37 research outputs found

    Endocarditis after Use of Tongue Scraper

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    We explored the neural substrate of anosognosia for cognitive impairment in Alzheimer's disease (AD). Two hundred nine patients with mild to moderate dementia and their caregivers assessed patients' cognitive impairment by answering a structured questionnaire. Subjects rated 13 cognitive domains as not impaired or associated with mild, moderate, severe, or very severe difficulties, and a sum score was calculated. Two measures of anosognosia were derived. A patient's self assessment, unconfounded by objective measurements of cognitive deficits such as dementia severity and episodic memory impairment, provided an estimate of impaired self-evaluative judgment about cognition in AD. Impaired self-evaluation was related to a decrease in brain metabolism measured with 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in orbital prefrontal cortex and in medial temporal structures. In a cognitive model of anosognosia, medial temporal dysfunction might impair a comparison mechanism between current information on cognition and personal knowledge. Hypoactivity in orbitofrontal cortex may not allow AD patients to update the qualitative judgment associated with their impaired cognitive abilities. Caregivers perceived greater cognitive impairments than patients did. The discrepancy score between caregiver's and patient's evaluations, an other measure of anosognosia, was negatively related to metabolic activity located in the temporoparietal junction, consistent with an impairment of self-referential processes and perspective taking in AD

    Is Alzheimer's disease a disconnection syndrome? Evidence from a crossmodal audio-visual illusory experiment

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    In Alzheimer's disease (AD), loss of connectivity in the patient's brain has been evidenced by a range of electrophysiological and neuroimaging studies. However, few neuropsychological research projects have sought to interpret the cognitive modifications following the appearance of AD in terms of a disconnection syndrome. In this paper, we sought to investigate brain connectivity in AD via the study of a crossmodal effect. More precisely, we examined the integration of auditory and visual speech information (the McGurk effect) in AD patients and matched control subjects. Our results revealed impaired crossmodal integration during speech perception in AD, which was not associated with disturbances in the separate processing of auditory and visual speech stimuli. In conclusion, our data suggest the occurrence of a specific, audio-visual integration deficit in AD, which might be the consequence of a connectivity breakdown and corroborate the observation from other studies of crossmodal deficits between the auditory and visual modalities in this population. (C) 2007 Elsevier Ltd. All rights reserved

    Action and noun fluency testing to distinguish between Alzheimer's disease and dementia with Lewy bodies

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    The objective of the present study was to establish whether performance in an action fluency task is of value in the differential diagnosis of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). After collecting normative data on performance in an action fluency task and a conventional animal fluency task in a cohort of French-speaking healthy controls, we assessed AD and DLB patients. Only the action fluency score differed significantly between the two demented groups, with DLB patients performing worse than AD patients. However, a composite action and animal fluency score was found to be more effective for discriminating between these two groups

    Alzheimer' Disease as a Disconnection Syndrome?

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    Sleeping brain, learning brain. The role of sleep for memory systems.

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    The hypothesis that sleep participates in the consolidation of recent memory traces has been investigated using four main paradigms: (1) effects of post-training sleep deprivation on memory consolidation, (2) effects of learning on post-training sleep, (3) effects of within sleep stimulation on the sleep pattern and on overnight memories, and (4) re-expression of behavior-specific neural patterns during post-training sleep. These studies convincingly support the idea that sleep is deeply involved in memory functions in humans and animals. However, the available data still remain too scarce to confirm or reject unequivocally the recently upheld hypothesis that consolidations of non-declarative and declarative memories are respectively dependent upon REM and NREM sleep processes.Journal ArticleResearch Support, Non-U.S. Gov'tReviewinfo:eu-repo/semantics/publishe

    Priming for possible, but not impossible, gestures

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    Priming for possible, but not impossible, gestures

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