Since dementia refers to a group of symptoms represented in various diseases, the causes tend to vary. The most common conditions develop due to changes in the brain, causing cells to die more rapidly than normal. Although most forms of dementia are not inherited, there are some cases when dementia runs in the family. Only in rare cases are offspring exposed to the gene in which develops into familial Alzheimer’s.
The majority of changes are experienced due to a build-up of protein, leading to a range of physical and mental symptoms. In order to focus more clearly on what causes dementia, let’s examine the most common forms. Vascular dementia, Alzheimer’s, dementia with Lewy bodies, and frontotemporal dementia tend to be the most common.
The Causes of Vascular Dementia
Our brains require nutrient and oxygen-rich blood in order to function properly. Also, cells require blood flow in order to stay healthy and active. In the case of vascular dementia, the blood supply to the brain is restricted, leading to brain cell death and eventual brain damage.
More specifically, blood vessels become damaged due to a number of possible reasons. In the case of subcortical vascular dementia, blood vessels deep in the brain narrow, reducing the blood supply. The same is true for those who have suffered from a stroke, as blood flow to the brain is suddenly cut off. Although not everyone who has a stroke develops dementia, these individuals are at an increased risk.
The Causes of Alzheimer’s Disease
Alzheimer’s is the most common and well-known type of dementia, as brain cells die and the brain begins to shrink. The true cause is not fully understood, however, the formation of an abnormal protein is believed to play a key role. Plaques and tangles are often core markers of this disease.
Basically, these proteins reduce the brain’s ability to function as Alzheimer’s disease damages the structure of the brain. As the condition progresses, damage spreads to the hippocampus where memory is significantly affected. What triggers this damage is not understood, but age, genetics, cardiovascular disease, head injuries, smoking, diabetes, and hypertension are believed to increase one’s risk.
The Causes of Dementia with Lewy Bodies
We still have a lot to learn about this form of dementia, but Lewy bodies play a significant role as they’re found across all patients with this condition. Lewy bodies are simply lumps of protein that develop inside the brain. Although researchers are unsure how they develop and how they cause brain damage, their influence on dopamine and acetylcholine may be a significant factor.
Both dopamine and acetylcholine play a key role in functions such as memory, mood, and attention, reflecting the interference potentially caused by Lewy bodies. Since this condition is closely linked to Parkinson’s disease, individuals often experience physical symptoms as well. Unlike Alzheimer’s, for instance, no gene has been identified that’s linked to dementia with Lewy bodies and a family history does not appear to be a contributing factor.
The Causes of Frontotemporal Dementia
Last, frontotemporal dementia occurs when two select areas of the brain are damaged and shrink, more specifically the frontal and temporal lobe. For those who are under the age of 65, this form of dementia tends to be the most common.
Since approximately 20 percent of cases have been linked to a genetic mutation passed on from parents, a family history should not be ignored. With that being said, many individuals who develop frontotemporal dementia have no family history. In these cases, a protein known as tau tends to flood the affected areas of the brain.
NHS. (2015). What Causes Dementia? National Health Services. Retrieved from http://www.nhs.uk/conditions/dementia-guide/pages/causes-of-dementia.aspx
NHS. (2015). Alzheimer’s Disease – Causes. National Health Services. Retrieved from http://www.nhs.uk/Conditions/Alzheimers-disease/Pages/Causes.aspx