There are a lot of sleep-related neurological disorders, and today, we will be talking about one of them, the RMD. RMD stands for Rhythmic Movement Disorder, which is a neurological condition during which people tend to rock or move their body while they are sleeping, or falling asleep. They do it repetitively, and sounds such as humming can often follow those movements. Although this disorder is more typical for children younger than 5, it can occur in adults as well. The first case of this disorder was written and described in 1905 by Zappert. And although we are more than 100 years away from that moment, we still do not know how to cure it or why it happens because there are a lot of potential triggers. In 1990 the International Classification of Sleep Disorders (ICSD) gave this disorder its name, the rhythmic movement disorder. The vast majority of RMD attacks occurs during the NREM phase of sleep, but there were some cases when it happened in the REM stage.
A Brief History of RMD
When Zapper described these repetitive motions in 1905, he conceived the term jactatio capitis nocturna, and around the same time, Cruchet of France called it rhythmie du sommeil. The usual symptoms such as head rolling, or headbanging were also used to determine this condition until it got its official name in 1990. It was first categorized as a parasomnia, in the subcategory of sleep-wake transition disorders, because these motions usually occurred in the phase of switching between wake and sleep.
In 2005 the disorder was renamed by ICSD to avoid common confusions with stereotypic rhythmic movement which occurs during the daytime. These motions include shaking, head banging, body rocking, self-biting, and they are all repetitive, purposeless actions, which can be potentially dangerous. In the same year, RMD was reclassified under a new nosological category dedicated to sleep-related movement disorders which also includes disorders, such as periodic limb movement, restless leg syndrome, sleep bruxism, leg cramps, etc.
One unusual thing about RMD is that around 60 years before Zappart first described this condition; it was depicted in Walt Disney’s greatest cartoon hits, Snow White and the Seven Dwarfs. This theory was published in 2007 and claims that one of the dwarfs called Dopey was performing these repetitive motions back and forth with his head and producing sounds when he was laying down in its bed. Once someone touched him, he opened his eyes, and the motions stopped, later he happily sighs while falling back to sleep. It is an interesting observation, and although we can only guess what was on Walt Disney’s mind, this theory seems to fit well to what we today identify and diagnose as RMD.
What Causes Rhythmic Movement Disorder?
The exact cause or pathophysiological basis of this disorder is unfortunately still unknown. This condition can strike children and adults, whether they are healthy or not. In some rare cases among the adults, the RMD can be triggered due to stress, head traumas, or herpes encephalitis. There is no proof that this disorder can be related to genetics, although we are aware of few cases in which RMD runs in families, that theory was never researched well enough, and those cases are usually considered for an exception rather than a rule. The vast majority of patients does not have this disorder in their medical family history.
There is a theory that RMD is a form of learned self-defense mechanism to reduce tension, stress, and induce relaxation, something very similar to tic movements.
Since the majority of patients are children, another theory suggests that these repetitive movements are helping the children’s vestibular system to develop, which can be a reasonable explanation because many children whose vestibular system was underdeveloped, benefited from these repetitive movements which are in charge to stimulate the vestibular system.
There is no difference in sex because this disorder strikes boys and girls equally. Body rocking usually starts when infants are only six months old, head banging can be noticed around nine months, and at that age 59% of infants perform either body rocking, head rolling or head banging. But most of these movements go away naturally by the third year of the child’s life.
Although RMD is rare among teens and adults, it can appear if some injury of the central nervous system occurs. In adults and older children, RMD can be connected to mental retardation and autism.
Symptoms of Rhythmic Movement Disorder
People who have RMD experience repetitive movements which are mainly related to the motions of their upper torso. These uncontrolled movements can occur just before falling asleep, or while the sleeper is in the first stage of NREM sleep. These moves may continue into the REM stage, but in those situations, they could be considered as symptoms of REM behavior disorder. Most patients have symptoms which include moving the entire body or head motions when it comes to particular body parts. There are some theories that the body’s sleep position may determine the type of actions that will be performed, but since this disorder is still not researched enough, and we do not know its cause, we cannot also be 100% sure in this.
The RMD “attack” or an episode can last up to 15 minutes, the moves are very rapid and often, repeating every 1 to 2 seconds. In some rare conditions, these episodes can last even for hours. Around 46% of RMD episodes happens only in the NREM phase, 30% in both, REM and NREM, and 22% only REM stage of sleep. During the seizure, it can be hard to wake up those people and make them stop, and in most cases, they will not remember what they did or how did it happen.
The three most common types of moves performed during the RMD episode are:
- Body rocking. Almost every second patient with RMD does this; hence, this is the most common type of movements. As the name itself says, the people who go through this will rock their entire body while sitting or lying down, and it usually happens during the night, but it can occur during the daytime when the patients are tired.
- Head is rolling. Every fourth patient performs this type of moves, and it usually occurs when people are lying on their backs, their head starts rocking back and forth.
- Headbanging is also not so common because only a quarter of patients have this symptom, and it can occur in two situations. In the first one, the patients are sitting upright, and their head is banging against the head of the bead, or the wall. In the second situation, patients are lying on their stomach, and they are hitting their head or entire upper body, by lifting them and banging down upon the mattress or pillow, repeatedly.
All of these three ways of movements can be accompanied by sounds similar to humming, but also by loud noises which are produced as a consequence of head banging. The actions will stop once the patients reach the second phase of sleep, or if something or someone wakes them up.
