Alzheimer's disease is a brain disorder that leads to progressive nerve damage and brain cell death that affects more than 5.3 million Americans, according to the Alzheimer's Association. Alzheimer's is characterized by aggregates of toxic proteins called amyloid plaques, and an instability of nerve cells leading to structures called neurofibrillary tangles. Alzheimer's disease leads to dementia, an overall decrease in quality of life and eventually leads to death. A number of regions within the brain become affected by Alzheimer's disease and damage to regions of the brain give rise to the specific symptoms of Alzheimer's.
Frontal Lobe
The frontal lobe, a region at the front of the brain, contains a number of brain cell centers that control a range of functions. The frontal lobe is responsible for intelligence, decision-making, problem-solving, proper social conduct and other higher mental functions. In general, the frontal lobe allows for the processing of information and makes the decision to signal for an appropriate response.
The frontal lobe is often affected by Alzheimer's disease, leading to a number of symptoms including erratic or inappropriate behavior, and personality changes. Dr. D. Royall, a professor at the University of Texas, explains that the extent of damage to the frontal lobe in the brain of Alzheimer's patients directly relates to their level of disability. Slowing the progression of Alzheimer's to prevent damage to the frontal lobe of the brain improves the patient's ability to care for themselves and increases their quality of life.
Temporal Lobe
Alzheimer's disease can also affect the temporal lobes of the brain, two regions located near the temples and ears. The temporal lobes are responsible for both long- and short-term memory, as well as learning. These areas of the brain often become damaged in Alzheimer's disease, leading to memory loss.
Among the first recognizable symptoms of Alzheimer's is memory loss, especially for newly acquired memories or recently learned skills. The University of California explains that this memory loss result because of damage to two structures called the hippocampus and the amygdala, two parts of the brain responsible for learning as well as memory. As damage to the brain progresses, the hippocampus and amygdala become destroyed, leading to severe memory loss.
Parietal Lobe
The parietal lobe, a region of the brain behind the temporal lobe, often becomes damaged in Alzheimer's disease. One major function of the parietal lobe is speech. Additionally, the parietal lobe helps integrate the visual system with the rest of the brain, to allow analysis of visual stimuli. Both of these functions often become disrupted during the progression of Alzheimer's, leading to abnormal speech and visual disturbances.
In a 1997 study published in Brain, Dr. B. Buck found that Alzheimer's patients with parietal lobe damage displayed a severely impaired ability to react to visual stimuli. Patients proved unable to recognize familiar objects, and were unable to visual spatial locations of objects. In Alzheimer's patients, this contributes to disorientation and confusion, leading to dementia.
