Restless Legs Syndrome in Children and Adolescents

Children with psychiatric comorbidities frequently are referred for evaluation of sleep complaints. Common sleep symptoms can include difficulty falling asleep, frequent nocturnal awakening, restless sleep, and symptoms of restless legs syndrome (RLS). The understanding of the sleep condition in relation to the psychiatric comorbidity often is a challenge to the physician and often sleep disorders remain undiagnosed, untreated, or undertreated. Restless legs syndrome has been associated with psychiatric comorbidities and with certain medications, such as antidepressants, antihistamines, and antipsychotics. This article reviews the presentation of RLS and restless sleep, the association with psychiatric comorbidities, and treatment options.

Daytime impulsiveness, attention, and learning in the restless legs syndrome

INTRODUCTION

Restless legs syndrome (RLS) is a sensorimotor condition characterized by disturbing sensations and the desire to move, often localized in the legs. Cognitive changes and impulsivity can be present in RLS, although the potential effect of commonly co-occurring attention-deficit/hyperactivity disorders (ADHD) or dopamine agonist (DA) use on these are unclear.

METHOD

Twenty-three RLS patients and 22 healthy controls were included. Rey Auditory Verbal Learning Test (RAVLT), Continuous Performance Test (CPT), Beck Depression Inventory (BDI), Epworth Sleepiness Scale (ESS), State and Trait Anxiety Inventory (STAI), and Adult Attention Deficit Self-Evaluation Scale (ASRS) were administered. Performance was compared between RLS patients and controls accounting for the presence of attention-deficit/hyperactivity disorder (ADHD) and DA use.

RESULTS

Age, education, BDI, ESS, STAI, and ASRS scores were similar for control and RLS groups. Control and RLS groups performed similarly on auditory verbal learning and general attention tests. In the CPT, commission error was significantly higher and response time was significantly shorter in the RLS group compared to controls (p = .014 and p = .010, respectively). These significant differences persisted after adjusting for ADHD and DA usage.

CONCLUSION

In this study, RLS patients were more impulsive than the healthy individuals independent of ADHD and DA use. However, learning and attention performances of the patients are not affected.

Attention deficit hyperactivity disorder and restless leg syndrome across the lifespan: A systematic review and meta-analysis

This systematic review aims to assess the association between attention deficit hyperactivity disorder (ADHD) and restless legs syndrome (RLS) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for original articles that reported prevalence data on ADHD and RLS until January 24th, 2023. Two independent reviewers evaluated the quality of the articles using the National Institutes of Health assessment tool. Among the 208 articles identified between 1996 and 2022, 29 were included. In large general population studies, 2.6-15.3% of participants met the RLS criteria, of which 3.2-17.4% presented with ADHD. In the ADHD group, RLS symptoms ranged from 11 to 42.9% in children and 20-33.0% in adults. This suggests a strong co-occurrence between RLS and ADHD. A common characteristic of these conditions is sleep fragmentation, as discussed in the reviewed papers. Although large-scale studies with comparable diagnostic criteria across the lifespan are required, our findings may advocate a possible common physiological pathway, including sleep fragmentation and dopaminergic system impairment.

Pediatric Restless Legs Syndrome

Early-onset restless legs syndrome has a relatively high prevalence in pediatrics, is highly familial, and is often preceded by a diagnosis of periodic limb movement disorder or childhood insomnia. Diagnostic criteria are derived but not equal to those of the adult syndrome and are adapted according to children's age and linguistic competence. Diagnosis requires parents or caregivers to participate; video-polysomnographic nocturnal recording, although not mandatory, may help confirm dubious cases. The syndrome severely impacts children's sleep and cognitive-behavioral abilities. Iron supplementation is currently the most used and viable therapeutic option.

Restless sleep disorder in children with attention-deficit/hyperactivity disorder

STUDY OBJECTIVES

Restless sleep is a very common parental complaint in children with attention-deficit/hyperactivity disorder (ADHD), but restless sleep has been seen in association with other comorbidities such as restless legs syndrome and obstructive sleep apnea. Restless sleep disorder (RSD) needs to be identified from other disorders when evaluating children with ADHD. In this study we aim to identify the prevalence of RSD in children with ADHD referred to our sleep center.

METHODS

This is a retrospective study of children with ADHD who underwent polysomnography. The following diagnostic and descriptive data were obtained for each patient: age, sex, presence/absence of RSD, other sleep disorders, psychiatric comorbidities, and medications. RSD was diagnosed per diagnostic criteria.

RESULTS

There were 66 children with ADHD. All of them underwent polysomnography, 17 were females, and 49 were males. Mean age was 11.6 years (± 3.6 standard deviation). The complaint of restless sleep was reported by the parents of 54 (81.1%) of the children; however, only 6 of them (9.1%) were diagnosed with RSD. Seventy-one percent had obstructive sleep apnea and 19.7% had restless legs syndrome. A significant number of patients had psychiatric comorbidities and were on various medications.

CONCLUSIONS

Although restless sleep is a common complaint reported in 81.1% of children with ADHD, only 9.1% had RSD. Most causes of restless sleep are secondary and associated with other sleep disorders, psychiatric comorbidities, or medication use.

Restless Legs Syndrome in Children and Adolescents

Children with psychiatric comorbidities frequently are referred for evaluation of sleep complaints. Common sleep symptoms can include difficulty falling asleep, frequent nocturnal awakening, restless sleep, and symptoms of restless legs syndrome (RLS). The understanding of the sleep condition in relation to the psychiatric comorbidity often is a challenge to the physician and often sleep disorders remain undiagnosed, untreated, or undertreated. Restless legs syndrome has been associated with psychiatric comorbidities and with certain medications, such as antidepressants, antihistamines, and antipsychotics. This article reviews the presentation of RLS and restless sleep, the association with psychiatric comorbidities, and treatment options.

