Sir Jackie Stewart's son on the impact of dementia

The son of legendary racing driver Sir Jackie Stewart has said it has been "awful" to see his mother become "no longer the person" he knew because of dementia.

Mark Stewart said his mother, Lady Stewart, was "constantly getting worse over time" because of the condition, which she has had for the past 12 years.

It comes as the family's charity, Race Against Dementia, launch a world-first clinical trial alongside the University of Oxford to help stop the condition developing.

The study is testing the use of ultrasound to improve cognitive function for people living with Lewy Body Dementia.

"One thing that we should have left is our memory, and our ability to recall our lives and the achievements and all the things that you've done together," Mark said.

"These moments are erased, they're no longer in their minds and you're unable to discuss them anymore because that's dementia, and it's just awful."

Lady Stewart was diagnosed with dementia in 2014, with Sir Jackie previously telling the BBC that it had led to "horrendous" behaviour and language changes - including forgetting who he was.

"She's still been pretty cheerful at times but very aggressive at others, and it's no longer the person that was the matriarch of our family - it's no longer that individual," Mark explained.

A decade ago, three‑time Formula 1 World Champion Sir Jackie started Race Against Dementia to speed up progress towards a world without the disease.

"I love that out of the box thinking and that Formula 1 mindset - they're constantly looking at new ways of doing business," Mark, who is the chair of the charity's trustees, said.

"That mindset is so incredibly important to what Race Against Dementia does - we are not just looking for cures, but prevention."

As part of its work, the charity has launched a new study alongside the University of Oxford to investigate whether focused ultrasound waves could help treat symptoms of Lewy Body Dementia.

There's currently no cure for the condition, and options to manage symptoms or slow its progression are very limited.

Dr Ashwini Oswal, who is leading the trial, explained: "What we're going to be doing is testing whether ultrasound can be used in a precise manner to stimulate areas [of the brain] that aren't working so well with Lewy Body Dementia."

Although most people would associate ultrasound with pregnancy scans, Dr Ashwini said the "very same technology" could be used to stimulate tissues.

"What we're really hoping is that we can provide some degree of hope for people that there are trials for treatments, but of course there's no guarantee that this will work," he added.

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