Your questions on Alzheimer’s disease answered

First, what is Alzheimer’s disease?

“Alzheimer’s disease is a brain disorder associated with the build-up of proteins called amyloid and tau in the brain. This process takes a long time, but eventually the accumulation of these proteins causes the gradual loss of neurons in the brain. Neurons are structures in your brain that carry messages around its different parts. The loss of these neurons means that important messages can’t reach key centres of your brain, leading to progressive cognitive impairment and the symptoms of Alzheimer’s disease.”

What are the symptoms of Alzheimer’s disease?

“The most common symptom of Alzheimer’s disease is memory loss as the disease primarily affects neurons in the memory centres of the brain. People might forget conversations they’ve recently had and ask questions repetitively, lose things or have trouble finding the right words when talking. 

“Over time, people with Alzheimer’s disease develop further cognitive difficulties. Their existing symptoms get worse and they become more confused and disorientated. They might have trouble performing calculations, problems making plans and decisions, and can have personality changes, with frequent mood swings and delusions or paranoia. Alzheimer’s disease can even cause visual impairment – not because it affects the eyes but due to the brain struggling to process visual information. Some rare forms of Alzheimer’s disease begin with other symptoms outside of memory loss, starting with visual problems or even speech and language problems which then develop into memory problems as well.”

Alzheimer’s disease and dementia are often talked about together – is there a difference between the two?

“In some regards, Alzheimer’s disease and dementia can be seen as the same thing – dementia is a broad term that covers a range of conditions that result in progressive cognitive impairment. But dementia is a collection of symptoms rather than a disease, and the underlying changes in the brain that cause the cognitive impairment are different for each type of dementia. Alzheimer’s is a specific disease that causes dementia. It’s also the most common cause of dementia, estimated to account for at least 60% of dementia cases.”

How is Alzheimer’s disease diagnosed as the specific type of dementia?

“The way we diagnose Alzheimer’s has progressed a lot over the years as we’ve developed new tests and technology. But it always begins with a clinical assessment, which helps us understand the progression of the patient’s symptoms over time. This is supported by carrying out some psychological tests to see if the patient has any cognitive impairment and, if they do, what the nature of the cognitive impairment is. 

“We then use a scan like an MRI to look for any abnormal changes in the brain, such as a loss in brain volume. We look at areas most likely to be affected by Alzheimer’s disease, in particular the memory centres of the brain. But now we also have tests to look at any reductions in brain function, like using a PET scan. Most importantly, the latest development we have is being able to use a PET scan to look for any amyloid build-up in the brain. This is the key hallmark of Alzheimer’s disease and helps us reach a diagnosis with much more certainty than before.”

Is Alzheimer’s disease hereditary?

“Although there is a very rare form of early onset Alzheimer’s disease has a strong genetic link, this is not the case for the majority of people who develop Alzheimer’s disease. For most people, there is a gene known as APOE that can increase the chance of developing the condition, depending on which version of the gene they have. However, this is seen more as a risk factor, rather than as a definitive cause. This is because even if you have copies of the ‘high-risk’ version of the APOE gene, it doesn’t mean that you will definitely develop Alzheimer’s disease. On the other hand, having the ‘low-risk’ genes doesn’t guarantee that you are protected from the disease as there’s a wide range of other factors involved outside of genetics.”

So, what are these other risk factors of Alzheimer’s disease? And what can you do to minimise your risk?

“We know from lots of studies that certain medical and health factors, such as heart and circulatory diseases, high blood pressure and high cholesterol, can all increase the risk of developing Alzheimer’s disease. Additionally, having poor levels of cognitive stimulation or poor mental health can also increase your risk of developing the condition. As such, we recommend a healthy lifestyle with a good diet such as the Mediterranean diet, which emphasises plant-based foods with some fish or poultry, and regular exercise to stay healthy and reduce your risks. Good levels of social interaction and mental stimulation, including hobbies that encourage creativity and new learning, can also reduce your risk of developing Alzheimer’s disease. But staying fit and healthy doesn’t just reduce your risk of Alzheimer’s disease – it helps protect you from a whole range of conditions as you get older, including heart disease and diabetes.”

What are the current treatments for Alzheimer’s disease like? 

“For a long time, we only had what we call symptomatic treatments for Alzheimer’s disease – we could prescribe medications that could help treat someone’s symptoms and boost memory function for a duration of time, but these didn’t address the underlying causes of Alzheimer’s disease or help prevent any further cognitive decline over time. Excitingly, we now have the new medications lecanemab and donanemab, which are amyloid-targeting therapies. These treatments work by clearing the amyloid protein that has built up in the brain. By doing this, they have been found to slow the progression of Alzheimer’s disease in its early stages by up to 30%. This is a really significant finding as prior to this, no treatment had been shown to demonstrate any similar effects.”

Alongside these new treatments, what do you think the future of Alzheimer’s treatment might look like?

“The future of Alzheimer’s treatment is looking brighter than it’s ever been. That’s because the new amyloid-targeting therapies are hopefully only the beginning of a new era of treatment for Alzheimer’s disease. Numerous new drugs are currently undergoing clinical trials to see if they can slow the progression of the condition further, either on their own or potentially in combination with another treatment. There are also trials underway in people who have amyloid build-up in their brains but aren’t yet symptomatic to see if treating people before they develop symptoms can completely avoid the development of any cognitive symptoms of Alzheimer’s disease. 

“Alongside the numerous treatments in development, we’re also seeing new technologies to detect Alzheimer’s disease at an earlier stage and in a more convenient way. We’re in the process of implementing the use of a blood test that’s able to detect Alzheimer’s disease which has very recently been validated by one of the top UK research centres. This test can potentially detect the build-up of amyloid without the need for a scan. There are of course some difficulties currently with using a blood test – while it’s simple to use, it’s not 100% accurate, so sometimes we’ll still need to follow it up with more accurate tests like PET scans. But it can hopefully make access to diagnostic tests for Alzheimer’s much easier, as it is much more convenient and also helps reduce costs. These new diagnostic tests will help us identify Alzheimer’s earlier, which is really important as this is when the current treatments are the most effective and have the biggest benefits.

“I’d say the future of Alzheimer’s treatment is really exciting, and I’m looking forward to seeing what’s going to be developed and how we can offer even better treatments for people with Alzheimer’s disease.” 

If you’d like to find out more about amyloid-targeting therapies or book a consultation with Dr Johnathan Chan, visit our amyloid-targeting therapies webpage.