A Historical Overview of the Role of Benzodiazepines including Clonazepam in the Treatment of Adult Restless Legs Syndrome and Periodic Limb Movements in Sleep.

In a recent survey of 16,694 people receiving treatment for Restless Legs Syndrome (RLS), approximately 25% were treated with benzodiazepines either singly or in combination with other RLS treatments. Because of the large number of people receiving benzodiazepines for treatment of RLS, we conducted a historical overview of the therapeutic role of benzodiazepines in RLS and its associated condition Periodic Limb Movements in Sleep (PLMS). We found 17 articles on the use of clonazepam in RLS, PLMS, or both, 3 on triazolam and PLMS, 1 on alprazolam and RLS, 1 on temazepam and PLMS, and 1 on nitrazepam and PLMS. The order of benefit of benzodiazepines from the summarized literature is Sleep>RLS>PLMS and arousals > PLMS. Most of the studies on clonazepam employed dosages of 0.5-2.0 mg. Dosages of 3 or 4 mg caused lethargy, somnolence and confusion. An epidemiological study on the therapy of RLS suggests that treatment of RLS with most types of RLS medications including benzodiazepines in combination with other RLS therapies lowers the future cardiovascular risk associated with RLS. The major effect of benzodiazepines is through potentiation of the effect of GABA on the GABA A receptor. Neuroimaging studies suggest that GABA is altered either positively or negatively in various brain regions in RLS and genetic studies suggest that there are alterations in the GABA receptor in RLS. These results suggest that medications with different GABAergic mechanisms such as tiagabine (Gabitril) or others should be investigated in RLS for their possible therapeutic benefit. Highlights: Benzodiazepines are frequently used as therapy in Restless Legs Syndrome (RLS) and Periodic Limb Movements in Sleep. The order of benefit is Sleep>RLS>PLMS and arousals > PLMS. For clonazepam dosages of 0.5 mg-2.0 mg/day are most frequently employed. Benzodiazepines exert their therapeutic effect through GABA-ergic mechanisms.

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.

Pharmacological responsiveness of periodic limb movements in patients with restless legs syndrome: a systematic review and meta-analysis.

STUDY OBJECTIVES: Periodic limb movements during sleep (PLMS) are a frequent finding in restless legs syndrome, but their impact on sleep is still debated, as well the indication for treatment. We systematically reviewed the available literature to describe which drug categories are effective in suppressing PLMS, assessing their efficacy through a meta-analysis, when this was possible. METHODS: The review protocol was preregistered on PROSPERO (CRD42021175848), and the systematic search was conducted on and EMBASE (last searched on March 2020). We included original human studies, which assessed PLMS modification on drug treatment with a full-night polysomnography, through surface electrodes on each tibialis anterior muscle. When at least 4 studies were available on the same drug or drug category, we performed a random-effect model meta-analysis. RESULTS: Dopamine agonists like pramipexole and ropinirole resulted the most effective, followed by l-dopa and other dopamine agonists. Alpha2delta ligands are moderately effective as well opioids, despite available data on these drugs are much more limited than those on dopaminergic agents. Valproate and carbamazepine did not show a significant effect on PLMS. Clonazepam showed contradictory results. Perampanel and dypiridamole showed promising but still insufficient data. The same applies to iron supplementation. CONCLUSIONS: Dopaminergic agents are the most powerful suppressors of PLMS. However, most therapeutic trials in restless legs syndrome do not report objective polysomnographic findings, there is a lack of uniformity in presenting results on PLMS. Longitudinal polysomnographic interventional studies, using well-defined and unanimous scoring criteria and endpoints on PLMS are needed. CITATION: Riccardi S, Ferri R, Garbazza C, Miano S, Manconi M. Pharmacological responsiveness of periodic limb movements in patients with restless legs syndrome: a systematic review and meta-analysis. J Clin Sleep Med. 2023;19(4):811-822.

Intravenous iron therapy in the pediatric sleep clinic: a single institution experience.

