Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
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
There are clinical trials being done to further research for treatments. At the National Institute of Neurological Disorders and Stroke (NINDS) they support research for rare diseases like agnosia. Some organizations that are recruiting for trials are using clincaltrials.gov and give status updates on the trials.
These strategies elicit the use of an unaffected modality. For example, visual agnosics can use tactile information in replacement of visual information. Alternatively, an individual with prosopagnosia can use auditory information in order to replace visual information. For example, an individual with prosopagnosia can wait for someone to speak, and will usually recognize the individual from their speech.
The affected individual may not realize that they have a visual problem and may complain of becoming "clumsy" or "muddled" when performing familiar tasks such as setting the table or simple DIY.
Anosognosia, a lack of awareness of the deficit, is common and can cause therapeutic resistance. In some agnosias, such as prosopagnosia, awareness of the deficit is often present; however shame and embarrassment regarding the symptoms can be a barrier in admission of a deficiency. Because agnosias result from brain lesions, no direct treatment for them currently exists, and intervention is aimed at utilization of coping strategies by patients and those around them. Sensory compensation can also develop after one modality is impaired in agnostics
General principles of treatment:
- restitution
- repetitive training of impaired ability
- development of compensatory strategies utilizing retained cognitive functions
Partial remediation is more likely in cases with traumatic/vascular lesions, where more focal damage occurs, than in cases where the deficit arises out of anoxic brain damage, which typically results in more diffuse damage and multiple cognitive impairments. However, even with forms of compensation, some afflicted individuals may no longer be able to fulfill the requirements of their occupation or perform common tasks, such as, eating or navigating. Agnostics are likely to become more dependent on others and to experience significant changes to their lifestyle, which can lead to depression or adjustment disorders.
Associative visual agnosia is a form of visual agnosia. It is an impairment in recognition or assigning meaning to a stimulus that is accurately perceived and not associated with a generalized deficit in intelligence, memory, language or attention. The disorder appears to be very uncommon in a "pure" or uncomplicated form and is usually accompanied by other complex neuropsychological problems due to the nature of the etiology. Afflicted individuals can accurately distinguish the object, as demonstrated by the ability to draw a picture of it or categorize accurately, yet they are unable to identify the object, its features or its functions.
Management strategies for acquired prosopagnosia, such as a person who has difficulty recognizing people's faces after a stroke, generally have a low rate of success. Acquired prosopagnosia sometimes spontaneously resolves on its own.
Integrative agnosia is a sub-disease of agnosia, meaning the lack of integrating perceptual wholes within
knowledge. Integrative agnosia can be assessed by several experimental tests such as the Efron shape test, which
determines the specificity of the disease being Integrative.
This disease is often caused by brain trauma, producing medial ventral lesions to the extrastriate cortex. Affecting this region of the brain produces learning impairments: the inability to
integrate parts such as spatial distances or producing visual images from short or long-term memory.
Treating auditory verbal agnosia with intravenous immunoglobulin (IVIG) is controversial because of its inconsistency as a treatment method. Although IVIG is normally used to treat immune diseases, some individuals with auditory verbal agnosia have responded positively to the use of IVIG. Additionally, patients are more likely to relapse when treated with IVIG than other pharmacological treatments. IVIG is, thus, a controversial treatment as its efficacy in treating auditory verbal agnosia is dependent upon each individual and varies from case to case.
As autotopagnosia arises from neurological and irreversible damage, options regarding symptom reversal or control are limited. As of April 2010, there are no known specific treatments for autotopagnosia.
No medications or pharmaceutical remedies have been approved by the U.S. Food and Drug Administration to treat or cure autotopagnosia. There have been cases in which extensive rehabilitation has been beneficial following restitution, repetitive training to correct the impaired function, and compensation of other skills to make up for the deficit. Rehabilitation is not a definitive treatment and only shows signs of slight improvement in a small percentage of autotopagnosia patients. The condition of the disease can be monitored with continued neurological examination and using a CT scan to note the progression of the parietal lesion.
