Coexistence of periodic limb movements during sleep with restless legs syndrome and its association with hypertension in Japanese patients.

BACKGROUND: Caucasian patients with restless legs syndrome (RLS) frequently exhibit periodic limb movements during sleep (PLMS), which may increase the risk of hypertension. We evaluated the positivity rate of PLMS and factors associated with positivity in Japanese patients with RLS, and tested whether the complications of PLMS are associated with the presence of hypertension. METHODS: We retrospectively investigated polysomnographic data and the presence or absence of hypertension in patients with RLS. Patients with systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg or those taking antihypertensive medication were categorized as the group with hypertension. RESULTS: Among 468 patients, 200 (42.7%) had periodic limb movement index (PLMI) values ≥ 15/h and 108 (23.1%) met the criteria of positivity for hypertension. Multiple logistic regression analysis revealed that only higher age was significantly associated with PLMI values ≥ 15/h. Multiple linear regression analyses of factors associated with an increased PLMI also showed that increased PLMI was significantly correlated with higher age and male sex, but not with the international restless legs scale scores. Multiple logistic regression analysis also revealed that higher age and body mass index, not PLMI values ≥ 15/h, were significantly associated with the presence of hypertension. CONCLUSION: The PLMS-positivity rate may be lower in Japanese patients with RLS than in Caucasian patients, and it increases with age and male sex, but not with the severity of the disorder. Furthermore, PLMS complications were not associated with the risk of hypertension in Japanese patients with RLS.

Association of Periodic Limb Movements and Obstructive Sleep Apnea With Risk of Cardiovascular Disease and Mortality.

BACKGROUND: Obstructive sleep apnea is a well-established risk factor for cardiovascular disease (CVD). Recent studies have also linked periodic limb movements during sleep to CVD. We aimed to determine whether periodic limb movements during sleep and obstructive sleep apnea are independent or synergistic factors for CVD events or death. METHODS AND RESULTS: We examined data from 1049 US veterans with an apnea-hypopnea index (AHI) <30 events/hour. The primary outcome was incident CVD or death. Cox proportional hazards regression assessed the relationships between the AHI, periodic limb movement index (PLMI), and the AHI×PLMI interaction with the primary outcome. We then examined whether AHI and PLMI were associated with primary outcome after adjustment for age, sex, race and ethnicity, obesity, baseline risk of mortality, and Charlson Comorbidity Index. During a median follow-up of 5.1 years, 237 of 1049 participants developed incident CVD or died. Unadjusted analyses showed an increased risk of the primary outcome with every 10-event/hour increase in PLMI (hazard ratio [HR], 1.08 [95% CI, 1.05-1.13]) and AHI (HR, 1.17 [95% CI, 1.01- 1.37]). Assessment associations of AHI and PLMI and their interaction with the primary outcome revealed no significant interaction between PLMI and AHI. In fully adjusted analyses, PLMI, but not AHI, was associated with an increased risk of primary outcome: HR of 1.05 (95% CI, 1.00-1.09) per every 10 events/hour. Results were similar after adjusting with Framingham risk score. CONCLUSIONS: Our study revealed periodic limb movements during sleep as a risk factor for incident CVD or death among those who had AHI <30 events/hour, without synergistic association between periodic limb movements during sleep and obstructive sleep apnea.

[Abnormal nocturnal behavior mimicking REM sleep behavior disorder episodes in a patient with periodic limb movement disorder].

Periodic limb movement disorder (PLMD) is a condition in which patients experience frequent periodic limb movements of sleep (PLMS). Synchronized arousal responses cause sleep fragmentation, resulting in insomnia, daytime sleepiness, and fatigue. A 59-year-old man was identified as having intense sleep-talking and body movements, suggesting rapid eye movement (REM) sleep behavior disorder (RBD). Attended video-polysomnography (PSG) revealed that sleep-talking and body movements occurred only during non-REM sleep and were associated with PLMS-induced arousals (periodic leg movement arousal index, 53.2/h). Pramipexole administration improved events during sleep and daytime sleepiness, and the PSG findings and clinical course led to a diagnosis of PLMD. This case demonstrates that PLMD mimics the symptoms of RBD and that a detailed analysis of monitored video PSG is crucial to confirm the diagnosis of RBD and to identify or exclude other causes of sleep talking and behavior.

