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Sample records for agnosia

  1. Visual agnosia.

    Science.gov (United States)

    Álvarez, R; Masjuan, J

    2016-03-01

    Visual agnosia is defined as an impairment of object recognition, in the absence of visual acuity or cognitive dysfunction that would explain this impairment. This condition is caused by lesions in the visual association cortex, sparing primary visual cortex. There are 2 main pathways that process visual information: the ventral stream, tasked with object recognition, and the dorsal stream, in charge of locating objects in space. Visual agnosia can therefore be divided into 2 major groups depending on which of the two streams is damaged. The aim of this article is to conduct a narrative review of the various visual agnosia syndromes, including recent developments in a number of these syndromes.

  2. Clinical management of agnosia.

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    Burns, Martha S

    2004-01-01

    Agnosia is a neurological recognition deficit that affects a single modality. Visual agnosias include pure object agnosia, prosopagnosia, akinetopsia, and pure alexia. Auditory agnosias include pure word deafness, phonagnosia, and pure sound agnosia. New neuroimaging tools have permitted scientists to better understand the loci of lesions that cause various agnosias and from that knowledge to develop theories about the processing networks that contribute to perception and recognition in each modality. These research data, in turn, inform the rehabilitation process. By utilizing current knowledge about neuroprocessing networks, clinical professionals can differentially diagnose agnosias from aphasia and other cognitive deficits. Practical approaches to treatment of agnosia will follow once the diagnosis is established.

  3. [Progressive visual agnosia].

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    Sugimoto, Azusa; Futamura, Akinori; Kawamura, Mitsuru

    2011-10-01

    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.

  4. Mirror image agnosia

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    Sadanandavalli Retnaswami Chandra

    2014-01-01

    Full Text Available Background: Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one′s own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. Material and Methods:: Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. Results: Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. Discussion: Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery

  5. [Visual Texture Agnosia in Humans].

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    Suzuki, Kyoko

    2015-06-01

    Visual object recognition requires the processing of both geometric and surface properties. Patients with occipital lesions may have visual agnosia, which is impairment in the recognition and identification of visually presented objects primarily through their geometric features. An analogous condition involving the failure to recognize an object by its texture may exist, which can be called visual texture agnosia. Here we present two cases with visual texture agnosia. Case 1 had left homonymous hemianopia and right upper quadrantanopia, along with achromatopsia, prosopagnosia, and texture agnosia, because of damage to his left ventromedial occipitotemporal cortex and right lateral occipito-temporo-parietal cortex due to multiple cerebral embolisms. Although he showed difficulty matching and naming textures of real materials, he could readily name visually presented objects by their contours. Case 2 had right lower quadrantanopia, along with impairment in stereopsis and recognition of texture in 2D images, because of subcortical hemorrhage in the left occipitotemporal region. He failed to recognize shapes based on texture information, whereas shape recognition based on contours was well preserved. Our findings, along with those of three reported cases with texture agnosia, indicate that there are separate channels for processing texture, color, and geometric features, and that the regions around the left collateral sulcus are crucial for texture processing.

  6. Dyspraxia and Agnosia in Schizophrenia

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    Liddle, P. F.; Haque, S; Morris, D. L.; Barnes, T R E

    1993-01-01

    A battery of tests for dyspraxia and agnosia was administered to 51 chronic schizophrenic patients to test the hypothesis that these cortical neurological signs are associated with psychomotor poverty syndrome (poverty of speech, flat affect, decreased spontaneous movement), disorganization syndrome (various disorders of the form of thought, inappropriate affect), abnormal involuntary movements, cognitive impairment, and duration of illness. The findings supported all elements of the hypothes...

  7. [Symptoms and lesion localization in visual agnosia].

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    Suzuki, Kyoko

    2004-11-01

    There are two cortical visual processing streams, the ventral and dorsal stream. The ventral visual stream plays the major role in constructing our perceptual representation of the visual world and the objects within it. Disturbance of visual processing at any stage of the ventral stream could result in impairment of visual recognition. Thus we need systematic investigations to diagnose visual agnosia and its type. Two types of category-selective visual agnosia, prosopagnosia and landmark agnosia, are different from others in that patients could recognize a face as a face and buildings as buildings, but could not identify an individual person or building. Neuronal bases of prosopagnosia and landmark agnosia are distinct. Importance of the right fusiform gyrus for face recognition was confirmed by both clinical and neuroimaging studies. Landmark agnosia is related to lesions in the right parahippocampal gyrus. Enlarged lesions including both the right fusiform and parahippocampal gyri can result in prosopagnosia and landmark agnosia at the same time. Category non-selective visual agnosia is related to bilateral occipito-temporal lesions, which is in agreement with the results of neuroimaging studies that revealed activation of the bilateral occipito-temporal during object recognition tasks.

  8. Dyspraxia and agnosia in schizophrenia.

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    Liddle, P F; Haque, S; Morris, D L; Barnes, T R

    1993-01-01

    A battery of tests for dyspraxia and agnosia was administered to 51 chronic schizophrenic patients to test the hypothesis that these cortical neurological signs are associated with psychomotor poverty syndrome (poverty of speech, flat affect, decreased spontaneous movement), disorganization syndrome (various disorders of the form of thought, inappropriate affect), abnormal involuntary movements, cognitive impairment, and duration of illness. The findings supported all elements of the hypothesis, and in particular, demonstrated a strong correlation of cortical signs with psychomotor poverty and with cognitive impairment. PMID:24487931

  9. Dyspraxia and Agnosia in Schizophrenia

    Directory of Open Access Journals (Sweden)

    P. F. Liddle

    1993-01-01

    Full Text Available A battery of tests for dyspraxia and agnosia was administered to 51 chronic schizophrenic patients to test the hypothesis that these cortical neurological signs are associated with psychomotor poverty syndrome (poverty of speech, flat affect, decreased spontaneous movement, disorganization syndrome (various disorders of the form of thought, inappropriate affect, abnormal involuntary movements, cognitive impairment, and duration of illness. The findings supported all elements of the hypothesis, and in particular, demonstrated a strong correlation of cortical signs with psychomotor poverty and with cognitive impairment.

  10. Neurodegeneration and mirror image agnosia

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    Sadanandavalli Retnaswami Chandra

    2014-01-01

    Full Text Available Background: Normal Percept with abnormal meaning (Agnosias has been described from nineteenth century onwards. Later literature became abundant with information on the spectrum of Prosopagnosias. However, selective difficulty in identifying reflected self images with relatively better cognitive functions leads to problems in differentiating it from non-organic psychosis. Aim: In the present study, we investigated patients with dementia who showed difficulty in identifying reflected self images while they were being tested for problems in gnosis with reference to identification of reflected objects, animals, relatives, and themselves and correlate with neuropsychological and radiological parameters. Patients and Methods: Five such patients were identified and tested with a 45 cm × 45 cm mirror kept at 30-cm distance straight ahead of them. Results: Mirror image agnosia is seen in patients with moderate stage posterior dementias who showed neuropsychological and radiological evidence of right parietal dysfunction. Conclusion: Interpretation of reflected self images perception in real time probably involves distinct data-linking circuits in the right parietal lobe, which may get disrupted early in the course of the disease.

  11. Associative visual agnosia: a case study.

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    Charnallet, A; Carbonnel, S; David, D; Moreaud, O

    2008-01-01

    We report a case of massive associative visual agnosia. In the light of current theories of identification and semantic knowledge organization, a deficit involving both levels of structural description system and visual semantics must be assumed to explain the case. We suggest, in line with a previous case study, an alternative account in the framework of (non abstractive) episodic models of memory.

  12. Associative Visual Agnosia: A Case Study

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    A. Charnallet

    2008-01-01

    Full Text Available We report a case of massive associative visual agnosia. In the light of current theories of identification and semantic knowledge organization, a deficit involving both levels of structural description system and visual semantics must be assumed to explain the case. We suggest, in line with a previous case study [1], an alternative account in the framework of (non abstractive episodic models of memory [4].

  13. [Agnosia for streets and defective root finding].

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    Takahashi, Nobuyoshi

    2011-08-01

    Topographical disorientation is identified as a condition in which patients are unable to find their way in familiar surroundings, such as their home neighborhood or the admitting hospital after the onset of illness. I proposed to classify topographical disorientation into two categories: agnosia for streets (landmark agnosia) and defective root finding (heading disorientation). Patients with agnosia for streets are unable to identify familiar buildings and landscapes. They can, however, morphologically perceive them and remember their way around familiar areas. The lesions are located in the right posterior part of the parahippocampus gyrus, anterior half of the lingual gyrus and adjacent fusiform gyrus. Clinical findings and functional imaging studies suggest that these regions play a crucial role in the interaction between the visual information of streets and memories of them, which are thought to be retained in the right anterior part of the temporal lobe. In particular, the posterior part of the parahippocampus gyrus is critical for the acquisition of novel information. On the other hand, patients with defective root finding can identify familiar streets, but cannot remember their own location or positional relation between two points within a comparatively wide range not surveyable at one time. The lesions are located in the right retrosplenial cortex (Areas 29, 30), posterior cingulate cortex (Areas 23, 31) and precuneus. Clinical findings and functional imaging studies suggest that these regions are involved in the orientation function for navigating in wide spaces. In particular, the retrosplenial cortex is critical for encoding novel information.

  14. Perception of biological motion in visual agnosia

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    Elisabeth eHuberle

    2012-08-01

    Full Text Available Over the past twenty-five years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral (‘what' and a dorsal ('where' visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non-biological motion has been suggested: Perception of biological motion might be impaired when 'non-biological' motion perception is intact and vice versa. The impact of object recognition on the perception of biological motion remains unclear. We thus investigated this question in a patient with severe visual agnosia, who showed normal perception of non-biological motion. The data suggested that the patient's perception of biological motion remained largely intact. However, when tested with objects constructed of coherently moving dots (‘Shape-from-Motion’, recognition was severely impaired. The results are discussed in the context of possible mechanisms of biological motion perception.

  15. Perception of biological motion in visual agnosia.

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    Huberle, Elisabeth; Rupek, Paul; Lappe, Markus; Karnath, Hans-Otto

    2012-01-01

    Over the past 25 years, visual processing has been discussed in the context of the dual stream hypothesis consisting of a ventral ("what") and a dorsal ("where") visual information processing pathway. Patients with brain damage of the ventral pathway typically present with signs of visual agnosia, the inability to identify and discriminate objects by visual exploration, but show normal perception of motion perception. A dissociation between the perception of biological motion and non-biological motion has been suggested: perception of biological motion might be impaired when "non-biological" motion perception is intact and vice versa. The impact of object recognition on the perception of biological motion remains unclear. We thus investigated this question in a patient with severe visual agnosia, who showed normal perception of non-biological motion. The data suggested that the patient's perception of biological motion remained largely intact. However, when tested with objects constructed of coherently moving dots ("Shape-from-Motion"), recognition was severely impaired. The results are discussed in the context of possible mechanisms of biological motion perception.

  16. Integrative agnosia following progressive multifocal leukoencephalopathy.

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    Butter, C M; Trobe, J D

    1994-03-01

    A 43 year-old man with presumed progressive multifocal leukoencephalopathy developed difficulty recognizing objects and faces in the presence of adequate visual acuity and visual fields. His copying and matching of line drawings was intact, suggesting that his agnosia was associative. However, he had difficulty perceiving overlapping forms and drawings of single objects as integrated wholes. Unlike control subjects, he made fewer errors identifying silhouettes compared to line drawings with internal details. These alterations, together with his feature-by-feature descriptions of objects and copying, suggest that his agnosia was due to a disturbance in integrating local form features, as described by Riddoch and Humphreys (1987). This interpretation is supported by the findings that his tactile recognition and semantic and structural knowledge of the objects he could not identify visually were intact. Furthermore, his deficient performance in categorical matching of photographs to objects was dependent upon the perceptual complexity of the photographs. Similar deficits in early form processing described by other investigators are discussed. PMID:8004984

  17. The neuropsychological and neuroradiological correlates of slowly progressive visual agnosia.

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    Giovagnoli, Anna Rita; Aresi, Anna; Reati, Fabiola; Riva, Alice; Gobbo, Clara; Bizzi, Alberto

    2009-04-01

    The case of a 64-year-old woman affected by slowly progressive visual agnosia is reported aiming to describe specific cognitive-brain relationships. Longitudinal clinical and neuropsychological assessment, combined with magnetic resonance imaging (MRI), spectroscopy, and positron emission tomography (PET) were used. Sequential neuropsychological evaluations performed during a period of 9 years since disease onset showed the appearance of apperceptive and associative visual agnosia, alexia without agraphia, agraphia, finger agnosia, and prosopoagnosia, but excluded dementia. MRI showed moderate diffuse cortical atrophy, with predominant atrophy in the left posterior cortical areas (temporal, parietal, and lateral occipital cortical gyri). 18FDG-PET showed marked bilateral posterior cortical hypometabolism; proton magnetic resonance spectroscopic imaging disclosed severe focal N-acetyl-aspartate depletion in the left temporoparietal and lateral occipital cortical areas. In conclusion, selective metabolic alterations and neuronal loss in the left temporoparietooccipital cortex may determine progressive visual agnosia in the absence of dementia.

  18. [Approaches to therapy of auditory agnosia].

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    Fechtelpeter, A; Göddenhenrich, S; Huber, W; Springer, L

    1990-01-01

    In a 41-year-old stroke patient with bitemporal brain damage, we found severe signs of auditory agnosia 6 months after onset. Recognition of environmental sounds was extremely impaired when tested in a multiple choice sound-picture matching task, whereas auditory discrimination between sounds and picture identifications by written names was almost undisturbed. In a therapy experiment, we tried to enhance sound recognition via semantic categorization and association, imitation of sound and analysis of auditory features, respectively. The stimulation of conscious auditory analysis proved to be increasingly effective over a 4-week period of therapy. We were able to show that the patient's improvement was not only a simple effect of practicing, but it was stable and carried over to nontrained items.

  19. A tale of two agnosias: distinctions between form and integrative agnosia.

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    Riddoch, M Jane; Humphreys, Glyn W; Akhtar, Nabeela; Allen, Harriet; Bracewell, R Martyn; Schofield, Andrew J

    2008-02-01

    The performance of two patients with visual agnosia was compared across a number of tests examining visual processing. The patients were distinguished by having dorsal and medial ventral extrastriate lesions. While inanimate objects were disadvantaged for the patient with a dorsal extrastriate lesion, animate items are disadvantaged for the patient with the medial ventral extrastriate lesion. The patients also showed contrasting patterns of performance on the Navon Test: The patient with a dorsal extrastriate lesion demonstrated a local bias while the patient with a medial ventral extrastriate lesion had a global bias. We propose that the dorsal and medial ventral visual pathways may be characterized at an extrastriate level by differences in local relative to more global visual processing and that this can link to visually based category-specific deficits in processing.

  20. [A case of agnosia for streets without visual memory disturbance].

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    Aoki, Kazuko; Hiroki, Masahiko; Bando, Mitsuaki; Miyamoto, Kazuhito; Hirai, Shunsaku

    2003-06-01

    A 70-year-old, right-handed man was admitted to our hospital for his sudden-onset topographical disorientation. He failed to find his way to familiar places, but he knew distance and direction to the places. Neurological examination revealed homonymous left-upper quadrantanopsia on Goldmann perimeter and hypoesthesia over the left side of his body. Magnetic resonance imaging showed an abnormal intensity area at the right medial temporo-occipital region, due to the infarct of the right posterior cerebral arterial territory. The neuropsychological examination revealed agnosia for streets, and prosopagnosia without any other disturbance of visual perception. Both visual and topographical memories were intact. It is suggested that, in this case, the agnosia for streets was caused by impairment of recognizing familiar streets and houses or disconnection between their recognition and memory.

  1. [A case of visual agnosia for picture with right occipital lobe infarction].

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    Koide, R; Bandoh, M; Isozaki, E; Hirai, S

    2001-06-01

    We report a 74-year-old right-handed man with visual agnosia for picture due to right occipital lobe infarction. The patient had a remarkable impairment in visual recognition for standardized pictures made by Snodgrass and Vanderwart, in addition to left hemianopsia, left visuospatial neglect, and mild prosopagnosia. The visual agnosia for picture was generally recognized as a mild-type of the visual object agnosia, which was extremely rare in the patients with right occipital lesion. We discussed the mechanism of the visual agnosia in the right occipital lesion. Therefore, it raises the possibility that the broad impairment of the right occipital artery territory including parahippocampal gyrus as well as corpus callosum can cause the visual agnosia for picture.

  2. Implicit integration in a case of integrative visual agnosia.

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    Aviezer, Hillel; Landau, Ayelet N; Robertson, Lynn C; Peterson, Mary A; Soroker, Nachum; Sacher, Yaron; Bonneh, Yoram; Bentin, Shlomo

    2007-05-15

    We present a case (SE) with integrative visual agnosia following ischemic stroke affecting the right dorsal and the left ventral pathways of the visual system. Despite his inability to identify global hierarchical letters [Navon, D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353-383], and his dense object agnosia, SE showed normal global-to-local interference when responding to local letters in Navon hierarchical stimuli and significant picture-word identity priming in a semantic decision task for words. Since priming was absent if these features were scrambled, it stands to reason that these effects were not due to priming by distinctive features. The contrast between priming effects induced by coherent and scrambled stimuli is consistent with implicit but not explicit integration of features into a unified whole. We went on to show that possible/impossible object decisions were facilitated by words in a word-picture priming task, suggesting that prompts could activate perceptually integrated images in a backward fashion. We conclude that the absence of SE's ability to identify visual objects except through tedious serial construction reflects a deficit in accessing an integrated visual representation through bottom-up visual processing alone. However, top-down generated images can help activate these visual representations through semantic links.

  3. Agnosia for mirror stimuli: a new case report with a small parietal lesion.

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    Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Lebas, Axel; Gerardin, Emmanuel; Hannequin, Didier

    2014-11-01

    Only seven cases of agnosia for mirror stimuli have been reported, always with an extensive lesion. We report a new case of an agnosia for mirror stimuli due to a circumscribed lesion. An extensive battery of neuropsychological tests and a new experimental procedure to assess visual object mirror and orientation discrimination were assessed 10 days after the onset of clinical symptoms, and 5 years later. The performances of our patient were compared with those of four healthy control subjects matched for age. This test revealed an agnosia for mirror stimuli. Brain imaging showed a small right occipitoparietal hematoma, encompassing the extrastriate cortex adjoining the inferior parietal lobe. This new case suggests that: (i) agnosia for mirror stimuli can persist for 5 years after onset and (ii) the posterior part of the right intraparietal sulcus could be critical in the cognitive process of mirror stimuli discrimination.

  4. The neural basis of body form and body action agnosia.

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    Moro, Valentina; Urgesi, Cosimo; Pernigo, Simone; Lanteri, Paola; Pazzaglia, Mariella; Aglioti, Salvatore Maria

    2008-10-23

    Visual analysis of faces and nonfacial body stimuli brings about neural activity in different cortical areas. Moreover, processing body form and body action relies on distinct neural substrates. Although brain lesion studies show specific face processing deficits, neuropsychological evidence for defective recognition of nonfacial body parts is lacking. By combining psychophysics studies with lesion-mapping techniques, we found that lesions of ventromedial, occipitotemporal areas induce face and body recognition deficits while lesions involving extrastriate body area seem causatively associated with impaired recognition of body but not of face and object stimuli. We also found that body form and body action recognition deficits can be double dissociated and are causatively associated with lesions to extrastriate body area and ventral premotor cortex, respectively. Our study reports two category-specific visual deficits, called body form and body action agnosia, and highlights their neural underpinnings.

  5. "Mirror agnosia" in a patient with right occipitotemporal infarct

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    Menon Bijoy

    2006-01-01

    Full Text Available We report the clinical profile and investigation of K, a patient suffering from agnosia for the concept of "mirrors". Normal people rarely confuse a mirror image for the real image. Our patient ′K′ has intact attention, memory and language with a left visual neglect with left hemianopia. When shown an object on his left with a mirror kept sagitally on his right, K grabs for the reflection and even gropes behind the mirror for it. Yet, when shown the mirror alone, he is able to tell that it is a mirror. Thus the concept of a ′mirror′ is lost in the experimental paradigm. An explanation for mirror ′agnosia′ is provided and recent controversies in the analysis of visuospatial functions in humans is highlighted.

  6. ''I Could See, and Yet, Mon, I Could Na' See'': William Macewen, the Agnosias, and Brain Surgery

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    Macmillan, Malcolm

    2004-01-01

    Two little noticed cases in which William Macewen used symptoms of visual agnosia to plan brain surgery on the angular gyrus are reviewed and evaluated. Following a head injury, Macewen's first patient had an immediate and severe visual object agnosia that lasted for about 2 weeks. After that he gradually became homicidal and depressed and it was…

  7. Detecting gradual visual changes in colour and brightness agnosia: a double dissociation.

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    Nijboer, Tanja C W; te Pas, Susan F; van der Smagt, Maarten J

    2011-03-01

    Two patients, one with colour agnosia and one with brightness agnosia, performed a task that required the detection of gradual temporal changes in colour and brightness. The results for these patients, who showed anaverage or an above-average performance on several tasks designed to test low-level colour and luminance (contrast) perception in the spatial domain, yielded a double dissociation; the brightness agnosic patient was within the normal range for the coloured stimuli, but much slower to detect brightness differences, whereas the colour agnosic patient was within the normal range for the achromatic stimuli, but much slower for the coloured stimuli. These results suggest that a modality-specific impairment in the detection of gradual temporal changes might be related to, if not underlie, the phenomenon of visual agnosia.

  8. Episodic epileptic verbal auditory agnosia in Landau Kleffner syndrome treated with combination diazepam and corticosteroids.

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    Devinsky, Orrin; Goldberg, Rina; Miles, Daniel; Bojko, Aviva; Riviello, James

    2014-10-01

    We report 2 pediatric patients who presented initially with seizures followed by subacute language regression characterized by a verbal auditory agnosia. These previously normal children had no evidence of expressive aphasia during their symptomatic periods. Further, in both cases, auditory agnosia was associated with sleep-activated electroencephalographic (EEG) epileptiform activity, consistent with Landau-Kleffner syndrome. However, both cases are unique since the episodic auditory agnosia and sleep-activated EEG epileptiform activity rapidly responded to combination therapy with pulse benzodiazepine and corticosteroids. Further, in each case, recurrences were characterized by similar symptoms, EEG findings, and beneficial responses to the pulse benzodiazepine and corticosteroid therapy. These observations suggest that pulse combination high-dose corticosteroid and benzodiazepine therapy may be especially effective in Landau-Kleffner syndrome.

  9. When apperceptive agnosia is explained by a deficit of primary visual processing.

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    Serino, Andrea; Cecere, Roberto; Dundon, Neil; Bertini, Caterina; Sanchez-Castaneda, Cristina; Làdavas, Elisabetta

    2014-03-01

    Visual agnosia is a deficit in shape perception, affecting figure, object, face and letter recognition. Agnosia is usually attributed to lesions to high-order modules of the visual system, which combine visual cues to represent the shape of objects. However, most of previously reported agnosia cases presented visual field (VF) defects and poor primary visual processing. The present case-study aims to verify whether form agnosia could be explained by a deficit in basic visual functions, rather that by a deficit in high-order shape recognition. Patient SDV suffered a bilateral lesion of the occipital cortex due to anoxia. When tested, he could navigate, interact with others, and was autonomous in daily life activities. However, he could not recognize objects from drawings and figures, read or recognize familiar faces. He was able to recognize objects by touch and people from their voice. Assessments of visual functions showed blindness at the centre of the VF, up to almost 5°, bilaterally, with better stimulus detection in the periphery. Colour and motion perception was preserved. Psychophysical experiments showed that SDV's visual recognition deficits were not explained by poor spatial acuity or by the crowding effect. Rather a severe deficit in line orientation processing might be a key mechanism explaining SDV's agnosia. Line orientation processing is a basic function of primary visual cortex neurons, necessary for detecting "edges" of visual stimuli to build up a "primal sketch" for object recognition. We propose, therefore, that some forms of visual agnosia may be explained by deficits in basic visual functions due to widespread lesions of the primary visual areas, affecting primary levels of visual processing.

  10. Grasping what is graspable: evidence from visual form agnosia.

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    McIntosh, Robert D; Dijkerman, H Chris; Mon-Williams, Mark; Milner, A David

    2004-01-01

    Patient DF has profound visual form agnosia. Despite this, she has no problem adjusting her finger-thumb grip aperture to the width of objects when reaching to grasp them. In a previous study, however, she was found to have great difficulty in scaling her grip aperture when attempting to grasp a transparent disc through two holes cut into it. This problem was attributed to a putative difference between the visual processing of size and distance in the brain, whereby DF retained the capacity for processing object size but not the separation between distinct elements such as holes. In the present study we have tested this idea more directly, and found no evidence to support such a distinction. Nonetheless, we replicated our earlier finding that DF is unable to produce normal prehension movements when attempting to grasp transparent stimuli by placing her digits into holes. We suggest that, whilst some simple objects offer themselves directly to the dorsal stream for grasping, an intact ventral stream is required to respond appropriately to more complex stimuli.

  11. Eye movements during object recognition in visual agnosia.

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    Charles Leek, E; Patterson, Candy; Paul, Matthew A; Rafal, Robert; Cristino, Filipe

    2012-07-01

    This paper reports the first ever detailed study about eye movement patterns during single object recognition in visual agnosia. Eye movements were recorded in a patient with an integrative agnosic deficit during two recognition tasks: common object naming and novel object recognition memory. The patient showed normal directional biases in saccades and fixation dwell times in both tasks and was as likely as controls to fixate within object bounding contour regardless of recognition accuracy. In contrast, following initial saccades of similar amplitude to controls, the patient showed a bias for short saccades. In object naming, but not in recognition memory, the similarity of the spatial distributions of patient and control fixations was modulated by recognition accuracy. The study provides new evidence about how eye movements can be used to elucidate the functional impairments underlying object recognition deficits. We argue that the results reflect a breakdown in normal functional processes involved in the integration of shape information across object structure during the visual perception of shape.

  12. Psychic blindness or visual agnosia: early descriptions of a nervous disorder.

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    Baumann, Christian

    2011-01-01

    This article briefly reports on three early contributions to the understanding of visual agnosia as a syndrome sui generis. The authors of the respective papers worked in different fields such as physiology, ophthalmology, and neurology, and, although they were not in direct contact with each other, their results converged upon a consistent view of a nervous disorder that they called psychic blindness.

  13. Independent Representation of Parts and the Relations between Them: Evidence from Integrative Agnosia

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    Behrmann, Marlene; Peterson, Mary A.; Moscovitch, Morris; Suzuki, Satoru

    2006-01-01

    Whether objects are represented as a collection of parts whose relations are coded independently remains a topic of ongoing discussion among theorists in the domain of shape perception. S. M., an individual with integrative agnosia, and neurologically intact ("normal") individuals learned initially to identify 4 target objects constructed of 2…

  14. Fixation and saliency during search of natural scenes: the case of visual agnosia.

    Science.gov (United States)

    Foulsham, Tom; Barton, Jason J S; Kingstone, Alan; Dewhurst, Richard; Underwood, Geoffrey

    2009-07-01

    Models of eye movement control in natural scenes often distinguish between stimulus-driven processes (which guide the eyes to visually salient regions) and those based on task and object knowledge (which depend on expectations or identification of objects and scene gist). In the present investigation, the eye movements of a patient with visual agnosia were recorded while she searched for objects within photographs of natural scenes and compared to those made by students and age-matched controls. Agnosia is assumed to disrupt the top-down knowledge available in this task, and so may increase the reliance on bottom-up cues. The patient's deficit in object recognition was seen in poor search performance and inefficient scanning. The low-level saliency of target objects had an effect on responses in visual agnosia, and the most salient region in the scene was more likely to be fixated by the patient than by controls. An analysis of model-predicted saliency at fixation locations indicated a closer match between fixations and low-level saliency in agnosia than in controls. These findings are discussed in relation to saliency-map models and the balance between high and low-level factors in eye guidance.

  15. [Simultanagnosia and scene agnosia induced by right posterior cerebral artery infarction: a case report].

    Science.gov (United States)

    Kobayashi, Yasutaka; Muramatsu, Tomoko; Sato, Mamiko; Hayashi, Hiromi; Miura, Toyoaki

    2015-01-01

    A 68-year-old man was admitted to our hospital for rehabilitation of topographical disorientation. Brain magnetic resonance imaging revealed infarction in the right medial side of the occipital lobe. On neuropsychological testing, he scored low for the visual information-processing task; however, his overall cognitive function was retained. He could identify parts of the picture while describing the context picture of the Visual Perception Test for Agnosia but could not explain the contents of the entire picture, representing so-called simultanagnosia. Further, he could morphologically perceive both familiar and new scenes, but could not identify them, representing so-called scene agnosia. We report this case because simultanagnosia associated with a right occipital lobe lesion is rare.