Magnesium, Iron, Zinc, Copper and Selenium Status in Attention-Deficit/Hyperactivity Disorder (ADHD)

In this study, we critically review the literature concerning the relation of Mg, Fe, Zn, Cu and Se and attention-deficit/hyperactivity disorder (ADHD). Elemental status is estimated using peripheral blood parameters, hair, urine, daily intake and response to supplementation. The observed associations between concentration levels of the elements Mg, Fe, Zn, Cu and Se and ADHD symptoms are contradictory. This is partly due to the heterogeneity and complexity of the disorder. As a trend, lower ferritin and zinc levels can be observed. However, this correlation is not causative, as illustrated by placebo-controlled trials reporting conflicting evidence on the efficacy of supplementation. Well-defined studies on changes in concentration levels of the elements in relation to ADHD symptoms before and after treatment with therapeutics it will be possible to shed more light on the significance of these elements in this behavioral disorder. The discussion on whether a change in concentration of an element is cause or consequence of ADHD is not within the scope of this article.

Sleep-Wake Disorders in Childhood

PURPOSE OF REVIEW

The presentation of sleep issues in childhood differs from the presentation in adulthood and may be more subtle. Sleep issues may affect children differently than adults, and distinct treatment approaches are often used in children.

RECENT FINDINGS

Sodium oxybate was approved by the US Food and Drug Administration (FDA) in October 2018 for an expanded indication of treatment of sleepiness or cataplexy in patients with narcolepsy type 1 or narcolepsy type 2 aged 7 years or older, with side effect and safety profiles similar to those seen in adults. Restless sleep disorder is a recently proposed entity in which restless sleep, daytime sleepiness, and often iron deficiency are observed, but children do not meet the criteria for restless legs syndrome or periodic limb movement disorder.

SUMMARY

Children's sleep is discussed in this article, including normal sleep patterns and effects of insufficient sleep. Sleep disorders of childhood are reviewed, including insomnia, obstructive sleep apnea, restless legs syndrome, parasomnias, narcolepsy, and Kleine-Levin syndrome. Children with neurologic issues or neurodevelopmental disorders frequently have sleep disorders arising from an interaction of heterogeneous factors. Further attention to sleep may often be warranted through a polysomnogram or referral to a pediatric sleep specialist. Sleep disorders may cause indelible effects on children's cognitive functioning, general health, and well-being, and awareness of sleep disorders is imperative for neurologists who treat children.

Restless legs syndrome and iron deficiency in adults with attention-deficit/hyperactivity disorder

STUDY OBJECTIVE

The association between restless legs syndrome (RLS), periodic leg movements during sleep (PLMS) and iron deficiency has been reported in children with attention-deficit/hyperactivity disorder (ADHD); however little is known in adults. The aim of this study was to assess frequencies of RLS, PLMS and other leg movements (LM) and iron deficiency and their relationships with ADHD phenotype in adults with ADHD.

METHODS

Two hundred adults with ADHD (112 males, median age 31 years) were evaluated on lifetime ADHD symptoms and sleep characteristics. RLS was diagnosed according to standard criteria. Serum ferritin levels were measured, with iron deficiency defined as <50 ng/mL. A subgroup of 48 ADHD patients with RLS, 48 ADHD without RLS and 48 controls underwent a polysomnography to record sleep, LM, and PLMS.

RESULTS

RLS was diagnosed in 33.0%, associated with earlier onset of ADHD, hyperactive presentation and more severe lifetime ADHD symptoms. Iron deficiency was found in 35.5% with higher frequency in patients with RLS. LM were more frequent in ADHD patients, with higher LM periodicity levels in those with comorbid RLS in comparison to controls. However, PLMS index did not differ between groups. Patients with ADHD and RLS had higher frequency of iron deficiency than other groups.

CONCLUSIONS

In a large sample of adults with ADHD, we individualized a subgroup characterized by earlier and severe ADHD symptoms, RLS, higher LM during sleep and iron deficiency. This endophenotype may reflect a different neurobiological mechanism that remains to be further studied.

Study of Sleep Disorders among Young Children Using Hindi Translated and Validated Version of Pediatric Sleep Questionnaire

OBJECTIVE

The objective of this study is to assess the prevalence of sleep disorders among children aging between 4 and 9 years using Hindi version of Pediatric Sleep Questionnaire (PSQ).

METHODS

This study had two parts first, translation and validation of PSQ into Hindi language, and second, assessment of the prevalence of sleep disorders using PSQ Hindi version. Hindi PSQ was distributed in randomly chosen primary schools in a semi-urban area. The children were requested to get them filled by their parents. When the questionnaires were returned, responses were analyzed.

RESULTS

Most of the items of the Hindi version had perfect agreement with original questionnaire in a bilingual population (κ =1). Totally, 435 children were included in the field study having average age of 6.3 years. Obstructive sleep apnea was reported in 7.5% children; symptoms suggestive of restless legs syndrome were reported by 2%-3%; teeth grinding by 13.9% and sleep talking by 22.6% children.

CONCLUSION

PSQ Hindi version is a validated tool to screen for sleep disorders among children. Sleep disorders are fairly prevalent among young children in India.

Prevalence and Clinical Characteristics of the Restless Legs Syndrome (RLS) in Patients Diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD) in Antioquia

Introduction:

Attention Deficit Hyperactivity Disorder (ADHD) is the most common behavioral issue for children. One of the sleeping disorders most frequently related to ADHD is the Restless Legs Syndrome (RLS), characterized by an irresistible urge to move the legs, something that is generally associated with paresthesias and motor restlessness. The prevalence rate of RLS in children diagnosed with ADHD is close to 18%, but in Colombia, these cases have been hardly studied.

Objective:

To determine the frequency of RLS, in children with ADHD.

Methods:

A cross-sectional study, filled out by parents of children diagnosed with ADHD, were analyzed. This questionnaire contained clinical criteria for classifying ADHD according to the DSM-IV, as well as diagnostic criteria for RLS by the National Institutes of Health (2003).

Results:

A predominance rate of 65.6% in combined ADHD was observed in children with RLS criteria. Upon carrying out an exploratory data analysis, it was found that having a family history of RLS and belonging to the middle or low socioeconomic strata are conditions associated with the presence of RLS in children with ADHD, with a significant p (p < 0.000) and a PR of 4.47 (3.16-6.32).

Conclusions:

The prevalence of RLS was similar to the findings of other clinical investigations. However, it highlights new prevalence values in relation to the comorbidity between ADHD and RLS, suggesting the need for new clinical and therapeutic alternatives amidst the presence of both syndromes.

