Restless leg syndrome baby

Restless Legs Syndrome (RLS) in Children and Adolescents

What is restless legs syndrome (RLS)?

Restless legs syndrome (RLS) is a movement disorder in which the child or adolescent reports an uncomfortable and irresistible urge to move his or her legs. This urge usually happens at bedtime but can occur at other times when the legs have been inactive, such as when sitting still for a long period of time (eg, during long car rides or while watching a movie).

To relieve the discomfort, the child or adolescent moves his or her legs, stretches his or her legs, tosses and turns, or gets up and walks or runs around. The relief experienced is usually immediate.

What causes restless legs syndrome (RLS)?

The exact cause of this disorder is not known. RLS can be related to a low iron level or sometimes associated with diabetes, kidney or some neurological diseases. RLS sometimes runs in families and there is thought to be a genetic link in these cases. Many types of drugs used in the treatment of other disorders may cause RLS as a side effect.

What are the signs and symptoms of restless legs syndrome (RLS)?

Symptoms of restless legs syndrome include:

  • Leg discomfort or “heebie-jeebies”: uncomfortable leg sensations described as creeping, itching, pulling, crawling, cramping, tugging, tingling, burning, gnawing, or pain. Feeling of “Coca Cola in the veins” has been described. These sensations usually occur at bedtime but can occur at other times of leg inactivity.
  • Urge to move legs: to relieve leg discomfort, children and adolescents have an uncontrollable urge to move their legs.
  • Sleep disruption: additional time is often needed to fall asleep because of the urge to move the legs to relieve the discomfort. Sometimes staying asleep may also be difficult.
  • Bedtime behavior problems: because children have a hard time falling asleep, they may not always stay in bed and sometimes need to get out of bed to stretch their legs to relieve discomfort.
  • Daytime sleepiness: problems with falling asleep and staying asleep may result in problems with daytime sleepiness.
  • Behavior and school performance problems: again, due to sleep disruption, problems may emerge in the child’s academic performance or in daytime behavior (irritability, moodiness, difficulty concentrating, hyperactivity, etc).

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What Is Restless Legs Syndrome (RLS)?

Restless legs syndrome (RLS) and periodic limb movements during sleep (PLMS) should not be confused with each other. Indeed, restless legs syndrome is a neurological disorder with established effects on the quality of life and health. In contrast, periodic leg movements during sleep is a polysomnographic finding of unknown clinical significance. While the majority of RLS patients also have PLMS witnessed during nocturnal polysomnography, many patients with PLMS do not have restless legs syndrome.

RLS is increasingly recognized as an important neurological disorder. It is about twice more common in women versus men and increases with aging. Awareness has come from public education efforts by the RLS Foundation and the realization by the pharmaceutical industry that a significant part of the population is affected by restless legs syndrome (3% severely affected). In spite of these efforts, however, the disorder is often not considered by neurologists, academia and funding agencies as an important condition.

Research in the area of RLS has advanced over the last few years. First, there has been a growing realization that low brain iron metabolism may be a critical pathway in the pathophysiology of RLS. Blood ferritin levels are often lower in RLS patients (typically below 50 µg/L), and iron deficiency seems to be most pronounced when measured in the brain or CSF. Iron deficiency can also produce anemia (low hemoglobin and red blood cell count) and fatigue. If iron deficiency is discovered, it is important to establish its cause.

The cause of RLS also likely involved abnormal Dopamine. Dopamine is an important neurochemical in the brain that is involved in sleep, movements (for example low dopamine is partially responsible for Parkinson’s disease), and the control of pleasurable emotions. For this reason some of the treatment used for Parkinson’s diseases called Dopaminergic agonist can be effective in the treatment of RLS, although they shoud be used with caution.

Genetic factors are strong predictors of RLS. First, RLS commonly runs in family, especially when it is severe and start early in life. DNA changes in five genes have been associated with RLS. These genes are MEIS1, BTBD9, MAP2K5/LBXCOR1, and PTPRD. Interestingly, these genes are mostly DNA binding factors and some are highly expressed in the spinal cord. Although unproven, it is likely that polymorphisms at the level of these genes modulate how the spinal cord process sensory inputs and/or regulate spinal cord motor reflexes. This disturbance would also explain the association of RLS with Periodic Leg Movements during sleep (PLMS).

Environmental factors and other medical problems are also associated with RLS. Most notably, RLS is frequently exacerbated or may start during pregnancy. Second, in addition to iron deficiency, RLS can be caused or exacerbated by renal/kidney failure, spinal cord/back pain issue, and is likely more frequent in people who have damaged peripheral nerves ending, such as in those with peripheral neuropathy (for example in patients with long term diabetes).

RLS may be associated with other conditions, and has been suggested to predispose to depression and heart disease.

Mayo Clinic Minute: Restless legs syndrome in kids

Jason Howland has more in this Mayo Clinic Minute.

Watch: The Mayo Clinic Minute

Journalists: Broadcast-quality video pkg (1:00) is in the downloads. Read the script.

“Sometimes kids will say that ‘I feel like I have to kick my legs’ or ‘I feel like I have to move my legs to get comfortable,'” says Dr. Kotagal.

That’s restless legs syndrome, a genetic disorder that Dr. Kotagal says is more common in children than you might think. Studies show that 1 in 50 kids have the condition, a discomfort that can prevent a child from falling asleep and repeatedly wake a child during sleep.

“They are tired in the daytime and frequently have troubles with attention span,” says Dr. Kotagal.

It often can be related to low levels of iron, which helps make dopamine, a chemical that helps in neurotransmission in the brain and learning.

“So if we don’t have enough dopamine, one is likely to have disturbed sleep,” he says.

