8 results on '"Moreaud O"'
Search Results
2. Impaired cerebral vasoreactivity to CO2 in Alzheimer's disease using BOLD fMRI
- Author
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S.Cantin, Villien, M., Moreaud, O., Tropres, I., Keignart, S., Chipon, E., Le Bas, J.-F., Warnking, J., and Krainik, A.
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ALZHEIMER'S disease , *CARBON dioxide , *MAGNETIC resonance imaging of the brain , *MILD cognitive impairment , *BRAIN physiology , *HIPPOCAMPUS (Brain) - Abstract
Abstract: Objective: To evaluate the cerebral vasoreactivity using blood oxygenation level dependent functional MRI during carbogen inhalation with 7% CO2 in Alzheimer''s disease and amnestic mild cognitive impairment. Participants and methods: Thirty nine subjects were included to be investigated using blood oxygenation level dependent (BOLD) functional MRI at 1.5T during a block-design carbogen inhalation paradigm, with a high concentration face-mask under physiological monitoring. Basal cerebral perfusion was measured using pulsed arterial spin labeling. Image analyses were conducted using Matlab® and SPM5 with physiological regressors and corrected for partial volume effect. Results: Among selected participants, 12 subjects were excluded because of incomplete protocol, leaving for analysis 27 subjects without significant microangiopathy diagnosed for Alzheimer''s disease (n=9), amnestic mild cognitive impairment (n=7), and matched controls (n=11). No adverse reaction related to the CO2 challenge was reported. Carbogen inhalation induced a whole-brain signal increase, predominant in the gray matter. In patients, signal changes corrected for gray matter partial volume were decreased (0.36±0.13% BOLD/mmHg in Alzheimer''s disease, 0.36±0.12 in patients with mild cognitive impairment, 0.62±0.20 in controls). Cerebral vasoreactivity impairments were diffuse but seemed predominant in posterior areas. The basal hypoperfusion in Alzheimer''s disease was not significantly different from patients with mild cognitive impairment and controls. Among clinical and biological parameters, no effect of apoE4 genotype was detected. Cerebral vasoreactivity values were correlated with cognitive performances and hippocampal volumes. Among age and hippocampal atrophy, mean CVR was the best predictor of the mini-mental status examination. Conclusion: This BOLD functional MRI study on CO2 challenge shows impaired cerebral vasoreactivity in patients with Alzheimer''s disease and amnestic mild cognitive impairment at the individual level. These preliminary findings using a new MRI approach may help to better characterize patients with cognitive disorders in clinical practice and further investigate vaso-protective therapeutics. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
3. What bilateral damage of the superior parietal lobes tells us about visual attention disorders in developmental dyslexia.
- Author
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Valdois, S., Lassus-Sangosse, D., Lallier, M., Moreaud, O., and Pisella, L.
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DYSLEXIA , *PARIETAL lobe , *VISION disorders , *ATTENTION span , *CHILDREN with dyslexia - Abstract
Neuroimaging studies have identified the superior parietal lobules bilaterally as the neural substrates of reduced visual attention (VA) span in developmental dyslexia. It remains however unclear whether the VA span deficit and the deficits in temporal and spatial attention shifting also reported in dyslexic children reflect a unitary spatio-temporal deficit of attention - probably linked to general posterior parietal dysfunction- or the dysfunction of distinct attentional systems that relate to different neural substrates. We explored this issue by testing an adult patient, IG, with a specific damage of the bilateral superior parietal lobules after stroke, on tasks assessing the VA span as well as temporal and spatial attention shifting. IG demonstrated a very severe VA span deficit, but preserved temporal attention shifting. Exogenous spatial orientation shifting was spared but her performance was impaired in endogenous attention. The overall findings show that distinct sub-systems of visual attention can be dissociated within the parietal lobe, suggesting that different attentional systems associated with specific neural networks can be selectively impaired in developmental dyslexia. • Investigation of a patient with bilateral superior parietal lobe (SPL) damage. • Evidence for poor visual attention span but normal temporal attention shifting. • Normal exogenous but impaired endogenous spatial attention. • Involvement of the SPLs in specific visual attention subskills. • Different visual attention systems are involved in developmental dyslexia. [ABSTRACT FROM AUTHOR]
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- 2019
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4. Deficits in egocentric-updating and spatial context memory in a case of developmental amnesia.
- Author
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Gomez, A., Rousset, S., Bonniot, C., Charnallet, A., and Moreaud, O.