[Periodic limb movements in sleep and cerebral small vessel disease progression: a prospective cohort study]. / Periodicheskie dvizheniya konechnostei vo sne i progressirovanie tserebral'noi mikroangiopatii: prospektivnoe kogortnoe issledovanie.

OBJECTIVE: To determine the predictive role of periodic limb movements in sleep (PLMS) in cerebral small vessel disease (cSVD) progression rate. MATERIAL AND METHODS: Fifty patients with cSVD, aged 60-75 y.o., were enrolled. The study protocol included MRI assessment of white matter hyperintensities (WMH), nocturnal actigraphy and cognitive assessment. Depending on the PLMS, the main (PLM index ≥15) and the control (PLM index <15) groups were formed. The second visit was carried out in one year follow-up period, the examination consisted of brain MRI and cognitive assessment under the same protocol. ANCOVA was performed to determine if PLMS influence the degree of MRI- and neuropsychological changes. RESULTS: A significant effect of PLMS on the increase in the volume of WMH was revealed, both in the form of an increase in the index by more than 15 movements per hour (p=0.03), and quantitatively in the form of a connection with the index value (p=0.048). The influence of PLMS on the progression of cognitive dysfunction has not been found, however, it has been shown that the presence of PLMS is associated with lesions in the deep white matter (r=0.42, p<0.0001), and the results of neuropsychological tests are associated with lesions in the periventricular and juxtacortical WMH (p < 0.05 for each test). CONCLUSION: PLMS predict WMH progression in cSVD.

A 9-year-old female with iron deficiency has severe periodic limb movements while taking mirtazapine for insomnia.

Mirtazapine is a Food and Drug Administration-approved atypical antidepressant used off-label for insomnia. Mirtazapine has been associated with movement disorders in adults. A 9-year-old female was seen in the sleep clinic for symptoms of insomnia, nocturnal awakenings, restless sleep, and growing pains. Mirtazapine was started prior to presentation for severe insomnia. A sleep study showed frequent repetitive leg movements prior to sleep onset as well as significant periodic limb movement disorder with a periodic limb movement index of 25.1/hour. The child was found to have a ferritin level of 23 ng/mL and an iron saturation of 10%. There were concerns that the presence of iron deficiency along with the use of mirtazapine may have contributed to the elevated periodic limb movement index. After starting iron therapy to treat the child's iron deficiency, mirtazapine was weaned off, with further clinical improvements in sleep quality reported. A follow-up sleep study showed a resolution of her periodic limb movement disorder with a periodic limb movement index of 1.4/hour. This is the first pediatric case to describe a sleep-related movement disorder associated with the use of mirtazapine and polysomnographic data to support resolution after discontinuation of mirtazapine along with iron therapy. CITATION: Hawkins M. A 9-year-old female with iron deficiency has severe periodic limb movements while taking mirtazapine for insomnia. J Clin Sleep Med. 2023;19(7):1369-1373.

Nocturnal Hypoxia and Sleep Fragmentation May Drive Neurodegenerative Processes: The Compared Effects of Obstructive Sleep Apnea Syndrome and Periodic Limb Movement Disorder on Alzheimer's Disease Biomarkers.