Dr. Kotagal says children with restless legs syndrome may go undiagnosed because there is a lack of awareness of the condition, and it can be attributed to attention deficit hyperactivity disorder instead. He says the first step is to talk about sleep disorders with your primary care provider or pediatrician.

The Genetics of Restless Legs Syndrome

Do you have uncomfortable sensations in your legs or an uncontrollable urge to move around when you’re trying to rest? Is it interfering with your sleep? These are all signs of restless legs syndrome, a type of sleep disorder that often runs in families. About half of all people with restless legs syndrome have a family history of the condition. Recent research has pinpointed several genetic variants that may increase the risk of developing restless legs syndrome.

One study followed 671 people with restless legs syndrome and their family members for 15 years. The researchers found that siblings of people with restless legs syndrome are 3.6 times more likely to develop the condition, compared with the general population. So while the cause of restless legs syndrome is unknown — although it’s common in people with low iron levels — the evidence is mounting that some people can trace their condition back to their relatives.

Sharing a Restless Leg Syndrome Diagnosis

If you have restless leg syndrome, you may want to alert close relatives and monitor your children for symptoms. Research has shown that people who are pregnant or have anemia or arthritis are at increased risk of developing familial restless legs syndrome, the type of restless legs syndrome that runs in families. They may want to be especially vigilant in watching for restless legs syndrome symptoms, since simple restless leg treatments, like iron supplements, can often bring relief.

For parents of children with restless legs syndrome, understanding the cause of your child’s symptoms can help you be more supportive. Researchers believe that early diagnosis and treatment may, in some cases, help relieve or eliminate restless legs syndrome symptoms.

The main symptom of restless legs syndrome is an uncomfortable sensation in one or both legs. People describe this sensation as a burning, creeping, crawling feeling, or tugging inside their legs. These feelings usually occur in the lower part of the leg, but they can also happen in the feet, upper leg, or arms and hands.

Symptoms of restless legs syndrome are usually most noticeable at rest and at night when you’re trying to sleep, and they often subside in the morning. Since moving the legs or walking around relieves the uncomfortable sensations in the legs, people with restless leg syndrome describe an uncontrollable urge to move their legs. In children, you may want to watch for:

  • Pacing the floor at night
  • Constant movement of the legs when sitting down
  • Tossing and turning in bed while trying to fall asleep

Restless Legs Treatment Strategies

There is currently no cure for restless legs syndrome, and symptoms tend to get worse with age. But if you, your child, or another family member is diagnosed with restless legs syndrome, there are some treatment options that can help make you more comfortable. They include:

  • Identifying the underlying cause. In some people with restless legs syndrome, the cause of the condition, such as peripheral neuropathy, diabetes, or anemia, can be identified. In these cases, treating the underlying condition can relieve symptoms of restless leg syndrome.
  • Making certain lifestyle changes. Taking steps such as limiting the use of caffeine, alcohol, and tobacco; taking iron, folate, and perhaps magnesium supplements; adjusting your sleep schedule; exercising moderately; and therapies such as soaking in a hot bath, icing the legs, or having a leg massage may help relieve or reduce restless leg symptoms.
  • Trying medications. Certain medications, such as dopaminergic drugs, benzodiazepines, or opioids, have been shown to help reduce symptoms of restless leg syndrome in some people.

Researchers are still working to determine how genes may play a part in your risk for developing restless legs syndrome, with the hope that future discoveries will help prevent it or lead to better treatment strategies.

Presenting Symptoms in Pediatric Restless Legs Syndrome Patients

INTRODUCTION

The diagnostic criteria for restless legs syndrome (RLS) in adults are well known.1,2 As an extension to the adult criteria, the criteria for pediatric RLS were coined in 2003 and published in 2005, see Table 1.2,3 Theoretically, the criteria for RLS allow for a final diagnosis of RLS that is based on the history of the patient and an examination to exclude so called mimics. In many cases, particularly in children, the patient history and/or examination do not provide clear data for the four essential questions or for the exclusion of mimics, which often leads to additional tests, such as polysomnography (PSG) and—in case a peripheral nervous disorder is suspected—EMG and neurography.

Table 1 Diagnostic criteria for restless legs syndrome in pediatric patients

The primary aim of this study was to describe the presenting symptoms (i.e., what the patients and their parents told during the first visit to the outpatient clinic) in a group of children who were ultimately diagnosed as having definite RLS. A 2008 study from the US examined the presenting symptoms of 18 pediatric RLS cases,4 and the present European results will be compared to this earlier work in an attempt to generate a consensus on the presenting symptoms of RLS patients.

BRIEF SUMMARY

Current Knowledge/Study Rationale: In adults the history told by the patient is pivotal in the diagnosis of RLS. Obviously, this is more difficult in (young) children.

Study Impact: This European study describes the complaints mentioned by the children themselves in their work-up to a diagnosis of RLS. The wording used by these children is different from that of adults, but is for many aspects similar to that described for children in the US.

