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Handbook of Clinical Neurology 2015Auditory agnosia refers to impairments in sound perception and identification despite intact hearing, cognitive functioning, and language abilities (reading, writing,... (Review)
Review
Auditory agnosia refers to impairments in sound perception and identification despite intact hearing, cognitive functioning, and language abilities (reading, writing, and speaking). Auditory agnosia can be general, affecting all types of sound perception, or can be (relatively) specific to a particular domain. Verbal auditory agnosia (also known as (pure) word deafness) refers to deficits specific to speech processing, environmental sound agnosia refers to difficulties confined to non-speech environmental sounds, and amusia refers to deficits confined to music. These deficits can be apperceptive, affecting basic perceptual processes, or associative, affecting the relation of a perceived auditory object to its meaning. This chapter discusses what is known about the behavioral symptoms and lesion correlates of these different types of auditory agnosia (focusing especially on verbal auditory agnosia), evidence for the role of a rapid temporal processing deficit in some aspects of auditory agnosia, and the few attempts to treat the perceptual deficits associated with auditory agnosia. A clear picture of auditory agnosia has been slow to emerge, hampered by the considerable heterogeneity in behavioral deficits, associated brain damage, and variable assessments across cases. Despite this lack of clarity, these striking deficits in complex sound processing continue to inform our understanding of auditory perception and cognition.
Topics: Agnosia; Humans
PubMed: 25726291
DOI: 10.1016/B978-0-444-62630-1.00032-9 -
Brain : a Journal of Neurology Oct 2021
Review
Topics: Agnosia; Humans; Imagination; Pattern Recognition, Visual; Visual Cortex; Visual Perception
PubMed: 33856025
DOI: 10.1093/brain/awab159 -
Current Opinion in Neurobiology Apr 1992Object recognition can break down in a variety of ways after brain damage. The resulting different forms of agnosia provide us with useful constraints on theories of... (Review)
Review
Object recognition can break down in a variety of ways after brain damage. The resulting different forms of agnosia provide us with useful constraints on theories of normal object recognition. Recent studies suggest a division of labor for the recognition of different types of stimuli (common objects, words, faces, direction of eye gaze, spatial relations among parts of the human body), a high degree of interactivity in the processes underlying object recognition, and the possibility that recognition and awareness of recognition may be neurally distinct.
Topics: Agnosia; Cognition; Humans
PubMed: 1638147
DOI: 10.1016/0959-4388(92)90005-6 -
Revue Neurologique 2017Visual agnosia encompasses all disorders of visual recognition within a selective visual modality not due to an impairment of elementary visual processing or other... (Review)
Review
Visual agnosia encompasses all disorders of visual recognition within a selective visual modality not due to an impairment of elementary visual processing or other cognitive deficit. Based on a sequential dichotomy between the perceptual and memory systems, two different categories of visual object agnosia are usually considered: 'apperceptive agnosia' and 'associative agnosia'. Impaired visual recognition within a single category of stimuli is also reported in: (i) visual object agnosia of the ventral pathway, such as prosopagnosia (for faces), pure alexia (for words), or topographagnosia (for landmarks); (ii) visual spatial agnosia of the dorsal pathway, such as cerebral akinetopsia (for movement), or orientation agnosia (for the placement of objects in space). Focal brain injuries provide a unique opportunity to better understand regional brain function, particularly with the use of effective statistical approaches such as voxel-based lesion-symptom mapping (VLSM). The aim of the present work was twofold: (i) to review the various agnosia categories according to the traditional visual dual-pathway model; and (ii) to better assess the anatomical network underlying visual recognition through lesion-mapping studies correlating neuroanatomical and clinical outcomes.
Topics: Agnosia; Brain Injuries; Brain Mapping; Cognition Disorders; Humans; Nerve Net; Neuroimaging; Neuropsychological Tests; Visual Pathways; Visual Perception
PubMed: 28843416
DOI: 10.1016/j.neurol.2017.07.009 -
Current Neurology and Neuroscience... Nov 2003The visual agnosias are an intriguing class of clinical phenomena that have important implications for current theories of high-level vision. Visual agnosia is defined... (Review)
Review
The visual agnosias are an intriguing class of clinical phenomena that have important implications for current theories of high-level vision. Visual agnosia is defined as impaired object recognition that cannot be attributed to visual loss, language impairment, or a general mental decline. At least in some instances, agnostic patients generate an adequate internal representation of the stimulus but fail to recognize it. In this review, we begin by describing the classic works related to the visual agnosias, followed by a description of the major clinical variants and their occurrence in degenerative disorders. In keeping with the theme of this issue, we then discuss recent contributions to this domain. Finally, we present evidence from functional imaging studies to support the clinical distinction between the various types of visual agnosias.
Topics: Agnosia; Humans; Neurodegenerative Diseases; Prosopagnosia
PubMed: 14565906
DOI: 10.1007/s11910-003-0055-4 -
Continuum (Minneapolis, Minn.) Jun 2018In part because of their striking clinical presentations, disorders of higher nervous system function figured prominently in the early history of neurology. These... (Review)
Review
PURPOSE OF REVIEW
In part because of their striking clinical presentations, disorders of higher nervous system function figured prominently in the early history of neurology. These disorders are not merely historical curiosities, however. As apraxia, neglect, and agnosia have important clinical implications, it is important to possess a working knowledge of the conditions and how to identify them.
RECENT FINDINGS
Apraxia is a disorder of skilled action that is frequently observed in the setting of dominant hemisphere pathology, whether from stroke or neurodegenerative disorders. In contrast to some previous teaching, apraxia has clear clinical relevance as it is associated with poor recovery from stroke. Neglect is a complex disorder with many different manifestations that may have different underlying mechanisms. Neglect is, in the author's view, a multicomponent disorder in which impairment in attention and arousal is a major contributor. Finally, agnosias come in a wide variety of forms, reflecting impairments ranging from low-level sensory processing to access to stored knowledge of the world (semantics).
