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Agnosia
Agnosia is the inability to process sensory information. Often there is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss. It is usually associated with brain injury or neurological illness, particularly after damage to the occipitotemporal border, which is part of the ventral stream. Agnosia only affects a single modality, such as vision or hearing. More recently, a top-down interruption is considered to cause the disturbance of handling perceptual information. Types Visual agnosia Visual agnosia is a broad category that refers to a deficiency in the ability to recognize visual objects. Visual agnosia can be further subdivided into two different subtypes: apperceptive visual agnosia and associative visual agnosia. Individuals with apperceptive visual agnosia display the ability to see contours and outlines when shown an object, but they experience difficulty if ask ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosopagnosia
Prosopagnosia (from Greek ''prósōpon'', meaning "face", and ''agnōsía'', meaning "non-knowledge"), also called face blindness, ("illChoisser had even begun tpopularizea name for the condition: face blindness.") is a cognitive disorder of face perception in which the ability to recognize familiar faces, including one's own face (self-recognition), is impaired, while other aspects of visual processing (e.g., object discrimination) and intellectual functioning (e.g., decision-making) remain intact. The term originally referred to a condition following acute brain damage (acquired prosopagnosia), but a congenital or developmental form of the disorder also exists, with a prevalence of 2.5%. The brain area usually associated with prosopagnosia is the fusiform gyrus, which activates specifically in response to faces. The functionality of the fusiform gyrus allows most people to recognize faces in more detail than they do similarly complex inanimate objects. For those with prosopagno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Agnosia
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 rather a neurological inability of the brain to process sound meaning. While auditory agnosia impairs the understanding of sounds, other abilities such as reading, writing, and speaking are not hindered. It is caused by bilateral damage to the anterior superior temporal gyrus, which is part of the auditory pathway responsible for sound recognition, the auditory "what" pathway. 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. All auditory agnosia patients read lips in order to e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autotopagnosia
Autotopagnosia from the Greek ''a'' and ''gnosis,'' meaning "without knowledge", ''topos'' meaning "place", and ''auto'' meaning "oneself", autotopagnosia virtually translates to the "lack of knowledge about one's own space," and is clinically described as such. Autotopagnosia is a form of agnosia, characterized by an inability to localize and orient different parts of the body. The psychoneurological disorder has also been referred to as "body-image agnosia" or "somatotopagnosia." ''Somatotopagnosia'' has been argued to be a better suited term to describe the condition. While autotopagnosia emphasizes the deficiencies in localizing only one's own body parts and orientation, ''somatotopagnosia'' also considers the inability to orient and recognize the body parts of others or representations of the body (e.g., manikins, diagrams). Typically, the cause of autotopagnosia is a lesion found in the parietal lobe of the left hemisphere of the brain. However, it as also been noted that p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associative Visual Agnosia
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. Affected 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. Classification Agnosias 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apperceptive 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 apperceptive agnosia Auditory apperceptive agnosia are impairments in audition that take place despite intact audiogram. In some cases the deficit is in the ability to recognize spoken words, and in other cases, may be a deficit in recognizing environmental sounds. In all cases individuals are able to read, write, name objects, and converse intelligently. Similar to visual impairments, the deficit arise because of damage in the primary sensory cortex. In the case of auditor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotopagnosia
Heterotopagnosia is a neuro-psychological syndrome caused by brain damage in the left parietal lobe and corresponding to an acquired inability in pointing at and locating another person's body parts.Degos JD, Bachoud-Levi AC, Ergis AM, Petrissans JL & Cesaro P (1997) Selective inability to point to extrapersonal targets after left posterior parietal lesions: An Objectivization disorder?, Neurocase, 3:1, 31-39, DOI: 10.1080/13554799708404032Degos JD, Bachoud-Levi AC. Pointing and its object: towards the neuropsychology of objectivation. Rev Neurol (Paris). 1998 May;154(4):283-90. Its name comes from the Greek: "hetero" which means the other from a pair, "a" combined with "gnosis" means without knowledge, and "topos" means location. This clinical syndrome is distinct from autotopagnosia, another group of cognitive deficits associated with difficulties in locating body parts on own's one body. Allotopagnosia is another related disorder in which the patient cannot point at any external ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Verbal Agnosia
