Completar frases Complete the text. Alzheimer'sVersión en línea In this task you will complete the missing words related to Alzheimer por Santiago Manrique Mosquera 1 proteins brain toxic seems dementia connections disorder role symptom Alzheimer's preclinical unravel disease healthy neurons Alzheimer's is an irreversible , progressive brain that slowly destroys memory and thinking skills , and , eventually , the ability to carry out the simplest tasks . In most people with , symptoms first appear in their mid - 60s . Estimates vary , but experts suggest that more than 5 . 5 million Americans , most of them age 65 or older , may have caused by Alzheimer's . Scientists continue to the complex brain changes involved in the onset and progression of Alzheimer's disease . It likely that changes in the may begin a decade or more before memory and other cognitive problems appear . During this stage of Alzheimer's disease , people seem to be - free , but changes are taking place in the brain . Abnormal deposits of form amyloid plaques and tau tangles throughout the brain . Once - neurons stop functioning , lose with other , and die . Many other complex brain changes are thought to play a in Alzheimer's , too .
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