  16. Pleasurable Emotional Response to Music: A Case of Neurodegenerative Generalized Auditory Agnosia

    OpenAIRE

    Matthews, Brandy R.; Chang, Chiung-Chih; May, Mary; Engstrom, John; Bruce L. Miller

    2009-01-01

    Recent functional neuroimaging studies implicate the network of mesolimbic structures known to be active in reward processing as the neural substrate of pleasure associated with listening to music. Psychoacoustic and lesion studies suggest that there is a widely distributed cortical network involved in processing discreet musical variables. Here we present the case of a young man with auditory agnosia as the consequence of cortical neurodegeneration who continues to experience pleasure when e...

  17. Evidence for perceptual deficits in associative visual (prosop)agnosia: a single-case study.

    Science.gov (United States)

    Delvenne, Jean François; Seron, Xavier; Coyette, Françoise; Rossion, Bruno

    2004-01-01

    Associative visual agnosia is classically defined as normal visual perception stripped of its meaning [Archiv für Psychiatrie und Nervenkrankheiten 21 (1890) 22/English translation: Cognitive Neuropsychol. 5 (1988) 155]: these patients cannot access to their stored visual memories to categorize the objects nonetheless perceived correctly. However, according to an influential theory of visual agnosia [Farah, Visual Agnosia: Disorders of Object Recognition and What They Tell Us about Normal Vision, MIT Press, Cambridge, MA, 1990], visual associative agnosics necessarily present perceptual deficits that are the cause of their impairment at object recognition Here we report a detailed investigation of a patient with bilateral occipito-temporal lesions strongly impaired at object and face recognition. NS presents normal drawing copy, and normal performance at object and face matching tasks as used in classical neuropsychological tests. However, when tested with several computer tasks using carefully controlled visual stimuli and taking both his accuracy rate and response times into account, NS was found to have abnormal performances at high-level visual processing of objects and faces. Albeit presenting a different pattern of deficits than previously described in integrative agnosic patients such as HJA and LH, his deficits were characterized by an inability to integrate individual parts into a whole percept, as suggested by his failure at processing structurally impossible three-dimensional (3D) objects, an absence of face inversion effects and an advantage at detecting and matching single parts. Taken together, these observations question the idea of separate visual representations for object/face perception and object/face knowledge derived from investigations of visual associative (prosop)agnosia, and they raise some methodological issues in the analysis of single-case studies of (prosop)agnosic patients.

  18. Dissociating 'what' and 'how' in visual form agnosia: a computational investigation.

    Science.gov (United States)

    Vecera, S P

    2002-01-01

    Patients with visual form agnosia exhibit a profound impairment in shape perception (what an object is) coupled with intact visuomotor functions (how to act on an object), demonstrating a dissociation between visual perception and action. How can these patients act on objects that they cannot perceive? Although two explanations of this 'what-how' dissociation have been offered, each explanation has shortcomings. A 'pathway information' account of the 'what-how' dissociation is presented in this paper. This account hypothesizes that 'where' and 'how' tasks require less information than 'what' tasks, thereby allowing 'where/how' to remain relatively spared in the face of neurological damage. Simulations with a neural network model test the predictions of the pathway information account. Following damage to an input layer common to the 'what' and 'where/how' pathways, the model performs object identification more poorly than spatial localization. Thus, the model offers a parsimonious explanation of differential 'what-how' performance in visual form agnosia. The simulation results are discussed in terms of their implications for visual form agnosia and other neuropsychological syndromes.

  19. Superior voice recognition in a patient with acquired prosopagnosia and object agnosia.

    Science.gov (United States)

    Hoover, Adria E N; Démonet, Jean-François; Steeves, Jennifer K E

    2010-11-01

    Anecdotally, it has been reported that individuals with acquired prosopagnosia compensate for their inability to recognize faces by using other person identity cues such as hair, gait or the voice. Are they therefore superior at the use of non-face cues, specifically voices, to person identity? Here, we empirically measure person and object identity recognition in a patient with acquired prosopagnosia and object agnosia. We quantify person identity (face and voice) and object identity (car and horn) recognition for visual, auditory, and bimodal (visual and auditory) stimuli. The patient is unable to recognize faces or cars, consistent with his prosopagnosia and object agnosia, respectively. He is perfectly able to recognize people's voices and car horns and bimodal stimuli. These data show a reverse shift in the typical weighting of visual over auditory information for audiovisual stimuli in a compromised visual recognition system. Moreover, the patient shows selectively superior voice recognition compared to the controls revealing that two different stimulus domains, persons and objects, may not be equally affected by sensory adaptation effects. This also implies that person and object identity recognition are processed in separate pathways. These data demonstrate that an individual with acquired prosopagnosia and object agnosia can compensate for the visual impairment and become quite skilled at using spared aspects of sensory processing. In the case of acquired prosopagnosia it is advantageous to develop a superior use of voices for person identity recognition in everyday life.

  20. Behavioral change and its neural correlates in visual agnosia after expertise training.

    Science.gov (United States)

    Behrmann, Marlene; Marotta, Jonathan; Gauthier, Isabel; Tarr, Michael J; McKeeff, Thomas J

    2005-04-01

    Agnosia, the impairment in object and face recognition despite intact vision and intelligence, is one of the most intriguing and debilitating neuropsychological deficits. The goal of this study was to determine whether S.M., an individual with longstanding visual agnosia and concomitant prosopagnosia, can be retrained to perform visual object recognition and, if so, what neural substrates mediate this reacquisition. Additionally, of interest is the extent to which training on one type of visual stimulus generalizes to other visual stimuli, as this informs our understanding of the organization of ventral visual cortex. Greebles were chosen as the stimuli for retraining given that, in neurologically normal individuals, these stimuli can engage the fusiform face area. Posttraining, S.M. showed significant improvement in recognizing Greebles, although he did not attain normal levels of performance. He was also able to recognize untrained Greebles and showed improvement in recognizing common objects. Surprisingly, his performance on face recognition, albeit poor initially, was even more impaired following training. A comparison of pre- and postintervention functional neuroimaging data mirrored the behavioral findings: Face-selective voxels in the fusiform gyrus prior to training were no longer so and were, in fact, more Greeble-selective. The findings indicate potential for experience-dependent dynamic reorganization in agnosia with the possibility that residual neural tissue, with limited capacity, will compete for representations.

  1. Electrophysiological correlates of associative visual agnosia lesioned in the ventral pathway.

    Science.gov (United States)

    Yamasaki, Takao; Taniwaki, Takayuki; Tobimatsu, Shozo; Arakawa, Kenji; Kuba, Hiroshi; Maeda, Yoshihisa; Kuwabara, Yasuo; Shida, Kenshiro; Ohyagi, Yasumasa; Yamada, Takeshi; Kira, Jun-ichi

    2004-06-15

    Visual agnosia has been well studied by anatomical, neuropsychological and neuroimaging studies. However, functional changes in the brain have been rarely assessed by electrophysiological methods. We carried out electrophysiological examinations on a 23-year-old man with associative visual agnosia, prosopagnosia and cerebral achromatopsia to evaluate the higher brain dysfunctions of visual recognition. Electrophysiological methods consisted of achromatic, chromatic and category-specific visual evoked potentials (CS-VEPs), and event-related potentials (ERPs) with color and motion discrimination tasks. Brain magnetic resonance imaging revealed large white matter lesions in the bilateral temporo-occipital lobes involving the lingual and fusiform gyri (V4) and inferior longitudinal fasciculi due to multiple sclerosis. Examinations including CS-VEPs demonstrated dysfunctions of face and object perception while sparing semantic word perception after primary visual cortex (V1) in the ventral pathway. ERPs showed abnormal color perception in the ventral pathway with normal motion perception in the dorsal pathway. These electrophysiological findings were consistent with lesions in the ventral pathway that were detected by clinical and neuroimaging findings. Therefore, CS-VEPs and ERPs with color and motion discrimination tasks are useful methods for assessing the functional changes of visual recognition such as visual agnosia.

  2. Structural and functional changes across the visual cortex of a patient with visual form agnosia.

    Science.gov (United States)

    Bridge, Holly; Thomas, Owen M; Minini, Loredana; Cavina-Pratesi, Cristiana; Milner, A David; Parker, Andrew J

    2013-07-31

    Loss of shape recognition in visual-form agnosia occurs without equivalent losses in the use of vision to guide actions, providing support for the hypothesis of two visual systems (for "perception" and "action"). The human individual DF received a toxic exposure to carbon monoxide some years ago, which resulted in a persisting visual-form agnosia that has been extensively characterized at the behavioral level. We conducted a detailed high-resolution MRI study of DF's cortex, combining structural and functional measurements. We present the first accurate quantification of the changes in thickness across DF's occipital cortex, finding the most substantial loss in the lateral occipital cortex (LOC). There are reduced white matter connections between LOC and other areas. Functional measures show pockets of activity that survive within structurally damaged areas. The topographic mapping of visual areas showed that ordered retinotopic maps were evident for DF in the ventral portions of visual cortical areas V1, V2, V3, and hV4. Although V1 shows evidence of topographic order in its dorsal portion, such maps could not be found in the dorsal parts of V2 and V3. We conclude that it is not possible to understand fully the deficits in object perception in visual-form agnosia without the exploitation of both structural and functional measurements. Our results also highlight for DF the cortical routes through which visual information is able to pass to support her well-documented abilities to use visual information to guide actions.

  3. Visual Agnosia for Line Drawings and Silhouettes without Apparent Impairment of Real-Object Recognition: A Case Report

    Directory of Open Access Journals (Sweden)

    Kotaro Hiraoka

    2009-01-01

    Full Text Available We report on a patient with visual agnosia for line drawings and silhouette pictures following cerebral infarction in the region of the right posterior cerebral artery. The patient retained the ability to recognize real objects and their photographs, and could precisely copy line drawings of objects that she could not name. This case report highlights the importance of clinicians and researchers paying special attention to avoid overlooking agnosia in such cases. The factors that lead to problems in the identification of stimuli other than real objects in agnosic cases are discussed.

  4. Visual agnosia for line drawings and silhouettes without apparent impairment of real-object recognition: a case report.

    Science.gov (United States)

    Hiraoka, Kotaro; Suzuki, Kyoko; Hirayama, Kazumi; Mori, Etsuro

    2009-01-01

    We report on a patient with visual agnosia for line drawings and silhouette pictures following cerebral infarction in the region of the right posterior cerebral artery. The patient retained the ability to recognize real objects and their photographs, and could precisely copy line drawings of objects that she could not name. This case report highlights the importance of clinicians and researchers paying special attention to avoid overlooking agnosia in such cases. The factors that lead to problems in the identification of stimuli other than real objects in agnosic cases are discussed.

  5. Visual agnosia in a child with non-lesional occipito-temporal CSWS.

    Science.gov (United States)

    Eriksson, Kai; Kylliäinen, Anneli; Hirvonen, Kari; Nieminen, Pirkko; Koivikko, Matti

    2003-06-01

    In this paper we describe a case of severe visual agnosia in a child with an electrophysiological pattern of continuous spike-wave discharges in slow sleep (CSWS) in the occipito-temporal regions. The neuropsychological spectrum related to this phenomenon is discussed. Published paediatric reports associate visual agnosia (i.e. an inability to recognize objects without impairment of visual acuity) mainly with symptomatic occipito-temporal aetiology (e.g. cortical dysplasia, vascular insults) and other neurological symptoms (e.g. autism). We describe a detailed 2 year electrophysiological and neuropsychological follow-up of an 8-year-old boy with sporadic seizures, occipito-temporal CSWS and visual agnosia. The growth and neurological development of the child had been considered as normal, neurological examination did not reveal any focal signs, visual acuity was intact and MRI was normal. First EEG and six consecutive 24 h video EEG recordings during the follow-up of 22 months showed continuous spike-and-wave activity covering over 85% of the non-REM sleep. According to structured neuropsychological tests (Wechsler Intelligence Scale for Children--Third Edition, A Developmental Neuropsychological Assessment (NEPSY), Test of Visual-Perceptual Skills, Corsi block, Hooper Visual Organization Test) the boy had normal verbal intelligence but major deficits in visual perception, especially in object recognition, impaired shape discrimination and detection, and poor copying skills. Attention and executive functions were intact. There were no difficulties in short- or long-term memory. Verbal cues and naming the objects improved visual memory. Tracing the objects with a finger or by moving the head improved object recognition. Currently the boy attends a special school with a rehabilitation plan including neuropsychological and occupational therapies. This case adds a new facet to the spectrum of neuropsychological deficits in children with CSWS. Sleep EEG should be

  6. Radical “Visual Capture” Observed in a Patient with Severe Visual Agnosia

    OpenAIRE

    Akiko Takaiwa; Hirokazu Yoshimura; Hirofumi Abe; Satoshi Terai

    2003-01-01

    We report the case of a 79-year-old female with visual agnosia due to brain infarction in the left posterior cerebral artery. She could recognize objects used in daily life rather well by touch (the number of objects correctly identified was 16 out of 20 presented objects), but she could not recognize them as well by vision (6 out of 20). In this case, it was expected that she would recognize them well when permitted to use touch and vision simultaneously. Our patient, however, performed poor...

  7. The Role of Sensory-Motor Information in Object Recognition: Evidence from Category-Specific Visual Agnosia

    Science.gov (United States)

    Wolk, D.A.; Coslett, H.B.; Glosser, G.

    2005-01-01

    The role of sensory-motor representations in object recognition was investigated in experiments involving AD, a patient with mild visual agnosia who was impaired in the recognition of visually presented living as compared to non-living entities. AD named visually presented items for which sensory-motor information was available significantly more…

  8. Visual object agnosia is associated with a breakdown of object-selective responses in the lateral occipital cortex.

    Science.gov (United States)

    Ptak, Radek; Lazeyras, François; Di Pietro, Marie; Schnider, Armin; Simon, Stéphane R

    2014-07-01

    Patients with visual object agnosia fail to recognize the identity of visually presented objects despite preserved semantic knowledge. Object agnosia may result from damage to visual cortex lying close to or overlapping with the lateral occipital complex (LOC), a brain region that exhibits selectivity to the shape of visually presented objects. Despite this anatomical overlap the relationship between shape processing in the LOC and shape representations in object agnosia is unknown. We studied a patient with object agnosia following isolated damage to the left occipito-temporal cortex overlapping with the LOC. The patient showed intact processing of object structure, yet often made identification errors that were mainly based on the global visual similarity between objects. Using functional Magnetic Resonance Imaging (fMRI) we found that the damaged as well as the contralateral, structurally intact right LOC failed to show any object-selective fMRI activity, though the latter retained selectivity for faces. Thus, unilateral damage to the left LOC led to a bilateral breakdown of neural responses to a specific stimulus class (objects and artefacts) while preserving the response to a different stimulus class (faces). These findings indicate that representations of structure necessary for the identification of objects crucially rely on bilateral, distributed coding of shape features.

  9. No double-dissociation between optic ataxia and visual agnosia: Multiple sub-streams for multiple visuo-manual integrations

    NARCIS (Netherlands)

    Pisella, L.; Binkofski, F.; Lasek, K.; Toni, I.; Rossetti, Y.

    2006-01-01

    The current dominant view of the visual system is marked by the functional and anatomical dissociation between a ventral stream specialised for perception and a dorsal stream specialised for action. The "double-dissociation" between visual agnosia (VA), a deficit of visual recognition, and optic ata

  10. Middle components of the auditory evoked response in bilateral temporal lobe lesions. Report on a patient with auditory agnosia

    DEFF Research Database (Denmark)

    Parving, A; Salomon, G; Elberling, Claus;

    1980-01-01

    An investigation of the middle components of the auditory evoked response (10--50 msec post-stimulus) in a patient with auditory agnosia is reported. Bilateral temporal lobe infarctions were proved by means of brain scintigraphy, CAT scanning, and regional cerebral blood flow measurements. The mi...

  11. Knowledge, implicit knowledge and metaknowledge in visual agnosia and pure alexia.

    Science.gov (United States)

    Feinberg, T E; Dyckes-Berke, D; Miner, C R; Roane, D M

    1995-06-01

    Residual or implicit knowledge has been observed in patients with object agnosia, optic aphasia and pure alexia. Previous investigators have considered implicit knowledge in these patients to be dissociated from awareness on the basis of intact semantic capabilities that are consistent with right hemisphere processing. The absence of explicit verbal identification is presumably dependent upon damaged left hemisphere systems. We describe a 72-year-old woman with a left occipital infarction, object agnosia and pure alexia who was unable to explicitly identify visual stimuli (objects and words), but was able to make reliable judgements of her residual knowledge on forced-choice matching tasks. While the patient could not consistently demonstrate awareness of knowledge prior to stimulus matching ('Do you know what this is?'), she was able to reliably demonstrate awareness of knowledge for response accuracy ('Are you sure?') assessed after stimulus matching. Further, the extent of the patient's metaknowledge corresponded to her degree of preserved knowledge. We propose that this pattern of performance suggests limited or partial access to preserved semantic knowledge which, though degraded, is not 'non-conscious'. PMID:7600095

  12. A case of complex regional pain syndrome with agnosia for object orientation.

    Science.gov (United States)

    Robinson, Gail; Cohen, Helen; Goebel, Andreas

    2011-07-01

    This systematic investigation of the neurocognitive correlates of complex regional pain syndrome (CRPS) in a single case also reports agnosia for object orientation in the context of persistent CRPS. We report a patient (JW) with severe long-standing CRPS who had no difficulty identifying and naming line drawings of objects presented in 1 of 4 cardinal orientations. In contrast, he was extremely poor at reorienting these objects into the correct upright orientation and in judging whether an object was upright or not. Moreover, JW made orientation errors when copying drawings of objects, and he also showed features of mirror reversal in writing single words and reading single letters. The findings are discussed in relation to accounts of visual processing. Agnosia for object orientation is the term for impaired knowledge of an object's orientation despite good recognition and naming of the same misoriented object. This defect has previously only been reported in patients with major structural brain lesions. The neuroanatomical correlates are discussed. The patient had no structural brain lesion, raising the possibility that nonstructural reorganisation of cortical networks may be responsible for his deficits. Other patients with CRPS may have related neurocognitive defects.

  13. Differential impact of parvocellular and magnocellular pathways on visual impairment in apperceptive agnosia?

    Science.gov (United States)

    Hildebrandt, Helmut; Schütze, Cathleen; Ebke, Markus; Spang, Karoline

    2004-06-01

    The term "visual form agnosia" describes a disorder characterized by problems recognizing objects, poor copying,and distinguishing between simple geometric shapes despite normal intellectual abilities. Visual agnosia has been interpreted as a disorder of the magnocellular visual system, caused by an inability to separate figure from ground by sampling information from extended regions of space and to integrate it with fine-grain local information. However,this interpretation has hardly been tested with neuropsychological or functional brain imaging methods, mainly because the magnocellular and parvocellular structures are highly interconnected in the visual system. We studied a patient (AM) who had suffered a sudden heart arrest, causing hypoxic brain damage. He was/is severely agnosic, as apparent in both the Birmingham Object Recognition Battery and the Visual Object and Space Battery. First- and especially second-order motion perception was also impaired, but AM experienced no problems in grasping and navigating through space. The patient revealed a normal P100 in visual evoked potentials both with colored and fine-grained achromatic checkerboards. But the amplitude of the P100 was clearly decreased if a coarse achromatic checkerboard was presented.The physiological and neuropsychological findings indicate that AM experienced problems integrating information over extended regions of space and in detecting second-order motion. This may be interpreted as a disorder of the magnocellular system, with intact parvocellular system and therefore preserved ability to detect both local features and colors.

  14. 2D but not 3D: pictorial-depth deficits in a case of visual agnosia.

    Science.gov (United States)

    Turnbull, Oliver H; Driver, Jon; McCarthy, Rosaleen A

    2004-01-01

    Patients with visual agnosia exhibit acquired impairments in visual object recognition, that may or may not involve deficits in low-level perceptual abilities. Here we report a case (patient DM) who after head injury presented with object-recognition deficits. He still appears able to extract 2D information from the visual world in a relatively intact manner; but his ability to extract pictorial information about 3D object-structure is greatly compromised. His copying of line drawings is relatively good, and he is accurate and shows apparently normal mental rotation when matching or judging objects tilted in the picture-plane. But he performs poorly on a variety of tasks requiring 3D representations to be derived from 2D stimuli, including: performing mental rotation in depth, rather than in the picture-plane; judging the relative depth of two regions depicted in line-drawings of objects; and deciding whether a line-drawing represents an object that is 'impossible' in 3D. Interestingly, DM failed to show several visual illusions experienced by normals (Muller-Lyer and Ponzo), that some authors have attributed to pictorial depth cues. Taken together, these findings indicate a deficit in achieving 3D intepretations of objects from 2D pictorial cues, that may contribute to object-recognition problems in agnosia.

  15. Intact automatic avoidance of obstacles in patients with visual form agnosia.

    Science.gov (United States)

    Rice, Nichola J; McIntosh, Robert D; Schindler, Igor; Mon-Williams, Mark; Démonet, Jean-François; Milner, A David

    2006-09-01

    In everyday life our reaching behaviour has to be guided not only by the location and properties of the target object, but also by the presence of potential obstacles in the workspace. Recent evidence from neglect and optic ataxia patients has suggested that this automatic obstacle avoidance is mediated by the dorsal, rather than the ventral, stream of visual processing. We tested this idea in two studies involving patients with visual form agnosia resulting from bilateral ventral-stream damage. In the first study, we asked patient DF to reach out and pick up a target object in the presence of obstacles placed at varying distances to the left or right of the target. We found that both DF and controls shifted their trajectories away from the potential obstacles and adjusted their grip aperture in such a way as to minimize risk of collision. In a second study, we asked DF and a second patient, SB, to either reach between, or to bisect the space between, two cylinders presented at varying locations. We found that both patients adjusted their reach trajectories to account for shifts in cylinder location in the reaching task, despite showing significantly worse performance than control subjects when asked to make a bisection judgement. Taken together, these data indicate that automatic obstacle avoidance behaviour is spared in our patients with visual form agnosia. We attribute their ability to the functional intactness of the dorsal stream of visual processing, and argue that the ventral stream plays no important role in automatic obstacle avoidance.

  16. [A case of carbon monoxide poisoning by explosion of coal mine presenting as visual agnosia: re-evaluation after 40 years].

    Science.gov (United States)

    Takaiwa, Akiko; Yamashita, Kenichiro; Nomura, Takuo; Shida, Kenshiro; Taniwaki, Takayuki

    2005-11-01

    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. Concerning visual agnosia, recognition of the real object was preserved, while recognition of object photographs and picture was impaired. Thus, this case was considered to have picture agnosia as he could not recognize the object by pictorial cues on the second dimensional space. MRI examination revealed low signal intensity lesions and cortical atrophy in the bilateral parieto-occipital lobes on T1-weighted images. Therefore, the bilateral parieto-occipital lesions are likely to be responsible for his picture agnosia.

  17. A case of carbon monoxide poisoning by explosion of coal mine presenting as visual agnosia: re-evaluation after 40 years

    Energy Technology Data Exchange (ETDEWEB)

    Takaiwa, A.; Yamashita, K.; Nomura, T.; Shida, K.; Taniwaki, T. [Kyushu University, Fukuoka (Japan). Department of Neurology, Graduate School of Medical Science

    2005-11-15

    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. Concerning visual agnosia, recognition of the real object was preserved, while recognition of object photographs and picture was impaired. Thus, this case was considered to have picture agnosia as he could not recognize the object by pictorial cues on the second dimensional space. MRI examination revealed low signal intensity lesions and cortical atrophy in the bilateral parieto-occipital lobes on T1-weighted images. Therefore, the bilateral parieto-occipital lesions are likely to be responsible for his picture agnosia.

  18. Dynamic visual speech perception in a patient with visual form agnosia.

    Science.gov (United States)

    Munhall, K G; Servos, P; Santi, A; Goodale, M A

    2002-10-01

    To examine the role of dynamic cues in visual speech perception, a patient with visual form agnosia (DF) was tested with a set of static and dynamic visual displays of three vowels. Five conditions were tested: (1) auditory only which provided only vocal pitch information, (2) dynamic visual only, (3) dynamic audiovisual with vocal pitch information, (4) dynamic audiovisual with full voice information and (5) static visual only images of postures during vowel production. DF showed normal performance in all conditions except the static visual only condition in which she scored at chance. Control subjects scored close to ceiling in this condition. The results suggest that spatiotemporal signatures for objects and events are processed separately from static form cues.

  19. Configural Gestalts remain nothing more than the sum of their parts in visual agnosia.

    Science.gov (United States)

    de-Wit, Lee H; Kubilius, Jonas; Op de Beeck, Hans P; Wagemans, Johan

    2013-01-01

    We report converging evidence that higher stages of the visual system are critically required for the whole to become more than the sum of its parts by studying patient DF with visual agnosia using a configural superiority paradigm. We demonstrate a clear dissociation between this patient and normal controls such that she could more easily report information about parts, demonstrating a striking reversal of the normal configural superiority effect. Furthermore, by comparing DF's performance to earlier neuroimaging and novel modeling work, we found a compelling consistency between her performance and representations in the early visual areas, which are spared in this patient. The reversed pattern of performance in this patient highlights that in some cases visual Gestalts do not emerge early on without processing in higher visual areas. More broadly, this study demonstrates how neuropsychological patients can be used to unmask representations maintained at early stages of processing.

  20. Normal pressure hydrocephalus manifesting as transient prosopagnosia, topographical disorientation, and visual objective agnosia.

    Science.gov (United States)

    Otani, Naoki; Nawashiro, Hiroshi; Ishihara, Shoichiro; Fukui, Shinji; Katoh, Hiroshi; Tsuzuki, Nobusuke; Ohnuki, Akira; Miyazawa, Takahito; Shima, Katsuji

    2004-04-01

    Usually, dementia, gait disturbance and urinary incontinence are an integral part of the clinical presentation of normal pressure hydrocephalus (NPH). However, NPH with transient visual cognitive disorders has not been reported previously. We herein describe an extremely rare case of NPH that presented with transient visual cognitive disorders and long lasting visual memory disturbances that subsided after CSF shunting. A 38-years-old man developed transient prosopagnosia, topographical disorientation, color vision disturbance, and visual objective agnosia that progressed over 5 years. Magnetic resonance images showed ventriculomegaly with ischemic lesions in the paraventricular deep white matter. ECD-SPECT showed a reduction of the cerebral blood flow (CBF) in the periventricular deep white matter. Three months after CSF shunting, the radiological findings normalized with dramatic improvement of the extremely rare symptoms.

  1. Configural Gestalts Remain Nothing More Than the Sum of Their Parts in Visual Agnosia

    Directory of Open Access Journals (Sweden)

    Lee H. de-Wit

    2013-12-01

    Full Text Available We report converging evidence that higher stages of the visual system are critically required for the whole to become more than the sum of its parts by studying patient DF with visual agnosia using a configural superiority paradigm. We demonstrate a clear dissociation between this patient and normal controls such that she could more easily report information about parts, demonstrating a striking reversal of the normal configural superiority effect. Furthermore, by comparing DF's performance to earlier neuroimaging and novel modeling work, we found a compelling consistency between her performance and representations in the early visual areas, which are spared in this patient. The reversed pattern of performance in this patient highlights that in some cases visual Gestalts do not emerge early on without processing in higher visual areas. More broadly, this study demonstrates how neuropsychological patients can be used to unmask representations maintained at early stages of processing.

  2. [Apperceptive form visual agnosia caused by anti-TNFalpha therapy to rheumatoid arthritis].

    Science.gov (United States)

    Kobayashi, Shunsuke; Tanno, Makoto; Nakamura, Ichiro; Ito, Katsumi; Ugawa, Yoshikazu

    2007-01-01

    TNFalpha plays an important role as an inflammatory mediator in both several autoimmune diseases and multiple sclerosis. Anti-TNFalpha antibody has been widely used to treat rheumatoid arthritis and Crohn's disease. On the. other hand, anti-TNFalpha antibody treatment increased recurrence rate in clinical trials for multiple sclerosis. We report a patient with rheumatoid arthritis without past history of any neurological disorders, who developed diplopia, ataxia, and visual agnosia specific to line drawing in the course of anti-TNFalpha antibody treatment. MRI studies detected multiple demyelinating lesions in the cerebral white matter and brainstem. The present case indicates that careful observation of neurological symptoms is important in the course of anti-TNFalpha antibody treatment, even in patients without past history of demyelinating diseases.

