Dementia is a broad term for a range of conditions that involve loss of mental ability and so causes problems with memory, language, behaviour and emotions. Dementia is most common in the elderly. Around five percent of people over the age of 65 are affected to some extent.

About dementia

Dementia is caused by problems in the way the brain works. The brain is made of billions of brain cells or 'neurones', through which electrical signals pass. Normally these cells signal to each other through narrow gaps (synapses) with the help of chemicals called 'neurotransmitters'.

Dementia is caused by neurones not working properly or dying. This often changes the levels of different neurotransmitters, which affect the function of the brain.

Dementia is not a normal part of ageing. It is different from the mild forgetfulness that can occur in the elderly.

What are the causes of dementia?

There are many causes of dementia. The most common is Alzheimer's disease, which accounts for up to 60% of all cases. Alzheimer's disease is caused by the destruction of certain brain cells leading to the loss of the neurotransmitter acetylcholine. This alters the transmission of signals through the brain. For more information, see the separate BUPA factsheet titled Alzheimer's disease.

Vascular (or blood vessel) dementia, which is sometimes called multi-infarct dementia, accounts for over 20% of all dementias. It is caused by small blood vessels in the brain becoming blocked. These blockages prevent oxygen from reaching the nearby brain cells, leading to their death. It is like having many tiny strokes in the brain, causing a gradual decline in mental ability.

Other dementias include Lewy body dementia, which is often found in people with Parkinson's disease, frontal lobe dementia (including Pick's disease), Creutzfeldt-Jakob disease, AIDS dementia and Huntington's disease.

Dementia can also be caused by excess alcohol intake or syphilis. These types of dementia can be treated and in the early stages it may be possible for the dementia to be reversed. However, most types of dementia cannot be prevented or cured.

A person can suffer from more than one type of dementia at a time.

Symptoms

People with dementia often have one or more of the following:

• memory loss, especially of more recent events. In the early stages of dementia, they misplace objects or forget what they were planning to do
• difficulty finding their way around, especially in new or unfamiliar surroundings
• problems finding the correct words
• poor concentration
• problems learning new ideas or skills
• psychological problems such as becoming irritable, saying or doing inappropriate things and becoming depressed, paranoid or aggressive
• severe mental and physical problems, including loss of speech, immobility, incontinence and frailty

Symptoms usually develop slowly over a number of years, often beginning with memory loss and progressing to mood changes and severe dementia. It can be difficult to determine exactly when dementia starts, as it usually begins with mild forgetfulness.

Although the speed of progression varies widely between different people, in Alzheimer's disease, it typically takes 7 to 10 years from the first signs of memory loss to severe dementia and death. Average life expectancy in Lewy body dementia is around 6 years after diagnosis.

Risk factors

Increasing age is the biggest risk factor in all types of dementia. By the age of 90, around 1 in 3 people are affected.

A family history of dementia is a further risk, although the precise relationship between genetics and dementia is unclear.

The risk of developing vascular dementia is increased by the same things that increase the risk of stroke and heart disease. These include high blood pressure, diabetes, smoking, poor diet and excessive alcohol intake.

It has been suggested that vitamin B12 deficiency increases the risk of diseases like Alzheimer's and dementia, because so many people with these conditions are deficient in this vitamin. However, there is no evidence to suggest that vitamin B12 treatment reverses existing dementia.

How is dementia diagnosed?

Memory loss in dementia is often first noticed by relatives and friends of the affected person.

Dementia can be diagnosed by a GP or a specialist (a neurologist, elderly care doctor, or psychiatrist) on the basis of standardised memory tests, such as the mini-mental state examination (MMSE).

Since all types of dementia have similar symptoms, it can sometimes be difficult to tell which type a patient has. A diagnosis is usually made based on the description of the mental disturbance, risk factors and family history. A brain scan, such a magnetic resonance imaging scan (MRI), can provide further information.

Further examinations and tests may be carried out to exclude other conditions which can cause symptoms similar to dementia. These can include treatable conditions such as depression or thyroid disorders.

Treatment

Dementia generally gets worse with age but the development of symptoms can often be slowed with drugs or other treatments.

Treatment of dementia usually aims to improve memory and concentration, reduce psychiatric problems, and to improve the quality of life for both the patient and their family and carers.

Improving memory and concentration

The memory difficulties seen in Alzheimer's disease can be relieved for a short time in some people with drugs that prevent the breakdown of acetylcholine in the brain. These drugs are called 'cholinesterase inhibitors' and are thought to work by increasing the levels of acetylcholine in the synapses. They can improve memory, as well as slow down some of the changes in personality and mood. They may also be of benefit in Lewy body dementia.

Reducing psychiatric problems

The depression associated with dementia can be alleviated with antidepressants. Other psychiatric drugs help with aggression and agitation, as may certain antiepileptic drugs.

Improving quality of life

There is some evidence that the herbal remedy Ginkgo biloba can delay the progression of dementia, and that long-term use of vitamin E may reduce the chances of developing dementia in old age. However, more research is needed.

There are several psychological techniques to help people cope with dementia. These include reality orientation, which involves regularly reminding patients of information such as the day, date, season and where they are. Since the memory of distant events is rarely impaired, reminiscence therapy which encourages people to talk about the past, may also help by bringing past experience into consciousness. Aromatherapy and art or music therapies are also thought to be beneficial, though there is no scientific evidence to support this.

Care

Looking after someone with dementia can be very difficult at home, especially when faced with changes in their personality or their loss of control over bodily functions. Support and advice can be sought from a number of sources, including:

• district nurses
• community psychiatric nurses
• general practitioners (GPs)
• psychiatrists specialising in dementia
• elderly care doctors
• social services
• voluntary organisations (eg Alzheimer's Society)

Although people with mild dementia can usually cope with minimal support, they need more help looking after themselves as the disease progresses. In advanced cases, finding a place in a residential or nursing home may be the best option for both the person affected and their carer.

Further information

Alzheimer's Resource ROom

http://www.aoa.gov/alz/

Alzheimer's Society

www.alzheimers.org.uk

Carers UK 

www.carersuk.org

Mayo Clinic

www.mayoclinic.com/health/alzheimers/AZ99999

Healing Well

http://www.healingwell.com/pages/Alzheimers_Disease/