PATIENTS AND METHODS

The present study was conducted on patients from two large sleep centers (i.e., Zwolle and Messina) between 2007 and 2010. Both of the sleep centers had a special interest in pediatric sleep disorders, particularly RLS. A pilot study was presented in 2008.5 Before the start of the study, the senior investigators, who both have longtime experience in child neurology and sleep, agreed on the data that needed to be collected: A detailed history based on a standardized questionnaire partially derived from the pediatric RLS guidelines of 2005, (demographic data, comorbidity, non-RLS medication, final diagnosis , age at start symptoms, RLS in the family, presenting symptoms, abnormalities at physical examination, therapy , effect of therapy), to be filled out by the authors, if applicable in cooperation with the referring physician. A physical examination and tests (hemoglobin, hematocrit, creatinine, thyroid stimulating hormone, and ferritin; EMG and nerve conduction studies, imaging) tailored to each patient to exclude mimics. If behavioral or psychological disorders were suspected, the child and his or her parents were seen by a psychologist or psychiatrist. A PSG in the sleep clinic was recorded and assessed according to the AASM rules6 and our own normal values7 for the children seen between 2008 and 2010 and the Rechtschaffen and Kales guidelines for children seen in 2007. The PSG helped in excluding other sleep disorders and—if showing periodic limb movements (PLMS)—were evidence in favor of RLS

Based on the results, the patient was diagnosed as either definitely having RLS or not having RLS. Finally, only 2 patients had to be excluded because of significant apneas during PSG. This resulted in a group of 31 patients to be included in the present study (25 boys) from Italy and The Netherlands. The median age of the patients at the time of the first visit to a sleep center was 10 years (range 5-12 years). The mean interval between the initial visit and the first manifestations of RLS was estimated to be 3 years (range 1-5 years). In all of the patients, the initial symptoms were still present at the first visit to the outpatient clinic.

As the work-up of all patients was similar to the normal clinical routine, the ethics committee had no objections to the study design.

One of the major problems of a history-based study with children is the communication skills of the children in the study. The ability to effectively communicate was a bigger factor than age in determining the participants of the present study. Indeed, even two 5-year-old children were able to participate in the present study because they could effectively communicate. Teenagers older than 14 years at the first visit and children suspected of secondary RLS were excluded from the study. Although parental descriptions were taken into account, the data provided by the children was deemed more important.

Data Analysis

Descriptive statistics (the mean and standard deviation or the median, range and interquartile range ) were used to present the data, and comparisons with previous data were performed using Student t test or the Mann-Whitney U test. The significance level for these comparisons was set at p < 0.05. Tests were chosen based on the parametric or nonparametric characteristics of the data.

RESULTS

An urge to move and sensory symptoms were mentioned by all 31 patients. The sensory symptoms were described as ants in the legs, itchy, hurts, deep ache, spiders in or on the legs, just need to move, funny, too much energy, legs want to kick, need to stretch, or were just called growing pains (Table 2). These descriptions were given by the patients themselves and confirmed by the parents. For 16 patients, the description was compatible with the adult definite RLS criteria, but in the other 15 the description did not point directly to RLS, for example ants or spiders in the legs, legs want to kick, funny, and growing pains. Furthermore, the patients complained about insomnia, tiredness, or even excessive sleepiness during the day (EDS). Table 2 gives the prevalence of these features. All children had their symptoms when at rest. They were worse during the evening and night and improved with movement. Thus, already at the first visit, 16 of the 31 patients (53%) presented with a history compatible with the diagnosis of definite RLS. The other 15 patients, who described the symptoms unconventionally, had insomnia (N = 14), a parent with RLS (N = 3), PLMS > 5/h of sleep (all 15). All 15 patients had ≥ 2 of these features and met current criteria for childhood RLS as well (Table 1). Figure 1 depicts the differences between the presenting symptoms in our study and those from a previous study by Picchietti’s group. Although our patients had a history of less insomnia and EDS, they had more complaints of being tired, which was not mentioned in the study of Picchietti et al.

Table 2 Presenting symptoms

Figure 1

Comparison of our data with the data from the Picchietti et al.3

Twenty-seven of the 31 patients suffered from a second disorder which was diagnosed before entering the study in 17 patients and during the work-up after the first interview in the other 10 patients. Remarkable differences between the present study and the Picchietti study were observed for epilepsy (19% vs. 0%, respectively), ADHD (42% vs. 72%, respectively), parasomnia (7% vs. 39%, respectively), anxiety (10% vs. 33%, respectively), and depression (0% vs. 28%, respectively). Comorbid ADHD was always the hyperactive or combined type. Furthermore, the genetic component appeared to be less prevalent in our study (19% vs.72%).

DISCUSSION

The present study provided data on the presenting symptoms of pediatric RLS patients from two different regions of Europe. Independent of the location, a variety of sensorimotor symptoms were described by the children. Complaints of insomnia, tiredness during the daytime and some overt EDS were primarily mentioned by the parents. The study group may be compared with the group of 18 patients described by Picchietti et al.3 The subjective measures of sleep and daytime performance suggested that there was less insomnia and EDS in the patients in the present study; however, the children in our group were more tired during the day. Because an MSLT may not give reliable information in children, we had to rely on answers obtained from the parents. Indeed, the sensation of being tired during the day and EDS may be difficult for children to differentiate.

Disorders other than RLS or PLMS occurred in 27 of the 31 patients—epilepsy, ADHD, and anxiety were the most common disorders. The relatively high prevalence of epilepsy observed in the present study may be due to the character of the participating centers, which specialize in both sleep and epilepsy. One can only speculate whether this influences the results of the study. As there is up to now no known interaction between epilepsy and RLS, this is probably of little importance. Cognitive deficits that are sensitive to sleep loss have been ascertained in adults with RLS.8 Although it is impossible to run the same tests in children, it is interesting to hypothesize that the daytime hyperactivity or ADHD that was observed in many of our children could be akin to the cognitive deficits observed in adults. In addition, the children in the present study were less likely to fall asleep. Interestingly, they showed hyperactivity features akin to the patients in the group described by Gamaldo et al.9 In particular, the Messina Sleep Center found that the percentage of children diagnosed with RLS and ADHD after the total work-up was nearly double the number of children diagnosed after the interviews with the children and their parents.10

The present study was originally started as part of a survey of many aspects of pediatric RLS in Europe. Most of our colleagues in child neurology and/or sleep who were approached to join the study told us that they only sporadically see children suspected of RLS (if at all). Despite many oral and written contacts with major pediatric sleep centers in the UK, France, Germany, Middle Europe, Italy, and The Netherlands, only a limited number of patients could be included in the present study. Although the present study was not designed to estimate the RLS prevalence in children, the difficulty in recruiting patients casts doubts on the frequent occurrence of pediatric RLS (estimated at 1% to 2%) mentioned in a previous publication.3 On the other hand, we suspect that in Europe, many children who in fact have RLS are diagnosed as having ADHD.

