Alzheimer’s disease has a position at the very forefront of the public’s attention. Many of us have personal stories of loss involving Alzheimer’s, and many more will experience the disease at some point in their life – personally or otherwise.
As such, it’s in all of our interests to learn as much about the disease as possible in an effort to learn how to combat its spread. Unfortunately, for all the research currently ongoing, much of the disease is still a mystery to the medical profession. With that said we do know quite a bit about Alzheimer’s, especially in regards to the brain.
Alzheimer’s disease, unlike many other mental conditions, affects every area of the brain. Put simply, the disease causes death of the nerve cells in the brain and tissue loss. Over time, this means that the brain shrinks dramatically, altering almost all of its functions.
During the course of Alzheimer’s disease, the cortex shrivels, which damages areas involved in thinking, planning and remembering things. One of the areas most affected is the hippocampus, which is the area of the brain which plays a key role in the formation of new memories. Many of those who have lived with or cared for somebody with Alzheimer’s will tell you that those afflicted with the disease struggle to form short term memories.
Looking at the brain under a microscope reveals that brain tissue with Alzheimer’s disease has many fewer nerve cells and synapses than a healthy brain. Inside those dead and dying nerve cells are twisted strands of proteins called tangles. In a healthy brain, the proteins in nerve cells are organised in straight parallel strands by another protein called tau. In a brain with Alzheimer’s disease, the tau has collapsed leading to those twisted strands and the death of the nerve cell.
There’s also a great number of abnormal clusters of protein fragments between nerve cells, known as plaques. These plaques make it difficult for the electrical signals of the brain arrive at their intended location, leading to diminished brain function. Though scientists aren’t absolutely sure what causes cell death and tissue loss, they believe plaques and tangles are likely suspects.
Those plaques and tangles tends to spread in a predictable pattern through the brain, starting at the front and then working its way up and around the brain, covering around 75% during the severe stages of Alzheimer’s disease.
In the earliest stages, the plaques and tangles begin to affect areas related to learning and memory, as well as thinking and planning. It’s these stages of forgetfulness and irrational behaviour that we recognise as the start of the disease’s progression. In the mild to moderate stages, those symptoms intensify and we see further degradation in areas of speech and spatial awareness, making it harder to move and coordinate. During this stage, individuals might experiences changes in personality and behaviour.
Finally, in the severe stages of Alzheimer’s disease, most of the cortex is seriously damaged. The brain begins to shrink dramatically due to cell death and individuals lose their ability to communicate, recognise others or care for themselves.