Behavioural neurology
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Behavioural neurology · Jan 2009
Functional MRI assessment of task-induced deactivation of the default mode network in Alzheimer's disease and at-risk older individuals.
Alzheimer's disease (AD) is the most common form of dementia in old age, and is characterized by prominent impairment of episodic memory. Recent functional imaging studies in AD have demonstrated alterations in a distributed network of brain regions supporting memory function, including regions of the default mode network. Previous positron emission tomography studies of older individuals at risk for AD have revealed hypometabolism of association cortical regions similar to the metabolic abnormalities seen in AD patients. ⋯ Our recent studies have revealed alterations in the pattern of deactivation also in elderly individuals at risk for AD by virtue of their APOE e4 genotype, or evidence of mild cognitive impairment (MCI). In agreement with recent reports from other groups, these studies demonstrate that the pattern of fMRI task-induced deactivation is progressively disrupted along the continuum from normal aging to MCI and to clinical AD and more impaired in e4 carriers compared to non-carriers. These findings will be discussed in the context of current literature regarding functional imaging of the default network in AD and at-risk populations.
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Behavioural neurology · Jan 2008
Case ReportsCapgras syndrome and unilateral spatial neglect in nonconvulsive status epilepticus.
Nonconvulsive status epilepticus can manifest as personality changes and psychosis. We report an 87-year-old right-handed male presenting with both Capgras syndrome and severe unilateral spatial neglect during nonconvulsive status epilepticus. After treatment of his seizures, his Capgras syndrome and hemispatial neglect resolved. This case illustrates a report of the confluence of Capgras syndrome and documented hemispatial neglect in nonconvulsive status epilepticus only reported once previously [1].
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Behavioural neurology · Jan 2008
Case Reports Comparative StudyAgraphia for kanji resulting from a left posterior middle temporal gyrus lesion.
To clarify whether agraphia or alexia occurs in lesions of the left posterior middle temporal gyrus. ⋯ The present patients demonstrate that damage to the left posterior middle temporal gyrus alone can cause agraphia for kanji. If the adjacent mid fusiform/inferior temporal gyri (Area 37) are spared, the kanji alexia is transient.
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Behavioural neurology · Jan 2008
Etiology of frontal network syndromes in isolated subtentorial stroke.
The neurobiology of the frontal network syndrome (FNS) that may occur with isolated subtentorial stroke is unknown. ⋯ The mismatch of scant neurological deficit manifested by low NIHSS but with FNS in the majority of isolated ST stroke and more so than with PO stroke, gives support for a state dependent or neurotransmitter perturbation. The clinical impact is that such syndromes may be amenable to neuropharmacological intervention.