During Australia’s Sleep Health Week, CogSleep, in collaboration with the Sleep Health Foundation and Monash University, conducted a panel event featuring five experts to explore sleep’s role in brain aging and its connection to dementia.

The panel was moderated by broadcaster Jon Faine.

Some of the most exciting research on preventing cognitive decline is focused on sleep, says professor Sharon Naismith, DPsych, chief investigator of CogSleep (Centre for Research Excellence to Optimise Sleep in Brain Ageing and Neurodegeneration) from the Brain and Mind Centre at the University of Sydney. “We now understand that 10 to 20 years before someone even presents with clinical symptoms, changes in the brain leading to dementia are already occurring,” she says in a release. “If we can target sleep early enough as a risk factor and find better ways to screen for sleep disturbance, potentially we may be able to delay the onset of dementia or reduce the cases of dementia.”

What Is Sleep Good For?

“Sleep is really critical for memory consolidation,” visiting Harvard Medical School professor Charles Cziesler, MD, PhD, told the panel, according to a release from Monash University. “It’s really at the beginning of the night, when you’re in deep, slow-wave sleep, that you will consolidate what you learn.

“In the latter part of the night, rapid eye movement (REM) sleep is associated with vivid dreaming and emotional regulation. That’s when you integrate what you learned today, with everything else you’re already doing. That’s when you have your creative thoughts, and you can rise above the individual pieces of information to solve problems.”

Over the past decade, researchers have begun homing in on the brain’s waste processing system. Professor Amy Brodtmann, PhD, of the Monash Clinical School, says in a release that the glymphatic system cranks up at night to clear proteins that are innocuous enough unless they’re allowed to build up. 

“It’s believed that if we don’t have a normal glymphatic rinse cycle each night, that may be contributing to the plaques and tangles that are a feature, pathologically, of Alzheimer’s disease,” she says in the release.

Is It Actually Dementia?

Brodtmann says one of the most common reasons people visit a memory clinic is not because they suspect dementia, but because they are living with depression or anxiety. All of these conditions are intimately related to sleep, and several conditions are associated with altered REM sleep, including Parkinson’s and Lewy Body disease.

“Neurologists will ask a lot about sleep,” she says in the release. “Depression and anxiety are the commonest causes of sleep disorders in our society, and they are ones that can be easily treated. We know that when we treat depression and anxiety, your sleep gets better, your mood gets better, and then your cognition gets better. So it’s one of the few times that we can actually cure someone with what looks like a dementia or a cognitive disorder,” she says in the release.

The Importance of Treating Sleep Apnea

Czeisler says it is also important to rule out sleep apnea or sleep-disordered breathing. “There’s tremendous overlap between obesity and sleep apnea,” he says in a release. 

It is rare for someone who’s overweight or obese not to have sleep apnea, but about 20% of people are unaware of their condition, according to a release from Monash University.

“Sometimes when that sleep apnea is treated, it turns out that the individual does not have the early stages of dementia or neurocognitive impairment but they actually have a sleep disorder,” he adds in the release.

Sleep: Dementia’s Canary in the Coalmine

Dementia Australia ambassador professor Kathryn Moyle, PhD, said the first obvious sign of her partner’s frontotemporal dementia was that he was sleeping 18-20 hours a day. The stress caused by the disruptions to her own sleep from her partner’s nighttime wakefulness was a major factor in her decision to retire.

Moyle says her experience has shown the importance of carers and clinicians understanding the journey of dementia, “that the symptoms change over time, and it’s important to understand that what we see today in one person may be different in a year’s time,” she says in a release.

CBT-I and Digital Interventions

Many general practitioners are unaware that cognitive behavioral therapy for insomnia (CBT-I) is the preferred first-line treatment for sleep problems, endorsed by the World Sleep Society, with input from Monash researchers.

CBT is expensive and not everyone responds to it. Monash researchers are also looking at digital interventions to help carers and people living with dementia.

“There’s a whole gamut of solutions on the market, but not all of them are evidence-based,” says associate professor Melinda Jackson, PhD, of the School of Psychological Sciences, in a release. Her research partnership with A Mindful Way is currently seeking older adults to take part in a trial that will evaluate sleep, mental health, and cognitive outcomes.

“A lot of people will finish a course in CBT-I and still have rumination and overthinking before bedtime. Mindfulness can give you a different relationship with those thoughts at night,” Jackson says in a release.

Including Carers at the Center of Research

Shantha Rajaratnam, PhD, professor of sleep and circadian medicine at the School of Psychological Sciences, was surprised when he examined the links between sleep behaviors and the mental health and well-being of adults and caregivers during the COVID-19 pandemic in the COPE project.

“We started this work early in the pandemic when there was a dramatic rise in the need for people to become involved in caregiving…we estimate…about 2.7 million individuals in Australia identify as a caregiver,” he says in a release. “Those individuals, whether they’re caregivers of children or caregivers of adults, have about double the risk of depression, anxiety, fatigue, and burnout, and if they are caregivers of children and adults, it’s about a five times increased risk of those conditions.”

Rajaratnam says the school’s research agenda is shaped by feedback from providers, caregivers, and patients or consumers about gaps in healthcare. “That is why we’re delighted to work with organizations like Dementia Australia because it reflects that critical role, that the individual, the person with the lived experience of the condition will play all the way through right through to the translation,” he says in the release. 

A booklet, “Harnessing the Power of Sleep and Healthy Brain Ageing: A Guide for Older Adults and People Living With Cognitive Decline,” can be downloaded here. 

Photo caption: L-R: Professor Charles Czeisler, associate professor Melinda Jackson, professor Shantha Rajaratnam, Jon Faine, professor Amy Brodtmann, and professor Kathryn Moyle.

Photo credit: Monash University