Tanja C W Nijboer, Martine J E van Zandvoort, Edward H F de Haan
Patients with colour agnosia can perceive colours and are able to match coloured patches on hue, but are unable to identify or categorise colours. It is a rare condition and there is as yet no agreement on the clinical definition or a generally accepted explanation. In line with observations from object agnosia and prosopagnosia, we hypothesised that (some of) these patients might still be able to process colour information at an implicit level. In this study, we investigated this possibility of implicit access to colour semantics and colour names in a man (MAH) who suffers from developmental colour agnosia...
2006: Neuropsychologia
Geneviève Desmarais, Mike J Dixon
Computer-generated shapes varying on visual dimensions such as curvature, tapering, and thickness have been used to investigate identification deficits in the category-specific visual agnosia (CSVA) Patient E.L.M.. However, whether the implemented variations on each of these dimensions were perceived by novice observers as "similar amounts of change" is unknown. To estimate distance in psychophysical shape space, sets of shapes were developed using two different scaling methods--an objective method based on visual search, and a subjective method based on judgments of similarity--and a third approach that did not involve scaling...
August 2005: Perception & Psychophysics
Deirdre M Cooke, Kryss McKenna, Jennifer Fleming
Occupational therapy assessment and treatment of visual perceptual impairments are integral to the rehabilitation of clients following stroke and other acquired brain injuries. Occupational therapists need to identify the nature of visual perceptual performance impairments in order to choose rehabilitation intervention strategies appropriate for remediation of specific problems or to compensate for limitations in daily function. This paper describes the variations in visual perception terminology and occupational therapy approaches to visual perceptual assessment...
June 2005: Scandinavian Journal of Occupational Therapy
Zuhal Yapici
Visual-spatial agnosis, praxis deficits and hallucinations can be the features of subacute sclerosing panencephalitis (SSPE) in the early period. This study describes a 15-year-old boy with SSPE presenting with visual agnosia, prosopagnosia, simultanagnosia, optic ataxia, and oculomotor apraxia which are compatible with Balint syndrome. MRI revealed heterogenous and abnormal signal changes in the bilateral parieto-occipital areas. The signals were more prominent on the left. The case discussed herein is important because he was diagnosed as Balint's syndrome by means of clinical and neuroradiological findings before the onset of known symptomatology as dementia/myoclonus of SSPE...
July 2006: Brain & Development
Ing-Feng Chang, Huo-Yen Hsiao
Novel experiments with Ultrasound Associated with High Frequency Electromagnetic Field (UAHFEMF) irradiation on rats and mice found evidences of characteristic Alzheimer's disease (AD) degenerations including neurite plaques, beta-amyloid, TAU plaque and deposition in cells, Neuro-Fibrillary Tangle and Paired Helical Filament (PHF) with rats and mice irradiated up to 2454 hours. Concomitant passive avoidance test was performed on six mice, and all showed signs of visual and auditory agnosia and lost cognition of threatening condition...
December 2005: Current Alzheimer Research
Akiko Takaiwa, Kenichiro Yamashita, Takuo Nomura, Kenshiro Shida, Takayuki Taniwaki
We re-evaluated a case of carbon monoxide poisoning presenting as visual agnosia who had been injured by explosion of Miike-Mikawa coal mine 40 years ago. In an early stage, his main neuropsychological symptoms were visual agnosia, severe anterograde amnesia, alexia, agraphia, constructional apraxia, left hemispatial neglect and psychic paralysis of gaze, in addition to pyramidal and extra pyramidal signs. At the time of re-evaluation after 40 years, he still showed visual agnosia associated with agraphia and constructional apraxia...
November 2005: Nō to Shinkei, Brain and Nerve
Narong Auvichayapat, Paradee Auvichayapat, Jintanaporn Watanatorn, Jureerut Thamaroj, Suthipun Jitpimolmard
Kluver-Bucy syndrome is a rare neurobehavioral condition characterized by visual agnosia, excessive oral tendencies, hypermetamorphosis, placidity, altered sexual behavior, and changes in dietary habits. This description of a 14-year-old boy presenting with complete Kluver-Bucy syndrome after Mycoplasma pneumoniae bronchitis is the first such case report. MRI revealed left temporal horn dilation and asymmetry of both temporal lobes. We hypothesize that the pathophysiology of our case is immune-mediated damage by M...
February 2006: Epilepsy & Behavior: E&B
C Trivelli, O H Turnbull, S D Sala
A case of visual agnosia is described. The patient, V C, complained of difficulties in identifying visual stimuli, after a stroke in the left occipital lobe. A neuropsychological examination demonstrated a range of symptoms consistent with (ventral) simultanagnosia, and a reaching disorder--suggesting Balint's syndrome. The patient's object recognition ability improved considerably over time.
August 1996: Applied Neuropsychology
Andrew J Larner
No abstract text is available yet for this article.
November 19, 2005: Lancet
J D W Greene
No abstract text is available yet for this article.
December 2005: Journal of Neurology, Neurosurgery, and Psychiatry
Richard Thomas, Emer Forde
We report a study on a patient (DW) with integrative visual agnosia and a category-specific recognition impairment for living things. We assessed DW's local and global processing and tested if his integrative agnosia could have led directly to his category-specific impairment. The main findings were: (i) DW was faster at identifying local compared to global letters. (ii) DW showed no local-to-global (or global-to-local) interference effects in selective attention tasks. (iii) DW showed a congruency effect in a divided attention task, suggesting that, when his attention was cued to both levels, he could process information simultaneously and integrate local and global information...
