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 currently no quantitative methods for diagnosing simultanagnosia. To establish the presence of simultanagnosic symptoms, patients are asked to describe complex visual displays, such as the commonly used "Boston Cookie Theft" picture, which is a component of the Boston Diagnostic Aphasia Examination. In the picture, the sink in the kitchen is overflowing as a boy and a girl attempt to steal cookies from the cookie jar without their mother noticing.
Patients take a clearly piecemeal approach to interpreting the scene by reporting isolated items from the image. For instance, a patient may report seeing a "boy," "stool," and a "woman." However, when asked to interpret the overall meaning of the picture, the patient fails to comprehend the global whole. Another picture used to assess visual impairments of patients with simultanagnosia is the "Telegraph Boy" picture. Upon examination of higher nervous system functions, patients display no general intellectual impairments.
Patients with simultanagnosia, a component of Bálint's syndrome, have a restricted spatial window of visual attention and cannot see more than one object at a time in a scene that contains more than one object. For instance, if presented with an image of a table containing both food and various utensils, a patient will report seeing only one item, such as a spoon. If the patient's attention is redirected to another object in the scene, such as a glass, the patient will report that they see the glass but no longer see the spoon. As a result of this impairment, simultanagnosic patients often fail to comprehend the overall meaning of a scene.
In addition, patients note that one stationary object may spontaneously disappear from view as they become aware of another object in the scene.
Simultanagnosic patients often exhibit a phenomenon known as "local capture" where they only identify the local elements of stimuli containing local and global features. However, recent studies have demonstrated that implicit processing of the global structure can occur. With the appropriate stimulus conditions, explicit processing of the global form may occur. For example, a study performed with Navon hierarchical letters, which are large letters composed of smaller ones, revealed that the use of smaller and denser Navon letters biased the patient towards global processing.
In terms of the specific rehabilitation of visuoperceptual disorders such as Bálint's syndrome, the literature is extremely sparse. According to one study, rehabilitation training should focus on the improvement of visual scanning, the development of visually guided manual movements, and the improvement of the integration of visual elements. Very few treatment strategies have been proposed, and some of those have been criticized as being poorly developed and evaluated.
Three approaches to rehabilitation of perceptual deficits, such as those seen in Bálint's syndrome, have been identified:
1. The adaptive (functional) approach, which involves functional tasks utilising the person's strengths and abilities, helping them to compensate for problems or altering the environment to lessen their disabilities. This is the most popular approach.
2. The remedial approach, which involves restoration of the damaged CNS by training in the perceptual skills, which may be generalised across all activities of daily living. This could be achieved by tabletop activities or sensorimotor exercises.
3. The multicontext approach, which is based on the fact that learning is not automatically transferred from one situation to another. This involves practicing of a targeted strategy in a multiple environment with varied tasks and movement demands, and it incorporates self-awareness tasks.
Some telltale signs suggesting Bálint's syndrome following bilateral brain insults may include:
- limitation to perceive only stimuli that is presented at 35 to 40 degrees to the right. They are able to move their eyes but cannot fixate on specific visual stimuli. (ataxia)
- patient's field of attention is limited to one object at a time. making activities like reading difficult because each letter is perceived separately.(ataxia)
- figure/ground defects in which a patient can see either the background but not the object residing somewhere in the whole scene, or conversely can see the object but sees no background around it (simultanagnosia)
- a patient, while attempting to put one foot into a slipper by trying to insert the foot into a nonexistent slipper several inches from the real slipper, even as the patient focuses on the actual slipper (oculomotor apraxia)
- a patient raising a fork or spoon containing food to a point on the patient's face above or below the mouth, and possibly finding the mouth by trial and error by manually moving the utensil on the face (optic ataxia)
Akinetopsia (Greek: a for "without", kine for "to move" and opsia for "seeing"), also known as cerebral akinetopsia or motion blindness, is a neuropsychological disorder in which a patient cannot perceive motion in their visual field, despite being able to see stationary objects without issue. There are varying degrees of akinetopsia: from seeing motion as a cinema reel to an inability to discriminate any motion. There is currently no effective treatment or cure for akinetopsia.
Akinetopsia can be separated into two categories based on symptom severity and the amount the akinetopsia affects the patient's quality of life.
Agnosia is the inability to recognize certain objects, persons or sounds. Agnosia is typically caused by damage to the brain (most commonly in the occipital or parietal lobes) or from a neurological disorder. Treatments vary depending on the location and cause of the damage. Recovery is possible depending on the severity of the disorder and the severity of the damage to the brain. Many more specific types of agnosia diagnoses exist, including: associative visual agnosia, astereognosis, auditory agnosia, auditory verbal agnosia, prosopagnosia, simultanagnosia, topographical disorientation, visual agnosia etc.
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.