One treatment thought to be effective is the repeated exposure to a particular face or object, where impaired perception may be reorganized in memory, leading to improvement on tests of imagery relative to tests of perception. The key factor for this type of treatment to be successful is a regular and consistent exposure, which will lead to improvements in the long run. Results may not be seen right away, but are eventually possible.
Visual agnosia is an impairment in recognition of visually presented objects. It is not due to a deficit in vision (acuity, visual field, and scanning), language, memory, or low intellect. While cortical blindness results from lesions to primary visual cortex, visual agnosia is often due to damage to more anterior cortex such as the posterior occipital and/or temporal lobe(s) in the brain. There are two types of visual agnosia: apperceptive agnosia and associative agnosia.
Recognition of visual objects occurs at two primary levels. At an apperceptive level, the features of the visual information from the retina are put together to form a perceptual representation of an object. At an associative level, the meaning of an object is attached to the perceptual representation and the object is identified. If a person is unable to recognize objects because they cannot perceive correct forms of the objects, although their knowledge of the objects is intact (i.e. they do not have anomia), they have apperceptive agnosia. If a person correctly perceives the forms and has knowledge of the objects, but cannot identify the objects, they have associative agnosia.
Apperceptive agnosia is a failure in recognition that is due to a failure of perception. In contrast, associative agnosia is a type of agnosia where perception occurs but recognition still does not occur. When referring to apperceptive agnosia, visual and object agnosia are most commonly discussed; This occurs because apperceptive agnosia is most likely to present visual impairments. However, in addition to visual apperceptive agnosia there are also cases of apperceptive agnosia in other sensory areas.
Auditory agnosia is a form of agnosia that manifests itself primarily in the inability to recognize or differentiate between sounds. It is not a defect of the ear or "hearing", but a neurological inability of the brain to process sound meaning. It is a disruption of the "what" pathway in the brain. Persons with auditory agnosia can physically hear the sounds and describe them using unrelated terms, but are unable to recognize them. They might describe the sound of some environmental sounds, such as a motor starting, as resembling a lion roaring, but would not be able to associate the sound with "car" or "engine", nor would they say that it "was" a lion creating the noise. Auditory agnosia is caused by damage to the secondary and tertiary auditory cortex of the temporal lobe of the brain.
In incidents where tumors and their pressure effects are the cause of pure word deafness, removal of the tumor has been shown to allow for the return of most auditory verbal comprehension.
There are three primary distinctions of auditory agnosia that fall into two categories.
As autotopagnosia is not a life-threatening condition it is not on the forefront of medical research. Rather, more research is conducted regarding treatments and therapies to alleviate the lesions and traumas that can cause autotopagnosia. Of all the agnosias, visual agnosia is the most common subject of investigation because it is easiest to assess and has the most promise for potential treatments. Most autotopagnosia studies are centered on a few test subjects as part of a group of unaffected or “controlled” participants, or a simple case study. Case studies surrounding a single patient are most common due to the vague nature of the disease.
Topographical disorientation, also known as topographical agnosia and topographagnosia, is the inability to orient oneself in one's surroundings as a result of focal brain damage. This disability may result from the inability to make use of selective spatial information (e.g., environmental landmarks) or to orient by means of specific cognitive strategies such as the ability to form a mental representation of the environment, also known as a cognitive map. It may be part of a syndrome known as visuospatial dysgnosia.
Visuospatial dysgnosia is a loss of the sense of "whereness" in the relation of oneself to one's environment and in the relation of objects to each other. Visuospatial dysgnosia is often linked with topographical disorientation.
"Developmental prosopagnosia" (DP), also called "Congenital prosopagnosia" (CP), is a face-recognition deficit that is lifelong, manifesting in early childhood, and that cannot be attributed to acquired brain damage. A number of studies have found functional deficits in DP both on the basis of EEG measures and fMRI. It has been suggested that a genetic factor is responsible for the condition. The term "hereditary prosopagnosia" was introduced if DP affected more than one family member, essentially accenting the possible genetic contribution of this condition. To examine this possible genetic factor, 689 randomly selected students were administered a survey in which seventeen developmental prosopagnosics were quantifiably identified. Family members of fourteen of the DP individuals were interviewed to determine prosopagnosia-like characteristics, and in all fourteen families, at least one other affected family member was found.