  3. Impairments in part-whole representations of objects in two cases of integrative visual agnosia.

    Science.gov (United States)

    Behrmann, Marlene; Williams, Pepper

    2007-10-01

    How complex multipart visual objects are represented perceptually remains a subject of ongoing investigation. One source of evidence that has been used to shed light on this issue comes from the study of individuals who fail to integrate disparate parts of visual objects. This study reports a series of experiments that examine the ability of two such patients with this form of agnosia (integrative agnosia; IA), S.M. and C.R., to discriminate and categorize exemplars of a rich set of novel objects, "Fribbles", whose visual similarity (number of shared parts) and category membership (shared overall shape) can be manipulated. Both patients performed increasingly poorly as the number of parts required for differentiating one Fribble from another increased. Both patients were also impaired at determining when two Fribbles belonged in the same category, a process that relies on abstracting spatial relations between parts. C.R., the less impaired of the two, but not S.M., eventually learned to categorize the Fribbles but required substantially more training than normal perceivers. S.M.'s failure is not attributable to a problem in learning to use a label for identification nor is it obviously attributable to a visual memory deficit. Rather, the findings indicate that, although the patients may be able to represent a small number of parts independently, in order to represent multipart images, the parts need to be integrated or chunked into a coherent whole. It is this integrative process that is impaired in IA and appears to play a critical role in the normal object recognition of complex images.

  4. The Right Place at the Right Time: Priming Facial Expressions with Emotional Face Components in Developmental Visual Agnosia

    OpenAIRE

    Aviezer, Hillel; Hassin, Ran R.; Perry, Anat; Dudarev, Veronica; Bentin, Shlomo

    2012-01-01

    The current study examined the nature of deficits in emotion recognition from facial expressions in case LG, an individual with a rare form of developmental visual agnosia (DVA). LG presents with profoundly impaired recognition of facial expressions, yet the underlying nature of his deficit remains unknown. During typical face processing, normal sighted individuals extract information about expressed emotions from face regions with activity diagnostic for specific emotion categories. Given LG...

  5. Category-specific visual agnosia: lesion to semantic memory versus extra-lesional variables in a case study and a connectionist model.

    Science.gov (United States)

    Barbeau, E; Giusiano, B

    2003-12-01

    There is a current debate on the causes of category-specific agnosia. The aim of this study was to examine the effects of lesional and extra-lesional variables on object recognition. Extra-lesional variables, such as visual complexity or familiarity, are factors that influence recognition. Using a connectionist model based on study, we provide evidence that extra-lesional variables can yield dissociations in the recognition rate of different categories. Furthermore, it is shown that lesional and extra-lesional variables can interact (p agnosia might thus result from complex interactions.

  6. Functional dissociation between action and perception of object shape in developmental visual object agnosia.

    Science.gov (United States)

    Freud, Erez; Ganel, Tzvi; Avidan, Galia; Gilaie-Dotan, Sharon

    2016-03-01

    According to the two visual systems model, the cortical visual system is segregated into a ventral pathway mediating object recognition, and a dorsal pathway mediating visuomotor control. In the present study we examined whether the visual control of action could develop normally even when visual perceptual abilities are compromised from early childhood onward. Using his fingers, LG, an individual with a rare developmental visual object agnosia, manually estimated (perceptual condition) the width of blocks that varied in width and length (but not in overall size), or simply picked them up across their width (grasping condition). LG's perceptual sensitivity to target width was profoundly impaired in the manual estimation task compared to matched controls. In contrast, the sensitivity to object shape during grasping, as measured by maximum grip aperture (MGA), the time to reach the MGA, the reaction time and the total movement time were all normal in LG. Further analysis, however, revealed that LG's sensitivity to object shape during grasping emerged at a later time stage during the movement compared to controls. Taken together, these results demonstrate a dissociation between action and perception of object shape, and also point to a distinction between different stages of the grasping movement, namely planning versus online control. Moreover, the present study implies that visuomotor abilities can develop normally even when perceptual abilities developed in a profoundly impaired fashion. PMID:26827163

  7. Congenital amusia in speakers of a tone language: association with lexical tone agnosia.

    Science.gov (United States)

    Nan, Yun; Sun, Yanan; Peretz, Isabelle

    2010-09-01

    Congenital amusia is a neurogenetic disorder that affects the processing of musical pitch in speakers of non-tonal languages like English and French. We assessed whether this musical disorder exists among speakers of Mandarin Chinese who use pitch to alter the meaning of words. Using the Montreal Battery of Evaluation of Amusia, we tested 117 healthy young Mandarin speakers with no self-declared musical problems and 22 individuals who reported musical difficulties and scored two standard deviations below the mean obtained by the Mandarin speakers without amusia. These 22 amusic individuals showed a similar pattern of musical impairment as did amusic speakers of non-tonal languages, by exhibiting a more pronounced deficit in melody than in rhythm processing. Furthermore, nearly half the tested amusics had impairments in the discrimination and identification of Mandarin lexical tones. Six showed marked impairments, displaying what could be called lexical tone agnosia, but had normal tone production. Our results show that speakers of tone languages such as Mandarin may experience musical pitch disorder despite early exposure to speech-relevant pitch contrasts. The observed association between the musical disorder and lexical tone difficulty indicates that the pitch disorder as defining congenital amusia is not specific to music or culture but is rather general in nature. PMID:20685803

  8. Radical “Visual Capture” Observed in a Patient with Severe Visual Agnosia

    Directory of Open Access Journals (Sweden)

    Akiko Takaiwa

    2003-01-01

    Full Text Available We report the case of a 79-year-old female with visual agnosia due to brain infarction in the left posterior cerebral artery. She could recognize objects used in daily life rather well by touch (the number of objects correctly identified was 16 out of 20 presented objects, but she could not recognize them as well by vision (6 out of 20. In this case, it was expected that she would recognize them well when permitted to use touch and vision simultaneously. Our patient, however, performed poorly, producing 5 correct answers out of 20 in the Vision-and-Touch condition. It would be natural to think that visual capture functions when vision and touch provide contradictory information on concrete positions and shapes. However, in the present case, it functioned in spite of the visual deficit in recognizing objects. This should be called radical visual capture. By presenting detailed descriptions of her symptoms and neuropsychological and neuroradiological data, we clarify the characteristics of this type of capture.

  9. Functional dissociation between action and perception of object shape in developmental visual object agnosia.

    Science.gov (United States)

    Freud, Erez; Ganel, Tzvi; Avidan, Galia; Gilaie-Dotan, Sharon

    2016-03-01

    According to the two visual systems model, the cortical visual system is segregated into a ventral pathway mediating object recognition, and a dorsal pathway mediating visuomotor control. In the present study we examined whether the visual control of action could develop normally even when visual perceptual abilities are compromised from early childhood onward. Using his fingers, LG, an individual with a rare developmental visual object agnosia, manually estimated (perceptual condition) the width of blocks that varied in width and length (but not in overall size), or simply picked them up across their width (grasping condition). LG's perceptual sensitivity to target width was profoundly impaired in the manual estimation task compared to matched controls. In contrast, the sensitivity to object shape during grasping, as measured by maximum grip aperture (MGA), the time to reach the MGA, the reaction time and the total movement time were all normal in LG. Further analysis, however, revealed that LG's sensitivity to object shape during grasping emerged at a later time stage during the movement compared to controls. Taken together, these results demonstrate a dissociation between action and perception of object shape, and also point to a distinction between different stages of the grasping movement, namely planning versus online control. Moreover, the present study implies that visuomotor abilities can develop normally even when perceptual abilities developed in a profoundly impaired fashion.

  10. Memory-guided saccade processing in visual form agnosia (patient DF).

    Science.gov (United States)

    Rossit, Stéphanie; Szymanek, Larissa; Butler, Stephen H; Harvey, Monika

    2010-01-01

    According to Milner and Goodale's model (The visual brain in action, Oxford University Press, Oxford, 2006) areas in the ventral visual stream mediate visual perception and oV-line actions, whilst regions in the dorsal visual stream mediate the on-line visual control of action. Strong evidence for this model comes from a patient (DF), who suffers from visual form agnosia after bilateral damage to the ventro-lateral occipital region, sparing V1. It has been reported that she is normal in immediate reaching and grasping, yet severely impaired when asked to perform delayed actions. Here we investigated whether this dissociation would extend to saccade execution. Neurophysiological studies and TMS work in humans have shown that the posterior parietal cortex (PPC), on the right in particular (supposedly spared in DF), is involved in the control of memory-guided saccades. Surprisingly though, we found that, just as reported for reaching and grasping, DF's saccadic accuracy was much reduced in the memory compared to the stimulus-guided condition. These data support the idea of a tight coupling of eye and hand movements and further suggest that dorsal stream structures may not be sufficient to drive memory-guided saccadic performance.

  11. Separate processing of texture and form in the ventral stream: evidence from FMRI and visual agnosia.

    Science.gov (United States)

    Cavina-Pratesi, C; Kentridge, R W; Heywood, C A; Milner, A D

    2010-02-01

    Real-life visual object recognition requires the processing of more than just geometric (shape, size, and orientation) properties. Surface properties such as color and texture are equally important, particularly for providing information about the material properties of objects. Recent neuroimaging research suggests that geometric and surface properties are dealt with separately within the lateral occipital cortex (LOC) and the collateral sulcus (CoS), respectively. Here we compared objects that differed either in aspect ratio or in surface texture only, keeping all other visual properties constant. Results on brain-intact participants confirmed that surface texture activates an area in the posterior CoS, quite distinct from the area activated by shape within LOC. We also tested 2 patients with visual object agnosia, one of whom (DF) performed well on the texture task but at chance on the shape task, whereas the other (MS) showed the converse pattern. This behavioral double dissociation was matched by a parallel neuroimaging dissociation, with activation in CoS but not LOC in patient DF and activation in LOC but not CoS in patient MS. These data provide presumptive evidence that the areas respectively activated by shape and texture play a causally necessary role in the perceptual discrimination of these features.

  12. Radical "visual capture" observed in a patient with severe visual agnosia.

    Science.gov (United States)

    Takaiwa, Akiko; Yoshimura, Hirokazu; Abe, Hirofumi; Terai, Satoshi

    2003-01-01

    We report the case of a 79-year-old female with visual agnosia due to brain infarction in the left posterior cerebral artery. She could recognize objects used in daily life rather well by touch (the number of objects correctly identified was 16 out of 20 presented objects), but she could not recognize them as well by vision (6 out of 20). In this case, it was expected that she would recognize them well when permitted to use touch and vision simultaneously. Our patient, however, performed poorly, producing 5 correct answers out of 20 in the Vision-and-Touch condition. It would be natural to think that visual capture functions when vision and touch provide contradictory information on concrete positions and shapes. However, in the present case, it functioned in spite of the visual deficit in recognizing objects. This should be called radical visual capture. By presenting detailed descriptions of her symptoms and neuropsychological and neuroradiological data, we clarify the characteristics of this type of capture.

  13. Colour agnosia impairs the recognition of natural but not of non-natural scenes.

    Science.gov (United States)

    Nijboer, Tanja C W; Van Der Smagt, Maarten J; Van Zandvoort, Martine J E; De Haan, Edward H F

    2007-03-01

    Scene recognition can be enhanced by appropriate colour information, yet the level of visual processing at which colour exerts its effects is still unclear. It has been suggested that colour supports low-level sensory processing, while others have claimed that colour information aids semantic categorization and recognition of objects and scenes. We investigated the effect of colour on scene recognition in a case of colour agnosia, M.A.H. In a scene identification task, participants had to name images of natural or non-natural scenes in six different formats. Irrespective of scene format, M.A.H. was much slower on the natural than on the non-natural scenes. As expected, neither M.A.H. nor control participants showed any difference in performance for the non-natural scenes. However, for the natural scenes, appropriate colour facilitated scene recognition in control participants (i.e., shorter reaction times), whereas M.A.H.'s performance did not differ across formats. Our data thus support the hypothesis that the effect of colour occurs at the level of learned associations.

  14. Making memories: the development of long-term visual knowledge in children with visual agnosia.

    Science.gov (United States)

    Metitieri, Tiziana; Barba, Carmen; Pellacani, Simona; Viggiano, Maria Pia; Guerrini, Renzo

    2013-01-01

    There are few reports about the effects of perinatal acquired brain lesions on the development of visual perception. These studies demonstrate nonseverely impaired visual-spatial abilities and preserved visual memory. Longitudinal data analyzing the effects of compromised perceptions on long-term visual knowledge in agnosics are limited to lesions having occurred in adulthood. The study of children with focal lesions of the visual pathways provides a unique opportunity to assess the development of visual memory when perceptual input is degraded. We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2  years and 3.7  years from the initial assessment. All children exhibited apperceptive visual agnosia and visual memory impairment. We observed a longitudinal improvement of visual memory modulated by the structural properties of objects. Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment.

  15. Visual object agnosia as a problem in integrating parts and part relations.

    Science.gov (United States)

    Saumier, Daniel; Arguin, Martin; Lefebvre, Christine; Lassonde, Maryse

    2002-01-01

    Current models of vision generally assume that the recognition of visual objects is achieved by encoding their component parts, as well as the spatial relations among parts. The current study examined how the processing of parts and their configurations may be affected in visual agnosia due to brain damage. Both a visual agnosic patient (AR) and healthy control subjects performed a visual search task in which they had to discriminate between targets and distractors that varied according to whether they shared their parts and/or their configuration. The results show that AR's visual search rates are disproportionally slow when targets and distractors share the same configuration than when they have different configurations. AR is also found to be disproportionately slow in discriminating targets and distractors that share identical parts when the targets and distractors share the same configuration. With differently configured targets and distractors, AR shows no part sharing effect. For controls, in contrast, the part and configuration sharing effects occur independently of one another. It is concluded that AR's object recognition deficit arises from difficulties in discriminating objects that share their configuration, and from an abnormal dependency of part information processing upon object configuration.

  16. Visuomotor performance in a patient with visual agnosia due to an early lesion.

    Science.gov (United States)

    Dijkerman, H Chris; Lê, Sandra; Démonet, Jean-François; Milner, A David

    2004-06-01

    We tested a patient with visual agnosia who had suffered severe bilateral brain damage early in life, on a series of visuomotor tasks. The broad pattern of results confirms that S.B., like the extensively tested patient D.F., shows an impressive array of preserved skills, despite his severe perceptual problems. Also like D.F., S.B. shows certain subtle visuomotor difficulties that can be related to the idea that his partially intact occipito-parietal areas are unable to benefit from interactions with the apparently severely damaged occipito-temporal regions. Unlike D.F., however, he is able to make accurate discriminations of simple visual features, such as object width and orientation, albeit with very slow response times. We hypothesize that several factors such as the early onset of S.B.'s lesion and the long period since his brain lesion have allowed his brain to compensate to a degree what has been impossible in D.F., whose brain damage occurred in adulthood. This may include an element of 'rewiring' and self-monitoring of visuomotor processes that allow S.B. to achieve perceptual access to visual information processed in the dorsal stream: information that is normally only available for on-line visuomotor control.

  17. Making Memories: The Development of Long-Term Visual Knowledge in Children with Visual Agnosia

    Directory of Open Access Journals (Sweden)

    Tiziana Metitieri

    2013-01-01

    Full Text Available There are few reports about the effects of perinatal acquired brain lesions on the development of visual perception. These studies demonstrate nonseverely impaired visual-spatial abilities and preserved visual memory. Longitudinal data analyzing the effects of compromised perceptions on long-term visual knowledge in agnosics are limited to lesions having occurred in adulthood. The study of children with focal lesions of the visual pathways provides a unique opportunity to assess the development of visual memory when perceptual input is degraded. We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2 years and 3.7 years from the initial assessment. All children exhibited apperceptive visual agnosia and visual memory impairment. We observed a longitudinal improvement of visual memory modulated by the structural properties of objects. Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment.

  18. Training-Induced Recovery of Low-Level Vision Followed by Mid-Level Perceptual Improvements in Developmental Object and Face Agnosia

    Science.gov (United States)

    Lev, Maria; Gilaie-Dotan, Sharon; Gotthilf-Nezri, Dana; Yehezkel, Oren; Brooks, Joseph L.; Perry, Anat; Bentin, Shlomo; Bonneh, Yoram; Polat, Uri

    2015-01-01

    Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and object agnosia. Yet it is unclear whether training during adulthood, at a post-developmental…

  19. Selective Impairment of Living Things and Musical Instruments on a Verbal "Semantic Knowledge Questionnaire" in a Case of Apperceptive Visual Agnosia

    Science.gov (United States)

    Masullo, Carlo; Piccininni, Chiara; Quaranta, Davide; Vita, Maria Gabriella; Gaudino, Simona; Gainotti, Guido

    2012-01-01

    Semantic memory was investigated in a patient (MR) affected by a severe apperceptive visual agnosia, due to an ischemic cerebral lesion, bilaterally affecting the infero-mesial parts of the temporo-occipital cortices. The study was made by means of a Semantic Knowledge Questionnaire (Laiacona, Barbarotto, Trivelli, & Capitani, 1993), which takes…

  20. Positron emission tomographic localization of left-sided unilateral spatial agnosia

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) was used to clarify the localization and the underlying mechanisms of left-sided unilateral spatial agnosia (LUSA). Eleven right-handed patients with cerebral infarction in the territory of the right middle cerebral artery who had LUSA were included in this study. Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured with PET using 15O steady state method. Sixteen right-handed patients with cerebral infarction who did not exhibit LUSA served as a control group. The mean local values of CBF and CMRO2 in the control group were 37.4 ml/100 ml tissue/min and 2.66 ml/100 ml tissue/min, respectively. By contrast, those values of CBF and CMRO2 in the patients with LUSA were 21.7 ml/100 ml tissue/min and 1.43 ml/100 ml tissue/min, respectively. Both CBF and CMRO2 in the right posterior parietal region were significantly lower in the patients with LUSA as compared with the control group (p 2 between 1.8 and 2.2 ml/100 ml tissue/min. These ranges of CBF and CMRO2 in the right parietal region were considered to include the threshold level producing LUSA. The CMRO2 values were more stabilized in the course of cerebral infarction as compared with the CBF values which may be variable on account of luxury perfusion syndrome. The right posterior parietal CMRO2 values less than 2.0 ml/100 ml tissue/min was considered to be critical in causing LUSA. The above results may suggest that severe damages of CBF and metabolism in the posterior part of the right parietal lobe play an important role in the occurrence of LUSA. (J.P.N.)

  1. Preserved implicit form perception and orientation adaptation in visual form agnosia.

    Science.gov (United States)

    Yang, Jiongjiong; Wu, Ming; Shen, Zheng

    2006-01-01

    Visual form agnosia is mainly characterized by profound deficits in visual form and shape discrimination. Previous studies have shown that patients retain the capacity for coordinated motor behaviors, color naming and implicit letter perception. However, it is unknown to what extent other visual functions, such as implicit form and orientation perception, are preserved. To address these questions, we investigated a single visual form agnosic patient, X.F., in two distinct experiments. X.F.'s visual lesions were mainly localized in the bilateral occipitotemporal cortex, with the dorsal visual stream and early visual cortex largely spared. In Experiment 1, X.F. named the color of different forms across 12 blocks of trials. After the first six blocks, the combinations of a form with its color were changed and the new combination was presented for the remaining six blocks. X.F.'s reaction time increased during the switch block and was significantly greater than the overall RT changes between adjacent, non-switch blocks. This indicates that X.F. retained the ability to perceive changes in form despite her inability to discriminate the forms. In Experiment 2, X.F. showed selective orientation adaptation effects to different spatial frequencies; that is, her contrast threshold was significantly higher when the adapting and test orientations were the same than when they were orthogonal, although her orientation discrimination performance was severely impaired. These data provide evidence of a functional dissociation between explicit and implicit visual abilities, and suggest that the residual early visual cortex mediates form and orientation processing in the absence of awareness.

  2. The anatomy of object recognition--visual form agnosia caused by medial occipitotemporal stroke.

    Science.gov (United States)

    Karnath, Hans-Otto; Rüter, Johannes; Mandler, André; Himmelbach, Marc

    2009-05-01

    The influential model on visual information processing by Milner and Goodale (1995) has suggested a dissociation between action- and perception-related processing in a dorsal versus ventral stream projection. It was inspired substantially by the observation of a double dissociation of disturbed visual action versus perception in patients with optic ataxia on the one hand and patients with visual form agnosia (VFA) on the other. Unfortunately, almost all cases with VFA reported so far suffered from inhalational intoxication, the majority with carbon monoxide (CO). Since CO induces a diffuse and widespread pattern of neuronal and white matter damage throughout the whole brain, precise conclusions from these patients with VFA on the selective role of ventral stream structures for shape and orientation perception were difficult. Here, we report patient J.S., who demonstrated VFA after a well circumscribed brain lesion due to stroke etiology. Like the famous patient D.F. with VFA after CO intoxication studied by Milner, Goodale, and coworkers (Goodale et al., 1991, 1994; Milner et al., 1991; Servos et al., 1995; Mon-Williams et al., 2001a,b; Wann et al., 2001; Westwood et al., 2002; McIntosh et al., 2004; Schenk and Milner, 2006), J.S. showed an obvious dissociation between disturbed visual perception of shape and orientation information on the one side and preserved visuomotor abilities based on the same information on the other. In both hemispheres, damage primarily affected the fusiform and the lingual gyri as well as the adjacent posterior cingulate gyrus. We conclude that these medial structures of the ventral occipitotemporal cortex are integral for the normal flow of shape and of contour information into the ventral stream system allowing to recognize objects.

  3. Patient DF's visual brain in action: Visual feedforward control in visual form agnosia.

    Science.gov (United States)

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Barat, Masihullah; Goodale, Melvyn A

    2015-05-01

    Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF's grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF's performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF's grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets. In a second condition, the haptic feedback was of a constant intermediate width while the visual target varied trial by trial. Despite this incongruent feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF's spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing.

  4. Modeling eye movements in visual agnosia with a saliency map approach: bottom-up guidance or top-down strategy?

    Science.gov (United States)

    Foulsham, Tom; Barton, Jason J S; Kingstone, Alan; Dewhurst, Richard; Underwood, Geoffrey

    2011-08-01

    Two recent papers (Foulsham, Barton, Kingstone, Dewhurst, & Underwood, 2009; Mannan, Kennard, & Husain, 2009) report that neuropsychological patients with a profound object recognition problem (visual agnosic subjects) show differences from healthy observers in the way their eye movements are controlled when looking at images. The interpretation of these papers is that eye movements can be modeled as the selection of points on a saliency map, and that agnosic subjects show an increased reliance on visual saliency, i.e., brightness and contrast in low-level stimulus features. Here we review this approach and present new data from our own experiments with an agnosic patient that quantifies the relationship between saliency and fixation location. In addition, we consider whether the perceptual difficulties of individual patients might be modeled by selectively weighting the different features involved in a saliency map. Our data indicate that saliency is not always a good predictor of fixation in agnosia: even for our agnosic subject, as for normal observers, the saliency-fixation relationship varied as a function of the task. This means that top-down processes still have a significant effect on the earliest stages of scanning in the setting of visual agnosia, indicating severe limitations for the saliency map model. Top-down, active strategies-which are the hallmark of our human visual system-play a vital role in eye movement control, whether we know what we are looking at or not.

  5. Impaired integration of emotional faces and affective body context in a rare case of developmental visual agnosia.

    Science.gov (United States)

    Aviezer, Hillel; Hassin, Ran R; Bentin, Shlomo

    2012-06-01

    In the current study we examined the recognition of facial expressions embedded in emotionally expressive bodies in case LG, an individual with a rare form of developmental visual agnosia (DVA) who suffers from severe prosopagnosia. Neuropsychological testing demonstrated that LG's agnosia is characterized by profoundly impaired visual integration. Unlike individuals with typical developmental prosopagnosia who display specific difficulties with face identity (but typically not expression) recognition, LG was also impaired at recognizing isolated facial expressions. By contrast, he successfully recognized the expressions portrayed by faceless emotional bodies handling affective paraphernalia. When presented with contextualized faces in emotional bodies his ability to detect the emotion expressed by a face did not improve even if it was embedded in an emotionally-congruent body context. Furthermore, in contrast to controls, LG displayed an abnormal pattern of contextual influence from emotionally-incongruent bodies. The results are interpreted in the context of a general integration deficit in DVA, suggesting that impaired integration may extend from the level of the face to the level of the full person.

  6. [Associative visual agnosia. The less visible consequences of a cerebral infarction].

    Science.gov (United States)

    Diesfeldt, H F A

    2011-02-01

    preserved abilities is considered to be a specific difficulty to access a full semantic representation from an intact structural representation of visually presented objects, i.e., a form of visual object agnosia.

  7. Pure associative tactile agnosia for the left hand: clinical and anatomo-functional correlations.

    Science.gov (United States)

    Veronelli, Laura; Ginex, Valeria; Dinacci, Daria; Cappa, Stefano F; Corbo, Massimo

    2014-09-01

    Associative tactile agnosia (TA) is defined as the inability to associate information about object sensory properties derived through tactile modality with previously acquired knowledge about object identity. The impairment is often described after a lesion involving the parietal cortex (Caselli, 1997; Platz, 1996). We report the case of SA, a right-handed 61-year-old man affected by first ever right hemispheric hemorrhagic stroke. The neurological examination was normal, excluding major somaesthetic and motor impairment; a brain magnetic resonance imaging (MRI) confirmed the presence of a right subacute hemorrhagic lesion limited to the post-central and supra-marginal gyri. A comprehensive neuropsychological evaluation detected a selective inability to name objects when handled with the left hand in the absence of other cognitive deficits. A series of experiments were conducted in order to assess each stage of tactile recognition processing using the same stimulus sets: materials, 3D geometrical shapes, real objects and letters. SA and seven matched controls underwent the same experimental tasks during four sessions in consecutive days. Tactile discrimination, recognition, pantomime, drawing after haptic exploration out of vision and tactile-visual matching abilities were assessed. In addition, we looked for the presence of a supra-modal impairment of spatial perception and of specific difficulties in programming exploratory movements during recognition. Tactile discrimination was intact for all the stimuli tested. In contrast, SA was able neither to recognize nor to pantomime real objects manipulated with the left hand out of vision, while he identified them with the right hand without hesitations. Tactile-visual matching was intact. Furthermore, SA was able to grossly reproduce the global shape in drawings but failed to extract details of objects after left-hand manipulation, and he could not identify objects after looking at his own drawings. This case

  8. Visual processing of words in a patient with visual form agnosia: a behavioural and fMRI study.

    Science.gov (United States)

    Cavina-Pratesi, Cristiana; Large, Mary-Ellen; Milner, A David

    2015-03-01

    Patient D.F. has a profound and enduring visual form agnosia due to a carbon monoxide poisoning episode suffered in 1988. Her inability to distinguish simple geometric shapes or single alphanumeric characters can be attributed to a bilateral loss of cortical area LO, a loss that has been well established through structural and functional fMRI. Yet despite this severe perceptual deficit, D.F. is able to "guess" remarkably well the identity of whole words. This paradoxical finding, which we were able to replicate more than 20 years following her initial testing, raises the question as to whether D.F. has retained specialized brain circuitry for word recognition that is able to function to some degree without the benefit of inputs from area LO. We used fMRI to investigate this, and found regions in the left fusiform gyrus, left inferior frontal gyrus, and left middle temporal cortex that responded selectively to words. A group of healthy control subjects showed similar activations. The left fusiform activations appear to coincide with the area commonly named the visual word form area (VWFA) in studies of healthy individuals, and appear to be quite separate from the fusiform face area (FFA). We hypothesize that there is a route to this area that lies outside area LO, and which remains relatively unscathed in D.F.

  9. Reprint of: Visual processing of words in a patient with visual form agnosia: A behavioural and fMRI study.

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    Cavina-Pratesi, Cristiana; Large, Mary-Ellen; Milner, A David

    2015-11-01

    Patient D.F. has a profound and enduring visual form agnosia due to a carbon monoxide poisoning episode suffered in 1988. Her inability to distinguish simple geometric shapes or single alphanumeric characters can be attributed to a bilateral loss of cortical area LO, a loss that has been well established through structural and functional fMRI. Yet despite this severe perceptual deficit, D.F. is able to "guess" remarkably well the identity of whole words. This paradoxical finding, which we were able to replicate more than 20 years following her initial testing, raises the question as to whether D.F. has retained specialized brain circuitry for word recognition that is able to function to some degree without the benefit of inputs from area LO. We used fMRI to investigate this, and found regions in the left fusiform gyrus, left inferior frontal gyrus, and left middle temporal cortex that responded selectively to words. A group of healthy control subjects showed similar activations. The left fusiform activations appear to coincide with the area commonly named the visual word form area (VWFA) in studies of healthy individuals, and appear to be quite separate from the fusiform face area (FFA). We hypothesize that there is a route to this area that lies outside area LO, and which remains relatively unscathed in D.F.

  10. The right place at the right time: priming facial expressions with emotional face components in developmental visual agnosia.