A limitation of the present study was in the long interval between the first manifestations of RLS and the visit to the outpatient clinics, which implies that the descriptions of the presenting symptoms were partly based on retrospective data. This potential bias is inevitable, but it may be mitigated by the persistence of the symptoms during the period between the first manifestations of RLS and the initial visit to the outpatient clinic (all of the parents mentioned that the symptoms persisted during this interval). We believe that the strong point of this study consisted in the consequent and comprehensive work-up for each patient, which led to a homogeneous group of children.

A recent paper from Arbuckle et al.11 explored the feasibility of a multidimensional, self-administered Pediatric RLS Severity Scale (P-RLS-SS) to measure the outcome and the impact of pediatric RLS symptoms. Symptoms were subdivided into four major symptom domains (RLS sensations, move/rub legs due to RLS, relief of RLS from moving/rubbing legs, RLS hurt/pain) and four impact domains (RLS impact on sleep, RLS impact on awake activities, RLS impact on emotions, RLS impact on tiredness). The scale would provide scores for the symptom and impact domains and a total RLS score. Interestingly, data from the 33 children and adolescents with definite RLS included in the Arbuckle study confirmed that there are no gender- or ADHD-comorbidity-based differences in RLS symptoms or impact. Age, however, played a major role in the different terms used for the descriptions. For example, “kick” and “wiggly” were used more often by children younger than 11, whereas “tingling” was used more often by adolescents. Subjective impairment of sleep was rated by 88% of the patients across all age groups, and impact on tiredness was mentioned by 70%. The impact of RLS on emotions and awake activities was less consistent despite parents’ reports on these measures. Although the P-RLS-SS requires further validation, the scale certainly represents an innovation in the RLS field and may be potentially used just like the validated scale for adults (International RLS Score, IRLS). Furthermore, the P-RLS-SS constitutes a constructive assessment instrument for future pediatric RLS trials, which will assist in the collection of additional data on pediatric RLS features and symptoms.

Recently, a proposal for more detailed criteria for pediatric RLS has been approved by the International RLS Study Group (IRLSSG). One of us (AW) was part of the committee that prepared the proposal, which is not yet formally published. However, all children in the present study would have met these criteria as well.

The most important finding of the present study was the similarity of the presenting symptoms of RLS among our patients. Although there were variations in the descriptions of symptoms, abnormal sensations in the legs and an urge to move were the major presenting symptoms in our study. The descriptions of abnormal sensations and urges to move were inherently supportive for the diagnosis of RLS at the first visit in 16 of the 31 cases in our study. In the other half of the patients, the history had to be verified through additional examinations and/ or the course of the disorder over time. The results of the present study were in broad lines similar to studies by Picchietti et al.3,4

In our opinion, the findings in Picchietti’s and our studies allow for the statement that many cases of pediatric RLS can be detected by collecting a detailed history from the parents and carefully listening to the description of the symptoms offered by the children. Similar to adults, sensorimotor symptoms prevail in children and are the cornerstone of the diagnosis. However, more anamnestic pitfalls occur in children. When doubt remains after a detailed history, the clinical course and results of additional tests (e.g., exclusion of mimics, PSG) should be taken into account before the final diagnosis of pediatric RLS is made.

DISCLOSURE STATEMENT

This was not an industry supported study. The authors have indicated no financial conflicts of interest.

Let’s face it, restless legs syndrome (also known as RLS or Willis-Ekbom disease) is not exactly a household word in most American families. And the notion that children and teens may have symptoms of this condition is even less appreciated. But let’s take a closer look at what is actually a pretty common sleep disorder and an oft overlooked reason kids have difficulty falling asleep.

RLS is a chronic neurological disorder characterized by a nearly irresistible urge to move, mostly the legs, often accompanied by uncomfortable or unpleasant feelings. These feelings are often described as “creepy-crawly”, “ants crawling on my legs”, “pins and needles.”

The urge (and sensations if present) occur only at rest or are worst at rest/ in the evening. Symptoms are temporarily relieved by movements such as jiggling or jerking the legs, walking around, or rubbing the legs.

It’s not hard to imagine that these symptoms would interfere with falling asleep. And to make matters worse, individuals with restless legs also frequently have what are called “periodic limb movements,” or PLMs, during sleep. These are characterized by sudden flexing of the legs (sometimes described as “kicking”) of which the sleeper is unaware, but which nevertheless can significantly disrupt sleep, leaving the sufferer feeling tired and irritable in the morning. Unlike RLS, which can be diagnosed by patient history, PLMs can only be reliably diagnosed with a sleep study.

So why should parents be informed about the symptoms of RLS?

For one thing, RLS is pretty common in adults and children; best estimates suggest that 10% of adults and about 2% of children age 8-17 years in the United States have symptoms at least once a month (that’s almost 980,000 children!).

RLS is under-diagnosed in general, but especially under-diagnosed in children. This is partly because children may have difficulty verbalizing their symptoms (and partly because no one thought to ask why they have trouble falling asleep!). RLS is also a highly inherited disorder; close relatives of RLS patients have an estimated 6-7 fold increased risk of also having RLS.