STUDY OBJECTIVES: Initial reports of intravenous (IV) iron administration have been promising for children with restless legs syndrome, periodic limb movement disorder, and restless sleep disorder. The aim of the current study was to evaluate further the clinical response to IV iron supplementation in children seen in a pediatric sleep clinic. METHODS: We performed a retrospective chart review of children cared for in a single pediatric sleep clinic who also underwent IV iron infusion. Pre and post IV data regarding their sleep symptoms and ferritin levels were abstracted. RESULTS: Overall, 63 pediatric sleep patients underwent IV iron infusion, mostly with ferric carboxymaltose (n = 60), for restless legs syndrome (n = 30), periodic limb movement disorder (n = 22), and restless sleep disorder (n = 17). Of the 59 patients with clinical follow-up, 39 (73%) noted improvement in at least 1 symptom, and 14 (26%) did not notice improvement or noticed worsening symptoms. Of the 59 patients with preinfusion and postinfusion labs, the average ferritin level increased from 21.7 (13.3) to 147.9 (120.9) µg/L, P < .001. Comparing patients who experienced clinical improvement vs those who did not, there were no statistically significant differences in change in ferritin levels (P = .278), sex (P = .452), or age (P = .391). Ferritin change with infusion according to diagnostic subgroups (restless legs syndrome/periodic limb movement disorder/restless sleep disorder) was examined, and no significant differences were noted (F(2,56) = 0.852, P = .432). In terms of immediate adverse reactions to the IV infusion, 7 (11%) experienced at least 1 side effect, with the most common being behavior change (n = 6) or gastrointestinal discomfort (n = 4); no episodes of anaphylaxis or extravasation were noted. CONCLUSIONS: These data provide additional support for the efficacy and safety of IV iron for pediatric restless legs syndrome, periodic limb movement disorder, and restless sleep disorder recalcitrant to oral iron. CITATION: Ingram DG, Al-Shawwa B, DelRosso LM, Sharma M. Intravenous iron therapy in the pediatric sleep clinic: a single institution experience. J Clin Sleep Med. 2022;18(11):2545-2551.

Restless Legs Syndrome and Other Common Sleep-Related Movement Disorders.

PURPOSE OF REVIEW: In this article, the different sleep-related movement disorders are discussed with special attention given to restless legs syndrome (RLS). RECENT FINDINGS: The differential diagnosis of sleep-related movement disorders can often be challenging; therefore, it is essential to have accurate information to make a correct diagnosis. This article focuses on RLS, highlighting the change in the paradigm of initial treatment, the role played by iron (pathophysiologic and therapeutic), and how to approach possible complications occurring with long-term treatment. SUMMARY: RLS is one of the most common neurologic conditions, and it is common in clinical practice to find patients experiencing symptoms suggestive of RLS. Neurologists must be careful and thorough in the diagnosis, excluding RLS mimics. The decisions regarding which specific sleep-related movement disorder is present and how it should be treated are important because in certain cases, especially in RLS, adverse effects and long-term complications are frequently reported with the use of certain drugs.

Actimetry-Documented Persistent Periodic Limb Movements During EEG-Confirmed Deep General Anesthesia: A Case Report.

Motor activity during general anesthesia (GA) without neuromuscular blockade is often interpreted as reflecting insufficient anesthesia. Here we present the case of an octogenarian undergoing deep sclerectomy with opioid-sparing electroencephalography (EEG)-guided anesthesia. Periodic leg movements (PLM) appeared during ongoing surgery while the patient's raw EEG displayed a pattern of deep anesthesia, evidenced by burst suppression. Recognizing PLM in the context of opioid-sparing GA is of importance for anesthesiologists, as deep anesthesia is not necessarily associated with a decrease in motor activity.

Determinants of ferritin response to oral iron supplementation in children with sleep movement disorders.