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    Aviezer, Hillel; Hassin, Ran R; Perry, Anat; Dudarev, Veronica; Bentin, Shlomo

    2012-04-01

    The current study examined the nature of deficits in emotion recognition from facial expressions in case LG, an individual with a rare form of developmental visual agnosia (DVA). LG presents with profoundly impaired recognition of facial expressions, yet the underlying nature of his deficit remains unknown. During typical face processing, normal sighted individuals extract information about expressed emotions from face regions with activity diagnostic for specific emotion categories. Given LG's impairment, we sought to shed light on his emotion perception by examining if priming facial expressions with diagnostic emotional face components would facilitate his recognition of the emotion expressed by the face. LG and control participants matched isolated face components with components appearing in a subsequently presented full-face and then categorized the face's emotion. Critically, the matched components were from regions which were diagnostic or non-diagnostic of the emotion portrayed by the full face. In experiment 1, when the full faces were briefly presented (150 ms), LG's performance was strongly influenced by the diagnosticity of the components: his emotion recognition was boosted within normal limits when diagnostic components were used and was obliterated when non-diagnostic components were used. By contrast, in experiment 2, when the face-exposure duration was extended (2000 ms), the beneficial effect of the diagnostic matching was diminished as was the detrimental effect of the non-diagnostic matching. These data highlight the impact of diagnostic facial features in normal expression recognition and suggest that impaired emotion recognition in DVA results from deficient visual integration across diagnostic face components.

  11. Development of a vocabulary of object shapes in a child with a very-early-acquired visual agnosia: a unique case.

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    Funnell, Elaine; Wilding, John

    2011-02-01

    We report a longitudinal study of an exceptional child (S.R.) whose early-acquired visual agnosia, following encephalitis at 8 weeks of age, did not prevent her from learning to construct an increasing vocabulary of visual object forms (drawn from different categories), albeit slowly. S.R. had problems perceiving subtle differences in shape; she was unable to segment local letters within global displays; and she would bring complex scenes close to her eyes: a symptom suggestive of an attempt to reduce visual crowding. Investigations revealed a robust ability to use the gestalt grouping factors of proximity and collinearity to detect fragmented forms in noisy backgrounds, compared with a very weak ability to segment fragmented forms on the basis of contrasts of shape. When contrasts in spatial grouping and shape were pitted against each other, shape made little contribution, consistent with problems in perceiving complex scenes, but when shape contrast was varied, and spatial grouping was held constant, S.R. showed the same hierarchy of difficulty as the controls, although her responses were slowed. This is the first report of a child's visual-perceptual development following very early neurological impairments to the visual cortex. Her ability to learn to perceive visual shape following damage at a rudimentary stage of perceptual development contrasts starkly with the loss of such ability in childhood cases of acquired visual agnosia that follow damage to the established perceptual system. Clearly, there is a critical period during which neurological damage to the highly active, early developing visual-perceptual system does not prevent but only impairs further learning.

  12. No double-dissociation between optic ataxia and visual agnosia: multiple sub-streams for multiple visuo-manual integrations.

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    Pisella, L; Binkofski, F; Lasek, K; Toni, I; Rossetti, Y

    2006-01-01

    The current dominant view of the visual system is marked by the functional and anatomical dissociation between a ventral stream specialised for perception and a dorsal stream specialised for action. The "double-dissociation" between visual agnosia (VA), a deficit of visual recognition, and optic ataxia (OA), a deficit of visuo-manual guidance, considered as consecutive to ventral and dorsal damage, respectively, has provided the main argument for this dichotomic view. In the first part of this paper, we show that the currently available empirical data do not suffice to support a double-dissociation between OA and VA. In the second part, we review evidence coming from human neuropsychology and monkey data, which cast further doubts on the validity of a simple double-dissociation between perception and action because they argue for a far more complex organisation with multiple parallel visual-to-motor connections: 1. A dorso-dorsal pathway (involving the most dorsal part of the parietal and pre-motor cortices): for immediate visuo-motor control--with OA as typical disturbance. The latest research about OA is reviewed, showing how these patients exhibit deficits restricted to the most direct and fast visuo-motor transformations. We also propose that mild mirror ataxia, consisting of misreaching errors when the controlesional hand is guided to a visual goal though a mirror, could correspond to OA with an isolated "hand effect". 2. A ventral stream-prefrontal pathway (connections from the ventral visual stream to pre-frontal areas, by-passing the parietal areas): for "mediate" control (involving spatial or temporal transpositions [Rossetti, Y., & Pisella, L. (2003). Mediate responses as direct evidence for intention: Neuropsychology of Not to-, Not now- and Not there-tasks. In S. Johnson (Ed.), Cognitive Neuroscience perspectives on the problem of intentional action (pp. 67-105). MIT Press.])--with VA as typical disturbance. Preserved visuo-manual guidance in patients

  13. Alteraciones en el reconocimiento de gestos por daño a nivel del praxicon de entrada de acciones. (Agnosia de las pantomimas

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    Daniel G. Politis

    2002-01-01

    Full Text Available Clásicamente el estudio de la apraxia estuvo limitado a los problemas en la ejecución gestual (Geschwind, 1965; Liepmann, 1908 [c.f. De Renzi, 1990]; Luria, 1977. Si bien se presentaron varias hipótesis sobre la capacidad de reconocer gestos y su alteración por lesiones cerebrales, González Rothi, Ochipa y Heilman (1991,1997 en su modelo cognitivo de las apraxias de los miembros incluyen la capacidad de reconocer gestos y proponen que la misma es mediada por un sub-componente específico, el praxicón de entrada de acciones. La alteración de este produce un cuadro caracterizado por un déficit en el reconocimiento de gestos que denominaron Agnosia de las Pantomimas. En este trabajo se presenta el estudio de un paciente con dificultades en el reconocimiento de gestos y sin dificultades en la producción gesrual lo que constituye una disociación, que reafirma la hipótesis planteada por González Rothi y colaboradores (1991, 1997 y se discute el valor de estos hallazgos en relación con el modelo antes mencionado.

  14. Complicações neurológicas no decurso de tratamento pelo ACTH: A propósito de um caso de agnosia visual

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    O. Freitas Julião

    1953-12-01

    Full Text Available Os autores relatam a observação de um menino de 8 anos de idade, portador de síndrome nefrótica tratada pelo ACTH e que apresentou uma série de graves distúrbios neurológicos conseqüentes a uma crise hipertensiva (a pressão arterial elevou-se a 220-130 mm Hg, ocorrida por ocasião desse tratamento. Manifestando-se inicialmente por cefaléia intensa, depois por crise convulsiva generalizada, à qual se seguiu estado comatoso e posteriormente síndrome confusional, a encefalopatía hipertensiva condicionou, como seqüelas neurológicas mais importantes, distúrbios visuais. Êstes, que se apresentaram, a princípio, sob a forma de amaurose total, assumiram depois o aspecto de distúrbios da percepção, tipo agnóstico, persistentes ainda hoje. A agnosia visual refere-se aos objetos, pessoas, figuras simbólicas e côres.

  15. Behavioral and neuroimaging evidence for a contribution of color and texture information to scene classification in a patient with visual form agnosia.

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    Steeves, Jennifer K E; Humphrey, G Keith; Culham, Jody C; Menon, Ravi S; Milner, A David; Goodale, Melvyn A

    2004-01-01

    A common notion is that object perception is a necessary precursor to scene perception. Behavioral evidence suggests, however, that scene perception can operate independently of object perception. Further, neuroimaging has revealed a specialized human cortical area for viewing scenes that is anatomically distinct from areas activated by viewing objects. Here we show that an individual with visual form agnosia, D.F., who has a profound deficit in object recognition but spared color and visual texture perception, could still classify scenes and that she was fastest when the scenes were presented in the appropriate color. When scenes were presented as black-and-white images, she made a large number of errors in classification. Functional magnetic resonance imaging revealed selective activation in the parahippocampal place area (PPA) when D.F. viewed scenes. Unlike control observers, D.F. demonstrated higher activation in the PPA for scenes presented in the appropriate color than for black-and-white versions. The results demonstrate that an individual with profound form vision deficits can still use visual texture and color to classify scenes-and that this intact ability is reflected in differential activation of the PPA with colored versions of scenes.

  16. Hurt but still alive: Residual activity in the parahippocampal cortex conditions the recognition of familiar places in a patient with topographic agnosia

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    Mitsouko van Assche

    2016-01-01

    Photographs of personally familiar and unfamiliar places were displayed during functional magnetic resonance imaging (fMRI. Familiar places were either recognized or unrecognized by the patient and 6 age- and education-matched controls in a visual post-scan recognition test. In fMRI, recognized places were associated with a network comprising the fusiform gyrus in the intact side, but also the right anterior PHC, which included the lesion site. Moreover, this right PHC showed increased connectivity with the left homologous PHC in the intact hemisphere. By contrasting recognized with unrecognized familiar places, we replicate the finding of the joint involvement of the retrosplenial cortex, occipito-temporal areas, and posterior parietal cortex in place recognition. This study shows that the ability for left and right anterior PHC to communicate despite the neurological damage conditioned place recognition success in this patient. It further highlights a hemispheric asymmetry in this process, by showing the fundamental role of the right PHC in topographic agnosia.

  17. Real-time vision, tactile cues, and visual form agnosia in pantomimed grasping: removing haptic feedback induces a switch from natural to pantomime-like grasps

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    Robert Leslie Whitwell

    2015-05-01

    Full Text Available Investigators study the kinematics of grasping movements (prehension under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. When patient DF, who suffers from visual form agnosia, performs natural grasps, her in-flight hand aperture is scaled to the widths of targets ('grip scaling' that she cannot discriminate amongst. In contrast, when DF's pantomime grasps are based on a memory of a previewed object, her grip scaling is very poor. Her failure on this task has been interpreted as additional support for the dissociation between the use of object vision for action and object vision for perception. Curiously, however, when DF directs her pantomimed grasps towards a displaced imagined copy of a visible object where her fingers make contact with the surface of the table, her grip scaling does not appear to be particularly poor. In the first of two experiments, we revisit this previous work and show that her grip scaling in this real-time pantomime grasping task does not differ from controls, suggesting that terminal tactile feedback from a proxy of the target can maintain DF's grip scaling. In a second experiment with healthy participants, we tested a recent variant of a grasping task in which no tactile feedback is available (i.e. no haptic feedback by comparing the kinematics of target-directed grasps with and without haptic feedback to those of real-time pantomime grasps without haptic feedback. Compared to natural grasps, removing haptic feedback increased RT, slowed the velocity of the reach, reduced grip aperture, sharpened the slopes relating grip aperture to target width, and reduced the final grip aperture. All of these effects were also observed in the pantomime grasping task. Taken together, these results provide compelling support for the view that removing haptic feedback induces a switch from real-time visual control to one that depends more on visual perception and cognitive supervision.

  18. Training-induced recovery of low-level vision followed by mid-level perceptual improvements in developmental object and face agnosia.

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    Lev, Maria; Gilaie-Dotan, Sharon; Gotthilf-Nezri, Dana; Yehezkel, Oren; Brooks, Joseph L; Perry, Anat; Bentin, Shlomo; Bonneh, Yoram; Polat, Uri

    2015-01-01

    Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and object agnosia. Yet it is unclear whether training during adulthood, at a post-developmental stage of the adult visual system, can overcome such developmental impairments. Here, we visually trained LG, a developmental object and face agnosic individual. Prior to training, at the age of 20, LG's basic and mid-level visual functions such as visual acuity, crowding effects, and contour integration were underdeveloped relative to normal adult vision, corresponding to or poorer than those of 5-6 year olds (Gilaie-Dotan, Perry, Bonneh, Malach & Bentin, 2009). Intensive visual training, based on lateral interactions, was applied for a period of 9 months. LG's directly trained but also untrained visual functions such as visual acuity, crowding, binocular stereopsis and also mid-level contour integration improved significantly and reached near-age-level performance, with long-term (over 4 years) persistence. Moreover, mid-level functions that were tested post-training were found to be normal in LG. Some possible subtle improvement was observed in LG's higher-order visual functions such as object recognition and part integration, while LG's face perception skills have not improved thus far. These results suggest that corrective training at a post-developmental stage, even in the adult visual system, can prove effective, and its enduring effects are the basis for a revival of a developmental cascade that can lead to reduced perceptual impairments.

  19. Selective impairment of living things and musical instruments on a verbal 'Semantic Knowledge Questionnaire' in a case of apperceptive visual agnosia.

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    Masullo, Carlo; Piccininni, Chiara; Quaranta, Davide; Vita, Maria Gabriella; Gaudino, Simona; Gainotti, Guido

    2012-10-01

    Semantic memory was investigated in a patient (MR) affected by a severe apperceptive visual agnosia, due to an ischemic cerebral lesion, bilaterally affecting the infero-mesial parts of the temporo-occipital cortices. The study was made by means of a Semantic Knowledge Questionnaire (Laiacona, Barbarotto, Trivelli, & Capitani, 1993), which takes separately into account four categories of living beings (animals, fruits, vegetables and body parts) and of artefacts (furniture, tools, vehicles and musical instruments), does not require a visual analysis and allows to distinguish errors concerning super-ordinate categorization, perceptual features and functional/encyclopedic knowledge. When the total number of errors obtained on all the categories of living and non-living beings was considered, a non-significant trend toward a higher number of errors in living stimuli was observed. This difference, however, became significant when body parts and musical instruments were excluded from the analysis. Furthermore, the number of errors obtained on the musical instruments was similar to that obtained on the living categories of animals, fruits and vegetables and significantly higher of that obtained in the other artefact categories. This difference was still significant when familiarity, frequency of use and prototypicality of each stimulus entered into a logistic regression analysis. On the other hand, a separate analysis of errors obtained on questions exploring super-ordinate categorization, perceptual features and functional/encyclopedic attributes showed that the differences between living and non-living stimuli and between musical instruments and other artefact categories were mainly due to errors obtained on questions exploring perceptual features. All these data are at variance with the 'domains of knowledge' hypothesis', which assumes that the breakdown of different categories of living and non-living things respects the distinction between biological entities and

  20. Real-time vision, tactile cues, and visual form agnosia: removing haptic feedback from a "natural" grasping task induces pantomime-like grasps.

    Science.gov (United States)

    Whitwell, Robert L; Ganel, Tzvi; Byrne, Caitlin M; Goodale, Melvyn A

    2015-01-01

    Investigators study the kinematics of grasping movements (prehension) under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. "Natural" prehensile acts are directed at the goal object and are executed using real-time vision. Typically, they also entail the use of tactile, proprioceptive, and kinesthetic sources of haptic feedback about the object ("haptics-based object information") once contact with the object has been made. Natural and simulated (pantomimed) forms of prehension are thought to recruit different cortical structures: patient DF, who has visual form agnosia following bilateral damage to her temporal-occipital cortex, loses her ability to scale her grasp aperture to the size of targets ("grip scaling") when her prehensile movements are based on a memory of a target previewed 2 s before the cue to respond or when her grasps are directed towards a visible virtual target but she is denied haptics-based information about the target. In the first of two experiments, we show that when DF performs real-time pantomimed grasps towards a 7.5 cm displaced imagined copy of a visible object such that her fingers make contact with the surface of the table, her grip scaling is in fact quite normal. This finding suggests that real-time vision and terminal tactile feedback are sufficient to preserve DF's grip scaling slopes. In the second experiment, we examined an "unnatural" grasping task variant in which a tangible target (along with any proxy such as the surface of the table) is denied (i.e., no terminal tactile feedback). To do this, we used a mirror-apparatus to present virtual targets with and without a spatially coincident copy for the participants to grasp. We compared the grasp kinematics from trials with and without terminal tactile feedback to a real-time-pantomimed grasping task (one without tactile feedback) in which participants visualized a copy of the visible target as instructed in our laboratory in the

  1. Exaggerated color perception in a patient with visual form agnosia.

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    Yang, Jiongjiong; Wu, Ming; Shen, Zheng

    2007-10-01

    Previous studies on visual form agnosic patients have shown that their color perception is relatively preserved when monochromatic figures are used. However, it is unclear whether their color perception remains normal when figures are composed of two parts in different colors. The results showed that patient X.F. had difficulty in naming both colors when the two colors were placed next to each other, and in discriminating the two-color figure from the figure presented in its larger color. In contrast, X.F. could name the two colors when they were physically separated. These data suggest that X.F. manifests exaggerated color perception, producing a color filling-in effect that may be mediated by her spared early visual area.

  2. The functional neuroanatomy of object agnosia: a case study.

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    Konen, Christina S; Behrmann, Marlene; Nishimura, Mayu; Kastner, Sabine

    2011-07-14

    Cortical reorganization of visual and object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, object-related, and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood.

  3. Visual agnosia and posterior cerebral artery infarcts: an anatomical-clinical study.

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    Olivier Martinaud

    Full Text Available BACKGROUND: To evaluate systematically the cognitive deficits following posterior cerebral artery (PCA strokes, especially agnosic visual disorders, and to study anatomical-clinical correlations. METHODS AND FINDINGS: We investigated 31 patients at the chronic stage (mean duration of 29.1 months post infarct with standardized cognitive tests. New experimental tests were used to assess visual impairments for words, faces, houses, and objects. Forty-one healthy subjects participated as controls. Brain lesions were normalized, combined, and related to occipitotemporal areas responsive to specific visual categories, including words (VWFA, faces (FFA and OFA, houses (PPA and common objects (LOC. Lesions were located in the left hemisphere in 15 patients, in the right in 13, and bilaterally in 3. Visual field defects were found in 23 patients. Twenty patients had a visual disorder in at least one of the experimental tests (9 with faces, 10 with houses, 7 with phones, 3 with words. Six patients had a deficit just for a single category of stimulus. The regions of maximum overlap of brain lesions associated with a deficit for a given category of stimuli were contiguous to the peaks of the corresponding functional areas as identified in normal subjects. However, the strength of anatomical-clinical correlations was greater for words than for faces or houses, probably due to the stronger lateralization of the VWFA, as compared to the FFA or the PPA. CONCLUSIONS: Agnosic visual disorders following PCA infarcts are more frequent than previously reported. Dedicated batteries of tests, such as those developed here, are required to identify such deficits, which may escape clinical notice. The spatial relationships of lesions and of regions activated in normal subjects predict the nature of the deficits, although individual variability and bilaterally represented systems may blur those correlations.

  4. Family resemblance: ten family members with prosopagnosia and within-class object agnosia.

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    Duchaine, Bradley; Germine, Laura; Nakayama, Ken

    2007-06-01

    We report on neuropsychological testing done with a family in which many members reported severe face recognition impairments. These 10 individuals were high functioning in everyday life and performed normally on tests of low-level vision and high-level cognition. In contrast, they showed clear deficits with tests requiring face memory and judgements of facial similarity. They did not show deficits with all aspects of higher level visual processing as all tested performed normally on a challenging facial emotion recognition task and on a global-local letter identification task. On object memory tasks requiring recognition of particular cars and guns, they showed significant deficits so their recognition impairments were not restricted to facial identity. These results strongly suggest the existence of a genetic condition leading to a selective deficit of visual recognition.

  5. Separate channels for processing form, texture, and color: evidence from FMRI adaptation and visual object agnosia.

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    Cavina-Pratesi, C; Kentridge, R W; Heywood, C A; Milner, A D

    2010-10-01

    Previous neuroimaging research suggests that although object shape is analyzed in the lateral occipital cortex, surface properties of objects, such as color and texture, are dealt with in more medial areas, close to the collateral sulcus (CoS). The present study sought to determine whether there is a single medial region concerned with surface properties in general or whether instead there are multiple foci independently extracting different surface properties. We used stimuli varying in their shape, texture, or color, and tested healthy participants and 2 object-agnosic patients, in both a discrimination task and a functional MR adaptation paradigm. We found a double dissociation between medial and lateral occipitotemporal cortices in processing surface (texture or color) versus geometric (shape) properties, respectively. In Experiment 2, we found that the medial occipitotemporal cortex houses separate foci for color (within anterior CoS and lingual gyrus) and texture (caudally within posterior CoS). In addition, we found that areas selective for shape, texture, and color individually were quite distinct from those that respond to all of these features together (shape and texture and color). These latter areas appear to correspond to those associated with the perception of complex stimuli such as faces and places.

  6. Visual object agnosia and pure word alexia: correlation of functional magnetic resonance imaging and lesion localization.

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    Salvan, Carmen V; Ulmer, John L; DeYoe, Edgar A; Wascher, Thomas; Mathews, Vincent P; Lewis, James W; Prost, Robert W

    2004-01-01

    We present a case of a 64-year-old, right-handed female with a metastatic breast cancer lesion involving the left posterior inferior temporal lobe causing complete loss of the ability to recognize visually common objects and words. After her symptoms resolved on corticosteroid therapy, functional magnetic resonance imaging (fMRI) mapping demonstrated strong left-hemispheric dominance for word recognition and right-hemispheric dominance for object recognition. The case illustrates the relationships among ventral occipito-temporal cortical activation, lesion localization, and lesion-induced deficits of higher visual function. The relationship between hemispheric dominance determined by fMRI and risk of postoperative deficit depends on the specific visual function of interest.

  7. Pointing to places and spaces in a patient with visual form agnosia.

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    Carey, David P; Dijkerman, H Chris; Murphy, Kelly J; Goodale, Melvyn A; Milner, A David

    2006-01-01

    Previous investigations of visuospatial abilities in the visual form agnosic patient D.F. suggest that her egocentric sensorimotor processing is intact while her 'allocentric' judgments of spatial position are impaired. The current investigation extends these previous observations by comparing D.F.'s performance at pointing to a set of spatially distributed stimuli, either directly or by 'pantomiming' the responses in an adjacent homologous workspace. The results showed accurate sensorimotor localization when D.F. pointed directly to single targets or to sequences of targets, presumably as she could use egocentric visual coding. In spite of making relatively spared spatial judgments about the arrays, however, D.F. performed quite poorly when copying them and on the pantomimed pointing task. In this latter task good performance presumably depends on an ability to represent both the categorical and coordinate properties of the array (as does copying them), and to translate these into the effector-based coordinates required for accurate action. D.F.'s pantomimed pointing was similar to her copies of target arrays, as in both tasks there was evidence of spared (although somewhat degraded) appreciation of the relative spatial positions of the stimuli. Remarkably, her accuracy in this allocentric task was not worsened by longer pointing sequences. It is possible that D.F.'s degraded performance reflects a relative (though not complete) preservation of categorical coding within the ventral stream, despite a loss of coordinate coding there.

  8. Concurrent visuomotor behaviour improves form discrimination in a patient with visual form agnosia.

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    Schenk, Thomas; Milner, A David

    2006-09-01

    It is now well established that the visual brain is divided into two visual streams, the ventral and the dorsal stream. Milner and Goodale have suggested that the ventral stream is dedicated for processing vision for perception and the dorsal stream vision for action [A.D. Milner & M.A. Goodale (1995) The Visual Brain in Action, Oxford University Press, Oxford]. However, it is possible that ongoing processes in the visuomotor stream will nevertheless have an effect on perceptual processes. This possibility was examined in the present study. We have examined the visual form-discrimination performance of the form-agnosic patient D.F. with and without a concurrent visuomotor task, and found that her performance was significantly improved in the former condition. This suggests that the visuomotor behaviour provides cues that enhance her ability to recognize the form of the target object. In control experiments we have ruled out proprioceptive and efferent cues, and therefore propose that D.F. can, to a significant degree, access the object's visuomotor representation in the dorsal stream. Moreover, we show that the grasping-induced perceptual improvement disappears if the target objects only differ with respect to their shape but not their width. This suggests that shape information per se is not used for this grasping task.

  9. The mitochondrial DNA 10197 G > A mutation causes MELAS/Leigh overlap syndrome presenting with acute auditory agnosia.

    Science.gov (United States)

    Leng, Yinglin; Liu, Yuhe; Fang, Xiaojing; Li, Yao; Yu, Lei; Yuan, Yun; Wang, Zhaoxia

    2015-04-01

    Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes/Leigh (MELAS/LS) overlap syndrome is a mitochondrial disorder subtype with clinical and magnetic resonance imaging (MRI) features that are characteristic of both MELAS and Leigh syndrome (LS). Here, we report an MELAS/LS case presenting with cortical deafness and seizures. Cranial MRI revealed multiple lesions involving bilateral temporal lobes, the basal ganglia and the brainstem, which conformed to neuroimaging features of both MELAS and LS. Whole mitochondrial DNA (mtDNA) sequencing and PCR-RFLP revealed a de novo heteroplasmic m.10197 G > A mutation in the NADH dehydrogenase subunit 3 gene (ND3), which was predicted to cause an alanine to threonine substitution at amino acid 47. Although the mtDNA m.10197 G > A mutation has been reported in association with LS, Leber hereditary optic neuropathy and dystonia, it has never been linked with MELAS/LS overlap syndrome. Our patient therefore expands the phenotypic spectrum of the mtDNA m.10197 G > A mutation.

  10. To know what it is for, but not how it is: semantic dissociations in a case of visual agnosia.

    Science.gov (United States)

    Peru, Andrea; Avesani, Renato

    2008-01-01

    We report the case of a woman who displayed impaired object recognition following a severe head injury. Her elementary visual functions were substantially preserved, allowing her a coherent percept. On the other hand, she was impaired in accessing stored knowledge from both visual and verbal input. In particular, she showed a dramatic dissociation between fully preserved access to functional knowledge, and severely impaired access to perceptual knowledge so that she could describe what objects are for, but not how they are. Our findings from this case suggest that different categories of object knowledge are represented independently in separate units within the semantic system.

  11. Which visual functions depend on intermediate visual regions? Insights from a case of developmental visual form agnosia.

    Science.gov (United States)

    Gilaie-Dotan, Sharon

    2016-03-01

    A key question in visual neuroscience is the causal link between specific brain areas and perceptual functions; which regions are necessary for which visual functions? While the contribution of primary visual cortex and high-level visual regions to visual perception has been extensively investigated, the contribution of intermediate visual areas (e.g. V2/V3) to visual processes remains unclear. Here I review more than 20 visual functions (early, mid, and high-level) of LG, a developmental visual agnosic and prosopagnosic young adult, whose intermediate visual regions function in a significantly abnormal fashion as revealed through extensive fMRI and ERP investigations. While expectedly, some of LG's visual functions are significantly impaired, some of his visual functions are surprisingly normal (e.g. stereopsis, color, reading, biological motion). During the period of eight-year testing described here, LG trained on a perceptual learning paradigm that was successful in improving some but not all of his visual functions. Following LG's visual performance and taking into account additional findings in the field, I propose a framework for how different visual areas contribute to different visual functions, with an emphasis on intermediate visual regions. Thus, although rewiring and plasticity in the brain can occur during development to overcome and compensate for hindering developmental factors, LG's case seems to indicate that some visual functions are much less dependent on strict hierarchical flow than others, and can develop normally in spite of abnormal mid-level visual areas, thereby probably less dependent on intermediate visual regions.

  12. Implicit face perception in a patient with visual agnosia? Evidence from behavioural and eye-tracking analyses.

    Science.gov (United States)

    Lê, Sandra; Raufaste, Eric; Roussel, Sophie; Puel, Michèle; Démonet, Jean-François

    2003-01-01

    This paper investigates face perception in a visual agnosic and prosopagnosic patient (SB). Despite very extensive lesions of visual areas, SB remains capable of some visual processing [Brain 125 (2002) 58]. However, in everyday situations SB does not exhibit signs of specific face recognition. To investigate how SB may process faces, we tested two hypotheses. According to the 'spared module hypothesis,' SBs abilities come from spared modules of implicit face processing. According to the 'general strategy hypothesis,' SB may have developed some deliberate compensatory strategies. A two-session experimental design was constructed. In both sessions, face and non-face pictures were shown to participants. In Session 1 (implicit condition), participants had to decide whether each picture was a vegetable. In Session 2 (explicit condition), participants had to decide whether each picture was a face. Verbal reports showed that SB was not aware of faces in Session 1. However, behavioural results showed that (1). SB could process faces; (2). even when SB was not aware of faces, he processed them differently than non-faces; (3). when knowing the presence of faces, he did not process faces better. In addition, eye-tracking data suggested that SB did not change the nature of his processing from Sessions 1 to 2. Pupil diameters showed that fixated facial features were processed similarly as in control participants. Together, these results are not compatible with a general compensatory strategy hypothesis and suggest sparing of an implicit face processing module in SB.

  13. Color picture drawings without form and eye movements: a case report of visual form agnosia in a girl.

    Science.gov (United States)

    Kaga, Kimitaka; Shindo, Mitsuko

    2012-04-01

    The case of an 8-year-old girl who manifested cortical blindness and whose color drawings of faces and objects were without outlines is reported. Her birth was uneventful. When she was 10 months old, she fell down to the floor from a chair, resulting in a subarachnoidal hemorrhage. A repeat brain MRI revealed localized lesions in the visual cortices in the right and left hemispheres. As she grew older she was found to have visual imperceptions. She was found to have difficulties in learning visually the names of objects with form and letters, and in recognizing faces of her family. However, she was able to discriminate well the colors of faces and objects and learn easily the names of the objects with form by touching. She seemed to utilize subcortical vision for seeing colors of faces and objects.

