Can you remember what you dreamt last night? Research has found that people who don’t remember their dreams may experience cognitive decline twice as fast as those who do.
A study published by Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, studied people aged over 60 and found those who have poor dream recall are more likely to be carrying the APOE ε4 gene — the biggest genetic risk factor for Alzheimer’s.
They were also found to have higher levels of the p-TAU 217 blood marker, which detects Alzheimer’s disease, the most common form of dementia.
Alzheimer’s disease causes progressive damage to the brain, resulting in problems with memory, cognition, social engagement, and, ultimately, a person’s ability to care for themselves.
The Australian Institute of Health and Welfare (AIHW), estimates between 400,000 and nearly 500,000 Australians are currently living with dementia, with Alzheimer's disease accounting for over 70 per cent of these cases.
Lead author and research fellow at the University of NSW’s Centre for Healthy Brain Ageing, Dr Darren Lipnicki, said the findings point to dream recall as a potential early indicator of Alzheimer’s.
While some of the participants were not able to remember their dreams, their active memory levels were reported to be normal.
"This isn’t just about forgetting dreams," Lipnicki said.
"It may indicate that the brain is producing fewer or less vivid dreams in the first place due to early neurodegenerative changes."
Lipnicki said changes to dream recall may reflect disruption in the brain’s default mode network, which is most active when a person isn’t doing anything.
"It involves things like self-reflection, daydreaming and imagination, particularly during rapid eye movement sleep, and is therefore responsible for dreaming," he said.
Because dream recall is measured by a yes or no question, it may be easier to identify Alzheimer’s risks much earlier than current methods.
"If someone notices they’ve stopped remembering their dreams later in life, it may be worth paying attention," Lipnicki said.
Data from more than 1,000 adults aged 60 and over was evaluated as part of the study, which tracked participants across a decade.
The research comes as another study from Lipnicki last month revealed adults aged 60-69 who reported experiencing disturbing dreams such as nightmares and "bad dreams" had nearly four times the risk of developing dementia compared to those who didn’t.
The study, which surveyed 10,000 adults aged 60 to 89 across Brazil, China, France, Italy, South Korea and Taiwan, found that among men, those who had disturbing dreams at least once a week were associated with three times the risk of developing Alzheimer’s disease.
But Lipnicki said it was important to emphasise that not everyone who experiences disturbing dreams would go on to develop dementia.
He hoped the findings from his studies would inspire researchers to further investigate and understand dream recall in the context of Alzheimer’s.
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