Sleep Disorders: Assessment and Treatment in Preschool-Aged Children

Sleep issues are common in preschoolers, defined in this article as ages 3 to 5 years. Sleep deprivation can cause behavioral and cognitive issues. Sleep issues seen in the preschool years include insomnia, obstructive sleep apnea, parasomnias, and restless legs syndrome. Sleep issues seem to exacerbate mood and attention disturbances. Conversely, children with psychiatric disorders are likely to have sleep problems. Treatment of sleep issues is important for long-term mental health and optimization of functioning.

Determination of restless legs syndrome prevalence in children aged 13-16years in the provincial center of Kayseri

OBJECTIVE

This study was conducted to determine the prevalence rate of restless legs syndrome (RLS) and associated factors in adolescents aged 13-16years in the provincial center of Kayseri.

MATERIALS AND METHODS

The study sample included 5720 adolescents who were selected from among 74,421 grade 7-10 students aged 13-16years in the provincial center of Kayseri. Overall, datas from 4792 subjects were included into analysis. Data were collected by using a self reported questionnaire and the Epworth Sleepiness Scale (ESS). The prevalence rate of RLS was determined by questionnaire datas and phone interviews. The effects of age, gender, economical status and body weight on RLS prevalence rate were analyzed. Mean ESS score was calculated. The effect of RLS on academic success, as measured by grade point average, was also assessed. The subjects were stratified as underweight, normal, overweight and obese according to the body mass index and the RLS prevalence rate was compared among groups.

RESULTS

The RLS prevalence rate was determined to be 2.9% among adolescents aged 13-16years in the study group. It was found that gender and economical status had no significant effect on RLS prevalence. Mean age at symptom onset was 11.4years of age. There was a positive family history in 11.3% of subjects. Mean body mass index (BMI) was found to be significantly higher in subjects with RLS (21.5±3.8 vs. 20.5±3.2). Academic success (72.0±11.2 vs. 77.0±12.0) was found to be poorer and daytime sleepiness level, as measured by ESS (11.4±3.9 vs. 6.3±4.0), was found to be higher in subjects with RLS.

CONCLUSION

The RLS prevalence rate was 2.9% in the study sample while gender and economical status had no significant effect on prevalence rate. The RLS, which results in decreased sleep quality and academic success, is an important disorder with a considerable prevalence in the population.

Sleep Problems in Children with Attention Deficit/Hyperactivity Disorder: Current Status of Knowledge and Appropriate Management

Attention deficit hyperactivity disorder (ADHD) affects approximately 5 % of children and adolescents, and sleep problems are common in these patients. There is growing evidence informing the significant importance of sleep problems in youth with ADHD. The sleep problems in children with ADHD include specific sleep disorders and sleep disturbances due to comorbid psychiatric disorders or ADHD medications. The specific sleep disorders of ADHD children include behaviorally based insomnia, sleep-disordered breathing, and restless legs syndrome/periodic limb movement disorder. Current practices on the management of sleep problems for ADHD children are based mostly on expert consensus, whereas more evidence-based literature can be found only recently. Assessment of the sleep conditions in ADHD children before initiation of pharmacotherapy is the currently recommended guideline, and good sleep hygiene can be considered as the first-line treatment option. In addition to modifying the dose regimens, formulation, or alternative stimulants when sleep problems are encountered in ADHD children, atomoxetine, once daily guanfacine extended release, and melatonin are potential choices for ADHD children with more severe sleep problems. In this review, we aimed to provide the most updated information, preferably based on meta-analyses, systemic review, and randomized controlled trials published in the latest 3 years, in order to be clinically useful for practitioners and clinicians.

An evaluation of sleep quality and the prevalence of restless leg syndrome in vitamin D deficiency

Vitamin D is known to increase levels of dopamine and its metabolites in the brain and also protects dopaminergic neurons against dopaminergic toxins. The aims of the study were to assess the frequency and symptom severity of restless leg syndrome (RLS) and sleep quality in vitamin D deficiency. A total of 102 patients were enrolled in this cross-sectional study, comprising 57 vitamin D deficient patients as Group 1 and 45 patients with normal levels of vitamin D as Group 2. RLS was diagnosed according to the International RLS Study Group (IRLSSG) diagnostic criteria. Symptom severity was assessed using the IRLSSG rating scale and sleep quality was measured with the Pittsburgh sleep quality index (PSQI). RLS incidence was higher in Group 1 (p = 0.034). The PSQI scores were higher in Group 1 and the difference between the groups was determined as statistically significant (p < 0.05). No statistically significant difference was determined in respect of the clinical evaluation and the IRLSSG Symptom Severity Scale between the patients in Group 1 diagnosed with RLS and the patients in Group 2 diagnosed with RLS (p > 0.05). The findings of this study support the hypothesis that RLS is more frequent and more severe in vitamin D deficiency and indicate a negative effect of vitamin deficiency on sleep parameters.

Restless legs syndrome: clinical presentation diagnosis and treatment

Restless legs syndrome (RLS) is a circadian disorder of sensory-motor integration that may be related to genetically determined dysregulation of iron transport across the blood-brain barrier. Dopamine agonists (DAs) have been considered the first-line therapy, but with the growing appreciation of problems associated with long-term treatment, particularly augmentation and impulse control disorder, alpha-2-delta drugs, such as gabapentin, are now considered the first line of treatment in patients with troublesome RLS. Opioids can be considered as an alternative therapy, particularly in patients with DA-related augmentation. In more severe cases, a combination therapy may be required. Intravenous iron therapy may be considered on those patients with refractory RLS.

Sleep disorders: A review of the interface between restless legs syndrome and iron metabolism

Restless legs syndrome (RLS) is characterized by unpleasant sensations mainly in the legs. 43% of RLS-associated conditions have also been associated with systemic iron deficiency. The objective of this study was to review in the literature the relationship between iron metabolism and RLS. With an initial search using the keywords combination “Iron Metabolism OR Iron Deficiency AND Restless Legs Syndrome,” 145 articles were screened, and 20 articles were selected. Few studies were found for this review in the period of 2001–2014, however, the correlation between RLS and iron was evident.

