Cognitive Impairment and the Dementias

Summary: The term mild cognitive impairment (MCI) was introduced as a stage in the Global Deterioration Scale to describe the progression from normal aging to dementia. Alzheimer's disease (AD) is the most common form of dementia in the United States. The potential clinical and demographic risk factors for developing AD at an earlier age of onset identified over the last three decades include depression, female gender, low levels of education, smaller head circumference, and family history of Down's syndrome. Dementia with Lewy bodies (DLB) is a synucleinopathy characterized by a progressive dementia syndrome that is usually associated with parkinsonism and typically dominated by attentional, visuospatial, and executive dysfunction and relatively preserved memory. Vascular cognitive impairment, frontotemporal dementia, primary progressive aphasia, prion diseases, and normal pressure hydrocephalus are also discussed in the chapter.