Accidentally kicking your partner or falling out of bed in the middle of the night might seem like something to laugh about in the morning. But dramatic sleep movements might actually be a sign of a more serious sleep disorder called REM sleep behavior disorder, or RBD.
RBD is becoming increasingly recognized, and it’s a focus of intense investigation in the sleep research community. Though fascinating, RBD can be a potentially serious condition.
RBD is a parasomnia — a sleep disorder characterized by unusual and undesirable physical events or experiences that disrupt slumber. The term “parasomnia” is derived from the Greek “para” meaning “alongside of” and “somnus” meaning “sleep.” Parasomnias involve complex, seemingly purposeful, goal-directed behaviors with reduced consciousness.
[Read: Sleep Reset: Getting Your Sleep Back to Normal.]
What Is REM Sleep?
Rapid eye movement, or REM, sleep is one of two deep sleep stages. The other stage, non-REM sleep, can also be called slow wave sleep, or SWS. We spend about 25% of the night in REM sleep, known as the dreaming stage.
REM sleep is characterized by high brain activity, comparable to the level of brain activity while awake, and is important for consolidation of memory and learning. REM sleep is associated with skeletal muscle paralysis, also known as atonia (lack of muscle tone). Muscle atonia or paralysis is a protective biological mechanism that prevents us from acting out vivid dreams and getting injured or injuring those around us in REM sleep.
[Read: What to Do When You Can’t Sleep]
When Sleep Goes Wrong
For some people, this biological protection mechanism doesn’t work. People with RBD have a lesion of sorts in a very specific part of the brainstem, the part of the central nervous system that connects the cerebral cortex to the spinal cord. This lesion prevents muscle atonia during REM sleep, essentially releasing the skeletal muscles to act out.
Because of this, bed partners of people with RBD often report kicking, punching, arguing or screaming in sleep, behaviors that appear self-protective. When awoken, those affected typically remember dreaming about being attacked or chased, or trying to protect a loved one from an attack. Some of these complex behaviors lead to physical injury as the person falls out of bed or attacks a bed partner misconstrued as a villain.
Just this week I met a patient with RBD who sustained a subdural hematoma (bleeding on the surface of the brain) that required surgical evacuation from hitting his head on the bedside table as he fell out of bed during an RBD attack. Events typically occur later in the slumber period, often between 2AM and 4AM when REM sleep predominates.
[See: Steps to Fall Asleep Fast.]
RBD and Neurological Disorders
However, not all people with the condition have such dramatic night moves. Rather, most have low-level vocalization or unintelligible speech with subtle twitching of the arms or legs that do not wake the individual or bed partner. These more subtle behaviors and movements are much more common than the more aggressive ones that bring the house down. This is the primary reason why RBD is so underdiagnosed.
The prevalence of RBD is approximately 1% in the general population, but this is thought to be a gross underestimate. Over 90% of cases are in men. It can be a precursor of a group of neurological disorders called the alpha-synucleinopathies, the most common being Parkinson’s disease.
Unfortunately, most people with RBD confirmed by sleep laboratory testing will develop one of these conditions within 10 to 15 years of onset. Researchers are actively working to better understand this relationship and identify ways to prevent its progression.
Causes and Testing for REM Sleep Behavior Disorder
RBD is the only parasomnia that requires confirmation in a sleep laboratory. Sleep studies for suspected RBD require sensors on the arms and high-resolution video and audio with special attention to muscle signals during REM sleep. An in-laboratory sleep study, known as a polysomnogram, or PSG, can also identify potentially related or alternative diagnoses including obstructive sleep apnea and non-REM parasomnias.
People with OSA can wake up abruptly from REM sleep due to airway blockage and experience vivid dream recall and movements that resemble RBD. This is known as “pseudo RBD” since the behaviors and motor activity resolve with treatment of sleep apnea. OSA affects over 30% of older men, making it substantially more common than RBD.
RBD is also observed in people with narcolepsy, autoimmune encephalitis, multiple sclerosis and strokes or malignancies secondarily involving the brainstem. In these cases of “secondary” RBD, the progression to Parkinson’s disease or another neurodegenerating condition is much less of a concern.
RBD can also be induced by certain medications, most notably, drugs used in the treatment of mood disorders. Withdrawal of the inciting medication resolves the parasomnia. Discontinuation of any prescription medication should be done under the guidance of the prescribing health care provider. Finally, the disorder has been known to occur due to abrupt withdrawal of alcohol and certain medications.
Other Causes of Sleep Disruption
Parasomnias of REM and non-REM sleep may coexist, complicating the diagnosis. While the non-REM parasomnias typically present in childhood, they can arise at any age. These are abnormal arousals from deep non-REM sleep that tend to run in families. In contrast to RBD, non-REM parasomnias usually occur in the first third of the sleep period. During these episodes, people rarely recall dreaming — a key differentiating factor from RBD.
The most common non-REM parasomnias include:
— Confusional arousals. Affected individuals typically sit up in bed and appear confused. Speech may be slow and slurred and responsiveness blunted.
— Sleep terrors. These events are characterized by intense fear and autonomic system activation (heart rate and respiratory rate increases, dilated pupils, sweating and screaming). Affected individuals are not consolable and have no idea what transpired in the morning.
— Sleepwalking. By definition, this parasomnia involves more complicated movements and behaviors leading to ambulation out of the bed that can lead to significant injury. One of the first parasomnia patients I ever met as a sleep doctor had jumped out of a window while dreaming the house was on fire, and he broke both legs.
Rarely, sleep-related seizures and psychiatric disorders of the dissociative type can cause events that mimic RBD.
Treatment for REM Sleep Behavior Disorder
Treatment of RBD includes education, implementation of safety measures and medications when events are frequent or injurious. There are no Food and Drug Administration-approved medications for the condition. However, clonazepam (a benzodiazepine drug), melatonin and pramipexole (a dopamine agonist agent) have all been proven to be effective at reducing events in some cases. The decision to treat with medication should take into account other medical and sleep disorders and medications (i.e. clonazepam can worsen sleep apnea).
People with RBD should be educated on securing the sleep environment. Here are a few suggestions:
— Consider moving the mattress to the floor for those prone to falling out of bed.
— Consider sleeping in a separate room if your bed partner is at risk of injury.
— Keep the bed away from windows.
— Remove dangerous objects such as firearms, sharp objects and hard furniture from around the bed.
— Use cushions or pads to cover sharp corners of surrounding furniture.
Finally, most but not all people with RBD want to be informed of the risks associated with the diagnosis including the potential for neurodegeneration. Clinical trials tracking RBD patients are available in many sleep programs around the country. If you or a loved one has symptoms of RBD or another parasomnia, talk with your doctor or get a referral to a sleep center.
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What to Know about REM Sleep Behavior Disorder originally appeared on usnews.com