Attention-deficit/hyperactivity disorder, iron deficiency, and obesity: is there a link?

The exact etiopathophysiology of attention-deficit/hyperactivity disorder (ADHD) remains elusive, likely because of its phenotypic heterogeneity. Given the involvement of iron in neurocognitive and behavioral functions, iron deficiency (ID) has been suggested as a possible etiopathophysiological factor in a subsample of individuals with ADHD. Most studies assessing ID in ADHD have focused on serum ferritin, a marker of peripheral iron status. Results from these studies are mixed, and the largest studies failed to find a significant association between ADHD and low serum ferritin levels. However, serum ferritin may be influenced by several conditions, including inflammatory status. Increasing evidence, especially from epidemiological studies, points to a significant association between ADHD and obesity. Interestingly, obesity is associated with a chronic inflammatory status, characterized by ID with normal-to-high serum ferritin levels. This article reviews the literature on iron status in ADHD and on the relationship between ADHD and obesity; discusses a possible link among ADHD, ID, and obesity; and proposes that comorbid obesity contributes to ID, via chronic inflammation, in a subsample of individuals with ADHD. Thus, the comorbidity between ADHD and obesity suggests moving beyond serum ferritin levels and assessing the molecular pathways of chronic inflammation that lead to ID in individuals with ADHD and obesity. In turns, this may pave the way for novel treatment strategies for cognitive and behavioral dysfunctions related to ID in ADHD.

Iron, Magnesium, Vitamin D, and Zinc Deficiencies in Children Presenting with Symptoms of Attention-Deficit/Hyperactivity Disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder increasing in prevalence. Although there is limited evidence to support treating ADHD with mineral/vitamin supplements, research does exist showing that patients with ADHD may have reduced levels of vitamin D, zinc, ferritin, and magnesium. These nutrients have important roles in neurologic function, including involvement in neurotransmitter synthesis. The aim of this paper is to discuss the role of each of these nutrients in the brain, the possible altered levels of these nutrients in patients with ADHD, possible reasons for a differential level in children with ADHD, and safety and effect of supplementation. With this knowledge, clinicians may choose in certain patients at high risk of deficiency, to screen for possible deficiencies of magnesium, vitamin D, zinc, and iron by checking RBC-magnesium, 25-OH vitamin D, serum/plasma zinc, and ferritin. Although children with ADHD may be more likely to have lower levels of vitamin D, zinc, magnesium, and iron, it cannot be stated that these lower levels caused ADHD. However, supplementing areas of deficiency may be a safe and justified intervention.

Restless legs syndrome/Willis-Ekbom disease diagnostic criteria: updated International Restless Legs Syndrome Study Group (IRLSSG) consensus criteria--history, rationale, description, and significance

BACKGROUND

In 2003, following a workshop at the National Institutes of Health, the International Restless Legs Syndrome Study Group (IRLSSG) developed updated diagnostic criteria for restless legs syndrome/Willis-Ekbom disease (RLS/WED). These criteria were integral to major advances in research, notably in epidemiology, biology, and treatment of RLS/WED. However, extensive review of accumulating literature based on the 2003 NIH/IRLSSG criteria led to efforts to improve the diagnostic criteria further.

METHODS

The clinical standards workshop, sponsored by the WED Foundation and IRLSSG in 2008, started a four-year process for updating the diagnostic criteria. That process included a rigorous review of research advances and input from clinical experts across multiple disciplines. After broad consensus was attained, the criteria were formally approved by the IRLSSG executive committee and membership.

RESULTS

Major changes are: (i) addition of a fifth essential criterion, differential diagnosis, to improve specificity by requiring that RLS/WED symptoms not be confused with similar symptoms from other conditions; (ii) addition of a specifier to delineate clinically significant RLS/WED; (iii) addition of course specifiers to classify RLS/WED as chronic-persistent or intermittent; and (iv) merging of the pediatric with the adult diagnostic criteria. Also discussed are supportive features and clinical aspects that are important in the diagnostic evaluation.

CONCLUSIONS

The IRLSSG consensus criteria for RLS/WED represent an international, interdisciplinary, and collaborative effort intended to improve clinical practice and promote further research.

Parent-reported sleep problems, symptom ratings, and serum ferritin levels in children with attention-deficit/hyperactivity disorder: a case control study

Background

Sleep problems are common among children with attention-deficit/hyperactivity disorder (ADHD). Serum ferritin levels have been associated with the severity of symptoms and sleep disturbances among children with ADHD. This study was conducted to investigate parent-reported sleep problems in a sample of Egyptian children with ADHD and to examine the relationship between their sleep, symptom-ratings, and low serum ferritin levels.

Methods

Parents of 41 ADHD children, aged 6 to 12 years, filled out the Children’s Sleep Habits Questionnaire (CSHQ) and Conners’ Parent Rating Scale-Revised: Long Version (CPRS-R:L) in Arabic. Serum ferritin levels were determined with an enzyme-linked immunosorbent assay. The parents of the 62 controls filled out the CSHQ.

Results

The ADHD group showed significantly higher scores in CSHQ subscales and total score. Children with serum ferritin levels <30 ng/mL had more disturbed sleep. There were significant negative correlations between sleep duration subscale, total score of CSHQ, and serum ferritin levels. There were no significant differences in hyperactivity, cognitive problems/inattention, oppositional, or ADHD index subscale scores between children with serum ferritin levels <30 ng/mL and those with serum ferritin levels ≥30 ng/mL.

Conclusions

Sleep problems are common, and this study suggests an association between low serum ferritin levels and sleep disturbances.

Iron and ADHD: time to move beyond serum ferritin levels

OBJECTIVE

(a) To compare serum ferritin levels in a sample of stimulant-naïve children with ADHD and matched controls and (b) to assess the association of serum ferritin to ADHD symptoms severity, ADHD subtypes, and IQ.

METHOD

The ADHD and the control groups included 101 and 93 children, respectively. Serum ferritin levels were determined with the enzyme-linked immunosorbent assay method.

RESULTS

Serum ferritin did not significantly differ between children with ADHD and controls, as well as among ADHD subtypes. Correlations between serum ferritin levels and measures related to IQ or ADHD severity were not significant.

