How Alzheimer's Disease Changes the Brain
By Amanda Page
First, Some Facts and Figures
Alzheimer's disease is not a normal part of aging. It is the most common form of dementia, a general term for memory loss and cognitive decline serious enough to interfere with daily life. It's also, according to the Centers for Disease Control, the 6th top cause of death in the United States. One in three seniors dies with Alzheimer's or another form of dementia.
In detailing the deterioration of a brain with Alzheimer's, it makes sense to start with the hippocampus. It's the part of the brain associated with creating new memories and being able to navigate through spaces.
How Alzheimer's Affects the Hippocampus
Alzheimer's disease usually first damages the hippocampus, leading to memory loss and disorientation. Hippocampal damage can also cause amnesia and an inability to form new memories, specifically those regarding time and location.
A study found that the volume and ratio of the hippocampus was reduced, on average, by 25 percent in Alzheimer’s disease.
The hippocampus is reduced by an average of 21 percent in mixed dementia – a condition in which abnormalities of more than one type of dementia occur.
The hippocampus is reduced by an average of 11 percent in vascular dementia – a decline in cognitive skills caused by conditions that block or reduce blood flow to the brain.
The hippocampus is reduced by an average of 5 percent in normal pressure hydrocephalus- a brain disorder in which excess brain fluid leads to thinking and reasoning problems.
The Frontal Lobe
The parietal lobe is located above the ear and receives and interprets sensations of pain, pressure, temperature, touch, size and shape, and body part awareness. In most people, the left side of the parietal lobe is thought to be dominant, as it processes information allowing us to read, write, and make calculations.
The non-dominant side of the parietal lobe, usually the right side, helps us 'picture' the world around us by processing appearances.
The Occipital Lobe
The Corpus Callosum
The brain is divided into the right and left hemisphere, which are connected by the corpus callosum.
The corpus callosum is the largest concentration of white matter in the brain, and its millions of nerve cells allow different parts of the brain to communicate with each other.
The Temporal Lobe
These are just the primary regions of the brain most affected by Alzheimer’s--other parts can also be damaged. That's why its impact can be so devastating and why finding a cure, or even a way to slow down its progression, remains one of the biggest challenges facing medical researchers today.
But scientists continue to look for answers, and experts feel they're getting closer to finding ways to cure and even prevent Alzheimer's. For updates on the latest research, see the Alzheimer's Association's website.