The human brain is a marvel, with billions of tiny particles that control all the systems of the body. But the brain of a person with Alzheimer’s is significantly altered, with damaged and destroyed brain cells. Over time, the size of the brain of a person with Alzheimer’s shrinks by a sizeable amount.
An Alzheimer’s-affected brain will have fewer nerve cells than a healthy brain. Plaque builds up between nerve cells and dead and dying nerve cells contain twisted strands of a protein. Scientists think that either plaque or twisted strands of protein, called tangles, may contribute to the tissue loss.
As the brain’s cortex shrinks, it damages thinking, planning and remembering. In the earliest stages—before a diagnosis can be made using current testing methods—the person with Alzheimer’s may already have plaque and tangles developing in the area of the brain that controls learning/memory and thinking/planning. As the disease progresses, memory and thinking issues begin to affect daily life. The person may become confused or have trouble organizing thoughts. Typically, this is the stage when a diagnosis is made. Plaque and tangles spread to areas involved with speaking and spatial relationship—where a body is in relation to objects around it.
By the advanced stage of Alzheimer’s, most of the cortex shows severe brain damage with widespread cell death. The person with the disease has lost the ability to communicate and to recognize friends and family.
Recent research, performed by studying the brains of deceased older adults, showed that 25-50 percent of those who appeared cognitively normal had significant accumulations of the plaque protein, indicating early stages of Alzheimer’s, though they might not have even known it. That shows that Alzheimer’s may be a much more widespread form of aging than previously imagined.
National Institute on Aging – https://www.nia.nih.gov/alzheimers/publication/2011-2012-alzheimers-disease-progress-report/primer-alzheimers-disease-and
Alzheimer’s Association – https://www.alz.org/braintour/alzheimers_changes.asp