CONCLUSION

This is the largest controlled study that assessed ferritin levels in stimulant-naïve ADHD children. The findings of this study do not support a significant relationship between serum ferritin levels and ADHD. However, the authors' results based on peripheral measures of iron do not rule out a possible implication of brain iron deficiency in ADHD, grounded on neurobiological hypotheses and preliminary empirical evidence.

The iron status of children and youth in a community mental health clinic is lower than that of a national sample

OBJECTIVE

Iron plays a key role in brain function, and a deficiency of iron has been implicated in various cognitive, motor, and psychiatric disorders. Because of recent evidence that iron deficiency may be related to attention-deficit/hyperactivity disorder (ADHD) and other psychiatric disorders, the goal of this study was to compare the iron status of children and youth seen in a community mental health clinic with a national sample of same-aged subjects.

METHODS

In this study, a consecutive series of 108 patients (79 males) referred to a community mental health clinic was compared with a National Health and Nutrition Examination Survey (NHANES) sample on measures of iron status. Wilcoxon sign rank and median tests were used to compare distributions of ferritin. Quantile regression was performed to compare the ferritin level in the two samples while adjusting for demographic differences. Chi squared (χ2) was used to compare rates of low hemoglobin in the two samples.

RESULTS

The iron status of the clinic sample, as measured by ferritin levels (median=23 μg/L), was significantly lower than that of the national sample (median=43 μg/L). After adjustment for age, gender, and race, the clinic sample was found to have 19.2 μg/L lower ferritin than the national sample (95% CI from 7.6 to 30.9, p value=0.001). There were also significantly more subjects in the clinic sample with low hemoglobin than in the national sample. There were no differences in ferritin levels between those patients in the clinic sample with and without an ADHD or other specific psychiatric diagnosis.

CONCLUSIONS

The ferritin levels of children and youth in a mental health clinic sample were significantly lower than those of the same-aged subjects in a national sample. Therefore, compromised iron status may be an additional biological risk factor for cognitive, behavioral, and psychiatric problems in pediatric populations served by the community mental health clinic.

Iron status in children with autism spectrum disorder

BACKGROUND AND OBJECTIVES

Children with autism spectrum disorders (ASDs) often have food selectivity and restricted diets, putting them at risk for nutritional deficiencies. Previous studies have demonstrated a high prevalence of iron deficiency (ID) in children with ASDs living in Wales, Canada, and Turkey. The objectives of this study were to determine the prevalence of ID and the adequacy of iron intake in children with ASD in the United States.

METHODS

Participants (age 2-11 years recruited from the Autism Treatment Network Diet and Nutrition Study) completed a 3-day diet record (n = 368) and had laboratory measures of serum ferritin (SF), complete blood count, iron, total iron binding capacity, and transferrin saturation (TS) (n = 222).

RESULTS

Of the 222 participants with laboratory data, 18 (8%) had SF <12 µg/L and 2 (1%) had ID defined by both low SF and TS (3 children with low SF had missing TS data). One subject had iron deficiency anemia. Fewer than 2% of subjects had iron intake below the estimated average requirement.

CONCLUSIONS

Although the determination of iron status is complex, these data do not support previous reports that children with ASD are at greater risk for ID than the general population; however, 8% percent of the sample did demonstrate low SF despite <2% of the sample demonstrating iron intake below the estimated average requirement. The prevalence of low SF may be an underestimate, because SF is an acute phase reactant and the study included no measure of inflammation.

Restless leg syndrome, periodic limb movements, febrile seizures and Attention deficit hyperactivity disorder in an Indian family

Restless leg syndrome (RLS) is a common neurological disorder which can affect individuals of all age groups and incidence increasing with age. It can cause severe sleep disruption and negatively impact quality of life of an individual. Its diagnosis is clinical, based on essential criteria of International RLS Study Group. It can be idiopathic or associated with various medical and other neurological disorders. Idiopathic RLS can be sporadic or may have a familial inheritance, with several genetic loci been reported till date. RLS has a strong association with periodic limb movements, both sleep and awake. Very few studies of familial RLS/Periodic limb movements in sleep and their associations have been reported. We report an Indian family with autosomal dominant RLS/PLMS, with RLS and PLMS as well as psychiatric disorders, febrile seizures and Attention Deficit Hyperactivity Disorder in different family members, over three generations.

Pediatric restless legs syndrome: analysis of symptom descriptions and drawings

The specific aims of this study were to collect and analyze detailed symptom descriptions from patients with pediatric restless legs syndrome, ages 6 to 17 years, as well as assess symptom impact and the usefulness of drawings. Trained qualitative interviewers conducted face-to-face audio-recorded interviews of children and adolescents who met criteria for definite restless legs syndrome. Thirty-three patients in 3 age groups used 16 different categories of descriptors for restless legs sensations, with a mean of 3 or more categories used per patient in each age group. "Need to move/kick," "pain/hurts," "uncomfortable/cannot get comfortable," and "like bugs or ants/crawling" were the most common descriptors. Two-thirds reported daytime sensations, and nearly half had arm involvement. They described impact on sleep, cognitive function, and affect. Drawings provided useful diagnostic information. These detailed empirical data will be useful in clinical practice, as well as in the development of formal diagnostic tools and severity measures.

Restless legs syndrome: a comprehensive overview on its epidemiology, risk factors, and treatment

PURPOSES

Restless legs syndrome (RLS) is underdiagnosed and poorly understood by clinicians and the general public alike; accordingly, a broad literature review with information most relevant to general practice is needed to help dispel misconceptions and improve level of care.

METHODS

Specifically, this review comprehensively provides an epidemiological analysis of RLS and examines the risk factors and treatment options for RLS by compiling the findings of past RLS studies. These RLS studies were identified through a retrospective PubMed search. The epidemiological analysis was conducted by calculating a weighted mean average of all the relevant general population RLS prevalence studies, separated into geographical/racial categories.