BACKGROUND: Sleep disorders may cause dysregulation in cerebral glucose metabolism and synaptic functions, as well as alterations in cerebrospinal fluid (CSF) biomarker levels. OBJECTIVE: This study aimed at measuring sleep, CSF Alzheimer's disease (AD) biomarkers, and cerebral glucose consumption in patients with obstructive sleep apnea syndrome (OSAS) and patients with periodic limb movement disorder (PLMD), compared to controls. METHODS: OSAS and PLMD patients underwent 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET), polysomnographic monitoring, and lumbar puncture to quantify CSF levels of amyloid-ß42 (Aß42), total tau, and phosphorylated tau. All patients were compared to controls, who were not affected by sleep or neurodegenerative disorders. RESULTS: Twenty OSAS patients, 12 PLMD patients, and 15 controls were included. Sleep quality and sleep structure were altered in both OSAS and PLMD patients when compared to controls. OSAS and PLMD patients showed lower CSF Aß42 levels than controls. OSAS patients showed a significant increase in glucose uptake in a wide cluster of temporal-frontal areas and cerebellum, as well as a reduced glucose consumption in temporal-parietal regions compared to controls. PLMD patients showed increased brain glucose consumption in the left parahippocampal gyrus and left caudate than controls. CONCLUSION: Sleep dysregulation and nocturnal hypoxia present in OSAS patients, more than sleep fragmentation in PLMD patients, were associated with the alteration in CSF and 18F-FDG PET AD biomarkers, namely reduction of CSF Aß42 levels and cerebral glucose metabolism dysregulation mainly in temporal areas, thus highlighting the possible role of sleep disorders in driving neurodegenerative processes typical of AD pathology.

Association between Self-Perceived Periodic Limb Movement during Sleep and Excessive Daytime Sleepiness Depend on Restless Leg Symptoms in Korean Adolescents.

Although periodic limb movement during sleep (PLMS) and restless legs syndrome (RLS) are common in children and adolescents, they are relatively overlooked as a target of treatment. PLMS has been evaluated as having a lower clinical significance than RLS. This study examined the relationship of socio-behavioral factors of PLMS in Korean adolescents and checked whether PLMS is associated with excessive daytime sleepiness (EDS), depending on whether restless legs symptoms accompany it. In a cross-sectional study, 25,789 adolescents between 12 and 18 years of age (15.76 ± 1.73 years; female 51.49%) were evaluated using an online survey. Various self-report questionnaires were used to assess PLMS and RLS symptoms, EDS, sleep habits, and various socio-behavioral factors. The prevalence of self-perceived PLMS and restless legs symptoms were 903 (3.50%) and 1311 (5.08%), respectively. Of the 1311 participants, 399 had self-perceived PLMS. The odds ratios (ORs) for self-perceived PLMS in participants with restless legs symptoms were: males (OR = 1.528; 95% CI: 1.145-2.040), usually/always experienced apnea apnea (OR, 3.006; 95% CI, 1.954-4.624), increased proneness to Internet addiction (OR = 1.013; 95% CI: 1.001-1.025), sometimes/often consuming coffee (OR = 1.312; 95% CI: 1.015-1.695), EDS (OR = 0.826; 95% CI: 0.488-1.398), and perceived insufficient sleep (OR = 1.143; 95% CI: 0.835-1.565). The male gender, witness apnea, consuming coffee, and being prone to Internet addiction were identified as factors significantly associated with self-perceived PLMS in participants with restless legs symptoms. However, EDS and insufficient sleep were associated with self-perceived PLMS in the absence of restless legs symptoms.

Restless Legs Symptoms and Periodic Leg Movements in Sleep Among Patients with Parkinson's Disease.

BACKGROUND: The association between restless legs syndrome (RLS) and Parkinson's disease (PD) remains controversial, with epidemiologic and descriptive evidence suggesting some potential overlap while mechanistic/genetic studies suggesting relative independence of the conditions. OBJECTIVE: To examine a known, objectively measured endophenotype for RLS, periodic leg movements (PLMS) in sleep, in patients with PD and relate that objective finding to restless legs symptoms. METHODS: We performed polysomnography for one (n = 8) or two (n = 67) consecutive nights in 75 PD patients and examined the association of PLMS with restless legs symptoms. RESULTS: We found no association between restless legs symptoms and PLMS in PD. Prevalence of both was similar to data reported previously in other PD samples. CONCLUSION: We interpret these results as suggesting that restless legs symptoms in PD patients may represent a different phenomenon and pathophysiology than RLS in the non-PD population.

