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Dementia with Lewy bodies (DLB), also known under a variety of other names including Lewy body dementia (LBD), diffuse Lewy body disease, cortical Lewy body disease, and senile dementia of Lewy type, is a type of dementia closely associated with Parkinson's disease. It is characterized anatomically by the presence of Lewy bodies, clumps of alpha-synuclein and ubiquitin protein in neurons, detectable in ''post mortem'' brain histology. ==Classification== Lewy body dementia (LBD) is a progressive degenerative dementia primarily affecting older adults. Its primary feature is cognitive decline, which can lead to hallucinations, as well as varied attention and alertness when compared to a person's baseline function.〔http://www.lbda.org/node/14〕 Persons with LBD display an inability to plan or a loss of analytical or abstract thinking and show markedly fluctuating cognition. Wakefulness varies from day to day, and alertness and short-term memory rise and fall. Persistent or recurring visual hallucinations with vivid and detailed pictures are often an early diagnostic symptom. REM sleep behavior disorder (RBD) is a symptom often first recognized by the patient's caretaker. RBD includes vivid dreaming, with persistent dreams, purposeful or violent movements, and falling out of bed.〔Lewy Body Dementia Association (lbda.org)〕 LBD symptoms overlap clinically with Alzheimer's disease and Parkinson's disease, but are more commonly associated with the latter.〔 Because of this overlap, LBD in its early years is often misdiagnosed. In LBD, loss of cholinergic (acetylcholine-producing) neurons is thought to account for degeneration of cognitive function (similar to Alzheimer's), while the death of dopaminergic (dopamine-producing) neurons appears to be responsible for degeneration of motor control (similar to Parkinson's) – in some ways, therefore, LBD resembles both disorders. The overlap of neuropathological and presenting symptoms (cognitive, emotional, and motor) can make an accurate differential diagnosis difficult. In fact, LBD is often confused in its early stages with Alzheimer's disease and/or vascular dementia (multi-infarct dementia), although, whereas Alzheimer’s disease usually begins gradually, LBD frequently has a rapid or acute onset, with especially rapid decline in the first few months. Thus, LBD tends to progress more rapidly than Alzheimer’s disease. Despite the difficulty, a prompt diagnosis is important because of the risks of sensitivity to certain neuroleptic (antipsychotic) drugs and because appropriate treatment of symptoms can improve life for both the person with LBD and the person's caregivers.〔 Benzodiazepines, anticholinergics, surgical anesthetics, some antidepressants, and OTC cold remedies can cause acute confusion, delusions and hallucinations. LBD is distinguished from the dementia that sometimes occurs in Parkinson's disease by the time frame in which dementia symptoms appear relative to Parkinson symptoms. Parkinson's disease with dementia (PDD) would be the diagnosis when dementia onset is more than a year after the onset of Parkinson's. LBD is diagnosed when cognitive symptoms begin at the same time or within a year of Parkinson symptoms. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dementia with Lewy bodies」の詳細全文を読む スポンサード リンク
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