Dementia is a collective name for brain diseases that cause a long-term and gradual decrease in memory and the ability to think. However, as many people do not know, dementia does not just affect memory. It includes problems with language, understanding, mood, judgement, movement, day-to-day activities, etc. Dementia has become very common, with one in fourteen people over 65 developing dementia and one in six people over 80 affected.
The most common type of dementia is Alzheimer’s diseases. There are more than 520,000 people in the UK with Alzheimer’s disease. Alzheimer’s affects the hippocampus, which is the part of the brain which has a major role in daily memory. Although the exact cause is unknown, researchers know that ‘plaques’ (which are formed by protein amyloid) and ‘tangles’ (which are formed by protein tau) occur in the brain. Amyloid comes from within us and it is natural, it creates beta amyloid which is toxic to brain cells. This results in a plaque forming which consists of dead cells and the protein amyloid. Tau is also naturally occurring and helps brain cells communicate with one another; however, it can clump together which leads to the death of brain cells affected. This ultimately leads to the loss of connections between nerve cells. As it is a progressive disease, the symptoms are not as bad to start with but get worse over time. The most common early symptom is one having difficulty recalling recent events and learning, but memory for events that happened a long time ago are not usually affected in the early stages.
Vascular dementia is the second most common type of dementia. This affects roughly 150,000 people in the UK. Symptoms start to arise when the brain is damaged due to problems with the supply of blood to the brain because of diseased blood vessels. A constant supply of blood is needed to allow oxygen and nutrients to enter brain cells, this is delivered to the brain by the vascular system. However, if the vascular system gets damaged, blood vessels may leak or get blocked and so the blood cannot reach the brain cells. This results in the brain cells eventually dying. This therefore results in problems with memory and thinking. The most common symptoms in the early stages are problems with organising and making decisions, slower thought speed, problems concentrating, etc. Some people may also have problems with visuospatial skills which is problems understand 3D objects. Age plays a major role in risk factors, those over 65 are more likely to develop this disease, but someone who has had a stroke or diabetes or heart disease is roughly twice as likely to develop vascular dementia.
Around ten percent of people with dementia experience mixed dementia, which is where they have more than one type at the same time. The most common is a mixture between Alzheimer’s and vascular dementia. The symptoms of mixed dementia will be a mixture of the symptoms of the two types.