Alzheimer's Disease is a degenerative brain process that produces, usually slowly over time, dementia or senility. It is also known as senile dementia. The brain is disrupted from the way it normally works – mental function becomes impaired -- and the patient's memory, ability to think clearly and sometimes the patient's language is impaired. The causes of Alzheimer's are still not known -- but we do know that the disease produces physical change in the brain. There is shrinking in some areas and widening in the others. When the brain shrinks or widens, connections inside the brain are broken, causing disruption of the electrical signals in the brain. Alzheimer's Disease affects 2-5% of people over 65 years of age and up to 20% of those over 85 years. AD is difficult to diagnose accurately pre-mortem without sophisticated brain imaging systems. Rate of decline varies from patient to patient but 8 years is the average lifespan between diagnosis and death (3-20years) Genetics may play a role; familial AD is a rare inherited form. Other genes eg ApoE4, presenilins and APP mutations are linked to increased risk. Pathology of Alzheimer's Disease Alzheimer’s disease has a very distinct pathology consisting of amyloid plaques, neurofibrillary tangles, and reduction in neurotransmitter levels. In the Alzheimer brain: The cortex shrivels up, damaging areas involved in thinking, planning and remembering. •Shrinkage is especially severe in the hippocampus, an area of the cortex that plays a key role in formation of new memories. Ventricles (fluid-filled spaces within the brain) grow larger. •Alzheimer tissue has many fewer nerve cells and synapses than a healthy brain. Plaques, abnormal clusters of protein fragments, build up between nerve cells. Dead and dying nerve cells contain tangles, which are made up of twisted strands of another protein. Plaques and tangles (shown in the blue-shaded areas) tend to spread through the cortex in a predictable...
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