Auditory verbal agnosia (AVA), also known as pure word deafness, is the inability to comprehend speech. Individuals with this disorder lose the ability to understand language, repeat words, and write from dictation. Some patients with AVA describe hearing spoken language as meaningless noise, often as though the person speaking was doing so in a foreign language. However, spontaneous speaking, reading, and writing are preserved. The maintenance of the ability to process non-speech auditory information, including music, also remains relatively more intact than spoken language comprehension. Individuals who exhibit pure word deafness are also still able to recognize non-verbal sounds. The ability to interpret language via lip reading, hand gestures, and context clues is preserved as well. Sometimes, this agnosia is preceded by cortical deafness; however, this is not always the case. Researchers have documented that in most patients exhibiting auditory verbal agnosia, the discriminatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrative Agnosia
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. Symptoms and signs Symptoms generally include memory or learning impairments, with the inability to integrate parts coherently. There is a big range to the severity of this disease and often the symptoms that are shown in each patient vary as well. As ambiguous as the general symptoms may be, patients are often treated of their respective symptoms as they appear and how critical the conditions are. Causes Some of the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonagnosia
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. History 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finger Agnosia
Finger agnosia, first defined in 1924 by Josef Gerstmann, is the loss in the ability to distinguish, name, or recognize the fingers—not only the patient's own fingers, but also the fingers of others, and drawings and other representations of fingers. It is one of a tetrad of symptoms in Gerstmann syndrome, although it is also possible for finger agnosia to exist on its own without any other disorders. Usually, lesions to the left angular gyrus and posterior parietal areas can lead to finger agnosia. Causes Lesions to the left angular gyrus are associated with finger agnosia, as well as the other symptoms of Gerstmann Syndrome, also known as Angular Gyrus Syndrome. In a study by Rusconi et al., repetitive transcranial magnetic stimulation was used in healthy individuals to simulate finger agnosia. Stimulation to the intraparietal sulcus, supramarginal gyrus, as well as the left and right angular gyrus and posterior parietal areas caused difficulties in naming, recognizing, and dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astereognosis
Astereognosis (or tactile agnosia if only one hand is affected) is the inability to identify an object by active touch of the hands without other sensory input, such as visual or sensory information. An individual with astereognosis is unable to identify objects by handling them, despite intact elementary tactile, proprioceptive, and thermal sensation. With the absence of vision (i.e. eyes closed), an individual with astereognosis is unable to identify what is placed in their hand based on cues such as texture, size, spatial properties, and temperature. As opposed to agnosia, when the object is observed visually, one should be able to successfully identify the object. Individuals with tactile agnosia may be able to identify the name, purpose, or origin of an object with their left hand but not their right, or vice versa, or both hands. Astereognosis refers specifically to those who lack tactile recognition in both hands. In the affected hand(s) they may be able to identify basic s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortical Deafness
Cortical deafness is a rare form of sensorineural hearing loss caused by damage to the primary auditory cortex. Cortical deafness is an auditory disorder where the patient is unable to hear sounds but has no apparent damage to the anatomy of the ear (see auditory system), which can be thought of as the combination of auditory verbal agnosia and auditory agnosia. Patients with cortical deafness cannot hear any sounds, that is, they are not aware of sounds including non-speech, voices, and speech sounds. Although patients appear and feel completely deaf, they can still exhibit some reflex responses such as turning their head towards a loud sound. Cause Cortical deafness is caused by bilateral cortical lesions in the primary auditory cortex located in the temporal lobes of the brain. The ascending auditory pathways are damaged, causing a loss of perception of sound. Inner ear functions, however, remains intact. Cortical deafness is most often caused by stroke, but can also result from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
