This is a bizarre or a fascinating sleep disorder, depending how one takes it, or if it frightens or intrigues the patient, and the bed partner. In this condition, a sleeping person acts out, usually suddenly and violently, by kicking, or shouting like fighting someone, or running away from danger, in a panic; in fact, just acting out a dream. The sleeping partner may get distraught, or hurt from a kick or a fist flying off this unusual commotion.  Patient may easily be brought back to reality, but in a perplexed state and no explanation of what just transpired. Research has shown that this odd behavior occurs during REM stage of sleep, the stage when we usually have dreams.

What are different stages and cycles of sleep?  

Sleep stages: Sleep is divided into four stages: N1, N2, N3, and REM. The letter N stands for non-REM sleep. It typically starts with getting drowsy followed by light sleep when we are still somewhat aware of our surroundings. This is the N1 stage of sleep. As we go deeper into sleep, we completely lose awareness of our surroundings by entering into N2 sleep. After that is N3 sleep, which is deep sleep and, if someone tries to wake us up, it is little difficult to come out of it. The next stage of sleep is REM sleep, which sometimes is also called paradoxical sleep. This is because our brain, if we check its electrical activity during this stage, seems to be awake but we are not. In this stage, our eyes flicker or move rapidly, so is the name of REM (rapid eye movement) sleep. I described these stages in these simple descriptive terms, though in practice, stages are determined based upon changes in brain’s electrical activity, or EEG. Sleep stages are in a continuum, meaning that N1 is followed by N2, to N3, and then REM sleep; but there may not be much or any N3 sleep during later parts of the sleep, while the duration of REM sleep increases with every passing cycle of sleep.

Sleep cycles: As we go into sleep, we start with N1 sleep that may last for a few minutes. It leads to N2 sleep, which may continue for 30-60 minutes. After that we may enter into N3 sleep, which may last for 10-30 minutes. Finally, we enter into REM sleep that may last for 10-20 minutes. The whole set of N1, N2, N3 and REM sleep stages lasts for about 90-120 minutes, and is called a sleep cycle. As one cycle ends, we go into another similar cycle, and before we wake up, we may have gone into one or two more cycles of sleep. Most of the deep sleep occurs in the first or early cycles, later replaced by N2 sleep. Also, the amount of REM sleep increases in later parts of sleep.

Sleep quality: Quality of sleep is a measure of different stages of sleep. In a good quality sleep, we go through normal amount of different stages of sleep. An example of a poor quality sleep is to have minimal or no N3 (deep) sleep.

Sleep efficiency: Efficiency of sleep is a measure of the amount of time we are asleep compared to the total amount in the bed. Sleep efficiency is considered excellent when a person is asleep more than 90% of sleep time. Efficiency of sleep declines if, while in the bed for sleeping, one spends less time sleeping and more staying awake.

What normally happens during REM sleep?

REM sleep is a relatively lighter stage of sleep. It comes at the tail end of each sleep cycle, and more so in morning hours. It is understood that memories are handled and cataloged in this stage, especially the ones with emotional undertones. It is also the stage when dreaming can occur, especially dreams with emotional undertones. Some of these dream situations can be emotional enough to wake the person up, like a fearful or a sexual encounter. Even in normal situations, these arousals can be so vivid that we may never forget them. REM sleep is actively turned on and off in the brain. When on, another circuitry that controls motor activity of body is disabled, so in normal circumstances we do not act out our dreams, at least not the way it happens in RBD.

Where exactly is the problem in REM sleep behavior disorder?

There is enough animal and human data to suggest that the physical location of abnormality in RBD is a small area of brainstem part of brain. Neuronal degeneration in this area disturbs the delicate balance of REM sleep, which keeps us having dreams but without our body acting them out. The degeneration of neurons is caused by accumulation of a protein called alpha-synuclein. At this time, technology is not available to define this abnormality by imaging. Hopefully, as technology improves, we may be able to find better and cheaper functional imaging methods. Our present understanding is the result of animal experiments, autopsy studies, and functional MRI studies. Though, most cases of RBD are caused by degeneration of neurons, some other causes inflicting damage to the same neurons and causing RBD are stroke, multiple sclerosis, or a tumor. Finally, deficiency of hypocretin (orexin), which typically causes narcolepsy, may also cause RBD.

Does having RBD increase chances of getting Parkinson disease?

This is true; it increases that chance but not everyone gets it. The type of pathology causing RBD (accumulation of alpha-synuclein in neurons) may also cause many other neurological diseases, such as Parkinson disease, dementia with Lewy bodies, and multi-system atrophy. In fact, majority of patients diagnosed with RBD may develop one of these conditions. The risk is higher if the patient also has chronic constipation and unexplained loss of sense of smell.

How is RBD diagnosed?

It has particular history that may suggest RBD. For a proper diagnosis, an overnight sleep study with video monitoring is required to make sure it is what it is.

What other conditions may look like RBD?

Examples of some other conditions that may cause somewhat similar symptoms are seizure disorder, obstructive sleep apnea, periodic limb movement disorder of sleep, and restless leg syndrome.

How is RBD treated?

Following measures are recommended:

A: Remove any object from the bedroom that may be used as a weapon, such as a picture frame, a lamp, or a weapon.

B: Keep sleeping place away from stairs or height to avoid any injury.

C: Separating the patient’s bedroom may be a safe measure for the spouse, but its benefit should be compared to its impact on the couple’s relationship. Also, in some situations, the partner may quickly wake the patient and break the dream.

D: If above measures are not enough or fail, a medicine is prescribed. Melatonin can be tried first, 3-6 mg at bedtime.

E: Clonazepam 0.25-1mg at bedtime can also help.

F: There are some other medicines that can be tried, if melatonin or clonazepam do not work. The list includes other benzodiazepines, donepezil, remelteron, dopamine agnoists, gabapentin, or sodium oxybate. Choice of medicine may depends upon patient’s other conditions.

G: Proper counseling. Because of its relationship with other brain diseases, proper patient and family counseling is warranted. It starts with education and addressing relevant issues in a measured and compassionate manner. 

Where can I get more information about RBD?

American Academy of Neurology

American Academy of Sleep Medicine