Lewy body dementia (LBD) affects more than 100,000 people in the UK, with those over the age of 60 facing a greater risk of developing the neurodegenerative disease.
According to NHS Inform, LBD is caused by deposits of abnormal protein called Lewy bodies inside brain cells - these build up in areas of the brain responsible for memory and muscle movement.
Research has shown that movement problems can manifest years before the condition is formally diagnosed, and strike while a person is sleeping.
In 2013, the Mayo Clinic identified a strong link between REM sleep disorder and LBD in their database.
The sleep disorder refers to a person physically acting out vivid, often unpleasant, dreams with vocal sounds and sudden arm and leg movements during REM sleep, explains the medical centre.
Scientists concluded that “the strongest predictor of whether a man is developing LBD is whether he acts out his dreams while sleeping”.
The report stated that “patients are five times more likely" to have LBD if they experience the condition, compared to having other risk factors such as hallucinations and fluctuating cognition.
REM sleep disorder occurs as a result of the loss of formal muscle paralysis that is expected in the REM phase.
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During the REM sleep stage, which happens multiple times throughout the night, the body is supposed to stay still.
It makes up approximately 20 percent of your sleep and it is typically during this sleep phase that a person dreams.
Not only does the disorder lead to lost sleep, but it may also cause injuries to individuals and their sleep partners.
The Mayo Clinic said: “It can appear three decades or more before a diagnosis of dementia with Lewy bodies is made in males,” but this link appears to be weaker in women.
Medline Plus states that it may even be the first sign of dementia with Lewy bodies.
Previous research has shown that sleep problems increase confusion and behavioural problems with LBD and add to a caregiver’s burden.
While the findings suggest there is a strong link between the two conditions, it is important to note that not everyone with REM sleep behaviour disorder will have LBD.
What the early research did find, however, is that as many as 75 to 80 percent of men with LBD in the Mayo database did experience REM sleep disorder.
What are the symptoms of REM sleep disorder?
Aside from making volatile movements and noises, a person with REM sleep disorder is often able to recall their dream when they awaken during an episode.
The symptoms of the disease are often confused with signs of other brain conditions or psychiatric disorders, however.
Anyone who suspects they have the condition is encouraged to speak to a doctor.
The National Institute on Ageing states: “A physician can order a sleep study to identify any underlying sleep disorders such as sleep apnea, restless leg syndrome and REM sleep behaviour disorder.”
