face of clear evidence of their blindness, that they are capable of seeing. Failing to accept being blind, the sufferer dismisses evidence of their condition and employs confabulation to fill in the missing sensory input. It is named after Gabriel Anton and Joseph Babinski.
Why patients with Anton–Babinski syndrome deny their blindness is unknown, although there are many theories. One hypothesis is that damage to the visual cortex results in the inability to communicate with the speech-language areas of the brain. Visual imagery is received but cannot be interpreted; the speech centers of the brain confabulate a response.
This is often seen in immunosuppressed patients with JC virus. Specifically, patients being treated with natalizumab—a monoclonal antibody currently used as a staple in treatment for multiple sclerosis—are quickly becoming classical examples of Anton–Babinski syndrome.
Patients have also reported visual anosognosia after suffering from ischemic vascular cerebral disease. A 96-year-old man, who was admitted to an emergency room complaining of a severe headache and sudden loss of vision, was discovered to have suffered from a posterior cerebral artery thrombosis and consequently lost his vision. He adamantly claimed he was able to see despite an ophthalmologic exam proving otherwise. An MRI of his brain proved that his right occipital lobe was ischemic. Similarly, a 56-year-old woman was admitted to the emergency room in a confused state and with severely handicapped psychomotor skills. Ocular movements and pupil reflexes were still intact, but the patient could not name objects and was not aware of light changes in the room, and seemed unaware of her visual deficit.
Explaining the causes of delusions continues to be challenging and several theories have been developed. One is the genetic or biological theory, which states that close relatives of people with delusional disorder are at increased risk of delusional traits. Another theory is the dysfunctional cognitive processing, which states that delusions may arise from distorted ways people have of explaining life to themselves. A third theory is called motivated or defensive delusions. This one states that some of those persons who are predisposed might suffer the onset of delusional disorder in those moments when coping with life and maintaining high self-esteem becomes a significant challenge. In this case, the person views others as the cause of their personal difficulties in order to preserve a positive self-view.
This condition is more common among people who have poor hearing or sight. Also, ongoing stressors have been associated with a higher possibility of developing delusions. Examples of such stressors are immigration, low socioeconomic status, and even possibly the accumulation of smaller daily hassles.
Although non-specific concepts of madness have been around for several thousand years, the psychiatrist and philosopher Karl Jaspers was the first to define the three main criteria for a belief to be considered delusional in his 1913 book "General Psychopathology". These criteria are:
- certainty (held with absolute conviction)
- incorrigibility (not changeable by compelling counterargument or proof to the contrary)
- impossibility or falsity of content (implausible, bizarre, or patently untrue)
Furthermore, when a false belief involves a value judgment, it is only considered a delusion if it is so extreme that it cannot be, or never can be proven true. For example: a man claiming that he flew into the sun and flew back home. This would be considered a delusion, unless he were speaking figuratively, or if the belief had a cultural or religious source.
There are hospital protocols for prevention, supplementing with thiamine in the presence of: history of alcohol misuse or related seizures, requirement for IV glucose, signs of malnutrition, poor diet, recent diarrhea or vomiting, peripheral neuropathy, intercurrent illness, delirium tremens or treatment for DTs, and others. Some experts advise parenteral thiamine should be given to all at-risk patients in the emergency room.
In the clinical diagnosis should be remembered that early symptoms are nonspecific, and it has been stated that WE may present nonspecific findings. There is consensus to provide water-soluble vitamins and minerals after gastric operations.
In some countries certain foods have been supplemented with thiamine, and have reduced WE cases. Improvement is difficult to quantify because they applied several different actions. Avoiding alcohol and having adequate nutrition reduces one of the main risk factors in developing Wernicke-Korsakoff syndrome.
Most symptoms will improve quickly if deficiencies are treated early. Memory disorder may be permanent.
In patients suspected of WE, thiamine treatment should be started immediately. Blood should be immediately taken to test for thiamine, other vitamins and minerals levels. Following this an immediate intravenous or intramuscular dose of thiamine should be administered two or three times daily. Thiamine administration is usually continued until clinical improvement ceases.
Considering the diversity of possible causes and several surprising symptomatologic presentations, and because there is low assumed risk of toxicity of thiamine, because the therapeutic response is often dramatic from the first day, some qualified authors indicate parenteral thiamine if WE is suspected, both as a resource for diagnosis and treatment. The diagnosis is highly supported by the response to parenteral thiamine, but is not sufficient to be excluded by the lack of it. Parenteral thiamine administration is associated with a very small risk of anaphylaxis.
Alcohol abusers may have poor dietary intakes of several vitamins, and impaired thiamine absorption, metabolism, and storage; they may thus require higher doses.
If glucose is given, such as in hypoglycaemic alcoholics, thiamine must be given concurrently. If this is not done, the glucose will rapidly consume the remaining thiamine reserves, exacerbating this condition.
The observation of edema in MR, and also the finding of inflation and macrophages in necropsied tissues, has led to successful administration of antiinflammatories.
Other nutritional abnormalities should also be looked for, as they may be exacerbating the disease. In particular, magnesium, a cofactor of transketolase which may induce or aggravate the disease.
Other supplements may also be needed, including: cobalamin, ascorbic acid, folic acid, nicotinamide, zinc, phosphorus (dicalcium phosphate) and in some cases taurine, especially suitable when there cardiocirculatory impairment.
Patient-guided nutrition is suggested. In patients with Wernicke-Korsakoff syndrome, even higher doses of parenteral thiamine are recommended. Concurrent toxic effects of alcohol should also be considered.
Immunosuppressive therapies, encompassing corticosteroids, azathioprine, methotrexate and more recently, rituximab, are the mainstay of therapy. Other treatments include PE, IVIG, and thymectomy. Patients reportedly exhibited a heterogenous response to immunomodulation.
Antiepileptics can be used for symptomatic relief of peripheral nerve hyperexcitability. Indeed, some patients have exhibited a spontaneous remission of symptoms.
Prognosis is poor, however, current analysis suggests that those associated with thymoma, benign or malignant, show a less favorable prognosis (CASPR2 Ab positive).