Alzheimer's disease is a cause of dementia. There is no cure and it can cause a great deal of distress for those affected and their families. However, early diagnosis is important because there is a great deal of support as well as medication that can help.
What is Alzheimer's disease?
Alzheimer's disease is the most common cause of dementia. Dementia is progressive and affects many brain functions, including memory.
The exact cause of Alzheimer's disease is not yet known. However it is known that there is a gradual process of damage to part of the brain called the cerebral cortex. This is called cortical atrophy, which means destruction of the cells of the cerebral cortex so that the cells can't function properly.
The damage to the cerebral cortex of the brain probably begins at least ten years before any symptoms develop.
How common is Alzheimer's disease?
Alzheimer's disease is the most common form of dementia. Alzheimer's disease affects about 850,000 people in the UK. It becomes more common with increasing age. About 1 in 14 people over the age of 65 and 1 in 6 people over the age of 80, have Alzheimer's disease.
Alzheimer's disease risk factors
The following increase the risk of a person having Alzheimer's disease:
- Increasing age.
- White skin.
- There is a small increased risk if a first-degree family member (father, mother, brother or sister) is affected.
- It is more common in women.
- People who have experienced a serious head injury.
- Lifestyle factors that also increase the risk of cardiovascular disease - for example, smoking, lack of physical exercise, and an unhealthy diet.
- People with Down's syndrome.
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Early-onset Alzheimer's disease
Most people who develop Alzheimer's disease are more than 65 years old. However, it can affect younger people - when this occurs, it is called early-onset Alzheimer's disease.
What are the symptoms?
Alzheimer's disease is a progressive condition, which means the symptoms gradually become more severe over the course of several years. It affects different functions of the brain, including:
- Memory problems. Recent events are usually forgotten first. Past events are usually remembered well until the dementia becomes severe.
- Language problems, such as difficulty understanding what is said or what is written down.
- Problems with attention and concentration.
- Disorientation, particularly in unfamiliar surroundings. Losing track of time.
- Difficulty with learning new skills.
- Psychological problems such as anxiety and depression.
- Changes in mood, behaviour and personality.
- Agitation and difficult and challenging behaviour, causing sleep problems, restlessness and aggression.
- Problems carrying out usual day-to-day activities.
Some people with dementia may no longer be able to drive. If you are in the UK, you should inform the DVLA if you have been diagnosed with Alzheimer's disease and they may ask your doctor to provide a report.
Alzheimer's disease can cause problems with swallowing and difficulty with eating. This can cause food to go down to the lungs when eating (aspiration), which can cause frequent chest infections, including aspiration pneumonia.
As Alzheimer's disease progresses, the symptoms become increasingly severe. Alzheimer's disease usually progresses slowly over a period of 7-10 years but the rate of progression varies from person to person.
How is Alzheimer's disease diagnosed?
As the symptoms progress slowly, it can be difficult to realise that there's a problem. In the early stages the symptoms are often dismissed as a sign of ageing. However, early diagnosis of Alzheimer's disease is very important in order that you can plan for the future and receive the best treatment and support that can be offered.
There's no single test that can be used to diagnose Alzheimer's disease. Your GP will use a simple test such as the mini mental state examination (MMSE) to assess how well your brain is working. Usually blood tests are also arranged to check whether your symptoms may be caused by a different condition, such as hypothyroidism or vitamin B12 deficiency.
If Alzheimer's disease is suspected, you may be referred to a specialist memory clinic for further assessment. Magnetic resonance imaging (MRI) scans are used to rule out any other conditions affecting the brain.
In the UK, the National Institute for Health and Care Excellence (NICE) advises perfusion hexamethylpropyleneamine oxime (HMPAO) single-photon emission computerised tomography (SPECT) to see whether the diagnosis is Alzheimer's disease or any other cause of dementia.
How is Alzheimer's disease treated?
There's no cure for Alzheimer's disease; however, medication is available that can help relieve some of the symptoms and slow down the progression of the condition in some people. The treatment and support that can be provided include:
- Support from social services, including carers and respite care.
- Help with legal issues such as Power of Attorney and a Living Will.
- Changes to your home environment to make it easier to deal with day-to-day activities..
- Overcoming difficulties with memory, such as reminder notes, lists and reorganising possessions.
- Cognitive behavioural therapy (CBT) to help with depression or anxiety.
- Other ways to help with anxiety, depression and difficulties with behaviour include aromatherapy, music and dance, using animals as therapy, massage and exercise.
- Medicines used for Alzheimer's disease include acetylcholinesterase (AChE) inhibitors (donepezil, galantamine or rivastigmine) or memantine.
What is the outlook?
There is no cure for Alzheimer's disease and the difficulties gradually become increasingly severe. This can cause a great deal of distress for both the person with Alzheimer's disease and for their family.
On average, people with Alzheimer's disease live for around 8 to 10 years after they start to develop symptoms but this is very variable from person to person.
Can Alzheimer's disease be prevented?
As the exact cause of Alzheimer's disease isn't clear, there's no known way to prevent the condition. However, there are things you can do that may reduce your risk or delay the onset of dementia, such as:
Further reading and references
Donepezil, galantamine, rivastigmine and memantine for the treatment of Alzheimer's disease; NICE Technology Appraisal Guidance, March 2011 - updated June 2018
Dementia Fact Sheet; World Health Organization (WHO), April 2016
Services for younger people with Alzheimer's disease and other dementias; Royal College of Psychiatrists, 2006
Dementia; NICE CKS, August 2016 (UK access only)
Assessing fitness to drive: guide for medical professionals; Driver and Vehicle Licensing Agency