SUMMARY
The classic behavioral disorders reviewed here were of immense interest to early neurologists because of their arresting clinical phenomenology; more recent investigations have done much to advance the neuroscientific understanding of the disorders and to reveal their clinical relevance.
Topics: Agnosia; Apraxias; Attention; Humans; Neglected Diseases; Perceptual Disorders; Stroke
PubMed: 29851877
DOI: 10.1212/CON.0000000000000606 -
Brain and Nerve = Shinkei Kenkyu No... Oct 2011Progressive visual agnosia was discovered in the 20th century following the discovery of classical non-progressive visual agnosia. In contrast to the classical type,... (Review)
Review
Progressive visual agnosia was discovered in the 20th century following the discovery of classical non-progressive visual agnosia. In contrast to the classical type, which is caused by cerebral vascular disease or traumatic injury, progressive visual agnosia is a symptom of neurological degeneration. The condition of progressive visual loss, including visual agnosia, and posterior cerebral atrophy was named posterior cortical atrophy (PCA) by Benson et al. (1988). Progressive visual agnosia is also observed in semantic dementia (SD) and other degenerative diseases, but there is a difference in the subtype of visual agnosia associated with these diseases. Lissauer (1890) classified visual agnosia into apperceptive and associative types, and it in most cases, PCA is associated with the apperceptive type. However, SD patients exhibit symptoms of associative visual agnosia before changing to those of semantic memory disorder. Insights into progressive visual agnosia have helped us understand the visual system and discover how we "perceive" the outer world neuronally, with regard to consciousness. Although PCA is a type of atypical dementia, its diagnosis is important to enable patients to live better lives with appropriate functional support.
Topics: Agnosia; Disease Progression; Humans
PubMed: 21987565
DOI: No ID Found -
Archives of Clinical Neuropsychology :... Jun 2017Landmark agnosia is a rare type of navigation impairment, for which various definitions have been presented. From a clinical as well as theoretical perspective,... (Review)
Review
OBJECTIVE
Landmark agnosia is a rare type of navigation impairment, for which various definitions have been presented. From a clinical as well as theoretical perspective, consensus on the characteristics of landmark agnosia would be valuable. In the current study we review the literature concerning landmark agnosia and present a new case study. Existing literature highlights the importance of examining familiar as well as novel landmark processing and substantial variation in performance patterns of individual patients.
METHOD
We performed a case study with patient KS, a 53-year-old male, suffering from landmark agnosia, making use of elaborate neuropsychological screening and virtual reality-based tests of navigation ability.
RESULTS
Our extensive examination of his impairment shows that landmark agnosia can be very narrow; in KS it is restricted to recognition of newly learned landmarks only. Also, he has no trouble recognizing familiar landmarks that are not part of a navigated route.
CONCLUSIONS
The literature review shows that the right temporal lobe, and the right hippocampus in particular are the main lesion sites for landmark agnosia. Furthermore, our case study substantiates that this disorder can occur for both familiar and novel landmarks, and can affect novel landmarks in isolation from familiar landmarks. Moreover, it can occur in isolation from problems with processing route information.
Topics: Agnosia; Humans; Male; Middle Aged; Neuropsychological Tests; Spatial Navigation
PubMed: 28164221
DOI: 10.1093/arclin/acx013 -
Neuropsychological Rehabilitation Dec 2019Visual agnosia and Balint's syndrome are complex neurological disorders of the higher visual system that can have a remarkable impact on individuals' lives.... (Review)
Review
Visual agnosia and Balint's syndrome are complex neurological disorders of the higher visual system that can have a remarkable impact on individuals' lives. Rehabilitation of these individuals is important to enable participation in everyday activities despite the impairment. However, the literature about the rehabilitation of these disorders is virtually silent. Therefore, the aim of this systematic review is to give an overview of available literature describing treatment approaches and their effectiveness with regard to these disorders. The search engines Psychinfo, Amed, and Medline were used, resulting in 22 articles meeting the criteria for inclusion. Only articles describing acquired disorders were considered. These articles revealed that there is some information available on the major subtypes of visual agnosia as well as on Balint's syndrome which practising clinicians can consult for guidance. With regard to the type of rehabilitation, compensatory strategies have proven to be beneficial in most of the cases. Restorative training on the other hand has produced mixed results. Concluding, although still scarce, a scientific foundation about the rehabilitation of visual agnosia and Balint's syndrome is evolving. The available approaches give valuable information that can be built upon in the future.
Topics: Agnosia; Humans; Prosopagnosia; Treatment Outcome; Vision Disorders; Visual Perception
PubMed: 29366371
DOI: 10.1080/09602011.2017.1422272 -
Recenti Progressi in Medicina Dec 1989The term agnosia defines an impairment of stimulus recognition, limited to one modality and not explainable in terms of sensory deficits or general mental deterioration.... (Review)
Review
The term agnosia defines an impairment of stimulus recognition, limited to one modality and not explainable in terms of sensory deficits or general mental deterioration. Visual object agnosia refers to the inability to recognize objects and prosopagnosia to the failure to recognize faces that are well familiar to the patient, when stimuli are visually perceived. Both deficits may appear in an apperceptive form, where it is the internal and external structure of the stimulus to be unrecognized and an associative form where the patient achieves a good percept, but cannot assign it a meaning. Apperceptive forms are preferentially associated with bilateral occipital damage, object associative agnosia with left occipital damage and associative prosopagnosia with right occipital damage.
Topics: Agnosia; Humans; Visual Perception
PubMed: 2697897
DOI: No ID Found