Children with RLS suffer daytime consequences as well as sleep disturbance. In particular, RLS symptoms are much more common in children with ADHD (and vice versa). But most importantly, RLS is very treatable.

One of the major contributing factors to RLS is low iron levels, which interfere with the production of a brain chemical called dopamine, known to be reduced in patients with RLS). Another is a blood ferritin level less than 50. This has been shown to increase RLS symptoms, which explains why RLS is so common in pregnant women. However, raising the ferritin level with iron supplements, typically for three months, can greatly relieve discomfort.

Other medications are rarely needed in children. I suggest getting plenty of sleep; avoiding substances that can worsen symptoms such as caffeine, nicotine, alcohol and certain drugs like antihistamines; and trying out massage/applying a hot or cold washcloth to the legs.

If your child or teen has trouble falling asleep, seems uncomfortable or very restless at bedtime, complains of leg pain or discomfort in the evening (otherwise known as “growing pains,” which in some cases are associated with RLS and PLMs) during the night, or seems overly fidgety when sitting still or lying down, talk to your doctor and get your child on the path to a good night’s sleep!

About the blogger: Judith Owens, MD, MPH, is the director of the Center for Pediatric Sleep Disorders and an associate in Neurology. She is deeply committed to providing evidence-based information about the importance of sleep to health, safety and performance to a wide variety of audiences.

Learn more about the Sleep Center at Boston Children’s

Restless Leg Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD)

What tests are used to diagnose RLS and PLMD?

Doctors often order a blood test to measure iron (serum ferritin) levels for patients who may have RLS. Studies have found associations between low stores of iron in the body and increased RLS symptoms, probably because of iron’s important role in brain dopamine function.

Similarly, iron deficiency can cause or worsen RLS in children and adolescents, even when the deficiency is not severe enough to cause anemia. A ferritin level of less than 50 mcg/L, which may even be in the low-normal range, indicates a potential problem.

A diagnosis of PLMD is based on three criteria:

  • Periodic limb movements during sleep exceeding norms for age ( more than 5 per hour for children)
  • Clinical sleep disturbance and
  • The absence of another primary sleep disorder or underlying cause (including RLS)

In a child with RLS, the physical exam is usually normal. Family history is important because there is a 50% chance of passing the RLS trait on to children if a parent has RLS.

How do providers at Children’s Hospital Colorado make a diagnosis?

Medical professionals have developed criteria for diagnosing RLS in children ages 2 through 12 years. with definite, probable or possible RLS:

  • Definite RLS: A child feels an urge to move the legs that begins or worsens with sitting or lying down and is partially or totally relieved by movement. The urge is worse in the evening or night than during the day, or occurs exclusively in the evening or nighttime hours. Children describe the discomfort using their own words, such as “owies, tickle, tingle, static, bugs, spiders, ants, boo-boos, want to run, a lot of energy in my legs,” etc. There is a clinical sleep disturbance for age. A biological parent or sibling has RLS. A sleep study has documented a periodic limb movement index of 5 or more per hour of sleep.
  • Probable RLS: There is an urge to move the legs and the move begins or worsens with sitting or lying down. The urge to move is partially or totally relieved by movement, and the child has a biological parent or sibling with definite RLS.
  • Possible RLS: The child has PLMD and a biological parent or sibling has definite RLS, but the child does not meet the criteria for definite or probable childhood RLS.

Adolescents (13 years and older) are evaluated with the adult criteria.

Mayo Clinic Finds Restless Legs Syndrome In Children Linked To Family History, Iron Deficiency

“It’s been known for decades that children have ‘growing pains,'” says Dr. Kotagal. “Studies by other investigators have now shown that growing pains in some children may actually be restless legs syndrome.”

Dr. Kotagal says that while infrequent “growing pains” may be immaterial, parents and children should be alert for a habitual pattern of discomfort in the limbs around bedtime.

“Occasional growing pains are nothing to worry about, but growing pains every night may be restless legs syndrome,” he says. “It’s like the fact that somebody might snore one or two days a month, but if it happens every night, it may be something that needs medical attention.”

The study examined the records of 538 children who had been seen in the pediatric sleep disorders program at Mayo Clinic between Jan. 2000 and March 2004. New, rigidly defined diagnostic criteria established by a consensus conference of the National Institutes of Health and the International Restless Legs Syndrome Foundation in 2003 allowed the Mayo Clinic researchers to classify their 32 patients as having probable restless legs in nine cases and definite restless legs syndrome in 23 cases. Those in the probable restless legs syndrome group were more likely to be younger. The most common symptoms were trouble getting to sleep or staying asleep, which affected 87.5 percent. One commonality in the restless legs syndrome patients was a low iron level in the blood (as measured by serum ferritin) seen in 83 percent of the patients, the explanation for which is unknown, according to Dr. Kotagal.

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“With regard to the iron deficiency, we don’t know if it’s the diet or a genetic predisposition to low iron levels,” says Dr. Kotagal. Drs. Kotagal and Silber also found family history of restless legs syndrome in 23 out of 32 patients identified to have restless legs syndrome in the study, or 72 percent. The child’s mother was three times more likely to be the parent affected with restless legs syndrome.

“There seems to be a strong genetic component in restless legs syndrome,” says Dr. Kotagal. “Very often when taking the medical history with the child, the parents say they have a similar condition.”

An additional characteristic seen in 25 percent of the patients was inattentiveness.

The researchers note that the symptoms of restless legs occur most often in the evening or around bedtime. Symptoms include discomfort or needing to move the legs, which is alleviated by moving around.

“Children very often describe it as ‘creepy crawlies,’ as ‘ouchies’ or ‘owies,'” says Dr. Kotagal. “It feels like bugs crawling on the legs. One child described it as feeling like he was walking though snow. There is also an uncontrollable urge to move the legs.”

