Bart De Strooper is founding director of the UK Dementia Research Institute (2016-2023). He is professor of molecular medicine at the KU Leuven and VIB, Belgium and professor in dementia research at the University College London, UK.
In 2018, Bart De Strooper, together with John Hardy, Christian Haas, and Michel Goedert, was awarded the Brain Prize for their ground-breaking research on the genetic and molecular basis of Alzheimer disease.
He agreed to speak to Anne-Marie about dementia, Parkinson’s disease, changing attitudes, research and the role of philanthropy.
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Professor, thank you very much for speaking to us. What can you tell us about dementia in Parkinson’s?
Parkinson’s dementia is a complex condition, and while it has differences from, say, Alzheimer’s, there are also clear overlaps. Parkinson’s dementia often develops as the disease progresses, and usually begins with changes in cognition, such as difficulty with concentration and planning. This differs from Alzheimer’s, where memory problems are often more prominent earlier. However, there are parallels. For example, both conditions lead to disruptions in the brain structures responsible for memory and cognitive functions. Later in life, the two forms can mix. So, a lot of Parkinson’s patients then also get Alzheimer’s. And vice versa. At an advanced stage, all these diseases start to look somewhat alike.
How common is dementia in Parkinson’s?
We estimate that 30 to 50 per cent of people with Parkinson’s disease eventually also develop dementia, particularly if they have lived longer with the disease. The risks increase with age and the severity of the disease. But it is not a black and white. Not everyone develops dementia. Dementia is most common in older people, even when Parkinson’s is diagnosed late in life. And it is also most frequent in patients who have other symptoms besides motor symptoms, such as cognitive problems, decision-making problems, sleep problems, depression, hallucinations, etc. So those are all things that put you in a group at higher risk. But, to be honest, there is very little research done on it. I think there is actually a lot of work to do there.
What do we know about the causes of dementia in Parkinson’s?
We are still struggling with that. We know that accumulation of the protein alpha-synuclein plays a major role. This accumulation occurs in the brains of people with Parkinson’s, but we do not fully understand why it sometimes leads to dementia and sometimes not. It involves a complex interplay of genetics, lifestyle and other factors. We have yet to put that puzzle together. As I often say, lifestyle advice is useful, but as a scientist you want to get to the heart of the problem. What is driving this process? And we don’t know that yet.
Can we reduce the risk of dementia in Parkinson’s?
Fortunately, yes. Besides medication to control the symptoms of the disease, physical and mental activity, a healthy diet, adequate sleep and avoiding social isolation can make a difference. Social interaction, especially talking to another physical person or persons, is the best cognitive training. You use sensory input, listen, interpret, think, have feelings. So go play cards with friends, strike up a conversation, organise things with the (a) charity. It may sound simple, but these are things that protect the brain. That said, to be honest: this advice may reduce the risk, but it does not eliminate the cause.
How does dementia affect Parkinson’s treatment?
If one already has physical limitations and then develops cognitive problems in addition, it is definitely a challenge to stay well organised, keep taking your medications, etc. This also puts more and more pressure on informal carers. If your partner, family member or friend raises (the subject of dementia) themselves, because it is clear, then you can discuss how to approach it. Your partner can say: “if I’m like this, you shouldn’t have to care for me anymore. If I am like this, maybe it is time to go to a care home, or maybe it is time to consider euthanasia. Such things can be discussed. And that’s already going to reduce the pressure for most people.
Where does the medical profession stand on this challenge?
For a hundred years, or more, medicine has focused mainly on symptom management. With Parkinson’s, people often said, ‘We already have symptom treatment, so why do more?’ This is basically an ostrich way of thinking and patients deserve better. Fortunately, patients and their organisations are now applying pressure. Through your charity, you have also shown how important awareness is, not only for patients, but for society as a whole.
How has the approach to Parkinson’s developed over the years?
We have known each other for a long time and have seen the evolution in the field together. The awareness around Parkinson’s and the wider impact has grown tremendously. You have done a fantastic job of reducing the taboo around Parkinson’s and confronting people with the reality: it could happen to you tomorrow. But you also show that a diagnosis is not the end. That is a powerful message, and it is essential.
Why is philanthropy so important?
Philanthropy is indispensable. The pharmaceutical industry is often focused on safe profits and invests mainly in research that carries little risk financially. Parkinson’s received little attention for a long time because it was felt that there was already a good treatment for it. The little money there was for research into neurodegeneration has for a long time only gone into (researching) Alzheimer’s. But now we are seeing a tipping point, thanks in part to the work of the Michael J. Fox Foundation and organisations like yours. But also, look at Alzheimer’s: for the first time, two phase 3 trials have proven that a disease process can be influenced. That proves that neurodegenerative diseases, like Alzheimer’s, but also Parkinson’s, can be treated causally, if only we invest enough in (researching) them.
Where should that money go?
It should be better spent. Too much research is being done now that yields little. We need to be harder on each other and focus on what really makes a difference. For Parkinson’s, we need to do 10, even 20, times as much to get to the same level as cancer. In fact, there are as many patients with neurodegenerative diseases as with cancer, but the attention and resources are much smaller. And yet the ‘rate of failure’ in clinical trials in cancer and neurodegeneration is about the same. This shows that the challenge is enormous, but that we should also not be afraid of failure: it’s part of the deal if you want to make progress.
Do you have hope for the future?
Sure. What we are learning in Alzheimer’s is inspiring. It has proven that we need to stop thinking in terms of ‘fighting symptoms’, but that causal treatments are possible. Parkinson’s needs to make that same leap. Together with you, researchers and patient organisations, we can make that progress. It’s a big challenge, but it’s also an opportunity. And as I often say, hope is exactly what patients and carers need.