Alzheimer‘sdisease

1、Senile Diseases Alzheimers disease(阿兹海默症)Alzheimers disease (AD), also known in medical literature as Alzheimer disease, is the most common form of dementia(痴呆). There is no cure for the disease, which worsens as it progresses, and eventually leads to death. It was first described by German psychiat

2、rist(心理医生) and neuropathologist(神经病理学家) Alois Alzheimer in 1906 and was named after him. Characteristicshe disease course is divided into four stages, with progressive patterns(渐进模式) of cognitive(认知) and functional impairments(功能障碍). Pre-dementiaEarlyModerateAdvancedgoThe first symptoms are often mi

3、stakenly attributed to ageing or stress. Detailed neuropsychological(神经心理学) testing can reveal mild cognitive(轻度认知) difficulties up to eight years before a person fulfils the clinical criteria for diagnosis(临床诊断标准) of AD. backPre-dementiaIn people with AD the increasing impairment of learning and me

4、mory eventually leads to a definitive diagnosis. In a small portion of them, difficulties with language, executive functions(执行功能), perception (agnosia)知觉(失认症), or execution of movements (apraxia)执行动作(失用症) are more prominent than memory problems. EarlybackModerateProgressive deterioration eventually

5、 hinders(阻碍) independence, with subjects being unable to perform most common activities of daily living. Speech difficulties become evident due to an inability to recall vocabulary, which leads to frequent incorrect word substitutions (paraphasias). Reading and writing skills are also progressively

6、lost. backbackAdvancedDuring the final stage of AD, the person is completely dependent upon caregivers. Language is reduced to simple phrases or even single words, eventually leading to complete loss of speech. Despite the loss of verbal language abilities, people can often understand and return emo

7、tional signals. CauseThe cause for most Alzheimers cases is still essentially unknown (except for 1% to 5% of cases where genetic differences have been identified). Several competing hypotheses(假设) exist trying to explain the cause of the disease. The oldest, on which most currently available drug t

8、herapies(治疗方法) are based, is the cholinergichypothesis(胆碱能假说), which proposes that AD is caused by reduced synthesis of the neurotransmitter acetylcholine(神经递质乙酰胆碱). DiagnosisAlzheimers disease is usually diagnosed clinically(临床) from the patient history, collateral history from relatives, and clini

9、cal observations, based on the presence of characteristic neurological(特性神经系统) and neuropsychological features(神经心理功能) and the absence of alternative conditions.At present, there is no definitive evidence to support that any particular measure is effective in preventing AD. Global studies of measure

10、s to prevent or delay the onset of AD have often produced inconsistent results.PreventionPrognosisThe early stages of Alzheimers disease are difficult to diagnose. A definitive diagnosis is usually made once cognitive impairment(认知功能障碍) compromises daily living activities, although the person may st

11、ill be living independently.Epidemiology(流行病学流行病学)Two main measures are used in epidemiological studies: incidence(发病率) and prevalence(患病率). Incidence is the number of new cases per unit of persontime at risk (usually number of new cases per thousand personyears); while prevalence is the total number of cases of the disease in the population at any given time.Incidence ratesafter age 65Research directionsAs of 2012, the safety and efficacy of more than 400 pharmaceutical treatments(药物治疗) had been or were being investigated in 1012 clinical trial