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EGOISM , *CONTEXT effects (Psychology) , *AMNESIA , *NEURAL development , *VECTION , *DISSOCIATION (Psychology) - Abstract
Patients with developmental amnesia usually suffer from both episodic and spatial memory deficits. DM, a developmental amnesic, was impaired in her ability to process self-motion (i.e., idiothetic) information while her ability to process external stable landmarks (i.e., allothetic) was preserved when no self-motion processing was required. On a naturalistic and incidental episodic task, DM was severely and predictably impaired on both free and cued recall tasks. Interestingly, when cued, she was more impaired at recalling spatial context than factual or temporal information. Theoretical implications of that co-occurrence of deficits and those dissociations are discussed and testable cerebral hypothesis are proposed. [ABSTRACT FROM AUTHOR]
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- 2015
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5. Risk of Alzheimer's disease biological misdiagnosis linked to cerebrospinal collection tubes.
- Author
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Perret-Liaudet A, Pelpel M, Tholance Y, Dumont B, Vanderstichele H, Zorzi W, Elmoualij B, Schraen S, Moreaud O, Gabelle A, Thouvenot E, Thomas-Anterion C, Touchon J, Krolak-Salmon P, Kovacs GG, Coudreuse A, Quadrio I, and Lehmann S
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- 2012
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6. Verb production during action naming in semantic dementia
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Méligne, D., Fossard, M., Belliard, S., Moreaud, O., Duvignau, K., and Démonet, J.-F.
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COMPARATIVE studies , *DEMENTIA , *INTELLECT , *LANGUAGE disorders , *MEMORY , *PROJECTIVE techniques , *SEMANTICS , *VIDEO recording , *VOCABULARY , *CASE-control method - Abstract
Abstract: In contrast with widely documented deficits of semantic knowledge relating to object concepts and the corresponding nouns in semantic dementia (SD), little is known about action semantics and verb production in SD. The degradation of action semantic knowledge was studied in 5 patients with SD compared with 17 matched control participants in an action naming task based on video clips. The pattern of errors, involving a huge proportion of generic verbs (e.g. “to remove” versus “to peel”) relative to responses in control subjects, suggested a hierarchical, bottom-up deficit of action knowledge in SD patients. In addition, abnormal responses in patients consisted of verbs that were semantically related to the expected verbs produced by control subjects (e.g. “to undress” versus “to peel” for the action [To peel_orange]). This study suggests that, in SD, non-canonical responses to action naming reflect lack of both specificity and semantic relatedness relative to the expected responses. Learning outcomes: As a result of this activity, readers will recognize that semantic word knowledge disappears in semantic dementia using video clips of object-related actions. As a result of this activity, readers will discover that this semantic impairment followed a hierarchical pattern with the more specific verbs vanishing first. [Copyright &y& Elsevier]
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- 2011
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7. Associative visual agnosia: A case study.
- Author
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Charnallet, A., Carbonnel, S., David, D., and Moreaud, O.
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VISION disorders , *MEMORY research , *SENSORY disorders , *VISUAL agnosia , *NEUROPSYCHOLOGY research - Abstract
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]. [ABSTRACT FROM AUTHOR]
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- 2008
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8. Influence of Motor Disorders on the Visual Perception of Human Movements in a Case of Peripheral Dysgraphia.
- Author
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Chary, C., Méary, D., Orliaguet, J. P., David, D., Moreaud, O., and Kandel, S.
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VISUAL perception , *SENSORY perception , *VISION , *AGRAPHIA , *PATIENTS - Abstract
We report the case of a 71 year-old female patient (DC) with a left parietal lesion resulting in a peripheral dysgraphia essentially characterized by difficulties in letter sequences writing. The aim of our experiments was to analyze the influence of motor difficulties on the visual perception of both writing and reaching movements. Results showed a strong link between motor and perceptual performance. For reaching movements, performances in both production and perception tasks conform to the motor principles identified in healthy subjects (Fitts' law and motor anticipation). By contrast, for handwriting movements, DC's productions do not follow the motor principles usually observed in normal subjects (isochrony principle, motor anticipation) and in perception the same results were observed. The motor references used by DC in the visual perception of writing movement were not the laws of movement but rather her own way of writing. Taken together these data strongly suggest that motor competences is involved in the visual perception of human movements. They are discussed in the general framework of the simulation theory. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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