Alzheimer's disease causes multiple parts of the brains to shrink, such as the Cerebral Cortex, Hippocampus, and causes severally enlarged ventricles. The Hippocampus regulates formation of new memories and Cerebral Cortex controls the functions of the Frontal lobe, Parietal lobe, Occipital lobe, and Temporal lobe (Morris, Maisto, & Dunn, 2006). The functioning lobes control reasoning, learning, sensory awareness, or perception (Alzheimer Advice,2007). This is why when certain parts of the brain begin to shrink due to the disease all the senses do as well because they are diminishing. These senses are supposed to be getting carried throughout the brain by its receptors but with minimal brain capacity it makes this process very difficult. Alzheimer's causes the human brain to lose as much as one-third of its volume (Morris, Maisto, & Dunn, 2006).
Today there are several medications that have been approved by the Food and Drug Administration (FDA) to help treat Alzheimer's. Donepezil, Rivastigmine, and Galantamine are prescribed to treat mild to moderate Alzheimer's, although Donepezil can also be used to treat the most severe cases. Memantine is the final drug that is used to treat moderate to severe Alzheimer's. How these drugs work are by the chemicals in them, they transmit messages between neurons. This helps maintain a regular thinking, memory, and speaking habit. Without a cure for Alzheimer's, all these drugs do is help maintain regularity, but does not help the brain return to its true form and the drugs may only help for a few months to a few years (Alzheimer Advice,2007).
Genetic research has turned up evidence of a link between Alzheimer's disease and genes on four chromosomes, labeled numerically as 1, 14, 19, and 21. The AOP gene on chromosome 19 has been liked to late-onset Alzheimer's disease, which is the most common form of the disease. Dozens of studies around the world have confirmed that inheritance of one particular variant of the APOE gene, termed APOE4, increases the lifetime risk of developing Alzheimer's disease. One of the puzzles surrounding APOE is why some people with the APOE4 variant do not develop Alzheimer's disease and why, conversely, many people develop the disease even thought they have not inherited APOE4. APOE, in other words, although