STUDY OBJECTIVES: To identify children who respond to oral iron supplementation as evidenced by increased ferritin levels and to identify factors that correlate with improvement in ferritin levels in those who respond. METHODS: A retrospective chart review of the PLMS/RLS/RSD database at Seattle Children's Hospital was carried out. Data collected included nocturnal polysomnography parameters, age, sex, initial and follow-up ferritin level and date of collection, and presence of restless legs syndrome (RLS), periodic limb movements of sleep (PLMS)/PLM disorder (PLMD), restless sleep disorder (RSD), obstructive sleep apnea (OSA), neurologic, psychiatric, neurodevelopmental, or medical comorbidity. Oral iron therapy was evaluated by side effects (none; constipation; bad taste/nausea), subjective outcome in symptoms (resolved, improved, no change), and adherence to therapy (poor, fair, good). RESULTS: Seventy-seven children were included in this study of whom 42 were classified as responders (increase in ferritin of ≥10 µg/L) and 35 were nonresponders. Age and sex were not different between groups. Adherence was the only significant predictor of an increase in ferritin of ≥10 µg/L. Constipation was seen in 7.1% of responders vs. 45.8% of nonresponders. No change in symptoms was reported in 26.2% of responders vs. 71.4% in nonresponders. A significant correlation was found between treatment duration and ferritin level change in responders but not in nonresponders. CONCLUSIONS: Side effects hinders adherence to oral iron supplementation in children. Responders to oral iron show improvement in ferritin levels and symptoms, while nonresponders show no improvement in ferritin levels despite a long-lasting treatment, at least in part of them.

Magnesium supplementation for the treatment of restless legs syndrome and periodic limb movement disorder: A systematic review.

Magnesium supplementation is often suggested for restless legs syndrome (RLS) or period limb movement disorder (PLMD) based on anecdotal evidence that it relieves symptoms and because it is also commonly recommended for leg cramps. We aimed to review all articles reporting the effects of magnesium supplementation on changes in RLS and/or PLMD. We conducted a systematic search looking for all relevant articles and then two reviewers read all article titles and abstracts to identify relevant studies. Eligible studies were scored for their quality as interventional trials. We found 855 abstracts and 16 of these could not be definitively excluded for not addressing all aspects of our research question. Seven full-text articles were unlocatable and one was ineligible which left eight studies with relevant data. One was a randomised placebo-controlled trial, three were case series and four were case studies. The RCT did not find a significant treatment effect of magnesium but may have been underpowered. After quality appraisal and synthesis of the evidence we were unable to make a conclusion as to the effectiveness of magnesium for RLS/PLMD. It is not clear whether magnesium helps relieve RLS or PLMD or in which patient groups any benefit might be seen.

Images: Identification and Effect of Periodic Limb Movements in End-Stage Renal Disease.

None: Sleep disorders are prevalent in patients with end-stage renal disease (ESRD). In those patients on nocturnal dialysis, it is important to perform objective sleep assessment during regular dialysis. We present the case of a man on continuous cycler peritoneal dialysis with disabling fatigue and moderate restless legs syndrome (RLS). Actigraphy demonstrated excessive nocturnal movement. Unattended home polysomnography, performed during his regular peritoneal dialysis, confirmed frequent nocturnal periodic limb movements with disturbed sleep. Treatment with low dose pramipexole led to improved RLS and marked improvement in his energy. Clinicians caring for patients with ESRD should have a low threshold for objective sleep assessment given that sleep disorders are common, disabling and eminently amenable to treatment.

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.

Lesson of the month 2: An unusual adverse reaction associated with pramipexole.

Dopamine agonists such as pramipexole are commonly used in the treatment of restless legs syndrome (RLS) as well as Parkinson's disease. Pramipexole's common side effects are well documented; however, adverse skin reactions are less well known. In this case, a 45-year-old male farmer presented with excessive daytime tiredness and reported a history suggestive of RLS. He was initiated on pramipexole but developed a maculopapular erythematous rash in sun-exposed areas 8 days after its commencement. The skin rash resolved following pramipexole's cessation and it is thought the patient experienced a drug-induced photosensitivity reaction to pramipexole. This case highlights the potential for photosensitivity reactions to pramipexole, which is especially significant in countries like Australia where UV solar radiation is especially high.