Dr. Kotagal believes that it is important to recognize and treat this condition, as it hampers a child’s lifestyle. “If affects the quality of life,” he says. “They wake up frequently in the night. They wake up tired. They may also be inattentive during the day.” The long-term outcome of childhood restless legs syndrome is not known, according to Dr. Kotagal, but it is treatable using medications that increase the levels of dopamine in the central nervous system. Dr. Kotagal notes that there is evidence that iron seems to be very important to the synthesis of dopamine in the body. He says that there is not yet sufficient evidence, however, that treatment with iron helps relieve restless legs syndrome in children.

Dr. Kotagal indicates that there may be connections between restless legs syndrome and attention deficit hyperactivity disorder. The treatments for both conditions address somewhat the same chemical imbalance, he notes.

“When we look at kids who have decreased attention span, over one-third of them will have sleep apnea or restless legs syndrome,” he says. “We can say that it goes to further affirm the fact that inattentiveness is multifactorial — due to depression, anxiety, stressors in the child’s life, obstruction of breathing passageways, sleep apnea or restless legs. We need to look at all of these possibilities.”

RLS IN CHILDREN

Like their adult counterparts, children with RLS tend to seek relief from their discomfort by moving their legs—often by fidgeting, stretching, walking, running, rocking or changing position in bed. Parents or healthcare providers may mistakenly also attribute the child’s discomfort to “growing pains.” In a classroom setting, attempts to relieve the uncomfortable feelings of RLS may be viewed as inattentiveness, hyperactivity, or disruptive behaviour.

Restless Legs Syndrome, however, is a real medical condition that calls for proper evaluation, diagnosis, and treatment. Unlike most adults with RLS, some children with RLS complain of the RLS sensations more during the day than at night.

Diagnosing RLS in children may be especially difficult, since it may be hard for a child to describe where it hurts, when and how often the symptoms occur, and how long symptoms last.

Children with RLS may sleep less well and thus are tired and hyperactive during the day. Further studies on the relationship between ADHD and RLS, as well as studies regarding safety and efficiency of dopamine therapy in children are urgently needed.

In the meantime, please take time to ensure your wider family are aware of RLS and the fact that it could impact on your children, grandchildren, nieces and nephews. Listen to your child’s description of their symptoms and be conscious that they may in fact be describing RLS.

Children presenting symptoms suspected to be RLS should not be treated in primary care but instead should be referred to a Neurologist.

Symptoms of Restless Legs Syndrome in Biological Caregivers of Children with Autism Spectrum Disorders

Child Behavior Checklist

The Child Behavior Checklist (CBCL6/18)28 is a norm-referenced parent report measure used to measure daytime behavior in children ages 6 to 18 y. The CBCL6/18 consists of eight syndrome scales that contribute to broad internalizing or externalizing problem domains and indicates overall patterns of aberrant behavior. The syndrome scales include: anxious/ depressed, somatic complaints, withdrawn, attention problems, aggressive behavior, social problems, thought problems, and rule breaking behavior. Parents rate their child’s behavior during the previous 2 mo on a scale of 0 (not true) to 2 (very true or often true) with higher scores indicating more aberrant behaviors. Test-retest reliability, interparent reliability, and internal reliability are good to excellent. The CBCL correlates with other measures of child behavior problems.28

Statistical Analysis

All data were analyzed using SPSS version 22 (SPSS Inc., Chicago, IL). Descriptive statistics were computed for all variables. Means and standard deviations (SD) were calculated for continuous normally distributed variables and medians and interquartile range were calculated for continuous non-normally distributed variables. Percentages were reported for categorical variables. Dichotomized variables were created from RLS data collected from the SHQ. The t-test and the Mann-Whitney U test were used to test for significant differences between groups for parametric and nonparametric data, respectively. For the non-normally distributed variables, the effect size (r) was calculated when there was a significant difference between groups. In the analysis of categorical variables, the Pearson chi-square test or the Fisher exact test were used due to small numbers in some of the cells. The level of statistical significance was established at 0.05 and unadjusted for multiple comparisons due to the exploratory nature of this cross-sectional study.

Descriptive characteristics of the study sample of caregivers and their children with ASD are presented in Table 1. Of the 50 participants, 11 (22%) indicated that they had RLS symptoms by their responses to the four key questions on the SHQ. The caregivers who reported symptoms of RLS were not significantly different in sex, age, ethnicity, education, or income, nor did their children with ASD differ in sex or age from the care-givers who did not report symptoms of RLS. Of the 11 participants who reported RLS, 4 of the participants, or 36%, stated that they had a relative with RLS symptoms. Only 1 of the 11 participants who indicated having symptoms of RLS reported a diagnosis of RLS from a healthcare provider. Four of the 11 participants indicated that their symptoms were present both “day and night”, which may indicate severe RLS or another condition that mimics RLS. One of these four participants indicated that she has a close relative with RLS. One of the four participants reported than she has had these symptoms since childhood and the remaining three participants report the presence of these symptoms for the past 1 to 5 y. A sensitivity analysis was completed that excluded only adoptive parents and included all 59 of the biological caregivers regardless of reported medical conditions. This analysis yielded results that were similar to the results with the nine caregivers excluded for medical conditions. Significant differences were found in the same variables between participants who reported RLS symptoms and those who did not report symptoms.

Table 1 Demographics of caregivers and their children with autism spectrum disorder.

