REM can foreshadow dementia
A little-known and poorly understood sleep disorder that occurs during the rapid eye movement, or REM, stage of sleep has been garnering attention for its role in foreshadowing neurodegenerative brain diseases such as Parkinson’s disease and dementia with Lewy bodies.
The disorder, known as REM sleep behavior disorder, or RBD in the medical field, affects around 1 percent of the general population worldwide and about 2 percent of adults over 65, sciencealert.com wrote.
“Every night, you go through four to five sleep cycles. Each cycle, lasting about 90 to 110 minutes, has four stages. That fourth stage is REM sleep,” Anelyssa D’Abreu, a neurologist who specializes in geriatric neurology, said.
She said REM sleep only comprises 20 percent to 25 percent of total sleep, but its proportion increases throughout the night.
She added that during REM sleep, your brain rhythms are similar to when you are awake, your muscles lose tone so you are unable to move, and your eyes, while closed, move quickly. This stage is often accompanied by muscle twitches and fluctuations in your respiratory rate and blood pressure.
D’Abreu said the disease mechanism is not well understood and in some cases of REM sleep behavior disorder, a clear cause cannot be identified.
She noted that in other cases, the disorder may be caused by something specific, such as obstructive sleep apnea, narcolepsy, psychiatric disorders, use of antidepressants, autoimmune disorders, and brain lesions, which are areas of damaged brain tissue.
D’Abreu said for most neurodegenerative disorders, there is a phase that may last for decades in which brain changes are taking place but the patient either remains asymptomatic or develops symptoms without the full expression of the disease. RBD, in that scenario, is an early sign of those disorders.
“This provides an opportunity to study how the disease progresses in the brain and to develop therapies that could either slow this process or prevent it from happening.
“At this time, there are no approved therapies to prevent the onset of these neurodegenerative diseases in those with REM sleep behavior disorder. There are, however, medications such as melatonin and clonazepam that may improve the symptoms,” she said.