The efficacy and tolerability of rotigotine on patients with periodic limb movement in sleep: A systematic review and meta-analysis.

OBJECTIVE: There is still no consensus on the treatment for periodic limb movement in sleep (PLMS). This study aimed to determine the efficacy and tolerability of rotigotine in patients suffering from PLMS. METHODS: Publications listed in PubMed, ScienceDirect, The Cochrane Library, and ClinicalTrials.gov were reviewed to assess the efficacy of rotigotine on PLMS. Analyses of PLMS frequency before and after rotigotine treatments (pre- and post-intervention studies) and PLMS frequency between placebo and rotigotine treatments (placebo-controlled trial studies) were included in our study. A systematic review and meta-analysis was conducted. RESULTS: Five publications involving 197 participants were included in this study. Among these articles, pre- and post-intervention data involving 55 participants were available from three articles, while placebo-controlled trial data from 107 participants receiving rotigotine and 70 participants receiving a placebo were available from an additional three articles. In the pre- and post-intervention studies, the periodic limb movement index was significantly decreased after therapy with rotigotine with a difference in means of -5.866/h (95% CI, -10.570 to -1.162, p = 0.015). In comparison with the placebo, the use of rotigotine significantly lowered the periodic limb movement index, with a difference in means of -32.105/h (95% CI, -42.539 to -21.671, p < 0.001), reduced the PLMS with arousal index, with a difference in means of -7.160/h (95% CI, -9.310 to -5.010, p < 0.001), and increased the withdrawal rate, with an odds ratio of 3.421 (95% CI, 1.230 to 9.512, p = 0.018). CONCLUSIONS: This meta-analysis revealed the considerable efficacy of rotigotine in alleviating the frequency of PLMS. However, the high withdrawal rate should be taken into account.

Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children: an IRLSSG task force report.

BACKGROUND: Brain iron deficiency has been implicated in the pathophysiology of RLS, and current RLS treatment guidelines recommend iron treatment when peripheral iron levels are low. In order to assess the evidence on the oral and intravenous (IV) iron treatment of RLS and periodic limb movement disorder (PLMD) in adults and children, the International Restless Legs Syndrome Study Group (IRLSSG) formed a task force to review these studies and provide evidence-based and consensus guidelines for the iron treatment of RLS in adults, and RLS and PLMD in children. METHODS: A literature search was performed to identify papers appearing in MEDLINE from its inception to July 2016. The following inclusion criteria were used: human research on the treatment of RLS or periodic limb movements (PLM) with iron, sample size of at least five, and published in English. Two task force members independently evaluated each paper and classified the quality of evidence provided. RESULTS: A total of 299 papers were identified, of these 31 papers met the inclusion criteria. Four studies in adults were given a Class I rating (one for IV iron sucrose, and three for IV ferric carboxymaltose); only Class IV studies have evaluated iron treatment in children. Ferric carboxymaltose (1000 mg) is effective for treating moderate to severe RLS in those with serum ferritin <300 µg/l and could be used as first-line treatment for RLS in adults. Oral iron (65 mg elemental iron) is possibly effective for treating RLS in those with serum ferritin ≤75 µg/l. There is insufficient evidence to make conclusions on the efficacy of oral iron or IV iron in children. CONCLUSIONS: Consensus recommendations based on clinical practice are presented, including when to use oral iron or IV iron, and recommendations on repeated iron treatments. New iron treatment algorithms, based on evidence and consensus opinion have been developed.

Pharmacological Management of Restless Legs Syndrome and Periodic Limb Movement Disorder in Children.

Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) are under-recognized sleep disorders in children and adolescents. Several recent epidemiological studies have shown that RLS and PLMD are common in the pediatric population, and if left untreated, may lead to cardiovascular and neurocognitive consequences. Therefore, early diagnosis and intervention may help preventing long-term consequences. The management of RLS and PLMD in children involves both non-pharmacologic and pharmacologic approaches. Although there is emerging literature supporting medical therapy in children with RLS and PLMD, the overall experiences with these medications remain limited. Most children and adolescents with RLS and PLMD have low iron storage; therefore, iron therapy should be considered as the first line of treatment in children. Currently, there is no FDA-approved medication for RLS and PLMD in children. There is increasing evidence on the effectiveness of dopaminergic medications in children but the data are quite limited. Other medications such as α2δ-1 ligands, benzodiazepine, and clonidine are frequently used, but have not been adequately investigated in children. Further studies are needed to evaluate the safety and efficacy of pharmacologic therapy for RLS and PLMD in children.

Outcomes of long-term iron supplementation in pediatric restless legs syndrome/periodic limb movement disorder (RLS/PLMD).

OBJECTIVES: Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) are thought to center around a genetically mediated sensitivity to iron insufficiency. Previous studies have shown the effectiveness of short-term iron therapy in children with low iron storage. Little is known, however, about long-term iron treatment in children with RLS and PLMD. Therefore, we performed this study to assess the long-term effect of iron therapy in children with RLS and PLMD. METHODS: A retrospective chart review was performed for children who met the following criteria: A) diagnosed as having either RLS or PLMD, B) started on iron supplementation, C) followed up for >2 years in a sleep clinic. Baseline values for iron, ferritin, and periodic limb movement of sleep index (PLMS index) were defined in the three months leading up to the initiation of iron therapy. Values were also computed for follow-up periods of 3-6 months, 1-2 years, and >2 years. Serum iron and ferritin levels and PLMS index were compared between baseline and all subsequent follow-ups. RESULTS: In total, 105 patients met inclusion criteria, of whom 64 were diagnosed with PLMD alone, seven with RLS alone, and 35 with both RLS and PLMD. The average age was 10.2 ± 5.3 years. Compared to the baseline (27.4 ± 12.1 ng/ml), the average ferritin values at 3-6 months (45.62 ± 21.2 ng/ml, p < 0.001, n = 34), 1-2 years (52.0 ± 48.3 ng/ml, p <0.001, n = 63), and >2 years (54.7 ± 40.5 ng/ml, p <0.001, n = 67) were all significantly increased. Inversely, compared to baseline (21 ± 27.0/h, n = 66), PLMS index values at 3-6 months (7.5 ± 9.5/h p < 0.05, n = 11), 1-2 years (6.9 ± 8.9/h, p <0.001, n = 29), and >2 years (10 ± 14.5/h, p <0.001, n = 31) were all significantly decreased. No significant change in serum iron levels was noted at any time point. CONCLUSION: While retrospective in nature, this study demonstrates a sustained improvement in PLMS index and maintenance of adequate ferritin levels >2 years after iron therapy initiation in our RLS/PLMD cohort with a long-term follow-up. Iron therapy appears to lead to long-lasting improvements in children with RLS/PLMD.

Rotigotine's effect on PLM-associated blood pressure elevations in restless legs syndrome: An RCT.

