What is sleep rhythmic movement disorder?

Sleep-related rhythmic movement disorder (RMD) involves repeated body movements. They occur while drowsy or asleep. It is typically seen in children. Rhythmic humming or other sounds are sometimes made along with the body motions. These sounds can be quite loud.

Episodes often occur when your child is falling asleep or almost asleep. They may also occur at any point in the night. At times, they may even happen during quiet activities when your child is awake. Your child may be listening to music or riding in a car.

The rate may vary, but the actions are rapid. One or two motions tend to occur every one or two seconds. An episode will often last up to 15 minutes. The motions may stop when a noise, movement or voice disturbs your child. Children who are old enough to talk will usually not recall the event in the morning.

These actions are common in normal infants and children. These motions alone do not qualify as a disorder. It is only a disorder if the actions severely injure your child or greatly disturb her sleep. The noises can greatly distress other family members. It is normal for a parent to be concerned. It is important for parents to discuss your child’s actions with other caretakers, family members, or babysitters.

There are several types of RMD, including:

Body rocking – Your child may rock her entire body while on hands and knees. She may also rock her upper body while sitting up.
Head banging – This often occurs with your child lying face down. He lifts his head or entire upper body. Then he forcibly bangs his head back down into the pillow or mattress. This action is repeated. It may also occur when your child is sitting up. He will bang the back of his head against the wall or headboard repeatedly. Body rocking and head banging may also be combined. Your child will rock on hands and knees. At the same time, he will bang the front of his head into the wall or headboard.
Head rolling (AKA Jactatio Capitus Nocturna) – The head is rolled back and forth. Your child is normally lying on his back.

Head banging is the most disturbing form of the problem. Typical cases in infants and toddlers pose little risk of serious injury. Strong motions can cause loud noises when your child hits the bed frame. The bed may also bang against the wall or scrape the floor.

Less common rhythmic movement forms include the following:

Body rolling
Leg banging
Leg rolling

What are symptoms of sleep rhythmic disorder?

Your child may have RMD if:

They make repeated body motions, such as body rocking, head banging, or head rolling
These body motions tend to occur when your child is drowsy or asleep
These actions interfere with your child’s sleep, make your child sleepy or grumpy during the day, or your child has an injury that requires medical treatment

It is also important to know if there is something else that is causing your child’s sleep problems. They may be a result of one of the following:

Another sleep disorder
A medical condition
Medication use
A mental health disorder
Substance abuse

What are risk factors for sleep rhythmic movement disorder?

RMD is very common in healthy infants and children. Body rocking begins at an average age of six months. Head banging begins at an average age of nine months. At nine months of age, 59% of all infants have been reported to have one of the following rhythmic movements:

Body rocking (43%)
Head banging (22%)
Head rolling (24%)

At 18 months of age, the overall rate drops to 33%. It commonly goes away by two or three years of age. By five years of age, the rate is only 5%.

It seems to occur at the same rate in both boys and girls. It may be more likely to occur among family members. One study found that children with body rocking had a higher level of anxiety.

RMD has been rarely reported in teens and adults. The condition may appear at an older age due to an injury to the central nervous system. In older children or adults, these actions may be related to one of the following:

Mental disability
Autism
Other neurodevelopmental disorders

In many of these cases, the motions are not sleep related. They tend to occur when the person is awake.

How to diagnose sleep rhythmic movement disorder?

Most children who display these actions do not need help. It is a common part of the way their sleep process develops. Talk about your concerns with your child’s doctor. You should see a sleep doctor if the motions injure your child or keep him from sleeping well.

First, the doctor will need to know when the motions began. She will also want to know what else has been going on in your child’s life. You should complete a two-week sleep diary for your child. Make note of any specific times when the actions occur. If possible, video record the event for your doctor to review. This will give the doctor clues as to what might be causing your child’s problems.

The doctor will need to know your child’s complete medical history. Be sure to inform her of any past or present medication use. Also, tell your doctor if your child has ever had any other sleep disorder.

No tests are needed to detect RMD in most children. Your doctor may have your child do a sleep study if the motions are severe or if there are concerns for other sleep disorders contributing to these behaviors. This study is called polysomnography. It charts your child’s brain waves, heartbeat and breathing as he sleeps. It also records how his arms and legs move. This will also show if there are other disorders, such as sleep apnea, that are causing the sleep problems.

The best sleep study will also record your child’s sleep on video. This will help show if your child moves or does anything unusual during the night.

How to treat sleep rhythmic movement disorder?

Medications may be prescribed if the movements are disturbing your child, interfering with your child’s sleep or causing injuries.