What is REM Behavior Disorder?

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REM sleep behavior disorder (1) is a parasomnia, a disorder that causes abnormal behavior as you sleep. Your brain normally keeps you immobilized during vivid rapid eye movement (REM) stage dreams, but people suffering from REM behavior disorder act out their dreams with complex movements and vocalizations.

Those with REM sleep behavior disorder don’t have conscious control over their physical movements as they dream. This lack of control can result in injury to the sleeper or their sleep partner. We’ll explore how REM behavior disorder (RBD) affects the normal stages of sleep, who’s at risk, and what to expect when seeking diagnosis and treatment.

What Does Normal REM Sleep Look Like?

Healthy sleep architecture involves two types of sleep (2), rapid eye movement, or REM sleep, and non-rapid eye movement, or NREM sleep. NREM sleep has three distinct stages. With each stage, you fall into a deeper and deeper sleep.

  • Stage 1 occurs as you’re falling asleep and transitioning from wakefulness to sleep.
  • Stage 2 is a period of relatively light sleep in which your heartbeat, breathing, and brain waves begin to slow.
  • Stage 3 represents deep restorative sleep that allows your body and brain to recover and rejuvenate

REM is sometimes referred to as stage 4 sleep because it follows stage 3 of NREM sleep. During REM sleep, your breathing and heart rate increase close to levels during wakefulness. Your brain becomes more active and your eyes flutter rapidly.

Your most vivid dreams occur during REM sleep. Dreams can be exhilarating and even terrifying, but your brain has a mechanism called muscle atonia to keep you paralyzed and prevent you from acting out your dreams in the physical world.

After REM, we begin another cycle through the stages of sleep. Most people go through four to six sleep cycles (3) in a typical night of sleep, with increasingly longer periods of REM.

How Does REM Behavior Disorder Alter Your Sleep?

As the name suggests, REM behavior disorder affects the REM stage of sleep. When you suffer from RBD, your brain fails to keep your body immobile as you dream. As a result, those with RBD physically act out their dreams with complex movements and talk in their sleep.

Although people with RBD can typically remember their dream upon awakening, the sleeper has no conscious control over their movements while dreaming. Their actions closely mirror the content of their dreams. Dreams associated with RBD are often frightening and frequently involve a theme of chase or attack (4). As a result, the symptoms of RBD can be potentially dangerous to the sleeper and their sleep partner.

Who Is at Risk of REM Behavior Disorder?

REM sleep behavior disorder is somewhat common. About 1% of the population (5) experiences REM behavior disorder, but certain factors can put you at a higher risk.

Two significant risk factors for RBD are age and gender. Approximately 2% of older adults have RBD, twice the prevalence of the general population. Of older adults with RBD, roughly 90% are men (6).

Although older adults are at a higher risk for RBD, younger adults often experience RBD symptoms secondary to other factors. Secondary RBD tends to correlate with other medical conditions such as narcolepsy or antidepressants use.

Up to 36% of people with narcolepsy (7) also experience RBD symptoms. Also, antidepressants (8) potentially bring on RBD symptoms in some people who take them. Researchers have also linked other conditions to a higher risk of RBD, including autoimmune disorders, inflammatory disorders, and demyelinating diseases such as multiple sclerosis (9).

Is REM Behavior Disorder Linked to Other Diseases?

RBD is closely associated with the eventual development of neurodegenerative disorders (10) such as Lewy body dementia, Alzheimer’s disease, and Parkinson's disease. The exact cause of RBD is still unknown, but clinical researchers think that the brain's failure to inhibit motion during REM sleep may be caused by lesions or damaged regions in the brainstem.

Brainstem lesions associated with RBD may be a sign of further damage to come. In one study, more than 75% of patients with RBD were diagnosed with Lewy body dementia, the second most common form of progressive dementia after Alzheimer's disease. Another study showed that about half of patients with RBD (11) were diagnosed with a neurodegenerative disorder within 12 years.

Those with RBD are also more likely to suffer from narcolepsy. Some people with obstructive sleep apnea may also show signs of RBD (12), but these cases don’t usually meet the full criteria for an RBD diagnosis.

How Is REM Behavior Disorder Diagnosed?

If you’re experiencing symptoms of RBD, you’ll need to talk with your primary care physician who can refer you to a sleep specialist. The only way to get a definitive RBD diagnosis is to undergo a sleep study, or polysomnography (13).

A sleep study is a clinical test that allows your sleep specialist to collect first-hand data on your sleep patterns. During a sleep study, a trained sleep technician attaches electrodes and sensors to your body to monitor and record your vital signs as you sleep. These vital signs include your:

  • Eye movement
  • Heart rate
  • Brain waves (EEG)
  • Blood oxygen levels
  • Muscle activity
  • Body position
  • Breathing rate

Your sleep specialist uses the results of your overnight observation to make a diagnosis. The diagnostic criteria for REM behavior disorder include:

  • Complex behavior as you sleep, including movement and vocalizations
  • Behaviors occur during REM sleep
  • REM sleep without atonia (14), meaning a failure to be temporarily paralyzed during REM sleep.
  • No clinical signs of seizure

An in-lab sleep-study is important for an accurate diagnosis because other disorders may mimic the symptoms of RBD. With the results from your sleep study, your sleep specialist can rule out other potential sleep disorders like sleep apnea, neurological disorders like epilepsy, or medications that could be causing your symptoms.

What Treatments Are Available for REM Sleep Disorder?

Once you receive a diagnosis, there are several options for REM sleep behavior disorder treatments, including both behavioral approaches and medication. First, you should modify your sleeping area to reduce the chances of injury.

  • Remove any potential hazards, such as glass objects and bedside furniture
  • Consider a zipped up sleeping bag to reduce limb movement
  • Add bed rails or another barrier to the sides of your bed
  • Pad the floor next to your bed
  • Install a customized bed alarm (15) to interrupt RBD episodes
  • Place your mattress directly on the floor

Your doctor may suggest switching or stopping antidepressant treatment as certain medications can make RBD symptoms worse (16). Severe symptoms may also require medication. Melatonin is usually the first-line treatment. However, it’s imperative not to make any changes to your medication or attempt to self-medicate for this disorder without speaking to your sleep physician.

It’s important to educate your sleep partner on the nature of RBD and its symptoms. If your symptoms are severe, you and your partner can consider sleeping separately. There is no cure for RBD, but with the right treatment, you can ensure a safe, comfortable sleeping environment for you and your sleep partner.

References

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  1. 1. Accessed on March 12, 2021.https://www.ncbi.nlm.nih.gov/books/NBK534239/
  2. 2. Accessed on March 9, 2021.https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-sleep
  3. 3. Accessed on March 9, 2021.https://www.ncbi.nlm.nih.gov/books/NBK526132/
  4. 4. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/20146689/
  5. 5. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/29216391/
  6. 6. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/22726815/
  7. 7. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/15854856/
  8. 8. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/18226952/
  9. 9. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/30150902/
  10. 10. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/17412731/
  11. 11. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/19109537/
  12. 12. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/16171244/
  13. 13. Accessed on March 9, 2021.https://medlineplus.gov/ency/article/003932.htm
  14. 14. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/26446247/
  15. 15. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/22171203/
  16. 16. Accessed on March 9, 2021.https://pubmed.ncbi.nlm.nih.gov/24179289/

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