2006: Neuropsychologia
Constant Rainville, Sven Joubert, Olivier Felician, Vanessa Chabanne, Mathieu Ceccaldi, Patrick Péruch
A 71-year-old right-handed man (F.G.) presents with prosopagnosia and with an inability to recognize famous and familiar buildings. Despite his deficit, F.G. obtained normal scores on neuropsychological tests of executive functions, language, praxis and primary visuoperceptual skills. Brain MRI showed atrophy predominantly in the right temporal lobe, particularly in the fusiform gyrus and the parahippocampal cortex. The present study investigated F.G.'s ability to orient himself in familiar and new environments...
October 2005: Neurocase
Elisabeth Huberle, Hans-Otto Karnath
Simultanagnosia is a rare deficit that impairs individuals in perceiving several objects at the same time. It is usually observed following bilateral parieto-occipital brain damage. Despite the restrictions in perceiving the global aspect of a scene, processing of individual objects remains unaffected. The mechanisms underlying simultanagnosia are not well understood. Previous findings indicated that the integration of multiple objects into a holistic representation of the environment is not impossible per se, but might depend on the spatial relationship between individual objects...
2006: Neuropsychologia
E Karner, C Jenner, E Donnemiller, M Delazer, T Benke
Posterior cortical atrophy (PCA) is a syndrome that involves distinct neuropsychological deficits. This paper presents the clinical and neuropsychological findings recorded in four patients with PCA and reviews the characteristics of the syndrome and other conditions that need to be considered in the differential diagnosis. The cardinal symptoms of PCA are deficits of higher visual and spatial functions (mostly taking the form of Balint's syndrome), variably associated with disorders of visual perception, topographical disorientation, visual object agnosia and prosopagnosia, and deficits affecting reading, copying, drawing, and calculation...
February 2006: Der Nervenarzt
Lionel Naccache
The scientific study of the cerebral substrate of consciousness has been marked by significant recent achievements, resulting partially from an interaction between the exploration of cognition in both brain-damaged patients and healthy subjects. Several neuropsychological syndromes contain marked dissociations that permit the identification of principles related to the neurophysiology of consciousness. The generality of these principles can then be evaluated in healthy subjects using a combination of experimental psychology paradigms, and functional brain-imaging tools...
2005: Progress in Brain Research
Marco Catani, Dominic H ffytche
In a brain composed of localized but connected specialized areas, disconnection leads to dysfunction. This simple formulation underlay a range of 19th century neurological disorders, referred to collectively as disconnection syndromes. Although disconnectionism fell out of favour with the move against localized brain theories in the early 20th century, in 1965, an American neurologist brought disconnection to the fore once more in a paper entitled, 'Disconnexion syndromes in animals and man'. In what was to become the manifesto of behavioural neurology, Norman Geschwind outlined a pure disconnectionist framework which revolutionized both clinical neurology and the neurosciences in general...
October 2005: Brain: a Journal of Neurology
Orna Rosenthal, Marlene Behrmann
Different areas of human visual cortex are thought to play different roles in the learning of visual information: whereas in low/intermediate cortical areas, plasticity may be manifested by enhanced selectivity to learned visual features, in higher-level areas, plasticity may result in generalization and development of tolerance to degraded versions of the learned stimuli. The most effective tolerance to degraded information is presumably achieved in the case of cooperation between the different forms of plasticity...
2006: Neuropsychologia
Jennifer K E Steeves, Jody C Culham, Bradley C Duchaine, Cristiana Cavina Pratesi, Kenneth F Valyear, Igor Schindler, G Keith Humphrey, A David Milner, Melvyn A Goodale
We tested functional activation for faces in patient D.F., who following acquired brain damage has a profound deficit in object recognition based on form (visual form agnosia) and also prosopagnosia that is undocumented to date. Functional imaging demonstrated that like our control observers, D.F. shows significantly more activation when passively viewing face compared to scene images in an area that is consistent with the fusiform face area (FFA) (p < 0.01). Control observers also show occipital face area (OFA) activation; however, whereas D...
2006: Neuropsychologia
B T Carroll, H W Goforth, L A Raimonde
Kluver-Bucy syndrome (KBS) is a rare neuropsychiatric disorder that may be characterized by visual agnosia, placidity, altered sexual activity, hypermetamorphosis, and hyperorality. Patients with KBS present with a complex behavioral syndrome. KBS is usually associated with lesions of the amygdala or amygdaloid pathways. However, partial KBS may occur in the absence of the classic bilateral temporal lesions. Pharmacologic treatment options have been developed from the results of case reports, which suggest that carbamazepine and antipsychotics may be helpful...
April 2001: CNS Spectrums
C F Vinci, C Pontesilli, D Fo
Art forms (music, painting, sculpture, literature and theatre) are essential components in all social and human contexts. The role of art, in this case of theatre, is to express a visual event that aims to help the spectator identify himself/herself in the characters. The play presented here is "A...come non so" and shows the characteristic aspects of Alzheimer's disease from the first stage of the disease to the last stage: amnesia, aphasia, agnosia and apraxia. It tells the story of Carlo Pontercoli, a gerontologist and specialist in cardiovascular disease, who, while writing his paper on "The elderly and sexuality", manifests the first signs of the disease that killed his mother not so long before...
July 2005: Neurological Sciences
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