Caregiver’s sleep duration, other sleep disorder symptoms, and HRQoL scores are characterized in Table 2. There were no significant differences between caregivers with RLS symptoms and caregivers without RLS symptoms in sleep duration and most sleep disorder symptoms. However, caregivers with RLS symptoms reported more sleep onset delay than caregivers without RLS symptoms. Although physical HRQoL was high and equivalent for both groups, mental HRQoL was poorer for caregivers with RLS symptoms (median = 29.67) than for caregivers without RLS symptoms (median = 39.58), U = 108.50, p = 0.01, r = 0.35.

Table 2 Caregiver sleep disorder symptoms, sleep duration, and health-related quality of life.

The CSHQ is summarized in Table 3. There were significant differences in one subscale, which indicated more nightwaking for the children with ASD whose biological caregivers reported RLS symptoms (median = 6.0) compared to children of caregivers without RLS symptoms (median = 4.0), U = 133.50, p = 0.05, r = 0.28. There were no significant differences be -tween the children of the caregivers with RLS and caregivers without RLS in any of the other subscales or in the total score of the CSHQ. A total sleep disturbance score of 41 on the CSHQ indicated child sleep problems. In this sample, 82% of the children with caregivers who reported RLS symptoms scored above the cutoff of score 41 (median = 48.00) on the CSHQ compared to 69% of the children of caregivers without RLS (median = 45.00). The difference between these two groups was not significant. The CSHQ contains only one question regarding restless sleep in children; “Child is restless and moves a lot during sleep.” Seventy-three percent of the care-givers with RLS symptoms reported their children had restless sleep “sometimes” (two to four times a week) or “usually” (five to seven times a week). However, this finding did not achieve a level of significance.

Table 3 Sleep and behavior scales for children with autism spectrum disorder.

Table 3 also summarizes the behavior scores of the children with ASD on the CBCL6/18. Children of caregivers with RLS symptoms scored higher on the Internalizing Behavior Scale (median = 11.00) than children of caregivers without RLS (median = 8.00), U = 121.50, p = 0.03, r = 0.31, demonstrating more behaviors such as anxiety, depression, and somatic complaints. Higher total scores on the CBCL6/18 or more aberrant behaviors in their children with ASD were reported by care-givers with RLS symptoms (median = 57.75) compared to care-givers without RLS symptoms (median = 49.00), U = 130.00, p = 0.05, r = 0.28.

This exploratory study reported the prevalence of RLS symptoms among biological caregivers of children aged 6 to 11 y with a diagnosis of ASD. An unexpected finding in this study was the relatively high percentage of biological caregivers who reported symptoms of RLS. The reported 22% of caregivers with RLS symptoms is much higher than the 7% prevalence from an epidemiology study of the general population in the United States and Europe.9

There were no differences for physical HRQoL for both groups. Notably, their scores were slightly higher than the US norms for adults aged 35 to 44 y.29 Our results are unlike a previous study of parents aged 35 to 44 y who had children with ASD. That study found lower physical HRQoL using the SF-12 version 2 among the parents of children with ASD compared to US population norms.2 Our results also differed from studies that found that the physical HRQoL of persons with RLS was poorer than the general US population norms.30 The better physical health of our sample may reflect the higher income bracket as many of the participants reported an annual family income of over $100,000. In comparison, only 10.5% of the participants in the study of the HRQoL of parents of children with ASD stated that their income was greater than $100,000 per year.2 Although no information was provided about access to health care in our study, it is well established that in the United States, individuals with higher incomes generally have better health care access and report better physical health.31 In our study, participants reported poorer mental HRQoL below the norms for the US general population,29 and consistent with other studies of caregivers of children with ASD.2 Furthermore, the mental HRQoL for caregivers with RLS symptoms was significantly lower than the biological caregivers without RLS symptoms. This is similar to other research findings that associated RLS in adults with poorer mental HRQoL.9,12

RLS is known as a sleep disorder that has strong heritability.14 Symptoms of RLS in parents may signal risk of possible RLS in the children of these parents, an often undetected condition that can affect sleep quality. This study also provided preliminary information concerning relationships between caregivers with and without RLS symptoms and their children’s sleep. Caregivers with RLS symptoms were more likely to report that their children with ASD had more nightwaking. It is possible that many of these children may have RLS symptoms but lack the verbal ability to describe their symptoms. RLS may contribute to a poor sleep quality and to more frequent night-waking.14 Unfortunately, the CSHQ contains only one item that addressed restless sleep in children; therefore, this measure may not have provided caregivers adequate opportunity to report symptoms that may relate to RLS. Caregivers of children with ASD may also perceive restless behaviors prior to and during sleep as a symptom of ASD rather than as a symptom of a discrete sleep disorder. This did not achieve statistical significance, perhaps due to the small sample size, and it suggests a need to further explore restless sleep in this population.

Research has indicated a higher prevalence of RLS in children with other health conditions, including attention deficit hyperactivity disorder (ADHD). A literature review examined associations between RLS and ADHD and found that up to 44% of study participants with ADHD also reported RLS. Additional studies found that up to 26% of participants with RLS had ADHD or ADHD symptoms.32 ADHD was found to be the second most common comorbid disorder in individuals with a diagnosis of ASD.33 Although there has been no research on the prevalence of RLS in children with ASD, one study found the prevalence of periodic limb movement disorder, a condition often associated with RLS, to be 47% in children with ASD compared to 8% in typically developing control patients.34 The pathogenesis of RLS, ASD, and ADHD are uncertain, although the dopamine-opiate system and iron as a cofactor have been implicated in each of these disorders.32,34–36 Given these linkages, it is suggested that future bench and clinical research examine further these relationships that could expand our knowledge of the complex relationships between these disorders and lead to interventions to ameliorate symptoms and improve child and family quality of life.