In 2005, a study led by Ingo Kennerknecht showed support for the proposed congenital disorder form of prosopagnosia. This study provides epidemiological evidence that congenital prosopagnosia is a frequently occurring cognitive disorder that often runs in families. The analysis of pedigree trees formed within the study also indicates that the segregation pattern of hereditary prosopagnosia (HPA) is fully compatible with autosomal dominant inheritance. This mode of inheritance explains why HPA is so common among certain families (Kennerknecht et al. 2006).
There are many developmental disorders associated with an increased likelihood that the person will have difficulties in face perception, of which the person may or may not be aware. The mechanism by which these perceptual deficits take place is largely unknown. A partial list of some disorders that often have prosopagnosiac components would include nonverbal learning disorder, Alzheimer's disease, and autism in general. However, these types of disorders are very complicated, so arbitrary assumptions should be avoided.
In 2012, it was shown that developmental prosopagnosia cases show poor integration of low and high spatial frequency information.
There is currently no known curative treatment for SD. The average duration of illness is 8–10 years, and its progression cannot be slowed. Progression of SD can lead to behavioral and social difficulties, thus supportive care is essential for improving quality of life in SD patients as they grow more incomprehensible.
Continuous practice in lexical learning has been shown to improve semantic memory in SD patients.
SD has no known preventative measures.
Topographical disorientation is the inability to orient in the surrounding as a result of focal brain damage.
Topographical Disorientation has been studied for decades using case studies of patients who have selectively lost their ability to find their way within large-scale, locomotor environments. Several dozen case reports of topographical disorientation have been presented over the last century. Studying these people will aid in the understanding of the complex, multi-component behavior of navigation. Topographical disorientation may result from a stroke or part of a progressive illness, hemispatial neglect, dementia, Alzheimer's disease.
While most cases of visual agnosia are seen in older adults who have experienced extensive brain damage, there are also cases of young children with less brain damage during developmental years acquiring the symptoms. Commonly, visual agnosia presents as an inability to recognize an object in the absence of other explanations, such as blindness or partial blindness, anomia, memory loss, etc.. Other common manifestations of visual agnosia that are generally tested for include difficulty identifying objects that look similar in shape, difficulty with identifying line drawings of objects, and recognizing objects that are shown from less common views, such as a horse from a top-down view.
Within any given patient, a variety of symptoms can occur, and the impairment of ability is not only binary but can range in severity. For example, Patient SM is a prosopagnosic with a unilateral lesion to left extrastriate cortex due to an accident in his twenties who displays behavior similar to congenital prosopagnosia. Although he can recognize facial features and emotions – indeed he sometimes uses a standout feature to recognize a face – face recognition is almost impossible purely from visual stimuli, even for faces of friends, family, and himself. The disorder also affects his memory of faces, both in storing new memories of faces and recalling stored memories.
Nevertheless, it is important to note the reach of symptoms to other domains. SM’s object recognition is similarly impaired though not entirely; when given line drawings to identify, he was able to give names of objects with properties similar to the drawing, implying that he is able to see the features of the drawing. Similarly, copying a line drawing of a beach scene led to a simplified version of the drawing, though the main features were accounted for. For recognition of places, he is still impaired but familiar places are remembered and new places can be stored into memory.
Social-emotional agnosia is mainly caused by abnormal functioning in a particular brain area called the amygdala. Typically this agnosia is only found in people with bilateral amygdala damage; that is damage to amygdala regions in both hemispheres of the brain. It can be accompanied by right or bilateral temporal lobe damage. The amygdala dysfunction causes the inability to select appropriate behaviors in a specific social context. Symptoms can include reduced aggression, fearfulness, competitiveness, and social dominance. Those with social-emotional agnosia have difficulty discerning the emotional meaning and significance behind objects, which causes a loss of fondness and familiarity. Bilateral amygdala damage has also been associated with social unresponsiveness, leading to an avoidance of social interactions and a preference for isolation from their own species. Evidence suggests that damage to the amygdala and the limbic system (specifically the amygdala-hypothalamus pathway) results in the loss of the core ability to recognize and interpret the mental states of others, a vital ability in social interactions. The amygdala evokes highly personal emotional memories and the loss of this function causes hypo-emotionality, a general lack of emotion when presented with different stimuli. Hypersexuality has also been observed in those with disconnection in the amygdala-hypothalamus pathway. Temporal lobe epilepsy has been shown to cause bilateral amygdala damage which could result in symptoms similar to social-emotional agnosia, but the precise relationship between the two disorders is unknown.