  14. Delayed action does not always require the ventral stream: a study on a patient with visual form agnosia.

    Science.gov (United States)

    Hesse, Constanze; Schenk, Thomas

    2014-05-01

    It has been suggested that while movements directed at visible targets are processed within the dorsal stream, movements executed after delay rely on the visual representations of the ventral stream (Milner & Goodale, 2006). This interpretation is supported by the observation that a patient with ventral stream damage (D.F.) has trouble performing accurate movements after a delay, but performs normally when the target is visible during movement programming. We tested D.F.'s visuomotor performance in a letter-posting task whilst varying the amount of visual feedback available. Additionally, we also varied whether D.F. received tactile feedback at the end of each trial (posting through a letter box vs posting on a screen) and whether environmental cues were available during the delay period (removing the target only vs suppressing vision completely with shutter glasses). We found that in the absence of environmental cues patient D.F. was unaffected by the introduction of delay and performed as accurately as healthy controls. However, when environmental cues and vision of the moving hand were available during and after the delay period, D.F.'s visuomotor performance was impaired. Thus, while healthy controls benefit from the availability of environmental landmarks and/or visual feedback of the moving hand, such cues seem less beneficial to D.F. Taken together our findings suggest that ventral stream damage does not always impact the ability to make delayed movements but compromises the ability to use environmental landmarks and visual feedback efficiently.

  15. A Patient with Difficulty of Object Recognition: Semantic Amnesia for Manipulable Objects

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    A. Yamadori

    1992-01-01

    Full Text Available We studied a patient who had recognition difficulty for manipulable objects. MRI showed a lesion in the left occipito-parietotemporal area. Differential diagnosis of agnosia, aphasia and apraxia is discussed. We believe this “object meaning amnesia” constitutes a distinct subtype of semantic amnesia.

  16. A Study to Determine the Existence and Characteristics of Distinctively Different Subpopulations Subsumed within the Reading Disabled Population.

    Science.gov (United States)

    Steinberg, Laurie S.

    Forty-five third-grade and fourth-grade boys identified by their schools as being both normal in intelligence and severely disabled in reading were given a battery of tests of language, visual perception, silent reading comprehension, and finger agnosia. Three consistent groups of subjects emerged from cluster analyses of the results. One group…

  17. Visual Barriers to Prevent Ambulatory ALzheimer's Patients from Exiting through an Emergency Door.

    Science.gov (United States)

    Namazi, Kevan H.; And Others

    1989-01-01

    Conducted study on Alzheimer's unit to test seven different visual barrier conditions for reducing patient exits. Findings indicated that exiting was eliminated under two conditions. Results suggest visual agnosia, the inability to interpret what the eye sees, may be used as tool in managing wandering behavior of Alzheimer's patients. (Author/NB)

  18. Establishing Visual Category Boundaries between Objects: A PET Study

    Science.gov (United States)

    Saumier, Daniel; Chertkow, Howard; Arguin, Martin; Whatmough, Cristine

    2005-01-01

    Individuals with Alzheimer's disease (AD) often have problems in recognizing common objects. This visual agnosia may stem from difficulties in establishing appropriate visual boundaries between visually similar objects. In support of this hypothesis, Saumier, Arguin, Chertkow, and Renfrew (2001) showed that AD subjects have difficulties in…

  19. Kluver-Bucy syndrome developed after convulsion: A case report

    OpenAIRE

    Okur, Mesut; Yılmaz, Cahide; Epçaçan, Serdar; Üstyol, Lokman; Kaya, Avni; Çaksen, Hüseyin

    2013-01-01

    Abstract. Kluver-Bucy syndrome is characterized by increased appetite, hypersexuality, hypermetamorphosis, memory disorders, visual agnosia, stagnancy, aphasia, bulimia, polyuria, and polydipsia. A 14 year old girl had generalized tonic-clonic convulsions at admission, and an incomplete Kluver-Bucy syndrome with hypersexuality, recent memory disturbance, hypermetamorphosis, speech disturbance, hyperactivity, agitation, aggressiveness, and hallucinations, developed the following day. Here in, ...

  20. [Visual disturbances following right cerebral lesion: a case report].

    Science.gov (United States)

    Sato, M; Yasui, N; Suzuki, A; Kobayashi, T

    1984-07-01

    A 49-year-old right handed male, who showed three types of visual disturbance, e. g. hemianopsia, obscuration phenomena and unilateral visuospatial agnosia at different times, was reported. At first, he had hemiparesis, hemisensory disturbance and homonymous hemianopsia on the left side because of multiple stenoses of posterior branches of the right middle cerebral artery. His motor and visual field disturbances improved for several days after onset, but there appeared transient obscuration phenomena on the left visual field. CT scan revealed an abnormal low density area in the right temporo-parietal region. At about 4.5 years after the first attack, he again had hemiparesis and homonymous hemianopsia on the left side. Cerebral angiography showed an occlusion of the right middle cerebral artery. Since his paresis was progressive, STA-MCA anastomoses was performed. Hemiparesis was improved, but homonymous hemianopsia remained. Moreover, at about one year after the second attack, left visuospatial agnosia participated in his hemianopsia. Cerebral angiography showed an additional occlusion in the crural segment of the right posterior cerebral artery. CT scan showed a lesion in the right basal ganglia and temporo-parietal lobe. In most cases, unilateral visuospatial agnosia occurs with hemianopsia. But, in this case, these symptoms occurred at different times. This may indicate the differentiation between unilateral visuospatial agnosia and hemianopsia. PMID:6487433

  1. Categorical Perception of Lexical Tones in Mandarin-speaking Congenital Amusics

    Directory of Open Access Journals (Sweden)

    Wan Ting Huang

    2015-06-01

    Full Text Available Previous research suggests that within Mandarin-speaking congenital amusics, only a subgroup has behavioral lexical tone perception impairments (tone agnosia, whereas the rest of amusics do not. The purpose of the current study was to investigate the categorical nature of lexical tone perception in Mandarin-speaking amusics with and without behavioral lexical tone deficits. Three groups of listeners (controls, pure amusics and amusics with tone agnosia participated in tone identification and discrimination tasks. Indexes of the categorical perception of a physical continuum of fundamental frequencies ranging from a rising to level tone were measured. Specifically, the stimulus durations were manipulated at 100 and 200 ms. For both stimulus durations, all groups exhibited similar categorical boundaries. The pure amusics showed sharp identification slopes and significantly peaked discrimination functions similar to those of normal controls. However, such essential characteristics for the categorical perception of lexical tones were not observed in amusics with tone agnosia. An enlarged step-size from 20 Hz to 35 Hz was not able to produce any discrimination peaks in tone agnosics either. The current study revealed that only amusics with tone agnosia showed a lack of categorical tone perception, while the pure amusics demonstrated typical categorical perception of lexical tones, indicating that the deficit of pitch processing in music does not necessarily result in the deficit in the categorical perception of lexical tones. The different performance between congenital amusics with and without tone agnosia provides a new perspective on the proposition of the relationship between music and speech perception.

  2. Visuomotor performance based on peripheral vision is impaired in the visual form agnostic patient DF.

    Science.gov (United States)

    Hesse, Constanze; Ball, Keira; Schenk, Thomas

    2012-01-01

    The perception-action model states that visual information is processed in different cortical areas depending on the purpose for which the information is acquired. Specifically, it was suggested that the ventral stream mediates visual perception, whereas the dorsal stream primarily processes visual information for the guidance of actions (Goodale & Milner, 1992). Evidence for the model comes from patient studies showing that patients with ventral stream damage (visual form agnosia) and patients with dorsal stream damage (optic ataxia) show divergent performance in action and perception tasks. Whereas DF, a patient suffering from visual form agnosia, was found to perform well in visuomotor tasks despite her inability to use vision for perceptual tasks, patients with optic ataxia show usually the opposite pattern, i.e. good perception but impaired visuomotor control. The finding that both disorders seem to provoke a mirror-reversed pattern of spared and impaired visual functions, led to the belief that optic ataxia and visual form agnosia can be considered as complementary disorders. However, the visuomotor performance of patients with optic ataxia is typically only impaired when they are tested in visual periphery while being often preserved when tested in central vision. Here, we show that DF's visuomotor performance is also only preserved when the target is presented centrally. Her reaching and grasping movements to targets in peripheral vision are abnormal. Our findings indicate that DF's visuomotor performance is quite similar to the visuomotor performance of patients with optic ataxia which undermines previous suggestions that the two disorders form a double-dissociation.

  3. Influencing factors for the disappearance of hemispatial neglect in patients during acute stroke

    Institute of Scientific and Technical Information of China (English)

    Yaobin Long

    2006-01-01

    BACKGROUND: Some researches are proved that early sitting balance and body motor control performed on patients with stroke and hemiplegia is related to functional prognosis. For patients with hemispatial neglect (HSN) during acute stroke, whether HSN disappearance is related to those trainings or not should be further studied.OBJ ECTIVE: To analyze the correlation between HSN disappearance and related intervention of patients during acute stroke.DESIGN: Case analysis.SETTING: Department of Neurology, First Affiliated Hospital of Guangxi Medical University.PARTICIPANTS: A total of 21 patients with stroke were selected from the Department of Neurology, the First Affiliated Hospital of Guangxi Medical University from May 2005 to March 2006. Diagnosis criteria: ① Stroke was diagnosed by CT and MRI; ② Diagnosis was coincidence with HSN evaluation criteria; ③ All cases were consent. Exclusion criteria: Patients who had poly-focus, conscious disturbance, severe amentia and hard communication combined with aphasia were excluded. A total of 12 males and 9 females were included, and the mean age was (68±10) years. Among them, 14 patients had cerebral infarction and 7 had cerebral hemorrhage.METHODS: Disappearance and existence of HSN were analyzed with HSN evaluation criteria: body agnosia, left and right agnosia, maintenance of supine position, place of things, sitting up straight, center of line measured by eyes, and cutting 30 lines with paring method. Items mentioned below belonged to HSN disappearance: ① without body agnosia; ② without left and right agnosia; ③ be able to maintain supine position; ④ knowing place of things; ⑤ sitting up straight by one's own; ⑥ be able to measure the center of line by eyes; ⑦ be able to cut 30 lines with paring method. However, only one item belonged to HSN remnant; but only one item belonged to HSN remnant. Numbers of patients who were of body agnosia, left and right agnosia and difficult maintenance of supine

  4. Object based attention and visual area LO.

    OpenAIRE

    de-Wit, L.; Kentridge, R. W.; Milner, A D

    2009-01-01

    We investigated the neural basis of so-called “object-based attention” by examining patient D.F., who has visual form agnosia caused by bilateral damage to the lateral occipital (LO) area of the ventral visual stream. We tested D.F.’s object-based attention in two ways. In the first experiment, we used a spatial cueing procedure to compare the costs associated with shifting attention within versus between two separate outline figures. D.F. did not show the normal advantage of within-object ov...

  5. [A Case of Musicophilia with Right Predominant Temporal Lobe Atrophy].

    Science.gov (United States)

    Shinagawa, Shunichiro; Nakayama, Kazuhiko

    2015-11-01

    A 68-year-old woman exhibiting musicophilia with right predominant temporal lobe atrophy happened to visit our clinic. She had no musical background, but beginning two years ago, she acquired a strong preference for especially popular music and sometimes sang at home. She did not exhibit obvious semantic aphasia or facial agnosia, and showed only mild behavioral changes including apathy. Her musicophilia can be explained as an instance of stereotypical behavior. Her right temporal lobe atrophy may have caused changes in her emotional and reward systems, resulting in her music specific behaviors. PMID:26560960

  6. Partial Kluver-Bucy syndrome secondary to tubercular meningitis.

    Science.gov (United States)

    Jha, Kunal Kishor; Singh, Satyajeet Kumar; Kumar, Prem; Arora, Charu Dutt

    2016-01-01

    Tubercular meningitis (TBM) is a devastating extra pulmonary manifestation of tuberculosis and demonstrates a high neurological morbidity. A rare complication of this condition is Kluver-Bucy syndrome (KBS), which is a neurobehavioral disorder characterised by hyper-sexuality, visual agnosia, bulimia, placidity, hyperorality and memory deficits caused by lesions to the amygdala. The amygdala lesions can be due to many causes, including traumatic brain injury, systemic conditions and infections such as tuberculosis. Here, we present a case of partial KBS in a patient undergoing treatment for TBM. PMID:27530874

  7. About the neurolinguistics of the implicatures: abstract of a study

    Directory of Open Access Journals (Sweden)

    Juliano Luís Fontanari

    1989-06-01

    Full Text Available Taking into account recent data on linguistics of production and comprehension in aphasia, a protocol was executed including the several types of implicatures. The protocol was applied to 90 subjects classified according to the localization of cerebral lesions, as shown by CT. Results are discussed in report to clinical manifestations of brain lesions, as aphasia, apraxia, agnosia, and intelligence and pragmatics disturbances. Discussion supports the impression that there is a mechanism that correlates extra-linguistics contexts with the 'said' at the right hemisphere.

  8. A Critical Review of Alzheimer's Disease Researches in the Past Decade%Alzheimer病近十年研究述评

    Institute of Scientific and Technical Information of China (English)

    高定国; 高尚仁; 郭丽

    2001-01-01

    Alzheimer病(Alzheimer'S disease-AD)也称Alzheimer型痴呆(dementia of Alzheimer’s type-DAT),是一种伴有神经病理学和神经化学特性的原发性退行性大脑认知功能疾病。主要表现为记忆力下降(不能学习或回忆)以及其它认知功能障碍:如失语(aphasia)、失动(apraxia)、失知(agnosia)

  9. Posterior cortical atrophy - a prototypical case of dementia beginning with visual symptoms: case report

    Directory of Open Access Journals (Sweden)

    Leonardo Ferreira Caixeta

    2013-10-01

    Full Text Available Dementia presenting with prominent higher order visual symptoms may be observed in a range of neurodegenerative conditions and is often challenging to diagnose. We describe a case of progressive dementia presenting with prominent visual cortical symptoms. A 55-year-old, right-handed, woman with early onset of visual impairment not associated with anterior visual pathology, presenting with dyslexia, visual agnosia, Balint's syndrome, and spatial disorientation. Ophthalmologists should consider this condition especially in presenile patients with slowly progressive higher-order visual symptoms. Although described in association with different conditions, it may also occur in Alzheimer disease.

  10. Posterior cortical atrophy--a prototypical case of dementia beginning with visual symptoms: case report.

    Science.gov (United States)

    Caixeta, Leonardo Ferreira; Taleb, Alexandre Chater; Ghini, Bruno Galafassi; Soares, Vânia Lúcia Dias; Caixeta, Victor de Melo; Vargas, Ciro

    2013-10-01

    Dementia presenting with prominent higher order visual symptoms may be observed in a range of neurodegenerative conditions and is often challenging to diagnose. We describe a case of progressive dementia presenting with prominent visual cortical symptoms. A 55-year-old, right-handed, woman with early onset of visual impairment not associated with anterior visual pathology, presenting with dyslexia, visual agnosia, Balint's syndrome, and spatial disorientation. Ophthalmologists should consider this condition especially in presenile patients with slowly progressive higher-order visual symptoms. Although described in association with different conditions, it may also occur in Alzheimer disease.

  11. Involvement of the right inferior longitudinal fascicle in visual hemiagnosia: a brain stimulation mapping study.

    Science.gov (United States)

    Fernández Coello, Alejandro; Duvaux, Sophie; De Benedictis, Alessandro; Matsuda, Ryosuke; Duffau, Hugues

    2013-01-01

    Neural foundations underlying visual agnosia are poorly understood. The authors present the case of a patient who underwent awake surgery for a right basal temporooccipital low-grade glioma in which direct electrostimulation was used both at the cortical and subcortical level. Brain mapping over the inferior longitudinal fascicle generated contralateral visual hemiagnosia. These original findings are in agreement with recent tractography data that have confirmed the existence of an occipitotemporal pathway connecting occipital visual input to higher-level processing in temporal lobe structures. This is the first report of a true transient visual hemiagnosia elicited through electrostimulation, supporting the crucial role of inferior longitudinal fascicle in visual recognition.

  12. Correlations between neurological signs and brain MR images of patients in consecutive stages of subacute sclerosing panencephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Kulczycki, J.; Kryst-Widzgowska, T.; Sobczyk, W.; Bochynska, A.; Pilkowska, E.; Milewska, D. [Pracownia Rezonansu Magnetycznego, Inst. Psychiatrii i Neurologii, Warsaw (Poland)

    1994-12-31

    Correlations between neurological symptoms and brain MRI changes during the course of SSPE in 10 patients were studied. Visual agnosia and mental regression - very frequent symptoms at the early stages of the disease were caused by nearly symmetrical, focal involvement of the occipital and frontal white matter in all cases. Pyramidal and extrapyramidal disturbances reflected rather diffuse lesions of both cerebral hemispheres in late second stage of the illness. In cases with clinical improvement the brain changes disclosed an entire stability, but not diminishing intensity. (author) 9 refs, 8 figs, 3 tabs

  13. Cortical Lewy Body Dementia

    Directory of Open Access Journals (Sweden)

    W. R. G. Gibb

    1990-01-01

    Full Text Available In cortical Lewy body dementia the distribution of Lewy bodies in the nervous system follows that of Parkinson's disease, except for their greater profusion in the cerebral cortex. The cortical tangles and plaques of Alzheimer pathology are often present, the likely explanation being that Alzheimer pathology provokes dementia in many patients. Pure cortical Lewy body dementia without Alzheimer pathology is uncommon. The age of onset reflects that of Parkinson's disease, and clinical features, though not diagnostic, include aphasias, apraxias, agnosias, paranoid delusions and visual hallucinations. Parkinsonism may present before or after the dementia, and survival duration is approximately half that seen in Parkinson's disease without dementia.

  14. [Overview and assessment of cognitive function in interpreting postoperative cognitive dysfunction].

    Science.gov (United States)

    Miura, Rina; Hattori, Hideyuki

    2014-11-01

    The most important point for evaluation of the post-operative cognitive dysfunction is that we understand "cognitive function". First we described the definition of the "cognitive function" and second, outlined each function (dysfunction) and introduced the main assessment methods from the view point of neuropsychology. Cognitive function (dysfunction) described in this paper includes consciousness (confusional state, disturbance of consciousness), generalized attention (disorder of generalized attention), memory (amnesia), orientation (disorientation), executive function (dysexecutive syndrome), social cognition (social cognitive impairment), language (aphasia), cognition (agnosia), behavior (apraxia), directed attention (unilateral spatial neglect), and construction (constructional disorder).

  15. Occipital lobe infarction and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tagawa, Koichi; Nagata, Ken; Shishido, Fumio (Research Inst. of Brain and Blood Vessels, Akita (Japan))

    1990-08-01

    Even though the PET study revealed a total infarct in the territory of the left PCA in our 3 cases of pure alesia, it is still obscure which part of the left occipital lobe is most closely associated with the occurrence of the pure alexia. In order to elucidate the intralobar localization of the pure alexia, it is needed to have an ideal case who shows an pure alexia due to the localized lesion within the left occipital lobe. Furthermore, high-resolution PET scanner will circumvent the problem in detecting the metabolism and blood flow in the corpus callosum which plays an important role in the pathogenesis. We have shown that the occlusion of the right PCA also produced a left unilateral agnosia which is one of the common neurological signs in the right MCA infarction. To tell whether the responsible lesion for the unilateral spatial agnosia differs between the PCA occlusion and the MCA occlusion, the correlation study should be carried out in a greater number of the subjects. Two distinctive neuropsychological manifestations, cerebral color blidness and prosopagnosia, have been considered to be produced by the bilateral occipital lesion. The PET studies disclosed reduction of blood flow and oxygen metabolism in both occipital lobes in our particular patient who exibited cerebral color blindness and posopagnosia. (author).

  16. Hurt but still alive: Residual activity in the parahippocampal cortex conditions the recognition of familiar places in a patient with topographic agnosia☆

    Science.gov (United States)

    van Assche, Mitsouko; Kebets, Valeria; Lopez, Ursula; Saj, Arnaud; Goldstein, Rachel; Bernasconi, Françoise; Vuilleumier, Patrik; Assal, Frédéric

    2016-01-01

    The parahippocampal cortex (PHC) participates in both perception and memory. However, the way perceptual and memory processes cooperate when we navigate in our everyday life environment remains poorly understood. We studied a stroke patient presenting a brain lesion in the right PHC, which resulted in a mild and quantifiable topographic agnosia, and allowed us to investigate the role of this structure in overt place recognition. Photographs of personally familiar and unfamiliar places were displayed during functional magnetic resonance imaging (fMRI). Familiar places were either recognized or unrecognized by the patient and 6 age- and education-matched controls in a visual post-scan recognition test. In fMRI, recognized places were associated with a network comprising the fusiform gyrus in the intact side, but also the right anterior PHC, which included the lesion site. Moreover, this right PHC showed increased connectivity with the left homologous PHC in the intact hemisphere. By contrasting recognized with unrecognized familiar places, we replicate the finding of the joint involvement of the retrosplenial cortex, occipito-temporal areas, and posterior parietal cortex in place recognition. This study shows that the ability for left and right anterior PHC to communicate despite the neurological damage conditioned place recognition success in this patient. It further highlights a hemispheric asymmetry in this process, by showing the fundamental role of the right PHC in topographic agnosia. PMID:26909331

  17. Dyscalculia, Dysgraphia, and Left-Right Confusion from a Left Posterior Peri-Insular Infarct

    Directory of Open Access Journals (Sweden)

    S. Bhattacharyya

    2014-01-01

    Full Text Available The Gerstmann syndrome of dyscalculia, dysgraphia, left-right confusion, and finger agnosia is generally attributed to lesions near the angular gyrus of the dominant hemisphere. A 68-year-old right-handed woman presented with sudden difficulty completing a Sudoku grid and was found to have dyscalculia, dysgraphia, and left-right confusion. Magnetic resonance imaging (MRI showed a focus of abnormal reduced diffusivity in the left posterior insula and temporoparietal operculum consistent with acute infarct. Gerstmann syndrome from an insular or peri-insular lesion has not been described in the literature previously. Pathological and functional imaging studies show connections between left posterior insular region and inferior parietal lobe. We postulate that the insula and operculum lesion disrupted key functional networks resulting in a pseudoparietal presentation.

  18. Dyscalculia, dysgraphia, and left-right confusion from a left posterior peri-insular infarct.

    Science.gov (United States)

    Bhattacharyya, S; Cai, X; Klein, J P

    2014-01-01

    The Gerstmann syndrome of dyscalculia, dysgraphia, left-right confusion, and finger agnosia is generally attributed to lesions near the angular gyrus of the dominant hemisphere. A 68-year-old right-handed woman presented with sudden difficulty completing a Sudoku grid and was found to have dyscalculia, dysgraphia, and left-right confusion. Magnetic resonance imaging (MRI) showed a focus of abnormal reduced diffusivity in the left posterior insula and temporoparietal operculum consistent with acute infarct. Gerstmann syndrome from an insular or peri-insular lesion has not been described in the literature previously. Pathological and functional imaging studies show connections between left posterior insular region and inferior parietal lobe. We postulate that the insula and operculum lesion disrupted key functional networks resulting in a pseudoparietal presentation. PMID:24817791

  19. Mindblindness: metaphor and neuroaesthetics in the works of Silas Weir Mitchell and Simon Baron-Cohen.

    Science.gov (United States)

    Swenson, Kristine

    2013-01-01

    Silas Weir Mitchell's novel, When All the Woods are Green (1894), acknowledges the medical use of mindblindness (agnosia) but also casts it as a developmental disorder, bringing it provocatively close to how current neuropsychologist, Simon Baron-Cohen and his followers use the term in relation to autism. This chapter traces the mindblindess metaphor in the works of Mitchell and Baron-Cohen to show how mindblindness informs the larger paradigms by which they theorize the brain. This analysis suggests that Baron-Cohen, and thus much current thinking about autism spectrum conditions, is influenced by Victorian-era cultural assumptions and neurosexism, a connection that calls for scrutiny of Baron-Cohen's current models of the brain and theories of autism. This chapter also demonstrates the extent to which Mitchell used fiction and advocated writing as neuroaesthetic tools and thus bridged in his work cognitive science and aesthetics--a connection that current scholars of neuroaesthetics are now theorizing. PMID:24290271

  20. Síndrome de gerstmann de desenvolvimento associada a neoplasia cerebelar: relato de um caso e revisão da literatura

    Directory of Open Access Journals (Sweden)

    Lineu César Werneck

    1975-03-01

    Full Text Available É relatado um caso de síndrome de Gerstmann de Desenvolvimento, que apresentava acalculia, agrafía, confusão direita-esquerda, agnosia de dedos e apraxia construcional, em um menino de 7 anos. O tratamento inicial com metilfenidato determinou bons resultados no que concerne à hiperatividade, à atenção e à apraxia construcional. Durante o curso clínico, o paciente apresentou sintomatologia cerebelar, hipertensão intracraniana, tendo sido feita intervenção cirúrgica na fossa posterior, sendo excisado um meduloblastoma de cerebelo. O autor acredita que é esta a primeira descrição na literatura da concomitância da síndrome de Gerstmann de Desenvolvimento e neoplasia de fossa posterior. São feitos comentários focalizando cada um dos aspectos clínicos, fatores etiológicos e topográficos.

  1. 视空间忽略症的康复

    Institute of Scientific and Technical Information of China (English)

    李红玲; 孔静

    2004-01-01

    视空间忽略症,主要以视觉形式表现,对身体一侧的事物,通常是左侧视野中的事物不注意。如请他读一张报纸上的通栏标题时,他只读右半侧而忽略了左侧半。故临床上有半侧无视(unilateral neglect)、半侧不注意(unilateral inattention)、视空间失认(visual spatial agnosia)、及偏侧空间不注意(hemispatial inattention)或单侧视觉忽略(unilateral visual neglect)之称,但多数作者认为使用单侧空间忽略更合适。

  2. Visuospatial deficits with preserved reading ability in a patient with posterior cortical atrophy.

    Science.gov (United States)

    Mendez, M F

    2001-09-01

    Visuospatial deficits are characteristic of posterior cortical atrophy (PCA). A 58 year old woman had progressive dressing apraxia and environmental disorientation but continued to read voraciously. Positron emission tomography revealed hypometabolism of the occipitoparietal regions bilaterally, consistent with PCA. The symptoms suggested predominant dysfunction of the dorsal ("where") stream with abnormalities in visual localization and visuospatial integration; however, the patient also had a less pronounced apperceptive object agnosia. Further analysis of her preserved reading ability was performed. Familiar irregular words were read rapidly, but nonsense words were read slowly in a letter-by-letter fashion. She had a word superiority effect for embedded words and words with obscured letters but had difficulty reading stylized script or printing in unusual fonts. These findings suggested a dissociation between reading routes. Although the patient had a phonological dyslexia, her visuospatial processing was sufficient for access to preserved visual word forms for efficient lexical reading. PMID:11721864

  3. A novel device for the study of somatosensory information processing.

    Science.gov (United States)

    Holden, Jameson K; Nguyen, Richard H; Francisco, Eric M; Zhang, Zheng; Dennis, Robert G; Tommerdahl, Mark

    2012-03-15

    Current methods for applying multi-site vibratory stimuli to the skin typically involve the use of multiple, individual vibrotactile stimulators. Limitations of such an arrangement include difficulty with both positioning the stimuli as well as ensuring that stimuli are delivered in a synchronized and deliberate manner. Previously, we reported a two-site tactile stimulator that was developed in order to solve these problems (Tannan et al., 2007a). Due to both the success of that novel stimulator and the limitations that were inherent in that device, we designed and fabricated a four-site stimulator that provides a number of advantages over the previous version. First, the device can stimulate four independent skin sites and is primarily designed for stimulating the digit tips. Second, the positioning of the probe tips has been re-designed to provide better ergonomic hand placement. Third, the device is much more portable than the previously reported stimulator. Fourth, the stimulator head has a much smaller footprint on the table or surface where it resides. To demonstrate the capacity of the device for delivering tactile stimulation at four independent sites, a finger agnosia protocol, in the presence and absence of conditioning stimuli, was conducted on seventeen healthy control subjects. The study demonstrated that with increasing amplitudes of vibrotactile conditioning stimuli concurrent with the agnosia test, inaccuracies of digit identification increased, particularly at digits D3 and D4. The results are consistent with prior studies that implicated synchronization of adjacent and near-adjacent cortical ensembles with conditioning stimuli in impacting TOJ performance (Tommerdahl et al., 2007a,b).