In this study, the children of caregivers with RLS symptoms were more likely to exhibit more withdrawal, depression, anxiety, and somatic complaints than the children of caregivers without RLS symptoms. Notably there was no significant relationship between RLS symptoms and a health provider diagnosis of depression in the caregivers. Prior research has reported relationships between RLS and some features of depression in adults10,37 and associations in children and adolescents between RLS and negative mood, and RLS and comorbid depression or anxiety disorders.14 Although a causal mechanism for the relationship between RLS and depression has not been established in either direction,37 there may be several factors that link depression and RLS. As with RLS, dopamine neurotransmission has been linked to depression. Altered dopaminergic function may underlie depression and persistent exacerbations of the symptoms of depression may promote further dopamine dysregulation.38 Other factors that may influence the relationship between depression and RLS may be higher scores on somatic items of depression scales related to sleep disturbances and loss of energy10 or possible aggravation of RLS through the use of antidepressants.39 Further research is needed to understand the associations and mechanisms that link depression and RLS in adults and children. An additional concern in a population of caregivers of children with ASD is their susceptibility to depression and psychological distress in comparison with caregivers of typically developing children40 and children with other disabilities.41 Optimal care for children with ASD depends on the good physical and psychological health of their caregivers. Attention to caregiver mental health needs within the intervention process is important to achieve positive outcomes for the child with ASD and the family unit.42

As with any study, there are limitations to this research. First, this study consisted of a small convenience sample of parents of children with ASD, and these results cannot be generalized to other caregivers of children with ASD. The demographics of our sample do not closely reflect families who have children with ASD in the United States or in Arizona. The majority or 82% of our participants identified as being non-Hispanic White compared to 48% of families in Arizona and 53% of families of children with ASD in the United States.43 Nevertheless, this study mirrors other published research with children with ASD in which minorities have been underrepresented.44

Second, our low response rate may reflect some self-selection of caregivers who have sleep problems. However, income level estimate, sex of the child, and ethnicity did not differ between participants and nonparticipants, mitigating potential bias. Nonetheless, our participants generally had younger children with ASD compared to our nonparticipants and younger children with ASD are reported to have more sleep problems such as night waking that disrupt parent sleep,4 thus potentially influencing our findings.

Third, the cross-sectional nature of this study is a limitation as it captured the caregiver’s perceptions at only one point in time. Fourth, this study relied on the self-report by caregivers of their own sleep disturbances as well as the sleep quality and behavior problems of their children with ASD. In particular, the ascertainment of RLS symptoms was based on questionnaire responses, and this may have resulted in some diagnostic imprecision. It is possible that the three participants who were excluded because of RLS mimics of anxiety and arthritis also had RLS. It was also impossible to determine if the participants who reported RLS symptoms “both day and night” had severe RLS or had another condition that mimics RLS. Fifth, parent reports of child sleep disturbances have not always been supported in studies by objective information.45 Therefore, actigraphy and polysomnography would corroborate information obtained by parent report concerning child sleep disturbances. Finally, because of the descriptive nature of this study, no causality can be inferred. If adjustments were made for multiple comparisons, some results would not achieve significance at the 0.05 level. The small sample size lacked power, and the effects of significant variables were all small to medium (0.28 to 0.35).

Despite these limitations, there are several major strengths of this study, including a confirmed diagnosis of ASD through an Autism Diagnostic Observation Schedule or Autism Diagnostic Observation Schedule 2 that have strong sensitivity and specificity for diagnoses.46 The poorer mental health of the caregivers with RLS even compared to their non-RLS cohorts makes a new contribution to the growing body of evidence regarding RLS and HRQoL literature. Importantly, to our knowledge, this is the first study of its kind to examine caregivers with and without RLS and the sleep and behavior of their children with ASD. Taken together, these findings can provide a springboard for future research of families of children with ASD.

In conclusion, the current study found a high prevalence of self-reported symptoms of RLS in biological caregivers of children with ASD. Associations between RLS symptoms and poorer mental health were found in this sample of care-givers. Additionally, parents with symptoms of RLS reported more nightwaking and greater internalized behavior problems in their children with ASD than parents without symptoms of RLS. This study underscores the importance of compiling information concerning caregiver sleep problems and HRQoL that may guide interventions to support caregivers in fulfilling their daily responsibilities to their children. Additionally, biological caregivers may offer insights into the sleep disruptions that may be common to them and to their children with ASD who may be unable to articulate their symptoms. Sleep problems in children with ASD and their caregivers may be linked by common genetic and environmental influences. Education of caregivers concerning sleep hygiene and possible sleep disruptors in their own sleep and in the sleep of their children with ASD is essential.

This paper was presented, in part, at the Associated Professional Sleep Societies 29th Annual Meeting, Seattle, WA, June 2015. This was not an industry supported study. Dr. Russell is a stockholder in and consultant for Northland Rural Therapy Associates. Dr. Quan is a consultant for Global Corporate Challenge; a stockholder in Merck and Pfizer; and has received honorarium from Harvard Health Publications. The other authors have indicated no financial conflicts of interest.

ABBREVIATIONS

ADOS

autism diagnostic observation schedule

ASD

autism spectrum disorder

ADHD

attention deficit hyperactivity disorder

CBCL6/18

child behavior checklist (ages 6–18)

CSHQ

children’s sleep habits questionnaire

HRQoL

health related quality of life

IQR

interquartile range

MCS

mental composite scale

mo

month(s)

MOS

medical outcomes study

PCS

physical composite scale

r

effect size

RLS

restless legs syndrome

SARRC

southwest autism research and resource center

SD

standard deviation

SF-12

short form-12

SHQ

sleep habits questionnaire

U

Mann-Whitney U test

US

United States

y

year(s)

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