Alzheimer disease is the most common type of dementia, affecting 11% of persons aged 65 years or older and 32% of persons aged 85 years or older in the United States.
14 A genetically-linked early onset type of AD (in which the onset of symptoms begins prior to age 65 years) is rare and estimated to account for less than 2% of AD diagnoses.
15 The neuropathologic process of AD includes intracellular neurofibrillary tangles and extracellular β-amyloid plaques. The hippocampus and adjacent temporal lobe are affected early in the disease course, accounting for AD's characteristic memory impairment with rapid forgetting.
16 As the tangles and plaques progress to the frontal and parietal regions of the brain, cognitive symptoms advance to include impaired judgment, word finding, temporal orientation, and route navigation. Speech is often confused or vague, missing nouns, and focused on the past.
12 Poor insight into the disease process is common,
12 hence it is
The number of patients with dementia is rapidly increasing, hence physicians must be knowledgeable about differential diagnosis and treatment.
common for patients to think that nothing is wrong or that their memory symptoms are minor.
12 Thus, family members often are the ones to raise concern about dementia. Social skills are generally preserved
12 with patients often described as “pleasantly confused.” Later in the disease course, patients with AD eventually exhibit changes in personality, agitated behavior, or both.
15 The typical disease course from symptom onset to death is 6 to 9 years.
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