OBJECTIVE: This double-blind, placebo-controlled, interventional trial was conducted to investigate the effects of rotigotine patch on periodic limb movement (PLM)-associated nocturnal systolic blood pressure (SBP) elevations. METHODS: Patients with moderate to severe restless legs syndrome (RLS) were randomized to rotigotine (optimal dose [1-3 mg/24 h]) or placebo. Continuous beat-to-beat blood pressure (BP) assessments were performed during polysomnography at baseline and at the end of 4-week maintenance. Primary outcome was change in number of PLM-associated SBP elevations (defined as slope of linear regression ≥2.5 mm Hg/beat-to-beat interval over 5 consecutive heartbeats [≥10 mm Hg]). Additional outcomes were total SBP elevations, PLM-associated and total diastolic BP (DBP) elevations, periodic limb movements index (PLMI), and PLM in sleep arousal index (PLMSAI). RESULTS: Of 81 randomized patients, 66 (37 rotigotine, 29 placebo) were included in efficacy assessments. PLM-associated SBP elevations were significantly reduced with rotigotine vs placebo (least squares mean treatment difference [95% confidence interval (CI)] -160.34 [-213.23 to -107.45]; p < 0.0001). Rotigotine-treated patients also had greater reduction vs placebo in total SBP elevations (-161.13 [-264.47 to -57.79]; p = 0.0028), PLM-associated elevations (-88.45 [-126.12 to -50.78]; p < 0.0001), and total DBP elevations (-93.81 [-168.45 to -19.16]; p = 0.0146), PLMI (-32.77 [-44.73 to -20.80]; p < 0.0001), and PLMSAI (-7.10 [-11.93 to -2.26]; p = 0.0047). Adverse events included nausea (rotigotine 23%; placebo 8%), headache (18% each), nasopharyngitis (18%; 8%), and fatigue (13%; 15%). CONCLUSIONS: Further investigation is required to determine whether reductions in nocturnal BP elevations observed with rotigotine might modify cardiovascular risk. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with moderate to severe RLS, rotigotine at optimal dose (1-3 mg/24 h) reduced PLM-associated nocturnal SBP elevations.

Valid measures of periodic leg movements (PLMs) during a suggested immobilization test using the PAM-RL leg activity monitors require adjusting detection parameters for noise and signal in each recording.

OBJECTIVE AND BACKGROUND: Individuals with restless legs syndrome (RLS) (Willis-Ekbom disease [WED]) usually have periodic leg movements (PLMs). The suggested immobilization test (SIT) measures sensory and motor features of WED during wakefulness. Surface electromyogram (EMG) recordings of the anterior tibialis (AT) are used as the standard for counting PLMs. However, due to several limitations, leg activity meters such as the PAM-RL were advanced as a potential substitute. In our study, we assessed the validity of the measurements of PLM during wakefulness (PLMW) in the SIT for PAM-RL using both default and custom detection threshold parameters compared to AT EMG. METHODS: Data were obtained from 39 participants who were diagnosed with primary WED and who were on stable medication as part of another study using the SIT to repeatedly evaluate WED symptoms over 6-12 months. EMG recordings and PAM-RL, when available, were used to detect PLMW for each SIT. Complete PAM-RL and polysomnography (PSG) EMG data were available for 253 SITs from that study. The default PAM-RL (dPAM-RL) detected leg movements based on manufacturer's noise (resting) and signal (movement) amplitude criteria developed to accurately detect PLM during sleep (PLMS). The custom PAM-RL (cPAM-RL) similarly detected leg movements except the noise and movement detection parameters were adjusted to match the PAM-RL data for each SIT. RESULTS: The distributions of the differences between either dPAM-RL or cPAM-RL and EMG PLMW were strongly leptokurtic (Kurtosis >2) with many small differences and a few unusually large differences. These distributions are better described by median and quartile ranges than mean and standard deviation. Despite an adequate correlation (r=0.66) between the dPAM-RL and EMG recordings, the dPAM-RL on average significantly underscored the number of PLMW (median: quartiles=-13: -51.2, 0.0) and on Bland-Altman plots had a significant magnitude bias with greater underscoring for larger average PLMW/h. There also was an adequate correlation (r=0.70) between cPAM-RL and EMG but with minimal underscoring of PLMW (median quartiles=0.0; -20, 10) and no significant magnitude bias. Two scorers independently scoring 13% of the SITs showed an adequate interscorer reliability of 0.96-0.98. CONCLUSIONS: Our study confirms our expectation that measuring PLMW in a SIT using dPAM-RL is not valid and that adjustments to the detection threshold criteria are required. The PAM-RL, using parameters customized for each SIT provided a valid and reliable measure of PLMW with minimal magnitude bias compared to the AT EMG recordings.