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
Assessment of behavioural markers of autonoetic consciousness during episodic autobiographical memory retrieval: a preliminary analysis.
There is ongoing theoretical debate regarding episodic memory and how it can be accurately measured, in particular if the focus should be content-based recall of episodic details or something more experiential involving the subjective capacity to mentally travel back in time and "re-live" aspects of the original event. The autonoetic subscale of the Episodic Autobiographical Memory Interview (EAMI) is presented here as a new test instrument that attempts to redress theoretical and methodological shortcomings in autobiographical memory assessment. ⋯ Key behavioural indices of autonoetic consciousness, notably those of viewer perspective, visual imagery, and emotional re-experiencing, emerged as being inextricably bound with the level of phenomenological detail recalled and the overall re-living judgment. The autonoetic subscale of the EAMI permits conceptually refined assessment of episodic personal memories and the accompanying subjective experience of mental re-living, characteristic of episodic memory.