Alzheimer’s disease is by far the most common intractable dementia. A few drugs have been approved for treating Alzheimer’s, but they alleviate symptoms only slightly.
Alzheimer’s disease has been known to be caused by abnormal protein clusters forming in the brain which interfere with neuron function. It is distinguished from other dementias by the presence of sticky beta-amyloid plaques outside brain cells (neurons) and fibrillary tangles within neurons. In people with Alzheimer’s these lesions tend to be more numerous and accumulate in areas of the brain involved in learning and memory.
The leading theory is that the damage to the brain results from inflammation and other biological changes that cause synaptic loss and malfunction, disrupting communication between brain cells. Eventually the brain cells die, causing tissue loss. In imaging scans, brain shrinkage is usually first noticeable in the hippocampus, which plays a central role in memory function.
The characteristic symptom of Alzheimer’s is difficulty in recalling new information. As Alzheimer’s progresses, the following may occur:
Cognitive decline. The individual may also experience decline in finding it hard to make decisions, solve problems, or make good judgments.
Mood or personality changes. An individual with Alzheimer’s may undergo significant changes in mood and personality such as becoming more irritable, hostile, or apathetic.
Some cognitive problems stem from insufficient blood flow to portions of the brain. The decrease in blood flow is often the result of atherosclerosis (the accumulation of fatty deposits on artery walls) in the blood vessels that feed the brain. The resulting interruption of blood flow creates areas of dead tissue.