Synonyms for agnosias or Related words with agnosias
Examples of "agnosias"
As in many other
, those with the disorder have difficulty recognizing their errors and often do not correct themselves.
Integrative agnosia(a subtype of associative agnosia) is the inability to integrate separate parts to form a whole image. With these types of
there is damage to the ventral (what) stream of the visual processing pathway.
are differential impairments in subject knowledge or recognition abilities pertaining to specific classes of stimuli, such as living things vs. non-living things, animate vs. inaminate things, food, metals, musical instruments, etc. Some of the most common category-specific
involve recognition impairments for living things, but not non-living things, or human faces, as in prosopagnosia. This type of deficit is typically associated with head injury or stroke, though other medical conditions have been implicated, such as, herpes encephalitis.
Although visual agnosia can be general, there exist many variants that impair recognition of specific types. These variants of visual agnosia include prosopagnosia (inability to recognize faces), pure word blindness (inability to recognize words, often called "agnosic alexia" or "pure alexia"),
for colors (inability to differentiate colors),
for the environment (inability to recognize landmarks or difficult with spatial layout of an environment, i.e. topographagnosia) and simultanagosia (inability to sort out multiple objects in a visual scene).
An agnosia that affects hearing, "auditory sound agnosia", is broken into subdivisions based on level of processing impaired, and a "semantic-associative" form is investigated within the auditory
Anosognosia, a lack of awareness of the deficit, is common and can cause therapeutic resistance. In some
, 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
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
Until the 1980s, there had been no scientifically accredited cases of autotopagnosia, rather
that have been secondary to other neurological deficits such as dementia. In fact the term autotopagnosia does not appear until Pick’s studies in 1908 and 1922. More recently, Carlos Semenza (2003) has expanded on Pick’s theories.
are generally attributed to anterior left temporal lobe infarction, caused by ischemic stroke, head injury, cardiac arrest, brain tumour, brain hemorrhage, or demyelination. Environmental toxins and pathogens have also been implicated, such as, carbon monoxide poisoning or herpes encephalitis and infrequent developmental occurrences have been documented.
Cognitive psychology often conceptualizes this deficit as an impairment in the object recognition process. Currently visual
are commonly explained in terms of cognitive models of object recognition or identification. The cognitive system for visual object identification is a hierarchal process, broken up into multiple steps of processing.
Sensory modality testing allows practitioners to assess for generalized versus specific deficits, distinguishing visual
from optic aphasia, which is a more generalized deficit in semantic knowledge for objects that spans multiple sensory modalities, indicating an impairment in the semantic representations themselves.
The distinction between visual
can be assessed based on the individual's ability to copy simple line drawings, figure contour tracking, and figure matching. Apperceptive visual agnostics fail at these tasks, while associative visual agnostics are able to perform normally, though their copying of images or words is often slavish, lacking originality or personal interpretation.
may be categorized based on the process which is impaired in the individual. Apperceptive music agnosia involves an impairment at the level of perceptual analysis involving an inability to encode musical information correctly. Associative music agnosia reflects an impaired representational system which disrupts music recognition. Many of the cases of music agnosia have resulted from surgery involving the middle cerebral artery. Patient studies have surmounted a large amount of evidence demonstrating that the left side of the brain is more suitable for holding long-term memory representations of music and that the right side is important for controlling access to these representations. Associative music
tend to be produced by damage to the left hemisphere, while apperceptive music agnosia reflects damage to the right hemisphere.
Similarly, associative visual agnosia is the inability to understand the significance of objects; however, this time the deficit is in semantic memory. Both of these
can affect the pathway to object recognition, like Marr's Theory of Vision. More specifically unlike apperceptive agnosia, associative agnosic patients are more successful at drawing, copying, and matching tasks; however, these patients demonstrate that they can perceive but not recognize.
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
include cortical deafness and auditory verbal agnosia also known as pure word deafness.
In 1887 Hermann Wilbrand was studying an elderly female subject with bilateral posterior cerebral artery thrombosis. This subject displayed a complete inability to dream coupled with an inability to recognize familiar places, a condition known more recently as topographic agnosia. Additionally a condition known as prosopagnosia, or the inability to recognize familiar faces was also noted in the patient. Wilbrand's contribution revolves around the complete inability to produce dreams with the presence of
as possible side conditions.
are sensory modality specific, usually classified as visual, auditory, or tactile. Associative visual agnosia refers to a subtype of visual agnosia, which was labeled by Lissauer (1890), as an inability to connect the visual percept (mental representation of something being perceived through the senses) with its related semantic information stored in memory, such as, its name, use, and description. This is distinguished from the visual apperceptive form of visual agnosia, "apperceptive visual agnosia", which is an inability to produce a complete percept, and is associated with a failure in higher order perceptual processing where feature integration is impaired, though individual features can be distinguished. In reality, patients often fall between both distinctions, with some degree of perceptual disturbances exhibited in most cases, and in some cases, patients may be labeled as integrative agnostics when they fit the criteria for both forms. Associative visual
are often category-specific, where recognition of particular categories of items are differentially impaired, which can affect selective classes of stimuli, larger generalized groups or multiple intersecting categories. For example, deficits in recognizing stimuli can be as specific as familiar human faces or as diffuse as living things or non-living things.
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
, 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.
Ennio De Renzi worked extensively with a variety of
in 1963 and 1970. He explored, on two patients with autotopagnosia in particular, the difficulties of mentally recognizing the physical division of a whole object into sections. For example, he found his patients could not describe the position or parts of a bike, and were unable to focus on a part of the whole. De Renzi’s studies gave way to countless others to give insight as to the complicated and varied mechanisms behind autotopagnosia.
The term "pure word deafness" is something of a misnomer. By definition, individuals with pure word deafness are not deaf – in the absence of other impairments, these individuals have normal hearing for all sounds, including speech. The term "deafness" originates from the fact that individuals with AVA are unable to "comprehend" speech that they hear. The term "pure word" refers to the fact that comprehension of verbal information is selectively impaired in AVA. For this reason, AVA is distinct from other auditory
in which the recognition of nonspeech sounds is impaired. Classical (or pure) auditory agnosia is an inability to process environmental sounds. Interpretive or receptive agnosia (amusia) is an inability to understand music.
Teuber described the associative agnostic as having a "percept stripped of its meaning," because the afflicted individual cannot generate unique semantic information to identify the percept, since though it is fully formed, it fails to activate the semantic memory associated with the stimulus. Warrington (1975) offered that the problem lies in impaired access to generic engrams (memory traces) that describe categories of objects made up of a multitude of similar elements. Essentially, damage to a modality-specific meaning process (semantic system), is proposed, either in terms of defective access to or a degradation of semantic memory store for visual semantic representations themselves. The fact that
are often restricted to impairments of particular types of stimuli, within distinct sensory modalities, suggests that there are separate modality specific pathways for the meaningful representation of objects and pictures, written material, familiar faces, and colors.
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