Annals of the New York Academy of Sciences
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Ann. N. Y. Acad. Sci. · Feb 2007
ReviewShifting paradigms in dementia: toward stratification of diagnosis and treatment using MRI.
Atrophy and cerebrovascular disease are the two most important magnetic resonance imaging (MRI) characteristics in the evaluation of dementia. On MRI, atrophy is the primary hallmark of neurodegenerative dementias including Alzheimer's disease (AD), while vascular dementia is characterized by the presence of ischemic vascular damage, such as territorial infarcts, lacunes, and white matter hyperintensities. Evidence is accumulating that vascular factors play an important role in the development of cognitive decline at old age and clinical AD. ⋯ The strict distinction between AD and vascular dementia is often artificial, as most patients suffer from both disorders to some extent. For the future, we see an important role for MRI in identifying those different compartments, regardless of clinical classification. Treatment could be directed by (and evaluated through) MRI patterns, rather than a diagnostic label.
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Ann. N. Y. Acad. Sci. · Feb 2007
Quantitative EEG and electromagnetic brain imaging in aging and in the evolution of dementia.
Electroencephalographic (EEG) changes with normal aging have long been reported. Departures from age-expected changes have been observed in mild cognitive impairment and dementia, the magnitude of which correlates with the degree of cognitive impairment. Such abnormalities include increased delta and theta activity, decreased mean frequency, and changes in coherence. ⋯ We have recently reported results from initial quantitative electroencephalography (QEEG) evaluations of normal elderly subjects (with only subjective reports of memory loss), predicting future cognitive decline or conversion to dementia, with high prediction accuracy (approximately 95%). In this report, source localization algorithms were used to identify the mathematically most probable underlying generators of abnormal features of the scalp-recorded EEG from these patients with differential outcomes. Using this QEEG method, abnormalities in brain regions identified in studies of AD using MEG, MRI, and positron emission tomography (PET) imaging were found in the premorbid recordings of those subjects who go on to decline or convert to dementia.