Why should you have a brain scan to test for dementia when there’s no cure? Knowing can help you delay its onset, neurologist says

This is the second instalment in a series on dementia, including the research into its causes and treatment, advice for carers, and stories of hope.

New research has discovered that signs of dementia can be spotted up to nine years before the symptoms of the disease begin to manifest.

“We have always suspected this might be the case … [In people with genetic types of dementia] you can pick up subtle signs on brain scans years before a formal diagnosis,” says Timothy Rittman, a neurologist who led the research at Cambridge University, in the United Kingdom.

Rittman says he and his team were instead interested to see how early they could pick up these changes in people without a genetic risk of developing the condition.

“There have been lots of studies of treatments to stop or slow down dementia, but many have started too late, as have prevention strategies, like blood-pressure management,” he says.

We should start managing our blood pressure in middle age or earlier – years before any sort of damage might begin.

It’s one of the reasons health screenings are so important – they monitor heart health, and good heart health is thought to contribute to good brain health.

Although it’s not possible to prevent dementia, it is possible to lower the risk of developing it by setting good patterns early in life, Rittman says.

The key is to build your brain’s resilience. Challenge yourself every day to build cognitive reserve – such as staying active, mentally stimulated and socially engaged – and protect against cognitive losses that can occur through age and disease.

Rittman says that healthy cognitive reserve might not prevent the pathology of dementia – the physical changes evident on a brain scan – but may help you withstand them and not go on to develop symptoms that become life-changing.

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Two-thirds of people will exhibit the pathology of dementia on brain imaging by the time they are 80, yet they won’t all outwardly appear to suffer from the condition.

Given there’s no cure for dementia, it can be unappealing to get a brain scan that may reveal signs of a potentially bleak fate.

As someone who has experienced the illness up close with my mother, I’ve considered numerous times whether to go for a screening.

Lizzie Perry founded London-based dementia awareness platform This is Dementia after her father was diagnosed with frontotemporal dementia – an uncommon type of dementia that causes problems with behaviour and language – at just 58.

She says that “as there are no cures, I would rather not know, and instead live my life as healthily as possible to reduce the chances of an illness like this developing due to my own lifestyle choices … Then, if anything happens down the road, I know I did what I could to lead a long and healthy life,” she says.

Rittman appreciates that asking people whether they want to know if they’re at risk of having dementia without being able to offer treatment of proven efficacy will result in “a 50-50 split between yes and no”.

However, the neurologist thinks that learning about people’s risk of dementia is important.

The nine years found to potentially elapse between the pathology of dementia becoming evident and the manifestation of symptoms provides a window in which people can be recruited into trials.

This will enable neurologists to gain further understanding of prevention strategies and to develop drugs to slow the disease down “at a time when those interventions are most likely to be effective”.

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There are increasing numbers of trials of this kind. The National Institute on Ageing, in the United States, is currently supporting 459 active clinical trials on Alzheimer’s disease and related dementias.

What’s more, the US Food and Drug Administration has just licensed the new drug lecanemab, which has been shown to moderately slow cognitive and functional decline in early stage Alzheimer’s.

Despite the medication not being an outright cure for dementia – as well as having unpleasant side effects – the fact it has any effect at all on Alzheimer’s is, Rittman says, something that will hopefully encourage drug companies which have stopped work on neurodegeneration to take it up again.

“It’s good to see drugs being tried and different strategies implemented, like targeting inflammation in the brain, which in the last five to 10 years has really crept up the agenda,” he says.

Rittman points out that rates of dementia in the population are – thankfully – decreasing. There are more people with dementia because we live longer, but the percentage of sufferers is falling – something attributed to people smoking less and living healthier lives, as well as to rising rates of education.

So what would he say to a person who was told they were developing the pathology of dementia?

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“I’d urge them to get involved in a clinical trial and sign up for research to help us understand what’s going on in the brain.”

The neurologist adds that he would ask them what their priorities for life were, encourage them to keep doing what they enjoy doing, and to have as fulfilling a life as possible for whatever lay ahead.

Good advice in general, really.

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