What you need to know about Alzheimer’s disease

Alzheimer’s disease is a progressive condition that damages the brain and, therefore, is a neurodegenerative disease. It is the most common neurodegenerative disease in the UK and the most common cause of dementia and memory loss. 

Here, we will explore how Alzheimer’s disease affects the brain, its symptoms, risk factors and treatments, as well as how you can reduce your risk of developing this disease. 

But first, it helps to understand Alzheimer’s disease in the broader context of dementia and ageing. 

Types of dementia

Dementia is a progressive loss of cognitive function. This refers to your mental abilities, such as reasoning, remembering and thinking. It affects almost one million people in the UK. 

There are several different types of dementia with Alzheimer’s disease being the most common type, accounting for 70% of dementia cases. It is caused by disturbances in several proteins that together lead to the death of nerve cells in the brain. 

Vascular dementia accounts for around 20% of dementia cases and is caused by reduced blood supply to the brain, for example, as the result of several small strokes. 

The remaining 10% of dementia cases are mostly caused by frontotemporal dementia, which affects the frontal and temporal regions of the brain, and Lewy body dementia, which is characterised by a build-up of structures called Lewy bodies in nerve cells. 

What is the difference between dementia and forgetfulness?

All types of dementia cause memory loss to varying degrees and at different stages of the progression of the disease. However, this is different from the forgetfulness that naturally occurs with age. 

Dementia is a disease process that causes more severe memory loss than occurs naturally as you get older. 

Dementia is also accompanied by significant losses in different mental abilities, rather than the milder, gradual decline experienced with natural ageing of the brain. 

How Alzheimer’s disease damages the brain

Research is ongoing into how and why nerve cells in the brain die due to Alzheimer’s disease. Currently, several proteins are known to be involved: amyloid-beta, tau and beta-lipoproteins. 

In Alzheimer’s disease, amyloid-beta is misshapen and consequently forms sticky clumps in the spaces between nerve cells. This leads to increased inflammation in the brain. 

Higher blood levels of beta-lipoprotein in Alzheimer’s disease also increase inflammation in the brain when this protein is broken down. 

Finally, the protein tau is misshapen too and forms tangled threads (neurofibrillary tangles) inside nerve cells, which damages these cells. 

Together, this leads to the death of nerve cells in the brain, usually starting in a part of the brain called the hippocampus, which is responsible for the formation of short-term memory. 

Risk factors for Alzheimer’s disease

Your risk of Alzheimer’s disease increases with age. Most people with Alzheimer’s disease are aged 65 and over and, consequently, are diagnosed as having late-onset Alzheimer’s disease. 

However, it is important to note that around five in every 100 people with Alzheimer’s disease develop the condition in their forties, fifties or sixties — this is called early-onset Alzheimer’s disease. 

Your risk of Alzheimer’s disease is higher if you have a family history of the condition due to inherited changes in your genes that increase your risk of developing the disease. 

Lifestyle factors also have a role to play. Uncontrolled high blood pressure, high cholesterol and diabetes increase your risk, as do leading an inactive lifestyle and following an unhealthy diet.

Symptoms and stages of Alzheimer’s disease

In the early stages of Alzheimer’s disease, which is considered to be a mild disease, you may forget events or names and need to rely more on memory aids (eg notes and electronic reminders). 

You may find familiar tasks, such as following a recipe or completing your household finances more challenging. You may misplace things more often and be unable to retrace your steps to find them. Also, you may find it harder to conduct or follow a conversation. 

However, despite these challenges in your mental abilities, in the early stages of Alzheimer’s disease, you will still be able to live independently and learn new things.

As the years pass, symptoms progress, on average, by about 15% per year but not necessarily across the board. Consequently, different symptoms may worsen at different times. As your memory loss worsens, for example, you may forget that you have paid a bill and pay twice or you may forget your route home and get lost. 

When Alzheimer’s disease enters the moderate stage of symptoms, it is no longer safe to live independently and your reflexes will be too slow for activities such as driving. Confusion and memory loss make tasks such as self-care very difficult.  

During the moderately severe stage of Alzheimer’s disease, your balance and mobility will be affected, making falls much more likely. Memory loss and a loss of mental abilities can cause you to become paranoid and suspicious of people around you. 

During the severe stage of Alzheimer’s disease, hallucinations, attention-seeking behaviour, aggression, depression and anxiety are common, alongside a loss of inhibitions.

Alzheimer’s disease and life expectancy

Alzheimer’s disease ultimately reduces your life expectancy but by how much varies depending on a variety of factors, including the age at which your disease began, your ethnicity, socioeconomic status, general health, and level of support and engagement with family and friends. 

In general, after a diagnosis of Alzheimer’s disease, life expectancy is usually another eight to 10 years; however, if you are diagnosed in your 90s, life expectancy is considerably less. That said, it is possible to live with Alzheimer’s disease for up to 20 years. 

Diagnosing Alzheimer’s disease

If you’re concerned that you may have Alzheimer’s disease or another type of dementia, see your GP. They will ask you about your medical history and symptoms, carry out some memory and thinking tests, and, if appropriate, perform a physical examination if you are having motor (movement-related) problems. 

They may also recommend that you have a blood test and/or urine test to rule out other causes of your symptoms. Depending on the results of your tests and examination, they may refer you to a specialist for further assessment (eg a local memory service or mental health team). 

You will then be asked to have an MRI scan of your brain to determine what type of dementia you have. Different parts of the brain can be affected depending on the type of dementia. In Alzheimer’s disease, the first part of the brain that shows signs of shrinking is the temporal lobe where the hippocampus is located. 

Alzheimer’s disease treatments

Medications

There is no cure for Alzheimer’s disease but when detected early, treatment can be highly effective at reducing symptoms and slowing the progression of the disease. 

In the first instance, this involves taking a type of drug called an acetylcholinesterase inhibitor, such as donepezil, galantamine or rivastigmine. These drugs block the activity of enzymes that break down a chemical in the brain called acetylcholine. Consequently, acetylcholine levels in the brain rise and this helps communication between nerve cells. 

For moderate to severe Alzheimer’s disease or for those who can’t tolerate acetylcholinesterase inhibitors, a drug called memantine can be taken. This works by blocking the effects of another chemical in the brain called glutamate; glutamate levels are excessively high in people with Alzheimer’s disease. 

Lifestyle changes

Lifestyle factors have an important role to play in managing Alzheimer’s disease and improving your quality of life. It is, therefore, important to follow a healthy, balanced diet that is rich in antioxidants (eg pomegranates, green left vegetables and oranges), exercise regularly and continue to engage with the people around you.

How to reduce your risk of Alzheimer’s disease

A healthy lifestyle can help reduce your risk of Alzheimer’s disease. As mentioned earlier, this means following a healthy, balanced diet, avoiding smoking, only drinking alcohol in moderation and taking at least 150 minutes of moderate exercises every week. 

While looking after your body is important, it is equally important to look after your brain to reduce your risk of Alzheimer’s disease. 

This means stimulating your brain as much as possible through a variety of activities, such as reading, playing sudoku, doing crosswords, word searches and jigsaw puzzles, and socialising. 

If maintaining social connections with friends and family isn’t easy or possible, getting out to interact with strangers, such as at the checkout till, can also help. 

Where to find support

You can find a wealth of information about Alzheimer’s disease and a variety of support for living with the condition or helping someone who has the condition at the Alzheimer’s Society, Admiral Nurses, Alzheimer’s Research UK and Age UK.