Findings of REM sleep research could help Australians be diagnosed with Parkinson's disease sooner

Wendy Merrington's father, uncle and grandmother all lived with dementia.

She's hoping to get an early insight into whether she, too, could develop the neurodegenerative condition or Parkinson's disease.

Ms Merrington is one of around 3,000 Tasmanians taking part in a rapid eye movement (REM) sleep behaviour disorder study and its link with dementia and Parkinson's disease.

"I've had a couple of incidences where I've woken up and thought I've acted out my dreams," Ms Merrington said.

"I've kicked the cat off the bed a couple of times.

"I have had an episode when I have been asleep on the plane and I must have been dreaming that I wanted to change the touch screen. And when I woke up there was no touch screen there, and my neighbours were looking at me strangely. So, I was actually acting that out."

People with REM sleep behaviour disorder usually have vivid dreams that they act out in violent ways, including kicking and punching.

Sleep scientist Samantha Bramich and researcher Jane Alty are behind the research project.

They hope their findings could help Australians be diagnosed with Parkinson's disease or other neurodegenerative conditions earlier and delay their onset.

"There has been a lot of research done in the area of REM sleep behaviour disorder in Europe and America," Ms Bramich said.

"They've found that about 80 to 90 per cent of people with this REM sleep disorder will go on to develop dementia, Parkinson's disease or another neurodegenerative disease in later life.

"So, it looks like it is an early symptom or neurodegeneration, but we don't know whether there are lifestyle risk factors that can modify this trajectory and hopefully prevent people from going on to develop these disorders.

"That's where our research is trying to find out more about it, so we can hopefully improve the lives of people who have this disorder and prevent them from developing these things later in life."

Ms Bramich said the first stage of the research was determining how many Australians actually had REM sleep behaviour disorder.

"We think that it might be about two per cent of people worldwide, but there's never been any prevalence studies done in Australia or Tasmania," Ms Bramich said.

"We're also looking at different features and characteristics of people with this sleep disorder that influence why they go on to develop other diseases.

"We think that factors such as smell loss or changes in sleep patterns can have an impact on the development of dementia and Parkinson's disease so we'd like to have a look at those in our participants and see what we find."

As part of the study, participants have been sent scratch and sniff cards to help inform researchers of their smell senses.

They will soon be sent actigraphy watches to track their sleep, and then participants who have high indicators for REM sleep behaviour disorder will go on to have full-home-based sleep studies.

Ms Bramich hoped the sleep study research would be completed late in 2024, and then researchers would monitor long-term neurological changes in those with the condition.

Allan Stent was diagnosed with Parkinson's 15 years ago and in recent years, has been diagnosed with REM sleep behaviour disorder.

His wife Sandra notices the disorder more than he does.

"Allan doesn't really remember that he's had the dreams or that he's called out," Ms Stent said.

"With the sleep, he cries out. It's like a blood-curdling cry, as if someone is chasing him or hurting him. But other times, he's in a dream where he's laughing.

"And he flails. His hands go out or he jumps or his legs flick up, but then he settles down and goes straight back to sleep.

"It's exhausting for Allan but it's also exhausting for me because I'm always waking up."

In Mr Stent's case, his REM sleep behaviour disorder diagnosis came years after his Parkinson's one.

"But I do believe the Parkinson's now is causing it [REM sleep behaviour disorder] and it's very often," Mrs Stent said.

Mr and Ms Stent said they would love to see people diagnosed with Parkinson's disease much earlier.

"Allan was not diagnosed and [was] then under-medicated for a long-time," Ms Stent said.

Ms Bramich said moving forward Tasmania also needed easier methods to diagnose REM sleep behaviour disorder.

"Currently to be diagnosed with REM sleep behaviour disorder you need to have a sleep study to measure things overnight," Ms Bramich said.

She said sleep studies were often difficult to access and hoped other clinicians could soon use home sleep tests, similar to what is being used in this study, to make sleep study tests more accessible.

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