Besides these primary symptoms, there are also several less common ones, which include body rolling, leg rolling, and leg banging. The humming sound, which often goes hand in hand with these symptoms, can often make your family members worry or stress, which is expected, especially for parents. That is why it is essential that parents inform their close friends, babysitter or other family members, who will perhaps be in a position to stay alone with the child, about what has been going on, how to react, etc.
Other conditions which can be related to rhythmic movement disorder as their possible symptom, cause, or indicator include autism, Tourette syndrome, sleep apnea, Rett syndrome, ADHD, and Angelman syndrome.
Many parents will be able to notice and track the changes in their child’s behavior, in this case, it is crucial to talk with a pediatrician about it to explain how and when the changes in movements occurred. These things can be essential for setting the proper diagnosis since there a few conditions with similar symptoms but with different treatments.
For example, uncontrolled moves of some body parts may be a symptom of a nocturnal seizure. Muscle contractions, also known as dystonia, are very similar in appearance to this disorder. And then there are some sleep disorders which are particularly common among children and can look the same at first glance, such as confusional arousals and parasomnias.
There is also the possibility that the use of particular medication triggers these moves, many children take medicine to treat vomiting, allergies, and even some psychiatric conditions which means that they will be using narcoleptics and antidepressants. In situations like this, it is best to talk with your pediatrician to change the medications and therapy.
Often to be 100% sure in their diagnosis, doctors will ask your child to perform specific tests such as electroencephalogram (EEG), and polysomnogram if they determine that child’s sleep should be examined more thoroughly by performing a sleep study.
It is essential to mention that although this condition is treated as a disorder, most children do not need any professional help since this is considered a somewhat regular part of the development of their sleep process. Anyhow it is always recommended to consult your doctor about any changes or new things you have noticed. If the performed motions caused some injury to your child or prevent him/her from sleeping well, then it is better to consult a sleep specialist. Doctors will want to know several things, when these motions began, and what else has been happening in the life of your child. The best is to prepare for that by creating a two-week long sleep journal in which you will write down exact times of these episodes. This will be extremely helpful to the doctor for setting the diagnose because it will give them some clue about what has been going on. Child’s medical history and potential history of other sleep disorders can also be helpful to doctors.
Unfortunately, there are no tests which can determine this disorder in children. Perhaps if the motions are more severe, the doctor will want to perform an overnight sleep study to measure a child’s heart beats, brain waves, and breathing while he/she sleeps. This sleep study will also show if there is some other sleep disorder involved, such as sleep apnea. Probably the best “sleep study” which parents can do on their own, is to record their child during these episodes or if they notice any unusual moves throughout the night. Medications will be prescribed if these movements are disrupting the child’s sleep or causing injuries.
Although in most cases, this condition will eventually go away on its own, there are some things which can be done to protect the child from injuries during these seizures. You should ensure that your child has a proper sleep schedule and sleep hygiene to prevent aggravation of this condition and sleep deprivation.
More violent and extreme motions can lead to some severe injuries, so it is better to take some measures of safety precaution. For example, placing a second mattress on the floor, right next to the child’s bed will keep him or her safe in case of rolling over the bed as well as setting the pads around the bed. Moving the bed away from walls will protect your child’s head from hitting into the wall, and there are even special protective helmets for headbanging. Installing rails or bed frames will also prevent your child from rolling over if it has the symptom of a rocking body, do not forget to place pads around the rails to minimize the chance of injury. If the bed has a headboard, pad it as well, it will prevent any injuries from banging head. Also, particular body pillows and neck ones can help your child to stabilize its body during the episodes and to induce sleep right after them
Sedating medications can be used to reduce the intensity of movements. One of them is clonazepam, which is usually prescribed for anxiety, but the doctors can also prescribe citalopram which will lower the strength of motions. Some other relaxation therapies have also been provenly efficient in reducing the symptoms.
Usually, the most challenging thing for parents is to observe these situations and remain calm and stress-free, but they are mostly harmless and not as scary as they appear, and children are not much aware or bothered by it. Since most of them will outgrow this condition, it does not require any long-term therapies. However, if it remains persistent, even then it could not be such a big problem for the person going through it if the symptoms are milder.
Rhythmic Movement Disorder Among Children
If you have noticed that your child is performing some motions while sleeping, it is most likely that those are the symptoms of RMD. This disorder is pretty common among children, and it affects girls and boys equally. Only 6% of children will still have to deal with this disorder after the age of five, and 3% after they turn thirteen years old. Among the older kids, this condition is so rare and almost benign in the vast majority of cases.
This condition strikes healthy children as well as the ones who have been diagnosed with autism or have some disabilities.
Here we would like to point out one huge mistake which all parents make while their child is having an episode of motions; they all tend to wake up their child immediately. This will stop their seizure but only for that brief period because as soon as the child goes back to sleep, it will continue. Interfering with these episodes is recommended if you notice that the child is going to get injured, or fall out of the bed.
Rhythmic Movement Disorder Among Adults
People who continue to deal with this as they age and grow into adults are usually more aware of what is going on to them. While they are perfectly aware that this is not harmful or too dangerous, they know that it is not normal and that most people of their age have already outgrown this condition, which is why some of them may feel embarrassed. In most cases, this does not cause any harm to adults, but it can be irritating or stressful to the partner who shares the bed with them, which stresses out the patients even more because they are aware that their condition is disturbing to their dear ones. It is always the best idea to be honest with yourself and your partner and to inform them on time about what is going on, to avoid any uncomfortable situations. You can also place cushions around the bed, or pads on the headboard.
Most adults who have to deal with this disorder are doing that since their childhood, and it can occur in seniors too, in that case, it is usually a sign that this disorder was triggered by some injury of the central nervous system.