  4. Visual body recognition in a prosopagnosic patient.

    Science.gov (United States)

    Moro, V; Pernigo, S; Avesani, R; Bulgarelli, C; Urgesi, C; Candidi, M; Aglioti, S M

    2012-01-01

    Conspicuous deficits in face recognition characterize prosopagnosia. Information on whether agnosic deficits may extend to non-facial body parts is lacking. Here we report the neuropsychological description of FM, a patient affected by a complete deficit in face recognition in the presence of mild clinical signs of visual object agnosia. His deficit involves both overt and covert recognition of faces (i.e. recognition of familiar faces, but also categorization of faces for gender or age) as well as the visual mental imagery of faces. By means of a series of matching-to-sample tasks we investigated: (i) a possible association between prosopagnosia and disorders in visual body perception; (ii) the effect of the emotional content of stimuli on the visual discrimination of faces, bodies and objects; (iii) the existence of a dissociation between identity recognition and the emotional discrimination of faces and bodies. Our results document, for the first time, the co-occurrence of body agnosia, i.e. the visual inability to discriminate body forms and body actions, and prosopagnosia. Moreover, the results show better performance in the discrimination of emotional face and body expressions with respect to body identity and neutral actions. Since FM's lesions involve bilateral fusiform areas, it is unlikely that the amygdala-temporal projections explain the relative sparing of emotion discrimination performance. Indeed, the emotional content of the stimuli did not improve the discrimination of their identity. The results hint at the existence of two segregated brain networks involved in identity and emotional discrimination that are at least partially shared by face and body processing.

  5. Síndrome de gerstmann de desenvolvimento associada a neoplasia cerebelar: relato de um caso e revisão da literatura Developmental Gerstmann syndrome associated with cerebellar neoplasm: a case report with review of litterature

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    Lineu César Werneck

    1975-03-01

    Full Text Available É relatado um caso de síndrome de Gerstmann de Desenvolvimento, que apresentava acalculia, agrafía, confusão direita-esquerda, agnosia de dedos e apraxia construcional, em um menino de 7 anos. O tratamento inicial com metilfenidato determinou bons resultados no que concerne à hiperatividade, à atenção e à apraxia construcional. Durante o curso clínico, o paciente apresentou sintomatologia cerebelar, hipertensão intracraniana, tendo sido feita intervenção cirúrgica na fossa posterior, sendo excisado um meduloblastoma de cerebelo. O autor acredita que é esta a primeira descrição na literatura da concomitância da síndrome de Gerstmann de Desenvolvimento e neoplasia de fossa posterior. São feitos comentários focalizando cada um dos aspectos clínicos, fatores etiológicos e topográficos.A Developmental Gerstmann syndrome in a 7 years-old-boy with hyperactivity, short attention span, acalculia, agraphia, right-left confusion, finger agnosia and constructional apraxia is reported. An initial trial with methylphenidate was done with good improvement regarding hyperactivity, attention span and constructional apraxia. In the clinical course developed a cerebellar syndrome and intracranial hypertension. Surgical exploration of the cerebellum discovered a medulloblastoma. The author believes that this is the first described association of Developmental Gerstmann syndrome and cerebellar neoplasia. The clinical findings, the etiology and the topography of the Gerstmann syndrome are discussed.

  6. 注意力缺陷多动障碍(ADHD)儿童的空间知觉失认研究%Study of spatial perception loss of ADHD children

    Institute of Scientific and Technical Information of China (English)

    刘加海; 刘斯彦; 周永平; 徐方忠

    2011-01-01

    Space perception refers to the spatial perception of one object, such as distance, shape, size, orientation etc. It has great significance to children's writing ability and understanding of the concept of digital processing, as well as calculation and comparison with the complex problem of learning. Although, some scholars have adopted Benton's Visual Retention Test (BVRT) in ADHD children spatial perception study and proved the space perception agnosia of ADHD children, this was the only method to this field, and recent researches of space perception for ADHD children still have big vacancy. This thesis provides more experimental methods for future study of ADHD children spatial perception. Also this thesis points out that the research of space perception agnosia of ADHD children need some refinement with more detailed research on aspects of shape-perception, distance-perception, orientation-perception, size-perception and so on.%空间知觉是对物体距离、形状、大小、方位等空间特性的知觉.空间知觉失认的患者往往会出现写字左右颠倒、间架结构处理混乱、对数量关系不易理解等缺陷,从而无法准确地感知物体的各种特性,难以形成良好的推理能力.对ADHD儿童空间知觉的研究目前还存在很大的空缺,虽已有学者将视觉本顿图形测试运用于ADHD儿童的空间知觉研究中,证明了ADHD儿童存在空间认知失认,但这是唯一一项应用于该领域的研究,尚缺乏普遍性.本文通过分析现有的视觉空间研究理论和实验方法,指出今后在ADHD儿童空间知觉研究中还需使用更多的实验方法,使对ADHD患儿在空间知觉失认的研究具有普遍性.笔者将研究内容进行了细化,分别从形状知觉、长度-距离知觉、方位知觉、大小知觉等方面进行具体、深入的论证.

  7. Mental rotation of faces in healthy aging and Alzheimer's disease.

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    Cassandra A Adduri

    Full Text Available BACKGROUND: Previous research has shown that individuals with Alzheimer's disease (AD develop visuospatial difficulties that affect their ability to mentally rotate objects. Surprisingly, the existing literature has generally ignored the impact of this mental rotation deficit on the ability of AD patients to recognize faces from different angles. Instead, the devastating loss of the ability to recognize friends and family members in AD has primarily been attributed to memory loss and agnosia in later stages of the disorder. The impact of AD on areas of the brain important for mental rotation should not be overlooked by face processing investigations -- even in early stages of the disorder. METHODOLOGY/PRINCIPAL FINDINGS: This study investigated the sensitivity of face processing in AD, young controls and older non-neurological controls to two changes of the stimuli -- a rotation in depth and an inversion. The control groups showed a systematic effect of depth rotation, with errors increasing with the angle of rotation, and with inversion. The majority of the AD group was not impaired when faces were presented upright and no transformation in depth was required, and were most accurate when all faces were presented in frontal views, but accuracy was severely impaired with any rotation or inversion. CONCLUSIONS/SIGNIFICANCE: These results suggest that with the onset of AD, mental rotation difficulties arise that affect the ability to recognize faces presented at different angles. The finding that a frontal view is "preferred" by these patients provides a valuable communication strategy for health care workers.

  8. Subgroup differences in the lexical tone mismatch negativity (MMN) among Mandarin speakers with congenital amusia.

    Science.gov (United States)

    Nan, Yun; Huang, Wan-ting; Wang, Wen-jing; Liu, Chang; Dong, Qi

    2016-01-01

    The association/dissociation of pitch processing between music and language is a long lasting debate. We examined this music-language relationship by investigating to what extent pitch deficits in these two domains were dissociable. We focused on a special neurodevelopmental pitch disorder - congenital amusia, which primarily affects musical pitch processing. Recent research has also revealed lexical tone deficits in speech among amusics. Approximately one-third of Mandarin amusics exhibits behavioural difficulties in lexical tone perception, which is known as tone agnosia. Using mismatch negativities (MMNs), our current work probed lexical tone encoding at the pre-attentive level among the Mandarin amusics with (tone agnosics) and without (pure amusics) behavioural lexical tone deficits compared with age- and IQ-matched controls. Relative to the controls and the pure amusics, the tone agnosics exhibited reduced MMNs specifically in response to lexical tone changes. Their tone-consonant MMNs were intact and similar to those of the other two groups. Moreover, the tone MMN reduction over the left hemisphere was tightly linked to behavioural insensitivity to lexical tone changes. The current study thus provides the first psychophysiological evidence of subgroup differences in lexical tone processing among Mandarin amusics and links amusics' behavioural tone deficits to impaired pre-attentive tone processing. Despite the overall music pitch deficits, the subgroup differences in lexical tone processing in Mandarin-speaking amusics suggest dissociation of pitch deficits between music and speech. PMID:26638759

  9. Neurological soft signs in Chinese adolescents with antisocial personality traits.

    Science.gov (United States)

    Wang, Xin; Cai, Lin; Li, Lingyan; Yang, Yanjie; Yao, Shuqiao; Zhu, Xiongzhao

    2016-09-30

    The current study was designed to explore the specific relationship between neurologic soft signs (NSSs) and characteristics of antisocial personality traits in adolescents, and to investigate particular NSSs linked to certain brain regions in adolescents with antisocial personality traits. The research was conducted on 96 adolescents diagnosed with ASP traits (ASP trait group) using the ASPD subscale of the Personality Diagnostic Questionnaire for the DSM-IV (PDQ-4+) and 96 adolescents without traits of any personality disorder (control group). NSSs were assessed using the soft sign subscales of the Cambridge Neurological Inventory. Adolescents with ASP traits showed more motor coordination, sensory integration, disinhibition, and total NSSs than the control group. Seven NSSs, including stereognosia in right hand, finger agnosia and graphesthesia in both hands, left-right orientation, and go/no go stimulus, were significantly more frequent in teenagers with ASP traits. Sensory integration was positively associated with ASP traits. Adolescents with antisocial personality traits might have abnormalities in the central nervous system, and sensory integration might be the particular indicator of antisocial personality disorder. PMID:27392230

  10. The neuropsychology of the Klüver-Bucy syndrome in children.

    Science.gov (United States)

    Lippe, S; Gonin-Flambois, C; Jambaqué, I

    2013-01-01

    The Klüver-Bucy syndrome (KBS) is characterized by a number of peculiar behavioral symptoms. The syndrome was first observed in 1939 by Heinrich Klüver and Paul Bucy in the rhesus monkey following removal of the greater portion of the monkey's temporal lobes and rhinencephalon. The animal showed (a) visual agnosia (inability to recognize objects without general loss of visual discrimination), (b) excessive oral tendency (oral exploration of objects), (c) hypermetamorphosis (excessive visual attentiveness), (d) placidity with loss of normal fear and anger responses, (e) altered sexual behavior manifesting mainly as marked and indiscriminate hypersexuality, and (f) changes in eating behavior. In humans, KBS can be complete or incomplete. It occurs as a consequence of neurological disorders that essentially cause destruction or dysfunction of bilateral mesial temporal lobe structures (i.e., Pick disease, Alzheimer disease, cerebral trauma, cerebrovascular accidents, temporal lobe epilepsy, herpetic encephalopathy, heat stroke). As for epilepsy, complete and incomplete KBS are well documented in temporal lobe epilepsy, temporal lobectomy, and partial status epilepticus. KBS can occur at any age. Children seem to show similar symptoms to adults, although some differences in the manifestations of symptoms may be related to the fact that children have not yet learned certain behaviors.

  11. CT and MRI findings of cerebral ischemic lesions in the cortical and perforating arterial system

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    Kameyama, Masakuni; Udaka, Fukashi; Nishinaka, Kazuto; Kodama, Mitsuo; Urushidani, Makoto; Kawamura, Kazuyuki; Inoue, Haruhisa; Kageyama, Taku [Sumitomo Hospital, Osaka (Japan)

    1995-07-01

    It is clinically useful to divide the location of infarction into the cortical and perforating arterial system. Computerized tomography (CT) and magnetic resonance imaging (MRI) now make the point of infarction a simple and useful task in daily practice. The diagnostic modality has also demonstrated that risk factors and clinical manifestations are different for infarction in the cortical as opposed to the perforating system. In this paper, we present various aspects of images of cerebral ischemia according to CT and/or MRI findings. With the advance of imaging mechanics, diagnostic capability of CT or/and MRI for cerebral infarction has markedly been improved. We must consider these points on evaluating the previously reported results. In addition, we always consider the pathological background of these image-findings for the precise interpretation of their clinical significance. In some instances, dynamic study such as PET or SPECT is needed for real interpretations of CT and/or MRI images. We paid special reference to lacunar stroke and striatocapsular infarct. In addition, `branch atheromatous disease (Caplan)` was considered, in particular, for their specific clinical significances. Large striatocapsular infarcts frequently show cortical signs and symptoms such as aphasia or agnosia in spite of their subcortical localization. These facts, although have previously been known, should be re-considered for their pathoanatomical mechanism. (author).

  12. An MR Brain Images Classifier System via Particle Swarm Optimization and Kernel Support Vector Machine

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    Yudong Zhang

    2013-01-01

    Full Text Available Automated abnormal brain detection is extremely of importance for clinical diagnosis. Over last decades numerous methods had been presented. In this paper, we proposed a novel hybrid system to classify a given MR brain image as either normal or abnormal. The proposed method first employed digital wavelet transform to extract features then used principal component analysis (PCA to reduce the feature space. Afterwards, we constructed a kernel support vector machine (KSVM with RBF kernel, using particle swarm optimization (PSO to optimize the parameters C and σ. Fivefold cross-validation was utilized to avoid overfitting. In the experimental procedure, we created a 90 images dataset brain downloaded from Harvard Medical School website. The abnormal brain MR images consist of the following diseases: glioma, metastatic adenocarcinoma, metastatic bronchogenic carcinoma, meningioma, sarcoma, Alzheimer, Huntington, motor neuron disease, cerebral calcinosis, Pick’s disease, Alzheimer plus visual agnosia, multiple sclerosis, AIDS dementia, Lyme encephalopathy, herpes encephalitis, Creutzfeld-Jakob disease, and cerebral toxoplasmosis. The 5-folded cross-validation classification results showed that our method achieved 97.78% classification accuracy, higher than 86.22% by BP-NN and 91.33% by RBF-NN. For the parameter selection, we compared PSO with those of random selection method. The results showed that the PSO is more effective to build optimal KSVM.

  13. Preserved local but disrupted contextual figure-ground influences in an individual with abnormal function of intermediate visual areas.

    Science.gov (United States)

    Brooks, Joseph L; Gilaie-Dotan, Sharon; Rees, Geraint; Bentin, Shlomo; Driver, Jon

    2012-06-01

    Visual perception depends not only on local stimulus features but also on their relationship to the surrounding stimulus context, as evident in both local and contextual influences on figure-ground segmentation. Intermediate visual areas may play a role in such contextual influences, as we tested here by examining LG, a rare case of developmental visual agnosia. LG has no evident abnormality of brain structure and functional neuroimaging showed relatively normal V1 function, but his intermediate visual areas (V2/V3) function abnormally. We found that contextual influences on figure-ground organization were selectively disrupted in LG, while local sources of figure-ground influences were preserved. Effects of object knowledge and familiarity on figure-ground organization were also significantly diminished. Our results suggest that the mechanisms mediating contextual and familiarity influences on figure-ground organization are dissociable from those mediating local influences on figure-ground assignment. The disruption of contextual processing in intermediate visual areas may play a role in the substantial object recognition difficulties experienced by LG.

  14. Cerebral hemorrhage without manifest motor paralysis. Reports of 5 cases

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    Taketani, T.; Dohi, I.; Miyazaki, T.; Handa, A. (Central Hospital of JNR, Tokyo (Japan))

    1982-01-01

    Before the introduction of computerized tomography (CT) there were some cases of intracerebral bleeding who were wrongly diagnosed as hypertensive encephalopathy or senile psychosis. We here report 5 cases who did not show any sign of motor paralysis. The clinical aspects of these cases were nausea and vomiting with dizziness (case 1), nausea and vomiting with slight headache (case 2), agnosia of left side with several kinds of disorientation (case 3), nausea and vomiting (case 4), and visual disturbance of right, lower quadrant (case 5). All of these cases showed no motor paralysis or abnormal reflex activities. By examination with CT each of them exhibited a high density area in the subcortical area of the right parietal lobe, the subcortical area of the right occipital lobe, the right temporal and parietal lobe, rather small portion of the left putamen and external capsule, and the subcortical area of left occipital lobe, respectively. Patients of cerebral hemorrhage without motor or sensory disturbances might often be taken for some psychic abnormality. We here have emphasized the importance of CT in such a group of patients. But for this technique, most of them would not be given adequate treatment and might be exposed to lifethreatening situations.

  15. Stereoscopic vision in the absence of the lateral occipital cortex.

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    Jenny C A Read

    Full Text Available Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field.

  16. Prosopagnosia: current perspectives

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    Corrow SL

    2016-09-01

    Full Text Available Sherryse L Corrow,1,2 Kirsten A Dalrymple,3 Jason JS Barton,1,2 1Human Vision and Eye Movement Laboratory, Neurology Division, Department of Medicine, 2Department of Ophthalmology and Visual Science, University of British Columbia, Vancouver, Canada; 3Institute of Child Development, University of Minnesota, Minneapolis, MN, USA Abstract: Prosopagnosia is a selective visual agnosia characterized by the inability to recognize the identity of faces. There are both acquired forms secondary to brain damage and developmental forms without obvious structural lesions. In this review, we first discuss the diagnosis of acquired and developmental prosopagnosia, and the challenges present in the latter case. Second, we discuss the evidence regarding the selectivity of the prosopagnosic defect, particularly in relation to the recognition of other objects, written words (another visual object category requiring high expertise, and voices. Third, we summarize recent findings about the structural and functional basis of prosopagnosia from studies using magnetic resonance imaging, functional magnetic resonance imaging, and event-related potentials. Finally, we discuss recent attempts at rehabilitation of face recognition in prosopagnosia. Keywords: face recognition, perception, fusiform gyrus, anterior temporal, review

  17. Visuo-Spatial Imagery Impairment in Posterior Cortical Atrophy: A Cognitive and SPECT Study

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    Simona Gardini

    2011-01-01

    Full Text Available This study investigated the cognitive profile and the cerebral perfusion pattern in a highly educated 70 year old gentleman with posterior cortical atrophy (PCA. Visuo-perceptual abilities, spatial memory, spatial representation and navigation, visuo-spatial mental imagery, semantic and episodic-autobiographical memory were assessed. Regional cerebral blood flow (rCBF was imaged with SPECT. Cognitive testing showed visual-perceptual impairment, apperceptive visual and landmark agnosia, topographical disorientation with way-finding deficits, impaired map learning and poor mental image generation. Semantic memory was normal, while episodic-autobiographical memory was impaired. Reduced rCBF was found mainly in the right hemisphere, in the precentral gyrus, posterior cingulate and middle temporal gyri, cuneus and precuneus, in the left superior temporal and lingual gyri and in the parahippocampus bilaterally. Hypoperfusion in occipito-parietal regions was associated with visuo-spatial deficits, whereas deficits in visuo-spatial mental imagery might reflect dysfunction related to hypoperfusion in the parahippocampus and precuneus, structures which are responsible for spatial and imagery processing. Dissociating performance between preserved semantic memory and poor episodic-autobiographical recall is consistent with a pattern of normal perfusion in frontal and anterior temporal regions but abnormal rCBF in the parahippocampi. The present findings indicate that PCA involves visuo-spatial imagery deficits and provide further validation to current neuro-cognitive models of spatial representation and topographical disorientation.

  18. Critical appraisal of the long-term impact of memantine in treatment of moderate to severe Alzheimer’s disease

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    Umamon Puangthong

    2009-10-01

    Full Text Available Umamon Puangthong, Ging-Yuek Robin HsiungDivision of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, CanadaAbstract: Alzheimer’s disease is the most common cause of dementia in older adults. The clinical features include progressive memory decline as well as cognitive deficits with executive dysfunction, language, visual perceptual difficulties, apraxia and agnosia. During the moderate to severe stage of the disease, there is a major decline in memory and function, while neuropsychiatric disturbances often emerge and patients become difficult to manage. These distressing symptoms increase caregiver burden and add to the direct costs of care of the patients. Any improvements in patient function and behavioral symptoms can reduce caregiver burden. Memantine has been available for a number of years in Europe and in North America. In this article, we examine the pharmacological rationale for its use, and the current clinical evidence for its efficacy and long-term effectiveness in the management of cognitive and behavioral symptoms in moderate to severe stages of Alzheimer’s disease.Keywords: memantine, Alzheimer’s disease, dementia

  19. Connecting art and the brain: an artist’s perspective on visual indeterminacy

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    Robert ePepperell

    2011-08-01

    Full Text Available In this article I will discuss the intersection between art and neuroscience from the perspective of a practicing artist. I have collaborated on several scientific studies into the effects of art on the brain and behaviour, looking in particular at the phenomenon of ‘visual indeterminacy’. This is a perceptual state in which subjects fail to recognise objects from visual cues. I will look at the background to this phenomenon, and show how various artists have exploited its effect through the history of art. My own attempts to create indeterminate images will be discussed, including some of the technical problems I faced in trying to manipulate the viewer’s perceptual state through paintings. Visual indeterminacy is not widely studied in neuroscience, although references to it can be found in the literature on visual agnosia and object recognition. I will briefly review some of this work and show how my attempts to understand the science behind visual indeterminacy led me to collaborate with psychophysicists and neuroscientists. After reviewing this work, I will discuss the conclusions I have drawn from its findings and consider the problem of how best to integrate neuroscientific methods with artistic knowledge to create truly interdisciplinary approach.

  20. Can patients without early, prominent visual deficits still be diagnosed of posterior cortical atrophy?

    Science.gov (United States)

    Suárez-González, A.; Crutch, S.J.; Roldán Lora, F.; Franco-Macías, E.; Gil-Néciga, E.

    2016-01-01

    Background Early and progressive disabling visual impairment is a core feature for the diagnosis of posterior cortical atrophy (PCA). However, some individuals that fulfil criteria over time might initially present with an onset of prominent posterior dysfunction other than visuoperceptual. Methods The clinical profile of five patients with a predominantly ‘non-visual’ posterior presentation (PCA2) was investigated and compared with sixteen individuals with visually predominant PCA (PCA1) and eighteen with typical amnestic Alzheimer disease (tAD). Results PCA2 patients showed significantly better performance than PCA1 in one visuospatial task and were free of Balint's syndrome and visual agnosia. Compared to tAD, PCA2 showed trends towards significantly lower performance in visuoperceptual tasks, more severe apraxia and more symptoms of Gerstmann's syndrome. Conclusions Our sample of PCA2 patients did not present with clinically prominent visual symptoms but did show visual dysfunction on formal neuropsychological assessment (less pronounced than in PCA1 but more than in tAD) in addition to other posterior deficits. Broadening the definition of PCA to encompass individuals presenting with prominent ‘non-visual’ posterior dysfunction should be potentially considered in clinical and research contexts. PMID:27423559

  1. Reducing Aβ load and tau phosphorylation: Emerging perspective for treating Alzheimer's disease.

    Science.gov (United States)

    Kalra, Jaspreet; Khan, Aamir

    2015-10-01

    Alzheimer's disease (AD) is a complex, progressive neurological disorder affecting elderly population of above 65 years of age, characterized by failure of memory, loss of acquired skills leading to apraxia, agnosia, aphasia and frequent disturbances in emotion with interpersonal and social deterioration. The extracellular senile plaques and intracellular neurofibrillary tangles composed of amyloid beta protein and highly phosphorylated tau protein, the key components involved in pathogenesis of AD are considered as the pathological hallmark of this disease. This has led to immense development in the field of treatment for AD. Recent evidences suggest that removal of protein deposits from AD brains are the newer attempts for treating AD. The major developments in this direction are the amyloid and tau based therapeutics, which could hold the key to treatment of AD in the near future. Several putative drugs have been thoroughly investigated in preclinical studies, but many of them have failed to produce results in the clinical scenario. Therefore, failures from the past can be treated as lessons for the development of efficacious drugs. In addition to this, various non- pharmacological interventions and miscellaneous drugs are also being used now for combating the AD like disease progression. Thus, present review discusses about the disease modifying therapies together with the various non-pharmacological interventions and miscellaneous drugs for treating AD. PMID:26209363

  2. Neurological soft signs in Chinese adolescents with antisocial personality traits.

    Science.gov (United States)

    Wang, Xin; Cai, Lin; Li, Lingyan; Yang, Yanjie; Yao, Shuqiao; Zhu, Xiongzhao

    2016-09-30

    The current study was designed to explore the specific relationship between neurologic soft signs (NSSs) and characteristics of antisocial personality traits in adolescents, and to investigate particular NSSs linked to certain brain regions in adolescents with antisocial personality traits. The research was conducted on 96 adolescents diagnosed with ASP traits (ASP trait group) using the ASPD subscale of the Personality Diagnostic Questionnaire for the DSM-IV (PDQ-4+) and 96 adolescents without traits of any personality disorder (control group). NSSs were assessed using the soft sign subscales of the Cambridge Neurological Inventory. Adolescents with ASP traits showed more motor coordination, sensory integration, disinhibition, and total NSSs than the control group. Seven NSSs, including stereognosia in right hand, finger agnosia and graphesthesia in both hands, left-right orientation, and go/no go stimulus, were significantly more frequent in teenagers with ASP traits. Sensory integration was positively associated with ASP traits. Adolescents with antisocial personality traits might have abnormalities in the central nervous system, and sensory integration might be the particular indicator of antisocial personality disorder.

  3. The right cerebral hemisphere: emotion, music, visual-spatial skills, body-image, dreams, and awareness.

    Science.gov (United States)

    Joseph, R

    1988-09-01

    Based on a review of numerous studies conducted on normal, neurosurgical and brain-injured individuals, the right cerebral hemisphere appears to be dominant in the perception and identification of environmental and nonverbal sounds; the analysis of geometric and visual space (e.g., depth perception, visual closure); somesthesis, stereognosis, the maintenance of the body image; the production of dreams during REM sleep; the perception of most aspects of musical stimuli; and the comprehension and expression of prosodic, melodic, visual, facial, and verbal emotion. When the right hemisphere is damaged a variety of cognitive abnormalities may result, including hemi-inattention and neglect, prosopagnosia, constructional apraxia, visual-perceptual disturbances, and agnosia for environmental, musical, and emotional sounds. Similarly, a myriad of affective abnormalities may occur, including indifference, depression, hysteria, gross social-emotional disinhibition, florid manic excitement, childishness, euphoria, impulsivity, and abnormal sexual behavior. Patients may become delusional, engage in the production of bizzare confabulations and experience a host of somatic disturbances such as pain and body-perceptual distortions. Based on studies of normal and "split-brain" functioning, it also appears that the right hemisphere maintains a highly developed social-emotional mental system and can independently perceive, recall and act on certain memories and experiences without the aid or active reflective participation of the left. This leads to situations in which the right and left halves of the brain sometime act in an uncooperative fashion, which gives rise to inter-manual and intra-psychic conflicts. PMID:2461390

  4. The hawkmoth fauna of Pakistan (Lepidoptera: Sphingidae).

    Science.gov (United States)

    Rafi, Muhammad Ather; Sultan, Amir; Kitching, Ian J; Pittaway, Anthony R; Markhasiov, Maxim; Khan, Muhammad Rafique; Naz, Falak

    2014-01-01

    This study represents the first complete modern account of the Sphingidae of Pakistan and takes the form of an annotated checklist, based on several national collections and those of a number of individuals. Of the 60 species and subspecies found, 14 are new records to the fauna of Pakistan, namely Agnosia orneus, Langia zenzeroides subsp. zenzeroides, Polyptychus trilineatus subsp. trilineatus, Dolbina inexacta, Ambulyx sericeipennis subsp. sericeipennis, Thamnoecha uniformis, Macroglossum belis, Macroglossum stellatarum, Cechetra scotti, Hippotion boerhaviae, Hyles euphorbiae subsp. euphorbiae, Rhagastis olivacea, Rethera brandti subsp. euteles and Theretra latreillii subsp. lucasii. Anambulyx elwesi subsp. kitchingi and Clanis deucalion subsp. thomaswitti are not recognised as valid subspecies and are synonymized with their respective nominotypical subspecies. An additional list is given of 30 taxa which may yet be found in Pakistan as they are present in neighbouring countries close to the border. Of the species/subspecies found, 24 are part of the Palaearctic fauna, 27 are part of the Oriental fauna and nine are Palaeo-Oriental/Palaeotropical. This reconfirms the transitional biogeographical position of the Pakistan fauna. PMID:24870331

  5. Cerebral hemorrhage without manifest motor paralysis

    International Nuclear Information System (INIS)

    Before the introduction of computerized tomography (CT) there were some cases of intracerebral bleeding who were wrongly diagnosed as hypertensive encephalopathy or senile psychosis. We here report 5 cases who did not show any sign of motor paralysis. The clinical aspects of these cases were nausea and vomiting with dizziness (case 1), nausea and vomiting with slight headache (case 2), agnosia of left side with several kinds of disorientation (case 3), nausea and vomiting (case 4), and visual disturbance of right, lower quadrant (case 5). All of these cases showed no motor paralysis or abnormal reflex activities. By examination with CT each of them exhibited a high density area in the subcortical area of the right parietal lobe, the subcortical area of the right occipital lobe, the right temporal and parietal lobe, rather small portion of the left putamen and external capsule, and the subcortical area of left occipital lobe, respectively. Patients of cerebral hemorrhage without motor or sensory disturbances might often be taken for some psychic abnormality. We here have emphasized the importance of CT in such a group of patients. But for this technique, most of them would not be given adequate treatment and might be exposed to lifethreatening situations. (author)

  6. Apraxias in neurodegenerative dementias

    Directory of Open Access Journals (Sweden)

    Sadanandavalli Retnaswami Chandra

    2015-01-01

    Full Text Available Background: Apraxia is a state of inability to carry out a learned motor act in the absence of motor, sensory or cerebellar defect on command processed through the Praxis circuit. Breakdown in default networking is one of the early dysfunction in cortical dementias and result in perplexity, awkwardness, omission, substitution errors, toying behavior and unrecognizable gestures in response to command with voluntary reflex dissociation where, when unobserved patient will carry out reflex movements normally. Awareness into the organicity of these phenomenas will help in early diagnosis, which will help in initiating appropriate treatment and slowing down the progression of the disease. Aims and Objectives: The aim was to look for the various kinds of apraxias in patients with dementia using appropriate simple tests. Patients and Methods: Three hundred patients satisfying Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for dementia were evaluated in detail with mandatory investigations for dementia followed by testing for ideational, ideomotor, limb-kinetic, buccopharyngeal, dressing apraxia, constructional apraxia and gait apraxias in addition to recording of rare apraxias when present. Results: Alzheimer′s disease showed maximum association with apraxias in all the phases of the disease ideational, ideomotor, dressing and constructional apraxias early and buccopharyngeal and gait apraxia late. Frontotemporal lobe dementia showed buccopharyngeal and gait apraxias late into the disease. Cortical basal ganglionic degeneration showed limb apraxias and diffuse Lewy body disease showed more agnosias and less apraxias common apraxias seen was Ideational and Ideomotor. Conclusion: Recognition of the apraxias help in establishing organicity, categorization, caregiver education, early strategies for treatment, avoiding anti-psychotics and introducing disease modifying pharmacotherapeutic agents and also prognosticating.