RESULTS

A comprehensive analysis of RLS epidemiological studies finds the prevalence rate of RLS to be 5-15% in the general population with 2.5% of adults having symptoms severe enough to require medical intervention. Some of the risk factors for RLS include female gender, pregnancy, low iron levels, lower socioeconomic status, poor health, elderly age, comorbidity with Parkinson's disease, positive family history of RLS, and comorbidity with psychiatric disorders. A wide array of treatment options exist for RLS including pharmacological and nonpharmacologic interventions.

CONCLUSIONS

Clinicians' understanding of RLS enigma has recently improved due to the increased intensity of RLS research over the past decade. This review summarizes the current findings in the RLS field as well as providing guidelines for future RLS-related research.

Restless legs syndrome, periodic leg movements, and periodic limb movement disorder in children

The characteristic symptoms of restless legs syndrome (RLS) have been known for hundreds of years and were first reported in medicine in the 1600s. Clinicians must consider potential mimics, comorbid, and associated conditions when evaluating children with RLS symptoms. The traditional differentiation of RLS from periodic limb movement disorder (PLMD) is noted in children as well as adults. Because current pediatric RLS research is sparse, this article provides the most up-to-date evidence-based as well as consensus opinion-based information on the subject of childhood RLS and PLMD. Prevalence, pathophysiology, diagnosis, treatment, and clinical associations are discussed.

L-Dopa improves Restless Legs Syndrome and periodic limb movements in sleep but not Attention-Deficit-Hyperactivity Disorder in a double-blind trial in children

BACKGROUND

In a previous open-label study, dopaminergic agents improved Restless Legs Syndrome (RLS) and Periodic Limb Movements in Sleep (PLMS), as well as Attention-Deficit-Hyperactivity Disorder (ADHD) in children with both disorders. We therefore conducted a double-blind placebo-controlled trial of L-DOPA in ADHD children with and without RLS/PLMS.

METHODS

Two groups of patients (total n = 29), those with ADHD only or those with ADHD and RLS/PLMS, were randomized to L-DOPA or placebo therapy. At baseline and after therapy patients were assessed with Conners' parent and teacher rating scales; polysomnography; RLS rating scale; and neuropsychometric measures of memory, learning, attention, and vigilance.

RESULTS

L-DOPA improved RLS/PLMS symptoms in all patients with those disorders compared with placebo (p = .007). When assessed by the Conners' Scales before therapy, ADHD was more severe in children without RLS/PLMS than in children with RLS/PLMS (p = 0.006). L-DOPA had no effect on Conners' scales, sleep, or neuropsychometric tests when all patients treated with the drug were compared to those on placebo or when patients with ADHD only were compared to those with ADHD and RLS/PLMS.

CONCLUSIONS

In this first double-blind study of a dopaminergic therapy in children with RLS/PLMS, L-Dopa significantly improved RLS/PLMS but not ADHD. These results, however, should be interpreted carefully since they may have been influenced by the relatively small sample size and the baseline differences in severity of ADHD symptoms. Further work needs to be done to elucidate the relationship between dopamine, ADHD and RLS/PLMS.

RLS in middle aged women and attention deficit/hyperactivity disorder in their offspring

BACKGROUND

Previous studies have suggested that attention deficit/hyperactivity disorder (ADHD) and restless legs syndrome (RLS) could share some common genetic backgrounds, but the effect of these genetic components could be modest. To test this hypothesis, we conducted a large-scaled cross-sectional study to examine whether women with a child with ADHD had a higher risk of having RLS than women of unaffected children.

METHODS

We included 65,554 women free of diabetes, arthritis, and pregnancy in the current analyses. Information on RLS was assessed using a set of standardized questions. Participants were considered to have RLS if they met four RLS diagnostic criteria recommended by the International RLS Study Group and had restless legs ≥5 times/month. Information on ADHD in offspring was collected via questionnaire.

RESULTS

We observed a significant association between presence of ADHD in the offspring and risk of having RLS; the multivariate-adjusted OR for RLS was 1.27 (95% CI: 1.15, 1.41; P<0.0001), after adjusting for age, body mass index, number of deliveries during life time and other covariates.

CONCLUSION

We found that mothers of children with ADHD had an increased risk of having RLS. Further studies are warranted to explore biological mechanisms underling this association.

Development of the Pediatric Restless Legs Syndrome Severity Scale (P-RLS-SS): a patient-reported outcome measure of pediatric RLS symptoms and impact

OBJECTIVE

To develop a questionnaire to measure Pediatric Restless Legs Syndrome (P-RLS) symptoms and impact for use in clinical research.

METHODS

Questionnaire items were developed based on open-ended, qualitative interviews of 33 children and adolescents diagnosed with definite RLS (ages 6-17 years) and their parents. The draft questionnaire was then tested through cognitive debriefing interviews with 21 of the same children/adolescents and 15 of their parents. This involved the children and parents answering the draft items and then interviewing them about the child's ability to understand and interpret the questionnaire. Expert clinicians provided clinical guidance throughout.

RESULTS

Draft severity questions were generated to measure the four-symptom and four-impact domains identified from the concept elicitation interviews: RLS sensations, move/rub due to RLS, relief from move/rub, pain, and impact of RLS on sleep, awake activities, emotions, and tiredness. RLS descriptions, symptoms, and impact were compared between those who had comorbid attention-deficit/hyperactivity disorder and those who did not. Revisions to several questions were made based on the cognitive debriefing interviews and expert clinician review, resulting in a severity scale with 17 morning and 24 evening items. Caution regarding self-administration in children ages 6-8 years is recommended. To complement the child/adolescent measures, a separate parent questionnaire was also developed.

CONCLUSIONS

The P-RLS-SS was constructed based on detailed input from children and adolescents with RLS, their parents, and clinical experts, thus providing a scale with strong content validity that is intended to be comprehensive, clinically relevant, and important to patients. Validation of this scale is recommended.

The relationship with iron and health outcomes in persons with restless legs syndrome

BACKGROUND

Restless Legs Syndrome (RLS) is a sleep disorder cause by inadequate iron metabolism. However, no studies have identified the impact of iron in RLS patients on sleep, depression, fatigue, or quality of life (QoL).

OBJECTIVE

The aims of this secondary data analysis was to determine relationships (a) between serum iron with RLS symptom severity, sleep quality, daytime sleepiness, depression, fatigue, and quality of life (QoL); and (b) based on demographics, specifically age and ethnicity.