Association of Periodic Limb Movements With Medication Classes: A Retrospective Cohort Study.

BACKGROUND AND OBJECTIVES: To investigate the association between various medication classes and the periodic limb movement index (PLMI) in a clinical cohort of adults who completed in-laboratory polysomnography. METHODS: A single, diagnostic, overnight, in-laboratory polysomnogram was completed for 3,488 patients consecutively referred from 2010 to 2015 to determine PLMI. Medication use and medical comorbidities were collected through patient questionnaires. Associations between medication classes and PLMI were ascertained using multivariable ordinal logistic regression models. RESULTS: The median age of the cohort was 56.0 years (48.2% male). After adjusting for age, sex, body mass index, relevant comorbidities, and sleep measures, the use of selective serotonin reuptake inhibitors (SSRIs) (odds ratio [OR] 1.52) and serotonin-norepinephrine reuptake inhibitors (SNRIs) (OR 1.99) was associated with increased PLMI. Conversely, gabapentinoids (OR 0.71), stimulants (OR 0.52), benzodiazepines (OR 0.79), and dopamine agonists (OR 0.38) were associated with decreased PLMI. A non-statistically significant trend for decreased PLMI with neuroleptic use was observed. No significant associations were found between PLMI and the use of antihypertensives, statins, tricyclic antidepressants, bupropion, anticoagulants, antiplatelets, modafinil, and antihistamines. DISCUSSION: The use of SSRIs and SNRIs was associated with elevated PLMI while the use of gabapentinoids, stimulants, benzodiazepines, and dopamine agonists was associated with decreased PLMI. These results can assist physicians in managing periodic limb movements in sleep (PLMS) and invite further research into the relationship between PLMS and medications with the modulating effects of dose, formulation type, and time of administration. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that SSRIs and SNRIs are associated with elevated PLMI while gabapentinoids, stimulants, benzodiazepines, and dopamine agonists are associated with decreased PLMI.

Large body movements on video polysomnography are associated with daytime dysfunction in children with restless sleep disorder.

Restless sleep disorder (RSD) is a newly defined sleep-related movement disorder characterized by large muscle movements (LMM) in sleep. We examined the sleep study, clinical characteristics, and daytime functioning in children with RSD and compared them to children with periodic limb movement disorder (PLMD) or restless legs syndrome (RLS). Video polysomnography from 47 children with restless sleep was retrospectively reviewed for LMM and age- and sex-matched to 34 children with PLMD and 12 children with RLS. Data examined included PSG characteristics, ferritin, Pediatric Quality of Life (PedsQL), and Epworth Sleepiness Scale (ESS). Fourteen children met the clinical criteria for RSD with an LMM index of 5 or more per hour of sleep. Mean ESS was elevated in patients with RSD compared to either the PLMD or RLS groups though the result did not reach statistical significance (RSD = 10.20 ± 6.81, PLMD = 6.19 ± 4.14, RLS = 6.25 ± 4.90). The PedsQL score was significantly decreased in the RLS group compared to RSD and was reduced overall in all three groups (PedsQL Total RSD = 70.76 ± 18.05, PLMD = 57.05 ± 20.33, RLS = 53.24 ± 16.97). Serum ferritin values were similar in all three groups (RSD = 26.89 ± 10.29, PLMD = 33.91 ± 20.31, RLS = 23.69 ± 12.94 ng/mL, p = ns). Children with RSD demonstrate increased daytime sleepiness compared to PLMD or RLS and all three disease groups showed decreased quality of life. Further studies are needed to examine long-term consequences of RSD.

Restless sleep disorder, restless legs syndrome, and periodic limb movement disorder-Sleep in motion!