  7. The Psychologic Treatment of the Hemiplegic Upper Limb%上肢偏瘫者康复治疗中的心理问题

    Institute of Scientific and Technical Information of China (English)

    张学斌

    2000-01-01

    偏瘫是许多神经系统疾病常见的功能障碍,偏瘫上肢的预后如何对ADL的恢复与改善和生活质量的高低有着决定性的意义。偏瘫上肢的功能恢复不仅涉及运动功能问题,而且还涉及心理问题,偏瘫上肢的心理问题除涵盖一般偏瘫病人的心理问题外,还因偏瘫上肢的功能障碍特点而有其特殊性。其中主要包括由于偏瘫上肢的运动功能恢复常较下肢缓慢,偏瘫上肢伴发的失认、失用,以及肩-手综合征等引起的心理问题,正确地处理好这些心理问题将有助于偏瘫者整体功能的恢复。%Hemiplegia is the common imparirment caused by many diseases of nerve system.The outcome of the hemiplegic upper limb plays and important role on the improvement of ADL and the level of QOL.The recovery of the hemiplegic upper limb diose not only involve the motional function,but,because of the speciality of its functional impairments,also involves the psychologic problem which mainly includes the slower recovery of he hemiplegic upper limb than the lower one,agnosia,apraxia and shoulder-hand syndrone.A proper treatment to these psychologic problems is helpful to the general recovery of the hemiplegic patients.

  8. A double dissociation of the acuity and crowding limits to letter identification, and the promise of improved visual screening.

    Science.gov (United States)

    Song, Shuang; Levi, Dennis M; Pelli, Denis G

    2014-05-05

    Here, we systematically explore the size and spacing requirements for identifying a letter among other letters. We measure acuity for flanked and unflanked letters, centrally and peripherally, in normals and amblyopes. We find that acuity, overlap masking, and crowding each demand a minimum size or spacing for readable text. Just measuring flanked and unflanked acuity is enough for our proposed model to predict the observer's threshold size and spacing for letters at any eccentricity. We also find that amblyopia in adults retains the character of the childhood condition that caused it. Amblyopia is a developmental neural deficit that can occur as a result of either strabismus or anisometropia in childhood. Peripheral viewing during childhood due to strabismus results in amblyopia that is crowding limited, like peripheral vision. Optical blur of one eye during childhood due to anisometropia without strabismus results in amblyopia that is acuity limited, like blurred vision. Furthermore, we find that the spacing:acuity ratio of flanked and unflanked acuity can distinguish strabismic amblyopia from purely anisometropic amblyopia in nearly perfect agreement with lack of stereopsis. A scatter diagram of threshold spacing versus acuity, one point per patient, for several diagnostic groups, reveals the diagnostic power of flanked acuity testing. These results and two demonstrations indicate that the sensitivity of visual screening tests can be improved by using flankers that are more tightly spaced and letter like. Finally, in concert with Strappini, Pelli, Di Pace, and Martelli (submitted), we jointly report a double dissociation between acuity and crowding. Two clinical conditions-anisometropic amblyopia and apperceptive agnosia-each selectively impair either acuity A or the spacing:acuity ratio S/A, not both. Furthermore, when we specifically estimate crowding, we find a double dissociation between acuity and crowding. Models of human object recognition will need to

  9. [Phenomenological and Diagnostic Implications of Paraschemazia: A Case Report].

    Science.gov (United States)

    Mehta, Urvakhsh Meherwan; Thippeswamy, Harish; Bharath, Rose Dawn; Satishcandra, Parthasarathy

    2015-01-01

    Paraschemazia is characterized by distortions of body image, and has been observed in neurological disorders (epilepsies, migraine, and non-dominant cortical lesions), retinal damage, and hallucinogenic drug use. This complex symptom cluster of subjective and objective perceptual abnormalities forms an essential feature of Todd's Alice in Wonderland syndrome. This neuropsychiatric manifestation must be phenomenologically differentiated from hallucinations, illusions, and agnosias. Herein we report a patient with paraschemazia that occurred during the ictal phase of temporal lobe epilepsy; the patient was referred to the department of psychiatry due to symptoms of transient intense fear and abnormal perceptions. We also discuss the diagnostic difficulty and phenomenological implications associated with this rare phenomenon. A 45-year-old female presented with brief episodes (30-45 s) of sensory distortion, during which the faces and limbs of other people and her own appeared distorted (e.g. protruding eyes, elongated nose, and oval or square head). The episodes of sensory distortion were associated with intense fear and were followed by loss of consciousness for 5 min. She had been experiencing these episodes since the age of 12 years and responded poorly to several antiepileptic medications. 3-Tesla MRI performed using a complex partial seizure protocol showed altered signal intensity and volume loss in the right hippocampus, suggestive of right mesial temporal sclerosis. Neuropsychological assessment showed impaired sustained attention, working memory, and verbal and visual learning and memory, suggestive of bilateral dorsolateral prefrontal and temporal lobe deficits. She improved in response to a combination of levetiracetam and clobazam, and was seizure free at the 2-year follow-up. PMID:26111290

  10. Dissociation of the Reach and the Grasp in the destriate (V1) monkey Helen: a new anatomy for the dual visuomotor channel theory of reaching.

    Science.gov (United States)

    Whishaw, Ian Q; Karl, Jenni M; Humphrey, Nicholas K

    2016-08-01

    Dual visuomotor channel theory proposes that reaching depends on two neural pathways that extend from visual cortex (V1) to motor cortex via the parietal lobe. The Reach pathway directs the hand to the target's location and the Grasp pathway shapes the hand and digits for purchase. Sighted human participants integrate the Reach and the Grasp, but without vision they dissociate the movements to capitalize on tactile cues. They use a Reach with a relatively open hand to locate the target and then they use touch cues to shape the fingers to Grasp. After a V1 lesion, the rhesus monkey, Helen, learned to make near-normal visual discriminations based on size and brightness but displayed visual agnosia. She also learned to reach for food with her mouth and her hands. The present analysis of film of her reaching behavior shows that she dissociated the Reach and the Grasp, as do unsighted human participants reaching for a food target at a fixed location. Her rapid and direct Reach was made with an open hand and extended fingers to contact the food with the palm whereas her Grasp was initiated after she touched the food. She also visually fixated the target during the Reach and visually disengaged after target contact, as do sighted human participants. In contrast, Helen did integrate the Reach and the Grasp to take food from her mouth, demonstrating that she could integrate the movements using online tactile cues. The finding that extrastriate pathways can direct the hand toward extrinsic target properties (location) but not intrinsic target properties (size and shape) is discussed as a novel addition to dual visuomotor channel theory. PMID:27056084

  11. CBF tomograms with (/sup 99m/Tc-HM-PAO in patients with dementia (Alzheimer type and HIV) and Parkinson's disease--initial results

    Energy Technology Data Exchange (ETDEWEB)

    Costa, D.C.; Ell, P.J.; Burns, A.; Philpot, M.; Levy, R.

    1988-12-01

    We present preliminary data on the utility of functional brain imaging with (99mTc)-d,l-HM-PAO and single photon emission computed tomography (SPECT) in the study of patients with dementia of the Alzheimer type (DAT), HIV-related dementia syndrome, and the on-off syndrome of Parkinson's disease. In comparison with a group of age-matched controls, the DAT patients revealed distinctive bilateral temporal and posterior parietal deficits, which correlate with detailed psychometric evaluation. Patients with amnesia as the main symptom (group A) showed bilateral mesial temporal lobe perfusion deficits (p less than 0.02). More severely affected patients (group B) with significant apraxia, aphasia, or agnosia exhibited patterns compatible with bilateral reduced perfusion in the posterior parietal cortex, as well as reduced perfusion to both temporal lobes, different from the patients of the control group (p less than 0.05). SPECT studies of HIV patients with no evidence of intracraneal space occupying pathology showed marked perfusion deficits. Patients with Parkinson's disease and the on-off syndrome studied during an on phase (under levodopa therapy) and on another occasion after withdrawal of levodopa (off) demonstrated a significant change in the uptake of (99mTc)-d,l-HM-PAO in the caudate nucleus (lower on off) and thalamus (higher on off). These findings justify the present interest in the functional evaluation of the brain of patients with dementia. (99mTc)-d,l-HM-PAO and regional cerebral blood flow (rCBF)/SPECT appear useful and highlight individual disorders of flow in a variety of neuropsychiatric conditions.

  12. CT classification of small thalamic hemorrhages. Topographic localization and clinical manifestation

    Energy Technology Data Exchange (ETDEWEB)

    Kawahara, Nobutaka; Kaneko, Mitsuo; Tanaka, Keisei; Muraki, Masaaki; Sato, Kengo (Hamamatsu Medical Center Hospital, Shizuoka (Japan))

    1984-06-01

    The thalamus is located deep in the cerebral hemispheres, and most of its nuclei have reciprocal fiber connections with specific areas over the cerebral cortex. Localized lesions in the thalamus, therefore, can cause specific neurological deficits, depending on their locations. From this point of view, we reviewed 110 cases, admitted over the past 7 years, with thalamic hemorrhages 37 (34%) of which were small hematomas less than 2 cm in diameter. These small hematomas could be divided into 4 types depending on their locations as follows: antero-lateral type, postero-lateral type, medial type, and dorsal type. Each type had the peculiar clinical features described below: 1) Postero-lateral Type (PL type, 28 cases, 76%): The original symptom was a sudden onset of moderate to severe sensori-motor deficits in most cases. The patients were mostly alert or only slightly confused. 2) Antero-lateral Type (AL type, 4 cases, 11%): The patients of this type first presented with sensori-motor disturbance and prefrontal signs. Both were generally mild and often disappeared early. 3) Medial Type (M type, 3 cases, 8%): The main symptom at onset was either a disturbance of consciousness or dementia. 4) Dorsal Type (D type, 2 cases, 5%): One patient with a right thalamic hematoma of this type showed geographical agnosia and visuo-constructive apraxia. The other patient, with a left-sided hematoma, exhibited transient clumsiness of the right hand and mild dysphasia. In our experience, the above classification of small hematomas clearly delineated the clinical symptoms and neurological signs of the different types; therefore, the symptoms and signs in larger hematoma could be explained by a combination of those of each type.

  13. Neuroinflammation in Alzheimer’s disease and Involvement of Interleukin-1: A Mechanistic View

    Directory of Open Access Journals (Sweden)

    Vivek Sharma

    2011-07-01

    Full Text Available Ageing is a universal biological fact and a natural process. It begins from the day we are born, or perhaps even before. Of the world’s 580 million elderly, 77 million (22% of total live in India. The increasing life expectancy of Indians, in the last decade, is likely to result in an increase in age-related disorders like Alzheimer’s disease and Parkinson’s disease. Alzheimer’s disease, the most common disorder of geriatric population, is a chronic, progressive, untreatable neurodegenerative disorder characterized by apraxia, aphasia, agnosia and severe cognitive deficits. Several behavioural changes like anxiety, hallucinations, depression and delusions are also experienced. Lot of progress has been made regarding understanding the pathological pathways involved, yet the available therapy only provide symptomatic relief but do not stop progression of disease. Several of key areas have been recognised and out of them inflammation has been regarded as inseparable and crucial factor involved. Interleukin-1 is a key molecule in systemic immune responses in health and disease and has analogous roles in the brain where it contributes to neuronal degeneration by energy dysfunction and triggering production of other cytokines, nitric oxide and others. IL-1 over expression is also associated with rheumatoid arthritis, vascular dementia, diabetes mellitus, periodontitis, systemic sclerosis, autoimmune encephalomyelitis and cerebral infarction. Present review is an effort to present IL-1 as potential therapeutic target in treatment of Alzheimer’s disease by linking it with several of pathological factors like amyloidβ, neurofibrillary tangles, neuron loss and cholinergic dysfunction.

  14. The Two Visual Systems Hypothesis: new challenges and insights from visual form agnosic patient DF

    Directory of Open Access Journals (Sweden)

    Robert Leslie Whitwell

    2014-12-01

    Full Text Available Patient DF, who developed visual form agnosia following carbon monoxide poisoning, is still able to use vision to adjust the configuration of her grasping hand to the geometry of a goal object. This striking dissociation between perception and action in DF provided a key piece of evidence for the formulation of Goodale and Milner’s Two Visual Systems Hypothesis (TVSH. According to the TVSH, the ventral stream plays a critical role in constructing our visual percepts, whereas the dorsal stream mediates the visual control of action, such as visually guided grasping. In this review, we discuss recent studies of DF that provide new insights into the functional organization of the dorsal and ventral streams. We confirm recent evidence that DF has dorsal as well as ventral brain damage – and that her dorsal-stream lesions and surrounding atrophy have increased in size since her first published brain scan. We argue that the damage to DF’s dorsal stream explains her deficits in directing actions at targets in the periphery. We then focus on DF’s ability to accurately adjust her in-flight hand aperture to changes in the width of goal objects (grip scaling whose dimensions she cannot explicitly report. An examination of several studies of DF’s grip scaling under natural conditions reveals a modest though significant deficit. Importantly, however, she continues to show a robust dissociation between form vision for perception and form vision for action. We also review recent studies that explore the role of online visual feedback and terminal haptic feedback in the programming and control of her grasping. These studies make it clear that DF is no more reliant on visual or haptic feedback than are neurologically-intact individuals. In short, we argue that her ability to grasp objects depends on visual feedforward processing carried out by visuomotor networks in her dorsal stream that function in the much the same way as they do in neurologically

  15. Remission of progressive multifocal leukoencephalopathy following highly active antiretroviral therapy in a man with AIDS

    Directory of Open Access Journals (Sweden)

    Yoganathan K

    2012-04-01

    Full Text Available Katie Yoganathan1, David Brown2, Kathir Yoganathan31Cardiff Medical School, Cardiff, Wales, UK; 2Virus Reference Department, Microbiology Services, Health Protection Agency, London, UK; 3Singleton Hospital, Abertawe Bro Morgannwg University Health Board, Swansea, UKAbstract: A 43-year-old Caucasian homosexual man with AIDS presented with blurring of vision, change of personality, and memory loss in March 1999. He had first been admitted 2 months previously for treatment of Pneumocystis jiroveci pneumonia. A magnetic resonance imaging scan on admission showed multiple white matter lesions involving both subcortical cerebral hemispheres and cerebellar regions, with no mass effect or surrounding edema. JC virus was detected by nested polymerase chain reaction in the cerebrospinal fluid. These findings were diagnostic of progressive multifocal leukoencephalopathy (PML. His CD4 count was 34 cells/mL, and his HIV ribonucleic acid level was 800,789 copies/mL. He was treated with a combination antiretroviral therapy. He was last reviewed in October 2011. He was fully independent socially and mentally, but he still had some residual neurologic signs with right-sided homonymous hemianopia and visual agnosia. His HIV ribonucleic acid level was undetectable, and his CD4 count was 574 cells/mm3. Although the median survival of patients with PML was poor before the antiretroviral therapy era, our patient, who is now aged 55 years, is still alive 12 years after the diagnosis. The diagnosis of PML and differential diagnosis of focal neurologic signs in HIV-positive patients are discussed in this case report.Keywords: HIV, focal neurologic signs, cerebral toxoplasmosis, primary brain lymphoma, ischaemic stroke

  16. Differential contribution of right and left temporo-occipital and anterior temporal lesions to face recognition disorders

    Directory of Open Access Journals (Sweden)

    Guido eGainotti

    2011-06-01

    Full Text Available In the study of prosopagnosia, several issues (such as the specific or non-specific manifestations of prosopagnosia, the unitary or non-unitary nature of this syndrome and the mechanisms underlying face recognition disorders are still controversial. Two main sources of variance partially accounting for these controversies could be the qualitative differences between the face recognition disorders observed in patients with prevalent lesions of the right or left hemisphere and in those with lesions encroaching upon the temporo-occipital or the (right anterior temporal cortex.Results of our review seem to confirm these suggestions. Indeed, they show that (a the most specific forms of prosopagnosia are due to lesions of a right posterior network including the OFA and the FFA, whereas (b the face identification defects observed in patients with left temporo-occipital lesions seem due to a semantic defect impeding access to person-specific semantic information from the visual modality. Furthermore, face recognition defects resulting from right anterior temporal lesions can usually be considered as part of a multimodal people recognition disorder.The implications of our review are, therefore, the following: (1 to consider the components of visual agnosia often observed in prosopagnosic patients with bilateral temporo-occipital lesions as part of a semantic defect, resulting from left-sided lesions (and not from prosopagnosia proper; (2 to systematically investigate voice recognition disorders in patients with right anterior temporal lesions to determine whether the face recognition defect should be considered a form of ‘associative prosopagnosia’ or a form of the ‘multimodal people recognition disorder’.

  17. Cross-cultural studies using a modified mini mental test for healthy subjects and patients with various forms of vascular dementia.

    Science.gov (United States)

    Thajeb, Peterus; Thajeb, Teguh; Dai, Daofu

    2007-03-01

    Existing neuropsychological tests are often complex and time-consuming. We designed a modified Mini Mental Test (MMT) battery for clinical assessment of the global and regional higher cortical functions of the brain. We tested its applicability in healthy subjects with different ethnic, cultural and educational backgrounds. The usefulness of our MMT as a tool for the clinical evaluation of patients with various forms of vascular dementia was determined. The MMT comprises five subtests, including clinical evaluations of: (A) orientation (6 points); (B) attention, right-left discrimination, speech, and calculation (20); (C) immediate recall, and recent and remote memory retrieval (10); (D) praxis (10); and (E) visuospatial orientation, agnosia, hemianopsia, and visual hemineglect (14). The MMT was administered to 100 healthy subjects from two different ethnic backgrounds (Indonesian and Chinese/Taiwanese) and diverse cultural and educational backgrounds, and to 61 patients with various forms of vascular dementia. MMT scores were significantly lower in healthy subjects with a low level of education regardless of their ethnic background (p<0.001). Patients with vascular dementia had much lower MMT scores than did the comparable age-adjusted normal controls (p<0.001). Of the patients with vascular dementia, those with Binswanger's disease had the lowest MMT scores (25.5+/-28.9), followed by those with large cerebral infarcts (48.0+/-7.1), cerebral haemorrhage (49.0+/-8.5), and multiple lacunar infarctions (55.0+/-0.5) (P<0.001). With a cut-off point of 33/55 (partial score/total score), the sensitivity and positive predictive value of the MMT were 0.98 and 0.94, respectively. The MMT is a simple and useful tool for clinical assessment of the cognitive functions of healthy subjects and patients with or without vascular dementia. It can be used for individuals with different ethnic, cultural and educational backgrounds. PMID:17258132

  18. POST-STROKE WRITING AND READING DISORDERS

    Directory of Open Access Journals (Sweden)

    Sinanović Osman

    2013-01-01

    Full Text Available The writing and reading disorders in stroke patients (alexias, agraphias and acalculias are more frequent than verified in routine exam, not only in the less developed but also in large neurological departments. Alexia is an acquired type of sensory aphasia where damage to the brain causes a patient to lose the ability to read. It is also called word blindness, text blindness orvisual aphasia. Alexia refers to an acquired inability to read caused by brain damage and must be distinguished from dyslexia, a developmental abnormality in which the individual is unable to learn to read, and from illiteracy, which reflects a poor educational back-ground. Most aphasics are also alexic, but alexia may occur in the absence of aphasia and may occasionally be the soledisability resulting from specific brain lesions. There are different classifications of alexias. Traditionally, the alexias are divided into three categories: pure alexia with agraphia, pure alexia without agraphia, and alexia associated with aphasia (“aphasic alexia”. Agraphia is defined as the disruption of previously intact writing skills by brain damage. Writing involves several elements—language processing, spelling, visual perception, visual-spatial orientation for graphic symbols, motor planning, and motor control of writing. A disturbance of any of these processes can impair writing. Agraphia may occur by itself or as association with aphasias, alexia, agnosia and apraxia. Agraphia can also result from “peripheral” involvement of the motor act of writing. Like alexia, agraphia must be distinguished from illiteracy, where writing skills were never developed. Acalculia is a clinical syndrome of acquired deficits in mathematical calculation, either mentally or with paper and pencil. This language disturbances can be classified differently, but there are three principal types of acalculia: acalculia associated with language disturbances, including number paraphasia, number

  19. [Motor amusia following a right temporal lobe hemorrhage--a case report].

    Science.gov (United States)

    Takeda, K; Bandou, M; Nishimura, Y

    1990-01-01

    A 65-year-old female was admitted to our hospital because of left hemiparesis with sudden onset one week before. She was congenitally right-handed. She had been a teacher of Japanese string instrument (samisen) playing and been able to sing Japanese traditional songs well. A tape on which she had recorded her songs one year before the admission also proved her to be a good singer. Neurological examination on admission revealed almost normal findings except for minimal weakness in her left hand fingers. Right temporal lobe hemorrhage was revealed by CT scan. One month after the admission, she complained that she was unable to sing her songs and to play samisen as she used to do. Her intelligence was normal (WAIS VIQ116, PIQ108) and there were no abnormal findings as follows: aprosodia, aphasia, agraphia, memory disturbance, agnosia and ideational, ideomotor, constructional or limb-kinetic apraxia. She could point out her errors while singing. However, musical receptive function was slightly disturbed with tonal memory in Seashore test. When she was asked to sing a song without any instrumental support, she hummed a melody occasionally with wrong pitch, but rhythmically. After hearing a song she knew well, she reproduced it with slight improvement. With the vocal or the instrumental accompaniment, she could sing fairly well. She had some mistakes of pitch while playing a samisen. MRI was performed one year and a half after the brain hemorrhage. It displayed a thin linear of hematoma in the white matter of the right upper temporal and transverse gyrus. It was proved in our case that motor amusia with minimal musical receptive dysfunction could appear following a cerebral lesion and musical function might be independent of intelligence or verbal function. PMID:2184966

  20. CBF tomograms with [/sup 99m/Tc-HM-PAO in patients with dementia (Alzheimer type and HIV) and Parkinson's disease--initial results

    International Nuclear Information System (INIS)

    We present preliminary data on the utility of functional brain imaging with [99mTc]-d,l-HM-PAO and single photon emission computed tomography (SPECT) in the study of patients with dementia of the Alzheimer type (DAT), HIV-related dementia syndrome, and the on-off syndrome of Parkinson's disease. In comparison with a group of age-matched controls, the DAT patients revealed distinctive bilateral temporal and posterior parietal deficits, which correlate with detailed psychometric evaluation. Patients with amnesia as the main symptom (group A) showed bilateral mesial temporal lobe perfusion deficits (p less than 0.02). More severely affected patients (group B) with significant apraxia, aphasia, or agnosia exhibited patterns compatible with bilateral reduced perfusion in the posterior parietal cortex, as well as reduced perfusion to both temporal lobes, different from the patients of the control group (p less than 0.05). SPECT studies of HIV patients with no evidence of intracraneal space occupying pathology showed marked perfusion deficits. Patients with Parkinson's disease and the on-off syndrome studied during an on phase (under levodopa therapy) and on another occasion after withdrawal of levodopa (off) demonstrated a significant change in the uptake of [99mTc]-d,l-HM-PAO in the caudate nucleus (lower on off) and thalamus (higher on off). These findings justify the present interest in the functional evaluation of the brain of patients with dementia. [99mTc]-d,l-HM-PAO and regional cerebral blood flow (rCBF)/SPECT appear useful and highlight individual disorders of flow in a variety of neuropsychiatric conditions

  1. Cross-cultural studies using a modified mini mental test for healthy subjects and patients with various forms of vascular dementia.

    Science.gov (United States)

    Thajeb, Peterus; Thajeb, Teguh; Dai, Daofu

    2007-03-01

    Existing neuropsychological tests are often complex and time-consuming. We designed a modified Mini Mental Test (MMT) battery for clinical assessment of the global and regional higher cortical functions of the brain. We tested its applicability in healthy subjects with different ethnic, cultural and educational backgrounds. The usefulness of our MMT as a tool for the clinical evaluation of patients with various forms of vascular dementia was determined. The MMT comprises five subtests, including clinical evaluations of: (A) orientation (6 points); (B) attention, right-left discrimination, speech, and calculation (20); (C) immediate recall, and recent and remote memory retrieval (10); (D) praxis (10); and (E) visuospatial orientation, agnosia, hemianopsia, and visual hemineglect (14). The MMT was administered to 100 healthy subjects from two different ethnic backgrounds (Indonesian and Chinese/Taiwanese) and diverse cultural and educational backgrounds, and to 61 patients with various forms of vascular dementia. MMT scores were significantly lower in healthy subjects with a low level of education regardless of their ethnic background (p<0.001). Patients with vascular dementia had much lower MMT scores than did the comparable age-adjusted normal controls (p<0.001). Of the patients with vascular dementia, those with Binswanger's disease had the lowest MMT scores (25.5+/-28.9), followed by those with large cerebral infarcts (48.0+/-7.1), cerebral haemorrhage (49.0+/-8.5), and multiple lacunar infarctions (55.0+/-0.5) (P<0.001). With a cut-off point of 33/55 (partial score/total score), the sensitivity and positive predictive value of the MMT were 0.98 and 0.94, respectively. The MMT is a simple and useful tool for clinical assessment of the cognitive functions of healthy subjects and patients with or without vascular dementia. It can be used for individuals with different ethnic, cultural and educational backgrounds.

  2. 非抽搐性癫痫持续状态五例及文献复习%Non-convulsive status epilepticus: 5 cases report and literature review

    Institute of Scientific and Technical Information of China (English)

    吴春波; 刘晓原; 裴立英; 席晓芳; 杨靓; 刘献增; 朱继红

    2010-01-01

    目的 探讨非抽搐性癫痫持续状态(NCSE)患者的临床表现及持续脑电监测的脑电图(EEG)特征.方法 对自2008年11月至2009年12月北京大学人民医院急诊科收治的5例NCSE患者行持续EEG监测检查,观察其EEG特征及临床表现.结果 5例均出现发作性意识障碍,其中4例出现烦躁、易怒或躁狂,3例表现出精神运动迟滞和遗忘,2例出现言语自动症和失认,1例出现定向障碍.所有患者的EEG均出现广泛性但一侧明显的异常放电.静脉注射地两泮后,3例患者临床症状迅速改善.结论 NCSE并非罕见,持续EEG监测能查出本病,早期诊断,及时治疗可改善患者预后,临床应注意与其他引起意识紊乱的疾病相鉴别.%Objective To describe the clinical and electroencephalographic features as well as the possible etiology and treatment of patients with non-convulsive status epilepticus (NCSE). Methods We identified 5 adult patients with NCSE from the epilepsy database of the comprehensive epilepsy. Continuous electroencephalographic (EEG) monitoring was analyzed and chart review was performed to analyze their clinical and electroencephalographic features. Results The patients ranged from 19 to 66 years old. All of the 5 patients showed impaired consciousness: 4 demonstrated agitation and paranoia; 3 had both psychomotor retardation and amnesia; 2 developed verbal automatisms and agnosia; and 1 had disorientation. All the patients had associated generalized discharges but lateralized dominant. Three patients showed clinical improvement following administration of benzodiazepines. Conclusion The NCSE is not a rare case and continuous EEG monitoring can help the diagnosis. Prompt recognition and treatment may be necessary in improving the neurological outcome, and attention should be paid to the identification with other diseases that cause impairment of conscience.

