What is dementia?

Dementia describes symptoms such as memory loss, difficulties with language, thinking and solving problems, which impact on daily living. Dementia is caused by diseases of the brain and is not a natural part of ageing, but the risk of having it increases with age. Most of the 850,000 people living with dementia in the UK are over 65, but there are more than 40,000 people with young onset dementia under this age.

Dementia is a progressive condition that gets worse in time although it can progress over a number of years. There is no cure although there are some drugs that can help to address certain symptoms, but they cannot halt the progression of the underlying disease. With support and understanding from family, friends and community, people with dementia can continue to live active and fulfilling lives. The most common types of dementia include:

Alzheimer’s disease – this is the most common form of dementia (62 per cent of those with dementia have Alzheimer’s disease) and is named after Alois Alzheimer, a German psychiatrist who first described the condition in the early 1900s after seeing a 51-year-old female patient called Auguste Deter suffering with short-term memory loss and other psychological changes. During her autopsy in 1906, it was discovered that she had shrinkage of the cortex (the largest portion of the brain) and abnormal deposits in and around nerve cells.

Over 520,000 people in the UK have Alzheimer’s disease. Proteins that build up in the brain to form structures called ‘plaques’ and ‘tangles’ are the cause, as they affect connections between nerve cells, eventually causing them to die.

Symptoms: memory loss, having trouble learning new skills or new information, repeating things, confusion and loss of concentration; depression, irritability and restlessness.

Vascular dementia – this is the second most common type of dementia and affects around 150,000 people in the UK. It is caused by a reduced blood flow to the brain. This can be caused by a stroke or a series of mini-strokes, or by small blood vessels deep in the brain becoming narrowed and hardened, which is known as atherosclerosis. Vascular dementia is more common in smokers, those with high blood pressure, Type 2 diabetes, obesity or heart problems. Age is also a strong risk factor for vascular dementia.

Symptoms: confusion, disorientation, problems with concentration, hallucinations, slower thought patterns, memory loss, language problems, depression or anxiety. A person with vascular dementia may experience rapid changes in mood and can be tearful and emotional.

Dementia with Lewy bodies – this is the third most common cause of dementia, affecting up to 15 per cent of those with dementia. It is named after Friederich H. Lewy, a scientist who discovered the condition when researching Parkinson’s disease in the early 1900s. Lewy bodies are lumps of protein that develop inside brain cells. Although more research is needed on dementia with Lewy bodies dementia, it is believed that these proteins interfere with chemical messengers in the brain that regulate brain functions such as memory, mood and our ability to learn. The exact way in which Lewy bodies cause dementia is not yet clear. Lewy bodies are the cause of several diseases that affect the brain and nervous system, including Parkinson’s disease. Some people with Parkinson’s will eventually develop dementia.

Symptoms: fluctuating attention, problems with perception, hallucinations, difficulty with balance and movement, greatly disrupted sleep, feelings of being persecuted.

Frontotemporal dementia – also known as ‘Pick’s disease’, this is a less common form of dementia whereby the two frontal lobes of the brain behind the forehead and the temporal lobes behind the ears are damaged. Brain tissue in the frontal and temporal lobes shrinks. The frontal lobes affect our behaviour and emotional state, while the temporal lobes on either side of the brain deal with words and grammar. This form of dementia is less common than Alzheimer’s disease or vascular dementia but is often diagnosed in younger people aged between 45 and 65.

Symptoms: inappropriate behaviour, lack of motivation, craving sweet foods, difficulty with speech, difficulty recognising others.

Parkinson’s disease dementia – people who already have Parkinson’s disease have an increased risk of developing dementia.

Symptoms: Memory loss, difficulty concentrating, hallucinations and paranoia.