Sleep-related movement disorders (SRMDs) represent an important part of pediatric sleep disorders. The most common complaint in SRMD is restless sleep at night. Restless sleep is reported in up to 80% of children with restless legs syndrome (RLS) and children with periodic limb movements of sleep (PLMS) disorder (PLMD). However, restless sleep causing daytime behavioral consequences can be seen in children without another apparent condition and has recently been identified as a new independent primary pediatric sleep disorder, called restless sleep disorder (RSD). This study describes these three main SRMDs (RSD, RLS, and PLMD), explains the new consensus criteria for RSD, emphasizes the rapidly evolving areas of research in this field, and proposes recommendations for future research. In particular, the published data constitute convincing evidence that sleep-related movements are disruptors of sleep quality and continuity. However, while important advancements have recently been reported in adults, a detailed analysis of the phenomenology and consequences of sleep-related movements has just started in children. New approaches, standardized diagnostic methods, and specific guidelines are needed in the field of pediatric SRMD.

Leg movement activity during sleep in multiple sclerosis with and without restless legs syndrome.

STUDY OBJECTIVES: To carry out an analysis of leg movement activity during sleep in a polysomnography dataset of patients with multiple sclerosis (MS) in comparison to idiopathic restless legs syndrome (iRLS) and healthy controls. METHODS: In this cross-sectional, observational, instrumental study, 57 patients (males/females: 11/46; mean age 46.2 ± 10.2 years) with a diagnosis of MS underwent a telephone interview assessing the 5 standard diagnostic criteria for RLS and polysomnography. Sleep architecture and leg movement activity during sleep were subsequently compared: 1) 40 patients with MS without RLS (MS-RLS) vs 28 healthy controls; 2) 17 patients with MS with RLS (MS+RLS) vs 35 patients with iRLS; 3) MS+RLS vs MS-RLS. RESULTS: MS-RLS and MS+RLS presented increased sleep latency, percentage of sleep stage N1, and reduced total sleep time compared to healthy controls and iRLS, respectively. The periodic limb movements during sleep (PLMS) index was higher in MS-RLS than in healthy controls (P = .035) and lower in MS+RLS compared to iRLS (P = .024). PLMS in MS+RLS were less periodic, less often bilateral, and with shorter single movements compared to the typical PLMS in iRLS. CONCLUSIONS: MS is a risk factor for RLS, PLMS, and for a lower sleep quality in comparison to healthy patients. PLMS in MS+RLS are fewer and shorter if compared to iRLS. Our results suggest a dissociation between motor (PLMS) and sensory symptoms (RLS sensory component) in RLS secondary to MS, with possible treatment implications. CITATION: Ferri R, Sparasci D, Castelnovo A, et al. Leg movement activity during sleep in multiple sclerosis with and without restless legs syndrome. J Clin Sleep Med. 2022;18(1):11-20.

Sleep state instabilities in patients with periodic limb movements in sleep - Detection and quantification with heart rate variability.

BACKGROUND: Restless legs syndrome (RLS) has been thought to increase the risk of hypertension, cardiovascular events, and all-cause mortality. Periodic limb movements in sleep (PLMS) can be observed in most patients with RLS. Using non-invasive physiologic measurement and analysis, including heart rate variability (HRV) analysis, we aimed to investigate sleep quality and sleep state stability. METHOD: A total of 53 healthy controls and 15 patients with RLS and PLMS were recruited. Patients with other sleep-related disorders such as obstructive sleep apnea (OSA) and major depressive disorder (MDD) were excluded. Each subject was evaluated using sleep and mood questionnaires and had to undergo polysomnography (PSG). HRV analysis was applied to assess autonomic function and analyze correlations with the severity of periodic leg movements (PLM). The power of different brainwaves was analyzed using electroencephalogram (EEG). Electromyogram (EMG) was also used to explore the temporal correlation between changes in HRV and leg movement events. RESULTS: Compared with healthy controls, PLMS group had not only poorer perceived sleep and mood questionnaires scales but also reductions in parasympathetic-related HRV indices and increases in sympathetic-related HRV parameters. The changes were in proportion to the severity of PLM. Brainwaves and sleep stage which indicate "deep sleep" decreased in the PLMS group. There were no significant temporal correlations between changes in HRV and leg movement events. CONCLUSIONS: Our findings suggest that patients with RLS and PLMS have poorer subjective sleep and mood scales. Besides, objective sleep quality including HRV analysis and brainwaves analysis revealed reduced parasympathetic tone, increased sympathetic tone, and sleep disturbance, which reveal the possibility of a higher risk for secondary disease.

