The Woolcock Institute of Medical Research

Most people associate Parkinson’s with an uncontrollable shake or tremor, but sleep can be one of the earliest warning signs of the disease. Associate Professor Elie Matar spoke to 2GB’s Healthy Living segment about the link between sleep and neurodegenerative conditions.

Parkinson's is a growing problem for our ageing population, with 200,000 Australians living with the disease. It’s also the fastest growing neurological condition worldwide. Over the past 20 years, research has expanded dramatically, shifting from symptom management to investigating the biological mechanisms driving the disease, early detection and therapies that may slow or modify the course of the disease.

“When most people think of Parkinson's they think of the tremor, stiffness or difficulty walking but one of the major shifts in the field is that we understand that it is much more than a movement disorder,” said Associate Professor Matar. “It actually affects a number of systems around the brain and body and can begin in these other systems years, sometimes decades, earlier.”

Research has found that one of the clearest early warning signs, possibly the earliest warning sign, is REM Behaviour Disorder (RBD).

REM (Rapid Eye Movement) is the phase of sleep when you have most of your dreams and when your body should be most still. People with RBD, however, may talk, shout, thrash about, move vigorously or hit out during REM sleep. They often report that their dreams are violent or aggressive.

“Normally when we dream or we are in REM sleep,” Associate Professor Matar explained, “the brain switches off the muscles so we don’t act out our dreams. In this condition, that safety switch fails and people may shout, punch, kick, fall out of bed and physically act out their dreams.”

Associate Professor Matar, a member of the Woolcock’s Sleep and Circadian research group and neurologist in the Woolcock Clinic, is leading a team at the University of Sydney studying the link between sleep and neurodegenerative conditions. They’re focusing on a region of the brain called the locus coeruleus and investigating sleep disruption as a driver, not just a symptom, of Parkinson’s.

“One of the reasons we're studying the locus coeruleus (called the blue spot because it looks a bit blue under the microscope), is that it sends signals widely across the brain and helps regulate how awake, alert and responsive we are. It’s closely linked to sleep and wakefulness, attention and other cognitive aspects. Our study is looking at how early damage in this region could lead to some of those early sleep symptoms that could be a warning sign for Parkinson's and explain some of the symptoms so that addressing and reversing the damage might also help improve the symptoms of the disease.”

The study also looks at how Parkinson’s interacts with Alzheimer’s-related changes.

“It’s very rare for people to pass away with just one pathology in the brain. Now, Alzheimer’s and Parkinson’s are the two most common neurodegenerative diseases of ageing and they’re often mixed in people as they get older. One might be driving the symptoms more than the other but we’re now learning that thinking of these together is really important because they can actually work synergistically. It could be that some patients may benefit from treatment of the other once we have good treatments for both.

Parkinson’s Disease has been found to be more closely linked with Lewy Body Dementia than Alzheimer’s.

“Lewy Body Dementia is a type of dementia that presents with a range of additional symptoms including movement problems, hallucinations, fluctuations with memory and thinking shifts day to day but importantly, also their sign of acting out dreams during sleep. But, half the people with Lewy Body Dementia also have some Alzheimer’s-related changes so we think that those Alzheimer’s-related changes are important with how this disease progresses. And the same thing for people with Parkinson’s who go on to develop dementia. So, we do need to think about those in parallel.”

Associate Professor Matar believes the work they are doing – using actigraphy throughout the day and night, MRI, in-lab and home sleep studies – will help identify early warning sleep changes.

“Once we combine all of that data, we will be able to figure out what are the cues that clinician could use to help inform the risk of someone going on to develop on of these conditions and, hopefully, ultimately act early to reduce their chances of developing it.”

“We want to move towards identifying individuals early in the disease course and preventing brain cell loss at that point.”

Find out more

• REM Behaviour Disorder
• The Woolcock NeuroSleep Clinic
• Our Neurologists