Alzheimer's Disease

What is Alzheimer’s disease?
Alzheimer’s disease is a type of dementia, which means it is a disease that causes a progressive decline in brain functioning. For example, in a person with Alzheimer’s disease, memory, reasoning (solving problems) and communication can be affected.[1.3] Alzheimer’s disease is the most common type of dementia, and about 1 in 20 people aged 65 years and older have the disease.[4]

People with Alzheimer’s disease lose nerve cells and connections in their brain, which impairs their memory, language and thinking processes, and also affects how they feel and behave.[5] It is thought that two structures in the brain called ‘plaques’ and ‘tangles’ are the main reasons that nerve cells are damaged in someone with Alzheimer’s disease.[6]

• Plaques are a build-up of bits of a protein called beta-amyloid in the spaces in between nerve cells.
• Tangles are twisted threads of another protein know as tau that builds up inside cells.

Most people develop some plaques and tangles as they get older, but people with Alzheimer’s disease tend to develop a lot more than normal, beginning in the areas important for memory before spreading to other areas of the brain.[7]

What are the risk factors for Alzheimer’s disease?
It is not fully understood what leads to the development of Alzheimer’s disease, but there are some things that can increase a person’s chances of getting the disease, called ‘risk factors’. Some risk factors are:[8,9]

• Age – the biggest risk factor for Alzheimer’s disease is increasing age.
• Genetics – some genes are associated with a higher risk of Alzheimer’s disease.
• Positive family history – the risk is a bit higher than normal if a parent or brother/sister is affected.
• Gender – Alzheimer’s disease is more common in women.
• Poor sleep.[10]
• Head injury.

What are the symptoms of Alzheimer’s disease?[3,8]

The symptoms of Alzheimer’s disease develop slowly over time. At first it can be difficult to work out if mild memory problems are just due to getting older, or if they are because of Alzheimer’s disease. The main symptoms can be different as the disease gets worse.

How is Alzheimer’s disease diagnosed?[11]
There is no single test for Alzheimer’s disease. A doctor will ask questions to learn the patient’s medical history, and will usually ask the person to do some memory, thinking and language tests to check how the different areas of the brain are working. The doctor might also do a blood test, or ask for a CT or MRI scan of the brain. If the doctor is not sure if someone has Alzheimer’s disease, they might send the person to a medical specialist like a psychiatrist or a neurologist. These specialists are experts in diagnosing, caring for and advising patients with Alzheimer’s disease and their families.

What are the stages of Alzheimer’s disease?
Alzheimer’s disease can be divided into three main stages:[12-14]

• Preclinical.
• Prodromal, also called Mild Cognitive Impairment (MCI).
• Alzheimer’s dementia.

Preclinical Alzheimer’s disease is the first stage of the disease, where changes are occurring in the brain but the patient does not have obvious symptoms.[12]

In prodromal Alzheimer’s disease, there are small changes to a person’s abilities or behaviour, which become more obvious over time.[13]

Alzheimer’s dementia is the final stage of the disease where the patient needs more help in carrying out their usual daily activities, and they can end up relying on nursing care or a family carer.[14]

What is the outlook for a person with Alzheimer’s disease?
Every person is affected differently by Alzheimer’s disease. On average, people with Alzheimer’s disease live for between 8 and 10 years after symptoms start, but some people have lived for up to 20 years after diagnosis.[15]

What treatment options are available for Alzheimer’s disease?
At the moment there is no cure for Alzheimer’s disease, so treatments are used to relieve symptoms and are aimed at improving quality of life. The main treatments used for Alzheimer’s disease patients are:[16]

• 'Acetylcholinesterase inhibitors’ – these increase levels of a neurotransmitter (a type of chemical messenger that transmits signals) called acetylcholine, a substance in the brain that helps nerve cells to communicate with each other (e.g. donepezil, galantamine, rivastigmine).
• Drugs that block the effects of too much of a chemical in the brain called glutamate (e.g. memantine).
• Medications to treat depression, agitation and hallucination (e.g. anti-depressants, anti-psychotics).
• Non-drug-based treatments like group activities designed to improve memory (‘cognitive stimulation therapy’), working to achieve a goal such as learning to do an everyday task (‘cognitive rehabilitation’), and ‘life story’ work where the patient talks about or does activities based on events from their past.

As well as family carers, there are many different medical professionals who might be involved in caring for an Alzheimer’s disease patient. These include the family doctor, a psychiatrist or neurologist, specialist nurses, occupational therapists and psychologists.

Research is under way to find new treatments to stop, slow or prevent Alzheimer’s disease. Most work is being done to find treatments targeting the plaques and tangles that are thought to be the main reason for the effects of Alzheimer’s disease.[17] Another research focus is to spot the disease as early as possible and scientists are trying to understand how the disease gets worse, and what role genetic factors play.