Phonagnosia (from Ancient Greek φωνή "phone", "voice" and γνῶσις "gnosis", "knowledge") is a type of agnosia, or loss of knowledge, that involves a disturbance in the recognition of familiar voices and the impairment of voice discrimination abilities in which the affected individual does not suffer from comprehension deficits. Phonagnosia is an auditory agnosia, an acquired auditory processing disorder resulting from brain damage, other auditory agnosias include cortical deafness and auditory verbal agnosia also known as pure word deafness.
Since people suffering from phonagnosia do not suffer from aphasia, it is suggested that the structures of linguistic comprehension are functionally separate from those of the perception of the identity of the speaker who produced it.
Phonagnosia is the auditory equivalent of prosopagnosia. Unlike Prosopagnosia, investigations of phonagnosia have not been extensively pursued. Phonagnosia was first described by a study by Van Lancker and Cantor in 1982. The subjects in this study were asked to identify which of four names or faces matched a specific famous voice. The subjects could not complete the task. Since then, there have been a couple studies done on patients with phonagnosia. The clinical and radiologic findings with computerized tomographic scans cat scan in these cases suggest that recognition of familiar voices is impaired by damage to the inferior and parietal regions of the right hemisphere while voice discrimination is impaired by temporal lobe damage of either hemisphere. These studies have also shown evidence for a double dissociation between voice recognition and voice discrimination. Some patients will perform normally on the discrimination tasks but poorly on the recognition tasks; whereas the other patients will perform normally on the recognition tasks but poorly on the discrimination tasks. Patients did not perform poorly on both tasks.
Associative phonagnosia is a form of phonagnosia that develops with dementia or other focal neurodegenerative disorders. Some research has led to questions of other impairments in phonagnosics. Recently, studies have shown that phonagnosics also have trouble in recognizing the sounds of familiar instruments. As it is with voices, they also show deficiency in distinguishing between sounds from different instruments. Although the disability is shown, phonagnosics are much less affected in this area of sound discrimination. In distinguishing voices, it is a complete agnosia, but this is not the case for musical instrument sounds, as they can correctly identify some of them. Controversy arises in that not all phonagnosics exhibit these symptoms, and so not all researchers agree that it should be attributed to the damage suffered that causes phonagnosia. Much debate has arisen over the fact that it seems that separate areas of the brain are utilized to handle information from language and music. This has led some researchers to skeptically consider this impairment as a clear symptom of the disorder. Again, more research is needed to create a clearer conclusion.
An interesting attribute that phonagnosics possess is that they can correctly detect emotions in voices when someone talks to them. They can also correctly match an emotion with a facial expression. Although surprising, this finding is sensible because it is known and well agreed upon that the limbic system, involved in expressing emotions and detecting emotions of others, is a separate system within the brain. The limbic system is made up of several brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix.
Presently, there is no therapy or treatment for phonagnosia. Clearly, more research is needed to accomplish the feat of developing treatment for the disorder. The lack of treatment stems from the lack of knowledge about the disorder. Increased research will reveal vital information needed to formulate effective treatments and therapies.
Treatment consists of finding ways to bring the patient's attention toward the left, usually done incrementally, by going just a few degrees past midline, and progressing from there. Rehabilitation of neglect is often carried out by neuropsychologists, occupational therapist,
speech-language pathologists, neurologic music therapists, physical therapists, optometrists and orthoptists.