METHOD

Data were collected on iron and ferritin concentrations in 48 persons with RLS.

RESULTS

Low serum iron levels were measured in 32% of the participants with only 1 person (4%) treated with iron supplementation. General linear models identified age and race as covariants: (a) being White (p = .047) and higher iron levels (p = .019) were independent predictors of higher social functioning; (b) being White (p = .047) and higher iron levels (p = .004) were independent predictors of less sleepiness; (c) younger age (p = .001) and lower iron levels (p = .025) were independent predictors of depression; and (d) younger age (p = .006) and lower iron levels (p = .005) were independent predictors of fatigue.

DISCUSSION

Findings from this study show that iron supplementation for persons with RLS not only improves motor and sensory symptoms but might also improve sleep, sleepiness, depression, fatigue, and QoL and should be considered by health care providers for treatment of RLS.

All the wrong moves: a clinical review of restless legs syndrome, periodic limb movements of sleep and wake, and periodic limb movement disorder

Restless legs syndrome, periodic limb movements in sleep, and periodic limb movement disorder are a group of conditions that merit awareness from the medical community. These disorders are commonly encountered yet are often confused and misdiagnosed by health care professionals. It is imperative that health care providers are able to recognize these conditions to accurately diagnose, manage, and appropriately refer patients.

Effects of zinc and ferritin levels on parent and teacher reported symptom scores in attention deficit hyperactivity disorder

OBJECTIVE

It has been suggested that both low iron and zinc levels might be associated with Attention Deficit Hyperactivity Disorder (ADHD) symptoms. However, the association of zinc and iron levels with ADHD symptoms has not been investigated at the same time in a single sample.

METHOD

118 subjects with ADHD (age = 7-14 years, mean = 9.8, median = 10) were included in the study. The relationship between age, gender, ferritin, zinc, hemoglobin, mean corpuscular volume and reticulosite distribution width and behavioral symptoms of children and adolescents with ADHD were investigated with multiple linear regression analysis.

RESULTS

Results showed that subjects with lower zinc level had higher Conners Parent Rating Scale (CPRS) Total, Conduct Problems and Anxiety scores, indicating more severe problems. CPRS Hyperactivity score was associated both with zinc and ferritin levels. Conners Teacher Rating Scale (CTRS) scores were not significantly associated with zinc or ferritin levels.

CONCLUSIONS

Results indicated that both low zinc and ferritin levels were associated with higher hyperactivity symptoms. Zinc level was also associated with anxiety and conduct problems. Since both zinc and iron are associated with dopamine metabolism, it can be speculated that low zinc and iron levels might be associated with more significant impairment in dopaminergic transmission in subjects with ADHD.

Methylphenidate improves cognitive deficits produced by infantile iron deficiency in rats

In humans, iron deficiency early in life produces persistent, impaired cognition. Dietary iron replacement does not ameliorate these problems and to date, no attempt to treat these individuals pharmacologically has been reported. The aim of this work was to test the hypothesis that rats made iron deficient in early infancy exhibit cognitive deficits similar to those seen in humans at adolescence. A second aim was to investigate whether the deficit could be treated pharmacologically. Sprague-Dawley rats were made iron deficient (ID) starting at postnatal day 4 by being placed with iron-deficient dams (vs. control). At weaning, all pups were placed on an iron-sufficient diet for the remainder of the study. At 45 days of age, the animals were tested for attention set shifting. After testing, the animals were assigned to one of three methylphenidate (MePh) dose groups, 1, 5 or 10 mg/kg, p.o., vs. vehicle control and treated daily for 15 days prior to a second round of attention set shift testing and continued throughout testing. The results showed that ID rats performed more poorly than controls overall on attentional set-shift testing. MePh improved ID rats' performance and lower doses were more effective than higher doses. This is the first demonstration that MePh can improve cognitive deficits produced by early ID in animals. These findings may open the possibility of pharmacotherapy to treat the persistent cognitive difficulties in children who were severely iron deficient in early infancy.

Nutritional status of children with attention deficit hyperactivity disorder: a pilot study

Objectives. This is a pilot study of the dietary intake and nutrient status of children with Attention Deficit Hyperactivity Disorder (ADHD). Method. Nutritional assessment of 43 children aged 6–12 with ADHD was performed using a 3-day food record, 24-hour recall, and serum assessors. Results. Macronutrient intake and consumption of Low-Nutrient Foods were comparable to population norms; however, 66% were found to be deficient in zinc and 23% in copper. Conclusions. This pilot study reports the food intake and nutrient status of children with ADHD and shows a predisposition for low zinc and copper status in ADHD.

Children show individual night-to-night variability of periodic limb movements in sleep

STUDY OBJECTIVE

Several studies have documented the occurrence of significant night-to-night variability of periodic limb movements in sleep (PLMS) in adults.The aim of this study was to investigate the night-tonight variability of PLMS in children.

DESIGN AND MEASUREMENTS

Two to 4 nights of polysomnography were performed as part of a multisite, placebo-controlled study investigating the effects of carbidopa/levodopa on attention-deficit/hyperactivity disorder in children who were not taking other medications that impacted the central nervous system. Baseline polysomnograms from all children and endpoint polysomnograms from children who were randomly assigned to a placebo group were scored using International Restless Legs Syndrome Study Group criteria for PLMS. PLMS indexes from 101 sleep studies of 36 children, aged 7 to 12 years, were compared.

INTERVENTIONS

N/A.

RESULTS

For all 36 children as a group, PLMS index on Night 1 was predictive of PLMS index on Night 2 (odds ratio 7.0, 95% confidence interval 1.4-38.4), suggesting that overall diagnostic classification (PLMS index above or below 5/h) was accurate. In addition, for the 15 children with 5 or more PLMS per hour on either night, there was no significant group difference on Night 1 versus Night 2 for mean PLMS index (10.6 vs 8.5/h, P = 0.92) or chance of having 5 or more PLMS per hour, indicating no first-night effect. When looking at individual data, however, 9 of these 15 children (60%) had PLMS indexes over and under the 5 per hour cutoff on these 2 nights. Of these 15, 10 had clinical diagnoses of restless legs syndrome and 5 of periodic limb movement disorder (PLMD). The PLMS indexes of all children who were medication free for a third and fourth night (n = 7) or just a third night (n = 2) and had not shown a PLMS index of 5 or greater on either of the first 2 nights remained under this threshold.