Mechanism of excessive wake time when associated with obstructive sleep apnea or periodic limb movements.

STUDY OBJECTIVES: It is uncertain whether obstructive apnea (OSA) or periodic limb movements (PLMs) contribute to excessive wake time (EWT) when EWT and these disorders coexist. We hypothesized that such EWT is an independent disorder related to central regulation of sleep depth. Accordingly, we compared sleep depth in patients with EWT and OSA/PLMs (EWT+P) with patients with EWT and no OSA/PLMs (EWT-NP) and patients with a normal wake time. METHODS: A total of 267 participants were divided into five groups: (1) EWT+P: n = 100 (wake time > 20% total recording time; TRT) with OSA (apnea-hypopnea index 5-110 events/h) and/or PLMs (PLM index 10-151 events/h); (2) EWT-NP: n = 49 (wake time > 20%TRT), no associated pathology; (3) normal wake time (NWT)+P: n = 54 (wake time < 20%TRT, with OSA/PLMs); (4) NWT-NP: n = 26; (5) Healthy participants: n = 38 (no sleep complaints, NWT and no OSA/PLMs). Sleep depth was evaluated by the odds ratio product (ORP; 0 = deep sleep, 2.5 = fully alert). We also measured ORP in the 9 seconds immediately following arousals (ORP-9) to distinguish between peripheral and central mechanisms of light sleep. RESULTS: ORP during sleep was higher (lighter sleep) in both EWT groups than in the three NWT groups (P < 1E-11) with no difference between those with and those without OSA/PLMs. ORP-9 was also significantly higher in the EWT groups than in the NWT groups (P < 1E-19), also with no difference between those with and without OSA/PLMs, indicating that the lighter sleep was of central origin. There were highly significant correlations between wake time and ORP-9 across all groups (P < 1E-35). CONCLUSIONS: EWT associated with OSA/PLMs is independent of OSA/PLMs and related to abnormal central regulation of sleep depth.

Association of periodic limb movements during sleep and Parkinson disease: A retrospective clinical study.

Both of periodic limb movements during sleep (PLMS) and Parkinson disease (PD) were related with dopaminergic system dysfunction. We aimed to investigate the detailed association of PLMS severity and PD.Clinical and overnight polysomnographic data of 2230 adults older than 40 from a community hospital between November 2011 and June 2017 in Taiwan were collected retrospectively. The association of PLMS severity and PD was analyzed by Fisher exact test, univariate, and multivariate logistic regression.The mean age was 55.6 years old (standard deviation = 9.8, range = 40-91) for all subjects. There were 2205 subjects without PD and 25 subjects with PD in this study. The distribution of PLMS severity was not significantly different between subjects without PD and with PD (Fischer exact test, P = .215). Also, PLMS was not significantly associated with PD using univariate and multivariate logistic regression.The PLMS severity was not associated with PD.

Association Between Periodic Limb Movements in Sleep and Cerebrovascular Changes in Children With Sickle Cell Disease.