Forms of treatment that have been tested with variable reports of success include prismatic adaptation, where a prism lens is worn to pull the vision of the patient towards the left, constrained movement therapy where the "good" limb is constrained in a sling to encourage use of the contralesional limb. Eye-patching has similarly been used, placing a patch over the "good" eye. Pharmaceutical treatments have mostly focused on dopaminergic therapies such as bromocriptine, levodopa, and amphetamines, though these tests have had mixed results, helping in some cases and accentuating hemispatial neglect in others. Caloric vestibular stimulation (CVS) has been shown to bring about a brief remission in some cases. however this technique has been known to elicit unpleasant side-effects such as nystagmus, vertigo and vomiting.
A study done by Schindler and colleagues examined the use of neck muscle vibration on the contralesional posterior neck muscles to induce diversion of gaze from the subjective straight ahead. Subjects received 15 consecutive treatment sessions and were evaluated on different aspects of the neglect disorder including perception of midline, and scanning deficits. The study found that there is evidence that neck muscle stimulation may work, especially if combined with visual scanning techniques. The improvement was evident 2 months after the completion of treatment.
Other areas of emerging treatment options include the use of prisms, visual scanning training, mental imagery training, video feedback training, trunk rotation, galvanic vestibular stimulation (GVS), transcranial magnetic stimulation (TMS) and transcranial direct-current stimulation (tDCS). Of these emerging treatment options, the most studied intervention is prism adaptation and there is evidence of relatively long-term functional gains from comparatively short-term usage. However, all of these treatment interventions (particularly the stimulation techniques) are relatively new and randomised, controlled trial evidence is still limited. Further research is mandatory in this field of research in order to provide more support in evidence-based practice.
In a review article by Pierce & Buxbaum (2002), they concluded that the evidence for Hemispheric Activation Approaches, which focuses on moving the limb on the side of the neglect, has conflicting evidence in the literature. The authors note that a possible limitation in this approach is the requirement for the patients to actively move the neglected limb, which may not be possible for many patients. Constraint-Induced Therapy (CIT), appears to be an effective, long-term treatment for improving neglect in various studies. However, the use of CIT is limited to patients who have active control of wrist and hand extension. Prism Glasses, Hemispatial Glasses, and Eye-Patching have all appear to be effective in improving performance on neglect tests. Caloric Stimulation treatment appears to be effective in improving neglect; however, the effects are generally short-term. The review also suggests that Optokinetic Stimulation is effective in improving position sense, motor skills, body orientation, and perceptual neglect on a short-term basis. As with Caloric Stimulation treatment, long-term studies will be necessary to show its effectiveness. A few Trunk Rotation Therapy studies suggest its effectiveness in improving performance on neglect tests as well as the Functional Independence Measure (FIM). Some less studied treatment possibilities include treatments that target Dorsal Stream of visual processing, Mental Imagery Training, and Neck Vibration Therapy. Trunk rotation therapies aimed at improving postural disorders and balance deficits in patients with unilateral neglect, have demonstrated optimistic results in regaining voluntary trunk control when using specific postural rehabilitative devices. One such device is the Bon Saint Côme apparatus, which uses spatial exploratory tasks in combination with auditory and visual feedback mechanisms to develop trunk control. The Bon Saint Côme device has been shown to be effective with hemiplegic subjects due to the combination of trunk stability exercises, along with the cognitive requirements needed to perform the postural tasks.
Social-emotional agnosia, also known as emotional agnosia or expressive agnosia, is the inability to perceive facial expressions, body language, and voice intonation. A person with this disorder is unable to non-verbally perceive others' emotions in social situations, limiting normal social interactions. The condition causes a functional blindness to subtle non-verbal social-emotional cues in voice, gesture, and facial expression. People with this form of agnosia have difficulty in determining and identifying the motivational and emotional significance of external social events, and may appear emotionless or agnostic (uncertainty or general indecisiveness about a particular thing). Symptoms of this agnosia can vary depending on the area of the brain affected. Social-emotional agnosia often occurs in individuals with schizophrenia and autism. It is difficult to distinguish from, and has been found to co-occur with, alexithymia.