CONCLUSIONS

In this sample of children, considerable individual night-to-night variability of PLMS indexes was observed. This finding has important clinical relevance for the diagnosis of restless legs syndrome and PLMD and may have an impact on future studies that correlate individual PLMS severity with frequently associated symptoms, such as negative affect, fatigue, and inattention. Our data, however, also suggest that individual PLMS variability is random and not likely to skew the group-level analysis of treatment outcome studies.

Sleep disturbances and serum ferritin levels in children with attention-deficit/hyperactivity disorder

BACKGROUND

A subset of children with attention-deficit/hyperactivity disorder (ADHD) may present with impairing sleep disturbances. While preliminary evidence suggests that iron deficiency might be involved into the pathophysiology of daytime ADHD symptoms, no research has been conducted to explore the relationship between iron deficiency and sleep disturbances in patients with ADHD. The aim of this study was to assess the association between serum ferritin levels and parent reports of sleep disturbances in a sample of children with ADHD.

SUBJECTS

Sixty-eight consecutively referred children (6-14 years) with ADHD diagnosed according to DSM-IV criteria using the semi-structured interview Kiddie-SADS-PL.

MEASURES

parents filled out the Sleep Disturbance Scale for Children (SDSC) and the Conners Parent Rating Scale (CPRS). Serum ferritin levels were determined using the Tinaquant method.

RESULTS

Compared to children with serum ferritin levels >or=45 microg/l, those with serum ferritin levels <45 microg/l had significantly higher scores on the SDSC subscale "Sleep wake transition disorders" (SWTD) (P = 0.042), which includes items on abnormal movements in sleep, as well as significantly higher scores on the CPRS-ADHD index (P = 0.034). The mean scores on the other SDSC subscales did not significantly differ between children with serum ferritin >or=45 and <45 microg/l. Serum ferritin levels were inversely correlated to SWTD scores (P = 0.043).

CONCLUSION

Serum ferritin levels <45 microg/l might indicate a risk for sleep wake transition disorders, including abnormal sleep movements, in children with ADHD. Our results based on questionnaires set the basis for further actigraphic and polysomnographic studies on nighttime activity and iron deficiency in ADHD. Research in this field may suggest future trials of iron supplementation (possibly in association with ADHD medications) for abnormal sleep motor activity in children with ADHD.

Exploring the genetic link between RLS and ADHD

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder of childhood onset. Clinical and biological evidence points to shared common central nervous system (CNS) pathology of ADHD and restless legs syndrome (RLS). It was hypothesized that variants previously found to be associated with RLS in two large genome-wide association studies (GWA), will also be associated with ADHD. SNPs located in MEIS1 (rs2300478), BTBD9 (rs9296249, rs3923809, rs6923737), and MAP2K5 (rs12593813, rs4489954) as well as three SNPs tagging the identified haplotype in MEIS1 (rs6710341, rs12469063, rs4544423) were genotyped in a well characterized German sample of 224 families comprising one or more affected sibs (386 children) and both parents. We found no evidence for preferential transmission of the hypothesized variants to ADHD. Subsequent analyses elicited nominal significant association with haplotypes consisting of the three SNPs in BTBD9 (chi2 = 14.8, df = 7, nominal p = 0.039). According to exploratory post hoc analyses, the major contribution to this finding came from the A-A-A-haplotype with a haplotype-wise nominal p-value of 0.009. However, this result did not withstand correction for multiple testing. In view of our results, RLS risk alleles may have a lower effect on ADHD than on RLS or may not be involved in ADHD. The negative findings may additionally result from genetic heterogeneity of ADHD, i.e. risk alleles for RLS may only be relevant for certain subtypes of ADHD. Genes relevant to RLS remain interesting candidates for ADHD; particularly BTBD9 needs further study, as it has been related to iron storage, a potential pathophysiological link between RLS and certain subtypes of ADHD.

Pediatric restless legs syndrome and periodic limb movement disorder: parent-child pairs

OBJECTIVE

Although recent publications have reported the occurrence of restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) in children and adolescents, the literature is relatively limited. The goals of this retrospective study were to (1) apply the recent International Classification of Sleep Disorders 2nd edition (ICSD-2) diagnostic criteria for RLS and PLMD in pediatric cases where periodic limb movements in sleep (PLMS) 5 per hour were found; (2) review parental history of RLS; and (3) further define the clinical characteristics of RLS and PLMD in a pediatric subgroup where each child had a parent with clinically assessed RLS.

METHODS

This was a retrospective analysis of consecutive polysomnograms (PSGs) with PLMS >5 per hour in patients 19 years of age from a single pediatric sleep/neurology practice over 11 years. Excluded were cases with sleep apnea, narcolepsy, or medication that might induce or aggravate PLMS or RLS. ICSD-2 diagnostic criteria for definite RLS and PLMD were applied to the pediatric cases, and parental history for RLS was assessed. A subset of cases was included for detailed review if the child or adolescent had RLS or PLMD and a biological parent met RLS criteria and had a formal sleep evaluation.

RESULTS

There were 204 cases that met the initial inclusion criteria. A positive parental history of RLS was found in 53% of pediatric RLS cases and in 52% of pediatric PLMD cases. A subset of 37 children or adolescents and 36 biological parents, from 33 different families, met full inclusion criteria and are presented in detail. Of these 37, 10 had a diagnosis of RLS and 27 a diagnosis of PLMD. Over this same period of time, PLMS >5 per hour were found in 74% of pediatric definite RLS cases assessed by PSG.

CONCLUSIONS

This case series adds to the growing literature describing RLS and PLMD in children and adolescents using recently revised diagnostic criteria. The similar prevalence of parental RLS in both pediatric RLS and pediatric PLMD cases suggests a close association between PLMD and RLS in some cases. This supports the emerging view that PLMS may be a marker or endophenotype for a specific, common RLS genotype.