  3. Japanese encephalitis (JE) part II: 14 years' follow-up of survivors.

    Science.gov (United States)

    Sarkari, N B S; Thacker, A K; Barthwal, S P; Mishra, V K; Prapann, Shiv; Srivastava, Deepak; Sarkari, M

    2012-01-01

    Japanese encephalitis, the commonest Arbovirus encephalitis, has been endemic in many parts of Asia, the Pacific Islands, and India; also, there have been many epidemics. Most of the post JE cases have been associated with neurological and neuropsychiatric deficits but have not been properly classified and followed. Practically all the previous studies were in children or young adults. The aim of this study, involving only adult cases, the largest ever being reported, has been to follow the 688/1,199 survivors of JE patients out of 1,282 of acute cases admitted during four epidemics for a period of 14 years after properly classifying the sequelae. This prospective study was conducted in B.R.D. Medical College Gorakhpur (India), involving 665/688 post JE cases with neuropsychiatric deficits from four epidemics of 1978, 1980, 1988 and 1989 which were properly classified in nine groups. While the first epidemic of 1978 was being studied, more disastrous episodes flared up and the patients were subsequently added. Hence, the total duration of this prospective study was from November 1978 to December 2003. There were 14 defaulted initially from 688 followed (23/688 without sequelae and 665/688 with neuropsychiatric deficits), and later 130 were lost from time to time at various stages of follow up. Four out of 23/688 discharged without any deficit had to be readmitted for bizarre movements, assaultative behaviour and euphoria without fever and altered sensorium. All of them improved by symptomatic treatment. Progressive improvement occurred in all the parameters consisting of psychological disturbances, higher cerebral dysfunction, speech disorders (dysphonia, dysarthria, dysphasias, apraxia and agnosia), extra pyramidal, pyramidal features, and hypothalamic disturbances, cranial nerves including pupils and fundi and seizures. Maximum cases improved between 6 months (55%) to 1 year (78%). Only some features improved between 5 to 14 years. Four patients of hemiplegia

  4. [What is impaired consciousness? Revisiting impaired consciousness as psychiatric concept].

    Science.gov (United States)

    Kanemoto, Kousuke

    2004-01-01

    observation of an additional 3 cases, descriptions of naissance of the first word (taken from the autobiography of Helen Keller), visual object agnosia, and chronic schizophrenia with schizophasia were discussed to examine the relationship between impairments of recursive consciousness and semantic generation dysfunction. Attempts to bridge semantic generation and recursive consciousness, performed by psychopathologists such as Bin Kimura and Hiroyuki Koide, were also briefly discussed. In light of these case presentations and related discussions, we re-examined traditional theories of impaired consciousness, including Mayer-Gross's Gestalt theory, later replaced by Conrad and Henri Ey's theory related to intentionality. Furthermore, we attempted to link Denett's theory of consciousness to those traditional theories as well as to our own postulations, and neuropsychological data such as those of implicit memory and blindsight. Finally, the significance of Freud's unconsciousness in the framework of neuroscience was discussed. PMID:15580868

  5. DF's visual brain in action: the role of tactile cues.

    Science.gov (United States)

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Byrne, Caitlin M; Goodale, Melvyn A

    2014-03-01

    Patient DF, an extensively-tested woman with visual form agnosia from ventral-stream damage, is able to scale her grip aperture to match a goal object's geometry when reaching out to pick it up, despite being unable to explicitly distinguish amongst objects on the basis of their different geometries. Using evidence from a range of sources, including functional MRI, we have proposed that she does this through a functionally intact visuomotor system housed within the dorsal stream of the posterior parietal lobe. More recently, however, Schenk (2012a). The Journal of Neuroscience, 32(6), 2013-2017; Schenk (2012b). Trends in Cognitive Sciences, 16(5), 258-259. has argued that DF performs well in visually guided grasping, not through spared and functioning visuomotor networks in the dorsal stream, but because haptic feedback about the locations of the edges of the target is available to calibrate her grasps in such tasks, whereas it is not available in standard visual perceptual tasks. We have tested this 'calibration hypothesis' directly, by presenting DF with a grasping task in which the visible width of a target varied from trial to trial while its actual width remained the same. According to the calibration hypothesis, because haptic feedback was completely uninformative, DF should be unable to calibrate her grip aperture in this task. Contrary to this prediction, we found that DF continued to scale her grip aperture to the visual width of the targets and did so well within the range of healthy controls. We also found that DF's inability to distinguish shapes perceptually is not improved by providing haptic feedback. These findings strengthen the notion that DF's spared visuomotor abilities are driven largely by visual feedforward processing of the geometric properties of the target. Crucially, these findings also indicate that simple tactile contact with an object is needed for the visuomotor dorsal stream to be engaged, and accordingly enables DF to execute

  6. Study of clinical and neuropsychology of Gerstmann syndrome%Gerstmann综合征临床与神经心理学研究

    Institute of Scientific and Technical Information of China (English)

    曹辉; 李华

    2011-01-01

    目的:研究Gerstmann综合征(GS)的临床与神经心理学特点.方法:采用汉语失语症成套测评(ABC)、书写及视空间检查,对259例经CT或MRI检查确诊为脑卒中或脑损伤的患者进行评价.结果:(1)259例患者中有19例患有Gerstmann综合征(GS),其中9例有GS四主征、10例有GS的核心症状、命名性失语(AA)5例、经皮质运动性失语(TCM)2例、经皮质感觉性失语(TCS)4例、Wernicke失语3例、构音障碍2例、无失语5例;(2)病变部位:左顶枕、左侧颞顶、左侧颞顶枕、左侧额顶枕和左侧基底节共17例,右侧基底节、顶叶损害2例.结论:(1)Gerstmann综合征不是一个独立的综合征;(2)其病变部位不仅仅限于优势半球顶叶.%Objective To study clinical and neuropsychology features of patients with Gerstmann syndrome (GS). Methods 259 patients with stroke diagnosed by CT or MRI were detected by the Aphasia Battery of Chinese( ABC) .Writing Test and the Visual Space Test. Results (1)19 patients of the 259 cases had Gerstmann syndrome(GS) ,and 9 patients of the 19 cases had agraphia, acalculia, the tetrad of GS-finger agnosia and left-right disorientation, and 10 cases of GS with core symptoms. 5 cases showed anomic aphasia ( AA) , 2 showed transcortical motor aphasia ( TCM ) , 4 showed transcortical sensory aphasia (TCS) ,3 with Wemicke aphasia ( WA) ,2 with dysarthria, and no aphasia was in 5 Cases. (2)The lesion site was as follows: 17 cases localized to left parietal occipital lesion,left temporoparietal,left temporoparietal occipital,left occipital and left basal ganglia;2 cases localized to right basal ganglia,parietal lobe damage. Conclusion Gerstmann syndrome is not a single disorder;The site of cerebral impairment can be seen not only in dominant lobus pari-etalis.

  7. The neuropsychological and cortical metabolic changes in two patients with Benson's syndrome%Benson综合征患者两例神经心理特征与皮质代谢异常

    Institute of Scientific and Technical Information of China (English)

    高晶; 郭佳翔; 李方; 冯逢; 朱朝晖; 牛娜; 有慧; 崔丽英; 郭玉璞

    2011-01-01

    Objective Standard neuropsychological assessment plus structural and functional imaging were used in accurate diagnosis of Benson's syndrome (posterior cortical atrophy).Method Serial neuropsychological screening and integrative assessments of visual spatial function, 3D structural MRIimaging and functional FDG-PET imaging were used in two cases of Benson' s syndrome.Results The clinical signs were agnosia, optic ataxia, apraxia, alexia, agraphia and prosopagnosia.MRI imaging revealed bilateral parietal and occipital lobe atrophy.FDG-PET imaging revealed low metabolism in the posterior cortex.The agraphia was constructive: the words were correct but written in the wrong location.Conclusion Standard neuropsychological assessments can recognize the disease nature.When combined with the structural and functional imaging, a correct diagnosis of Benson's syndrome can be made.%目的 应用规范的神经心理评价结合结构影像以及功能影像正确诊断后部皮质萎缩,即Benson综合征.方法 对于综合认知功能评价证实以视空间功能异常为主要改变的2例Benson综合征患者进行系列的视空间功能检查、3D磁共振以及脱氧葡萄糖(FDG)-PET检查.结果 2例以记忆障碍为主诉就诊的患者,其中1例多次就诊于眼科诊断"视力障碍"而无其他异常发现,但经过仔细询问临床过程,规范的神经心理评价,结果证实患者有失认、视觉共济失调、失用、失读、失写(患者书写笔画正确,只是空间位置错误)等症状.2例患者MRI检查示双侧顶枕叶萎缩.FDG-PET反映顶枕皮质代谢减低,符合Benson综合征的诊断.结论 规范的神经心理评价可以正确地认识疾病本质,结构影像和功能影像对鉴别诊断Benson综合征有重要价值.

  8. [What is impaired consciousness? Revisiting impaired consciousness as psychiatric concept].

    Science.gov (United States)

    Kanemoto, Kousuke

    2004-01-01

    observation of an additional 3 cases, descriptions of naissance of the first word (taken from the autobiography of Helen Keller), visual object agnosia, and chronic schizophrenia with schizophasia were discussed to examine the relationship between impairments of recursive consciousness and semantic generation dysfunction. Attempts to bridge semantic generation and recursive consciousness, performed by psychopathologists such as Bin Kimura and Hiroyuki Koide, were also briefly discussed. In light of these case presentations and related discussions, we re-examined traditional theories of impaired consciousness, including Mayer-Gross's Gestalt theory, later replaced by Conrad and Henri Ey's theory related to intentionality. Furthermore, we attempted to link Denett's theory of consciousness to those traditional theories as well as to our own postulations, and neuropsychological data such as those of implicit memory and blindsight. Finally, the significance of Freud's unconsciousness in the framework of neuroscience was discussed.

  9. 一般少年人群神经系统软体征的发生状况%Prevalence of neurological soft signs in normative adolescents in China

    Institute of Scientific and Technical Information of China (English)

    蔡琳; 朱熊兆; 蚁金瑶; 姚树桥; 白玫; 李玲艳; 张丽; 罗英姿

    2013-01-01

    Objective: To investigate the prevalence of Neurological Soft Signs (NSS) in normative adolescents and to estimate the difference of neurological soft signs between different gender group and among different age groups. Method: Using two-stage randomized cluster sampling method, totally 3247 mainstream school students aged from 14 to 19 years old were recruited in the present study from 5 cities. The soft signs examinations of the Cambridge Neurological Inventory were administered to all participants to assess neurological soft signs. The soft signs examinations contain three factors, namely motor coordination, sensory integration and disinhibition. Higher scores in each subscale and total soft signs scale reflected greater levels of neurological soft signs. Results: The prevalence of individual neurological soft signs was from 0. 5% to 27. 2%. The most common neurological soft signs were finger agnosia of left hand (27. 2% ), finger agnosia of right hand (25. 7% ), abnormal rhythm tapping (25. 1%), abnormal left-right orientation (18. 3%) and abnormal graphesthesia of left hand (14. 5% ). Boys obtained significant higher scores in motor coordination [ (0. 8 ± 1.4) vs. (0. 6 ± 1. 2) ], sensory integration [(1.2 ± 1. 4) vs. (1. 0 ± 1. 3)], disinhibition [(0. 3 ±0. 6) vs. (0. 2 ±0. 5)] and the total of neurological soft signs [(2. 6 ± 2. 9) vs. (2.0 ±2. 5) ] than the scores of girls (P < 0. 01). The scores for the motor coordination, sensory integration and disinhibition and total soft signs scale had significant difference among different age groups (P <0. 001), showing that the scores in younger age group were higher than that in older age group. Conclusion: The current findings indicate that normative adolescents show some degrees of neurological soft signs. Boys have significantly more neurological soft signs than girls. There is a tendency that neurological soft signs decrease with age increase.%目的:调查一般少年神经系统软体征的发生状

  10. Gravidez Gemelar com Morte Fetal de Um dos Gêmeos: Avaliação Neurológica dos Gemelares Sobreviventes Neurological Evaluation of the Surviving Twin When One Dies In Utero

    Directory of Open Access Journals (Sweden)

    Carolina Araújo Rodrigues Funayama

    2002-03-01

    Full Text Available Objetivo: verificar as intercorrências pré e perinatais e a evolução neurológica de crianças de gestações gemelares em que um dos fetos apresentou óbito intra-uterino. Métodos: foram avaliados 14 casos de gestações gemelares ocorridas no período de 1988 a 1994 com óbito de um dos fetos, acompanhadas no Setor de Patologia Obstétrica do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da USP. Dados do acompanhamento pré e perinatal, bem como de autópsia dos fetos mortos, foram obtidos. As crianças foram convocadas no ano de 1996 para exame neurológico, sendo avaliados dados evolutivos e sinais patológicos nas áreas motoras, sensitivas, sensoriais e funções corticais superiores, incluindo linguagem, praxias e agnosias. Resultados: do total de 14 casos, 10 retornaram para a avaliação neurológica tardia. Destas, apenas uma criança apresentou alteração no exame neurológico, cursando com paresia espástica de MIE de grau leve, tendo apresentado Apgar 0 no primeiro minuto e 5 no quinto minuto. A avaliação da placentação e idade gestacional mostrou 5 casos (35,7% com placentação monocoriônica e um caso com monoamniótica, 8 casos de pré-termo e 6 casos a termo. O óbito de um dos fetos ocorreu no segundo trimestre em 6 casos (42,8% e os demais no terceiro trimestre. Conclusões: o problema neurológico constatado em um único feto pode ser atribuído às intercorrências perinatais que este recém-nascido apresentou. Não tivemos como resultado outros RN com seqüelas provavelmente pela opção da conduta conservadora, tendo-se resolvido as gestações após a 32ª semana com diminuição das complicações do parto pré-termo extremo.Purpose: to analyze the effects of prenatal and perinatal complications and the neurological development of surviving twins when the other had died in utero. Methods: fourteen cases of twin pregnancies where one of the twins had died during the pregnancy were analyzed

  11. [A 74-year-old man with urinary incontinence, right leg weakness and multiple cranial nerve palsies].

    Science.gov (United States)

    Mochizuki, H; Satoh, S; Saikawa, M; Mori, H; Shirai, T; Kondo, T; Mizuno, Y

    1995-02-01

    We report a 74-year-old man with a lung cancer, who developed right leg weakness, neurogenic bladder, and multiple cranial nerve palsies. The patient was well until December of 1992, when he was 74-year-old, when he noted transient double vision; in February of 1993, he noted numb sensation and weakness in his right leg. Later in the same month, he developed overflow incontinence of urine and weakness in his right face. He also noted deafness in his left ear (he had a marked loss of hearing in his right ear since childhood because of otitis media). His weakness in his right leg had progressed, and he was admitted to our service on March 19, 1993. On admission, he was afebrile and BP was 130/50 mmHg. General physical examination was unremarkable. On neurologic examination, he was alert and oriented to all spheres; no dementia was noted nor were detected aphasia, apraxia, and agnosia. His optic fundi were unremarkable; ocular movement appeared normal, however, he complained of diplopia in far vision. Sensation of the face was intact. He had right facial palsy of peripheral type; he was unable to close his right eye, and Bell's phenomenon was observed on attempted eye closure. On the left side, he had facial spasm. He had marked bilateral deafness. He had no dysarthria or dysphagia. The remaining of the cranial nerves were intact. Motor wise, he was unable to stand or walk alone; weakness did not appear to account for his difficulty in gait; manual muscle testing revealed 4/5 weakness in his tibialis anterior muscle, 1/5 in the peroneus longus, 0/5 in his extensor hallucis longus and extensor digitorum longus, all on the right side. Brachioradial and quadriceps femoris reflexes were increased to 3/4; plantar response was equivocal on the right side, and flexor on the left. Sensory examination revealed loss of touch and pain sensation in the L5 and S1 distributions in his right leg: vibration and position sensations were also diminished in his right foot. He had

  12. 失眠与认知障碍的关系%Research status of relationship between insomnia and cognitive impairment

    Institute of Scientific and Technical Information of China (English)

    王椿野; 邢佳

    2016-01-01

    睡眠是人体的一种保护机制,是机体维持正常功能的生理活动,睡眠可以促使疲劳的神经细胞恢复到正常生理功能水平,保障神经系统正常的生理功能。原发性失眠属于一种心理疾患,长期的失眠会导致亚健康或多种心身疾病。目前,失眠与认识之间的研究逐渐受到重视,长期失眠患者常可见到轻度认知障碍的表现,而失眠的发生、发展又与其认知心理模式关系密切。对睡眠各方面的认知歪曲均可导致失眠,通过探讨睡眠认知歪曲的机制,目前主要形成5种理论模式,而由长期失眠导致的认知功能下降,即轻度认知障碍,主要包括记忆障碍、失语、失用、失认、执行功能、视空间功能、定向力等能力下降。认知与失眠互为因果、呈双向关系,两种认知的概念是不同的,通过探讨两者的关系,对失眠的认识会更加深入。%Sleep is a protective inhibition of the human body, which can make the fatigue of the nerve cells to restore the normal physiological function, maintain normal operation of the nervous system. Insomnia is a kind of psychological disease, long-term of insomnia is often visible in patients with mild cognitive impairment, and the occurrence of insomnia is closely related to cognitive psychology. Cognitive impairment and insomnia causal, but it is not the same as the connotation of the cognitive. To sleep in every aspects of cognitive distortions can cause insomnia, sleep at present there are five main cognitive schema theory, purpose is to explore the mechanism of insomnia. And cognitive impairment caused by insomnia, is mainly refers to people’s cognitive decline, including memory impairment, aphasia, disuse, agnosia, executive function, visual space function, disorientation, and so on. Cognition and insomnia interact as both cause and effect, each concept of cognitive is different. By discussing the relationship between

  13. Research progress of acupuncture therapy on mild cognitive impairment after stroke%针刺治疗脑卒中后轻度认知障碍的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨红玲; 郑健刚; 张杰; 刘涛

    2016-01-01

    Mild cognitive impairment after stroke is a neuropsychological disorder, which is common in cerebrovascular disease and sequel of cerebrovascular disease. Cognitive impairment is a brain dysfunction caused by ischemic or hemorrhagic cerebrovascular disease, which usually manifested memory impairment, aphasia, apraxia, agnosia, alexia, visual spatial barriers. All the symptoms cause great inconvenience to the patient's daily life, social adjustment and comprehensive rehabilitation. The acupuncture therapy has a significant effect on mild cognitive impairment after stroke. Respectively use “stroke, cerebral infarction, cerebral hemorrhage, mild cognitive impairment, acupuncture”as keywords on PubMed, Cochrane, Embase, CNKI, Wan Fang DATA and VIP database from 2004 to 2014, retrieve nearly 10-year Chinese and English collections of published clinical studies. The acupuncture therapy for mild cognitive impairment after stroke in recent years was summarized to guide the clinical application, to provide new thinking with mild cognitive impairment after stroke, and pointed out the existing problems and the prospects with the future research direction and depth of acupuncture treatment of the disease.%脑卒中后轻度认知功能障碍是一种神经心理障碍,常见于脑血管病及脑血管病后遗症,表现为记忆障碍、失语、失用、失认、失读、视空间障碍等,给患者的日常生活、社会适应和全面康复造成极大的不便。针刺疗法对罹患卒中后轻度认知障碍的患者有显著疗效。分别以“卒中,脑梗死,脑出血,轻度认知障碍,针刺”为关键词,对PubMed、Cochrane、Embase、中国知网(CNKI)、万方数据库和维普数据库2004—2014年近10年收录已发表的相关临床研究报道进行中英文检索,对近年来应用针刺治疗轻度认知障碍的方法及操作加以归纳、总结。旨在指导临床应用,为治疗卒中后轻度认知障碍提供新的

  14. A 58-year-old female with blurred vision and apraxia

    Directory of Open Access Journals (Sweden)

    Zhi-hong SHI

    2014-07-01

    Full Text Available A 58-year-old right handed woman, with 12 years of formal education, had a five-year history of slowly progressive blurred vision and apraxia. Five years before the examination she gradually became blurred vision and had difficulties identifying static objects within the visual field. Then she went to an ophthalmologist and received cataract surgery. However, the symptoms were not improved after surgery. Two years later, she had difficulty doing household chores and was unable to dress herself. She developed an anxiety disorder in the absence of prominent language or memory deficits. Five years after onset, she showed global cognitive decline and abilities of daily life decline. On neurological examination she was alert. Neuropsychological testing revealed a mini-mental state examination (MMSE score of 20/30 with anomia, agraphia, alexia and partial impairment on time orientation. Biochemical investigations for disorders involving thyroid function, vitamin B12, and folate were unremarkable. A brain MRI showed diffuse cortical atrophy and hippocampus atrophy. An 18F-FDG PET scan showed bilateral hypometabolism at the frontal lobes, tempoparietooccipital adjunction, posterior cingulate cortices and precuneus, insular lobes, caudate nuclei and right thalamus. An 11C-PIB PET scan showed bilateral amyloid deposits at bilateral frontal lobes and occipital lobes, left temporal lobe and insular, basal ganglia, bilateral cingulate cortices and precuneus. No PSEN1, PSEN2 or APP mutations were identified. This early-onset patient had an unusual cognitive complaint, including visual agnosia and apraxia. The clinical features, structural and functional imaging findings of this case were compatible with the diagnosis of Posterior Cortical Atrophy (PCA. PCA is a neurodegenerative condition characterized by a progressive, often dramatic and relatively selective decline in visual processing skills and other functions subserved by parietal, occipital and

  15. Clinical features and efficacy of different treatments on 5 cases with Landau-Kleffner syndrome with poor prognosis%预后不良Landau-Kleffner综合征5例的临床特征与治疗

    Institute of Scientific and Technical Information of China (English)

    潘岗; 周水珍

    2015-01-01

    using the Engel classification scheme and the outcome of electrical status epilepticus during sleep (ESES) was classified by the decrease in spike wave index (SWI).Results All of 5 patients (2 male and 3 female) had auditory agnosia and epileptic seizure.All patients had normal background activity and epileptiform discharges,and the location of epileptiform discharge was mainly from bilateral temporal;3 patients had ESES.Four out of the 5 patients had refractory epilepsy and the other one got seizure free with antiepileptic drug.Four patients received corticosteroids for 6 months.The aphasia disappeared in 1 patient,improved in 1 patient and sustained in the other 2 patients.Three patients who had ESES did not response to corticosteroids.Among 3 patients receiving ketogenic diet,1 patient was seizure free and the ESES disappeared;in another SWI was reduced;the rest one had a significant reduction in seizure.All the patients had improvement in their aphasia and cognition,however they still had cognitive disorder of various degrees.Conclusions The patients who had multiple seizure type or special seizure type may have poor outcome.Most of these patients have refractory epilepsy or persistent ESES.Corticosteroids can improve aphasia and cognition,but the persistence of ESES can make aphasia and cognition worse.Ketogenic diet can be used as an alternative treatment for refractory epilepsy or persistent ESES in LKS.

  16. Clinical and neuroimaging characterization of posterior cortical atrophy%后皮质萎缩临床和影像学特点分析

    Institute of Scientific and Technical Information of China (English)

    石志鸿; 蔡莉; 刘帅; 王颖; 韩彤; 刘淑玲; 周玉颖; 王晓丹; 王新平

    2015-01-01

    .The above indictors were compared between PCA and AD patients.Results The most common symptoms at onset were visual space impairment,visual agnosia,apraxia,disorientation,agrapha,and acalculia in PCA patients.PCA subjects had marked impairment in visuospatial tasks,writing and calculationon neuropsychological testing.Posterior cortical atrophy were greater in PCA patients than in tAD patients (P<0.05),but atrophy in medial temporal lobe (MTL) was greater in mild AD patients than in tAD patients,and there was no significant difference in posterior cortical and MTL atrophy between moderate AD and PCA patients.The results of 18F-FDG PET showed that relative regional cerebral uptake (rCMRGlu) was decreased in temporal-parieto-occipital cortex (R> L) in PCA,but more diffused cortical decreased in typical AD.Occipical cortex(BA18,19,37) was the most obvious rCMRGlu decreasing place in PCA relative to tAD.The voxel-based automatic quantitative analysis showed that the mean PIB standardized uptake value ratio (SUVR) was higher in the inferior parietal lobe,lateral temporal cortex,middle frontal gyrus,medial prefrontal cortex,posterior cingulate cortex and precuneus,occipital lobe,supplementary motor area,and striatum in PCA and typical AD patients as compared with controls (1.6-2.6 vs.1.1-1.2,P<0.05).No significant difference in the PIB SUVR was found between the PCA and typical AD patients in all regions of interest (ROIs) (P> 0.05).Conclusions PCA has visual spatial impairment,apraxia,parietal cortex atrophy and hypometabolism in right temporo-parieto-occipital region as the main characteristics,and amyloid deposition in cortex in PCA patients is similar to that in typical AD patients.

  17. Landau-Kleffner 综合征六例%Si xcases reports for Landau-Kl effner syndrome

    Institute of Scientific and Technical Information of China (English)

    李志梅; 崔韬

    2015-01-01

    目的:研究Landau-Kleffner综合征(LKS)的临床、脑电图(EEG)特征、治疗反应及预后。方法对6例LKS患儿的临床及EEG资料进行分析,并对其治疗效果进行随访。结果该组患儿起病年龄3~8岁,男女比例2:1。起病前智力及语言发育正常。无癫痫家族史。均有获得性失语,表现为听觉性失认。均出现癫痫发作,表现为部分性发作、全面强直阵挛发作和不典型失神发作。听力检查正常。 EEG均异常,清醒期EEG显示单侧或双侧颞区为著高波幅棘慢波;睡眠期EEG显示癫痫样放电均较清醒期明显增多,并泛化至全导,其中2例表现为慢波睡眠期持续性棘慢复合波。头颅磁共振( MRI)检查均正常。6例患儿经抗癫痫药物治疗其癫痫发作均完全控制。经皮质激素治疗,3例患儿失语完全恢复,2例部分恢复,1例未恢复。结论 Landau-Kleffner综合征是以获得性失语和癫痫发作为主要临床表现的儿童期癫痫综合征。 EEG表现为以颞区为著的癫痫样放电,睡眠期全导泛化。癫痫发作经抗癫痫药物治疗可以控制且转归良好。早期合理应用皮质激素可以改善失语状况,但仍有患儿遗留语言障碍。%ObjectiveToinvestigatetheclinicalandelectroencephalographic(EEG)characteristics, therapeutic response and prognosis of Landau -Kleffner syndrome (LKS).Metho ds We analyzed the clinical and EEG data of 6 children with LKS,and then followed up the therapeutic response and the long-term outcome.Rseults The age of onset was from 3 to 8 years old.Epileptic family histories were negative .All patients had acquired aphasia,characterized by verbal auditory agnosia.All patients had epileptic seizure, including partial seizure, generalized tonic-clonic seizure and atypical absence .There were no abnormalities of hearing test in all patients .All patients had EEG abnormalities , Repetitive, high-amplitude focal spike and

  18. Caracterização da patologia cerebral, da psicopatologia e da heredologia psiquiátrica na doutrina de Kleist

    Directory of Open Access Journals (Sweden)

    Aníbal Silveira

    1959-06-01

    Full Text Available O ano de 1959 assinala três datas especiais em uma das mais férteis carreiras científicas: completa 80 anos Karl Kleist, nascido em Mülhausen, na Alsácia, a 31 de janeiro de 1879, que comemora o jubileu de venia legendi (1909; e há um quarto de século veio à luz a Gehirnpathologie (1934, que marca a nova era da fisiopatologia cerebral. A construção doutrinária de Kleist combina e aperfeiçoa as diretrizes isoladas de Meynert, de Wernicke e de Kraepelin. Constitui nela uma constante a união da psicopatologia à patologia cerebral; e a pesquisa no domínio clínico se norteia pela patogenia, pela heredologia e pela catamnese sistemática. Na própria patogênese - tanto dos quadros clínicos como dos sintomas - há a considerar a diferente participação do tronco cerebral e da corticalidade. E aqui, a seu turno, é preciso distinguir as funções que dependem de regiões posteriores. Assim, descreveu Kleist, respectivamente, os distúrbios agramáticos e os paragramáticos, os alógicos e os paralógicos, em analogia com os afásicos e os parafásicos. Demonstrou pela primeira vez, em 1905, a existência da afasia de condução e isolou dois novos tipos de apraxia: a apraxia segmentar e a apraxia de construção. Outros quadros psicopatológicos descritos por êle também se tornaram clássicos: a carência de iniciativa, a apraxia de iniciativa, a apraxia de ação coordenada (Handlungsfolge, a cegueira espacial (Ortsblindheit, a agnosia cromática - que depende da noção abstrata de côr e nada tem a ver com o daltonismo - e ainda os quadros psiquiátricos cíngulo-orbitários. Divide a esfera da personalidade em diversos estratos de grande relevância clínico-localizatória (quadro 1. A carta localizatória - plano estrutural e funcional do cérebro - ultrapassa a qualquer empreendimento análogo, tanto pela análise penetrante quanto pela adaptação à realidade clínica (figs. 1 e 2. Sobreleva notar aí que Kleist separa