STUDY OBJECTIVES: Periodic limb movements (PLMs) have been associated with increased risk of stroke, but there is currently scarce research exploring this relationship in the setting of sickle cell disease (SCD). The aim of this study was to explore whether increased PLMs in children with SCD are associated with increased risk of cerebrovascular disease and to determine if there are any clinical or laboratory differences between children with SCD with elevated periodic limb movement index (PLMI) versus those with normal PLMI. METHODS: This study is a comprehensive review of medical records of 129 children with SCD (aged ≤ 18 years) who had undergone polysomnography for evaluation of sleep-disordered breathing. RESULTS: Elevated PLMI (PLMI > 5 events/h) was present in 42% (54/129) of children with SCD. Children with elevated PLMI were found to have higher percentage of hemoglobin S, lower total iron, higher arousal index and tendency toward elevated transcranial Doppler velocity (P = .063, odds ratio = 3.9, 95% CI 0.93-16.22). While association between elevated PLMI and isolated cerebrovascular stenosis (P = .050, odds ratio 5.6, 95% CI 1.0-31.10) trended toward significance, there was significantly greater proportion of children with elevated PLMI who had cerebrovascular stenosis with Moyamoya disease (P = .046) as demonstrated by magnetic resonance imaging (MRI). CONCLUSIONS: The prevalence of elevated PLMI in children with SCD was higher than in previously published data. Elevated PLMI was significantly associated with greater rates of cerebrovascular disease as detected by MRI.

Restless legs syndrome, periodic limb movements during sleep and cardiovascular risk.

Multiple mechanisms may modulate an association between restless legs syndrome/Willis-Ekbom disease (RLS/WED) and cardiovascular disease (CVD), including chronic sleep deprivation, intermittent, periodic limb movements in sleep (PLMS)-related autonomic fluctuations and possible autonomic dysfunction intrinsically associated with RLS per se. The purpose of this paper is to review the existing RLS/WED literature focusing on the pathophysiologic evidence for possible associations between RLS/WED and PLMS with CVD and events (CVE). Specific intrinsic dysautonomic aspects of the disease, which may contribute to generating CVD, are separately discussed. The association between RLS/WED and both CV risk factors and CVD still remains elusive. Although several shared pathophysiological causes could explain these possible relationships, the emerging body of literature focusing on these disorders remains controversial. Not only longitudinal population-based studies and meta-analyses, but also more animal models and therapeutic interventions are needed in order to build a sufficiently robust body of evidence on this topic.

Improvement of Parasomnias After Treatment of Restless Leg Syndrome/ Periodic Limb Movement Disorder in Children.

STUDY OBJECTIVES: Previous studies have shown that non-rapid eye movement (NREM) sleep parasomnias commonly coexist with restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) in children, leading to speculation that RLS/PLMD may precipitate or worsen parasomnias. However, there are limited data about the effect of the treatment of RLS/PLMD on parasomnias in children. Hence, we performed this study to determine whether the treatment of RLS/PLMD with oral iron therapy is associated with improvement of parasomnias in children. METHODS: A retrospective database was created for children with RLS/PLMD who were treated with iron therapy. These participants were followed for at least 1 year at Cincinnati Children's Hospital Medical Center. All participants had ferritin level testing and were treated with iron therapy. In addition, all participants underwent polysomnography before starting iron therapy for RLS/PLMD except for one participant who was already on iron but required a higher dose. Most participants underwent polysomnography after iron therapy. RESULTS: A total of 226 participants were identified with the diagnosis of RLS/PLMD. Of these, 50 had parasomnias and 30 of them were treated with iron therapy. Of the 30 participants, RLS symptoms improved in 15 participants (50%) and resolution of parasomnias was noted in 12 participants (40%) participants after iron therapy. Repeat polysomnography after iron therapy was performed in 21 participants (70%). After iron therapy, there was a significant decrease in periodic limb movement index (17.2 ± 8.8 [before] versus 6.7 ± 7.3 [after] events/h, P < .001). In addition, there were significant decreases in PLMS (24.52 ± 9.42 [before] versus 7.50 ± 7.18 [after] events/h, P < .0001), PLMS-related arousals (4.71 ± 1.81 [before] versus 1.35 ± 1.43 [after] events/h, P < .0001), and total arousals (11.65 ± 5.49 [before] versus 8.94 ± 3.65 [after] events/h, P < .01) after iron therapy. CONCLUSIONS: Parasomnias are common in our cohort of children with RLS/PLMD. Iron therapy was associated with a significant improvement in periodic limb movement index, RLS symptoms, and resolution of a significant proportion of NREM sleep parasomnias, suggesting that RLS/PLMD may precipitate NREM sleep parasomnia.