Types of dementia and common signs and symptoms

The term ‘dementia’ describes a set of symptoms which can include loss of memory, mood changes and problems with communication and reasoning. These symptoms occur when the brain is damaged by certain conditions and diseases, including Alzheimer’s disease, vascular dementia and Creutzfeldt-Jakob disease. 
Age is the greatest risk factor for dementia. Dementia affects one in 14 people over the age of 65 and one in six over the age of 80. However, dementia is not restricted to older people: in the UK, there are over 17,000 people under the age of 65 with dementia, although this figure is likely to be an underestimate.

Alzheimer’s Disease
Alzheimer’s disease affects around 496,000 people in the United Kingdom and is the most common cause of dementia. Alzheimer’s disease is a physical disease which affects the brain. It was first described by a German neurologist, Alois Alzheimer. During the course of the disease, protein plaques and tangles develop in the structure of the brain, leading to the death of brain cells. People with Alzheimer’s also have a shortage of some important chemicals in their brain which are involved with the transmission of messages. 
Alzheimer’s is a progressive disease, meaning that over time more parts of the brain are damaged. As this happens, the symptoms become more severe. 
People in the early stages of Alzheimer’s disease may experience lapses of memory and have problems finding the right words.

As the disease progresses, some symptoms that a person may experience are: Confusion; frequently forgetting the names of people, places, appointments and recent events. Mood swings; feeling sad or angry, or scared and frustrated by their increasing memory loss. Withdrawal; due to either a loss of confidence or communication problems. Difficulty when carrying out everyday activities; a person with Alzheimer’s may get muddled checking their change at the shops or become unsure how to work the television remote. So far, no one single factor has been identified as a cause for Alzheimer’s disease. It is likely that a combination of factors including age, genetic inheritance, environmental factors, lifestyle and overall general health, are responsible. In some people, the disease may develop silently for many years before symptoms appear.

Vascular Dementia
Vascular dementia is the second most common form of dementia after Alzheimer’s disease. It is caused by problems in the supply of blood to the brain. Brain cells need a good supply of blood in order to be healthy and function properly. Blood is delivered through a network of blood vessels called the vascular system. If the vascular system within the brain becomes damaged and blood cannot reach the brain cells, the cells will eventually die. This can lead to the onset of vascular dementia. 
Factors that can increase a person’s risk of developing vascular dementia include: A medical history of stroke, high blood pressure, high cholesterol, diabetes (particularly type II), heart problems or sleep apnoea (where breathing stops for a few seconds or minutes during sleep). A lack of physical activity, drinking more that recommended levels of alcohol, smoking, eating a fatty diet or leaving conditions such as high blood pressure or diabetes untreated. A family history of stroke or cardiovascular disease.

An Indian, Bangladeshi, Pakistani or Sri Lankan ethnic background as differences in vascular risk factors (such as heart disease) in these communities may contribute to the increased risk. An African-Caribbean ethnic background.

There are different types of vascular dementia: Stroke-related dementia, sub-cortical vascular dementia and mixed dementia (vascular dementia and Alzheimer’s disease). The difference between these types depends on what has caused the damage in the brain and which part of the brain has been damaged.
Common signs and symptoms of vascular dementia may include: Problems with speed of thinking, concentration and communication. Depression and anxiety accompanying the dementia.

Symptoms of a stroke, such as physical weakness or paralysis. Seizures.
Periods of severe confusion.
Visual mistakes and misperceptions (for example, seeing a rug as a pond). Changes in behaviour (for example, restlessness).
Difficulties with walking and unsteadiness.
Hallucinations and delusions.
Problems with continence.
Psychological symptoms such as becoming more obsessive.

Dementia with Lewy Bodies
Dementia with Lewy bodies (DLB) is a form of dementia which shares characteristics with both Alzheimer’s and Parkinson’s disease. It accounts for around 10% of all cases of dementia in older people and tends to be under-diagnosed. 
Named after the doctor who first identified them in 1912, Lewy bodies are tiny, spherical protein deposits found in nerve cells. Their presence in the brain disrupts the brain’s normal functioning, interrupting the action of important chemical messengers. Lewy bodies are also found in the brains of people with Parkinson’s disease, a progressive neurological disease that affects movement. 
Dementia with Lewy bodies is also a progressive disease, which means that over time the symptoms will become worse. DLB progresses at about the same rate as Alzheimer’s disease, typically over several years.

Symptoms of DLB can include: Problems with attention and alertness, often have spatial disorientation and experience difficulty with ‘executive function’, which includes difficulty in planning ahead and co-ordination mental activities. Memory is affected, although it is typically less so than in Alzheimer’s disease. Slowness. muscle stiffness. trembling of the limbs, a tendency to shuffle when walking, loss of facial expression and changes in the strength and tone of the voice. Experience detailed and convincing visual hallucinations, often of people or animals. Find that their abilities fluctuate daily or hourly.

Fall asleep very easily by day, and have restless, disturbed nights with confusion, nightmares and hallucinations. Faint, fall or have ‘funny turns’.
Researchers have yet to understand fully why Lewy bodies occur in the brain and how they cause damage.

Creutzfeldt-Jakob Disease
Creutzfeldt-Jacob disease (CJD) is a rare form of dementia. Rarer forms of dementia account for around only 5% of all dementia cases in the UK. 
CJD is caused by an infection protein in the brain called a prion. These prions accumulate at high levels in the brain and cause irreversible damage to nerve cells. There are four main types of Creutzfeldt-Jakob disease: Sporadic CJD, variant CJD, familial or inherited CJD and iatrogenic CJD. Sporadic CJD, which normally affects people over 40, is the most common form of the disease. It is estimated that the disease affects about one out of every 1 million people every year. There may be many years between a person being infected and the development of symptoms. Symptoms of Creutzfeldt-Jakob disease include: Loss of intellect and memory.

Change in personality.
Loss of balance and co-ordination.
Slurred speech.
Visual problems and blindness.
Abnormal jerking movements.
Progressive loss of brain function and mobility.
Most people with Creutzfeldt-Jakob disease will die within a year of the symptoms starting, usually from infection. This is because the immobility caused by the disease can make people with the condition vulnerable to infection.