Periodic limb movements during sleep and cardiac arrhythmia in older men (MrOS sleep)

Transvenous phrenic nerve stimulation is associated with normalization of nocturnal heart rate perturbations in patients with central sleep apnea

STUDY OBJECTIVES

To determine the effect of transvenous phrenic nerve stimulation (TPNS) on nocturnal heart rate perturbations in patients with CSA.

METHODS

In this ancillary study of the remedē System Pivotal Trial, we analyzed electrocardiograms from baseline and follow-up overnight polysomnograms (PSG) in 48 CSA patients in sinus rhythm with implanted TPNS randomized to stimulation (treatment group; TPNS on) or no stimulation (control group; TPNS off). We quantified heart rate variability in the time and frequency domain. Mean change from baseline and standard error is provided.

RESULTS

TPNS titrated to reduce respiratory events is associated with reduced cyclical heart rate variations in the very low-frequency domain across REM (VLFI: 4.12 ± 0.79% vs. 6.87 ± 0.82%, p = 0.02) and NREM sleep (VLFI: 5.05 ± 0.68% vs. 6.74 ± 0.70%, p = 0.08) compared to the control group. Further, low-frequency oscillations were reduced in the treatment arm in REM (LFn: 0.67 ± 0.03 n.u. vs. 0.77 ± 0.03 n.u., p = 0.02) and NREM sleep (LFn: 0.70 ± 0.02 n.u. vs. 0.76 ± 0.02 n.u., p = 0.03).

CONCLUSION

In adult patients with moderate to severe central sleep apnea, transvenous phrenic nerve stimulation reduces respiratory events and is associated with the normalization of nocturnal heart rate perturbations. Long-term follow-up studies could establish whether the reduction in heart rate perturbation by TPNS also translates into cardiovascular mortality reduction.

CLINICAL TRIAL

A Randomized Trial Evaluating the Safety and Effectiveness of the remedē® System in Patients With Central Sleep Apnea, ClinicalTrials.gov, NCT01816776.

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.

Periodic limb movements during sleep: a narrative review

Objective

Using narrative review techniques, this paper evaluates the evidence for separable underlying patho-mechanisms of periodic limb movements (PLMs) to separable PLM motor patterns and phenotypes, in order to elucidate potential new treatment modalities.

Background

Periodic limb movement disorder (PLMD) is estimated to occur in 5–8% of the paediatric population and 4–11% of the general adult population. Due to significant sleep fragmentation, PLMD can lead to functional impairment, including hyperactivity and delayed language development in children, and poor concentration and work performance in adults. Longitudinal data demonstrate that those with PLMD are at greater risk of depression and anxiety, and a 4-fold greater risk of developing dementia. PLMD has been extensively studied over the past two decades, and several key insights into the genetic, pathophysiological, and neural correlates have been proposed. Amongst these proposals is the concept of separable PLM phenotypes, proposed on the basis of nocturnal features such as the ratio of limb movements and distribution throughout the night. PLM phenotype and presentation, however, varies significantly depending on the scoring utilized and the nocturnal features examined, across age, and co-morbid clinical conditions. Furthermore, associations between these phenotypes with major neurologic and psychiatric disorders remain controversial.

Methods

In order to elucidate potential divergent biological pathways that may help clarify important new treatment modalities, this paper utilizes narrative review and evaluates the evidence linking PLM motor patterns and phenotypes with hypothesised underlying patho-mechanisms. Distinctive, underlying patho-mechanisms include: a pure motor mechanism originating in the spinal cord, iron deficiency, dopamine system dysfunction, thalamic glutamatergic hyperactivity, and a more cortical-subcortical interplay. In support of the latter hypothesis, PLM rhythmicity appears tightly linked to the microarchitecture of sleep, not dissimilarly to the apnoeic/hypopneic events seen in obstructive sleep apnea (OSA).

Conclusions

This review closes with a proposal for greater investigation into the identification of potential, divergent biological pathways. To do so would require prospective, multimodal imaging clinical studies which may delineate differential responses to treatment in restless legs syndrome (RLS) without PLMS and PLMS without RLS. This could pave the way toward important new treatment modalities.

Comorbidities in children with elevated periodic limb movement index during sleep

STUDY OBJECTIVES

Little is known about comorbidities in children who have elevated periodic limb movement index (PLMI) during overnight polysomnogram (PSG). The aim of this study is to identify comorbidities in children with elevated PLMI (PLMI > 5) versus children with PLMI < 5 presenting to a pediatric sleep center.

METHODS

This study was a retrospective review of all clinically indicated PSGs obtained consecutively from 3/2017-3/2019 at Seattle Children's Sleep Disorders Center. Data collected included demographics, clinical presentation, medications, medical history, family history specifically for restless legs syndrome (RLS), ferritin levels, and PSG metrics. Characteristics between those with (cases) elevated PLMI (AASM criteria) and without (controls) were summarized.

RESULTS

We identified 148 subjects with elevated PLMI (67% male, mean age 7.95 years, range 1-20), yielding a PLMI > 5 prevalence of 5%. There were 188 controls included (58% male, mean age 8.0 years, range 1-19). Neither sex (chi-square = 2.8, NS) nor age (Mann-Whitney U = 1339.5, NS) differed between groups. Case subjects had a higher prevalence of RLS, snoring, insomnia, mood disorders, behavioral problems, morning headaches, chronic kidney disease, epilepsy, and chronic heart disease. Similarly, the use of antidepressants, antipsychotics, antiseizure medication, and other medications was statistically more frequent in children with elevated PLMS. The prevalence of PLMI > 5 was 5% and the prevalence of periodic limb movement disorder (PLMD) was 0.3% in children referred to polysomnography. Ferritin levels did not differ.

CONCLUSIONS

We identified the prevalence of PLMD in a sleep medicine-referred population. We have also identified comorbidities and medications associated with elevated PLMI in children.No clinical trial.

Individual periodic limb movements with arousal are temporally associated with nonsustained ventricular tachycardia: a case-crossover analysis

STUDY OBJECTIVES

Both periodic limb movements during sleep (PLMS) and arousals are associated with sympathetic nervous system activation and may be arrhythmogenic. We hypothesize a temporal relationship exists between individual PLMS, particularly with arousal, and nonsustained ventricular tachycardia (NSVT) events.

METHODS

A bidirectional time-stratified case-crossover design was used to assess temporal associations between PLMS and NSVT during sleep in 49 Osteoporotic Fractures in Men Sleep Study participants with NSVT in a community-based cohort (n = 2,911). Sleep time was divided into approximate 30-min segments. For each NSVT (n = 141), we selected a preceding 30-s hazard period and three randomly chosen 30-s control periods from sleep within the same segment and evaluated for PLMS, respiratory events, minimum saturation, and arousals. Odds ratios and 95% confidence intervals-OR (95% CI)-were determined by conditional logistic regression; covariates included EEG arousals, minimum saturation, and respiratory events in the same hazard/control period.

RESULTS

Participants with NSVT were 79.5 ± 6.2 years with a PLMS index of 32.1 (IQR: 10.1, 61.4) and apnea-hypopnea index of 17.1 (IQR: 9.4, 26.1). PLMS without arousal were not significantly associated with NSVT (OR = 0.80, 95% CI: 0.41-1.59). PLMS with arousal were associated with NSVT in unadjusted analyses (OR = 2.50, 95% CI: 1.11-5.65) and after adjustment (OR = 2.31, 95% CI: 1.02-5.25). Arousals associated with PLMS were associated with NSVT in unadjusted (OR = 2.84, 95% CI: 1.23-6.56) and adjusted analyses (OR = 2.61, 95% CI: 1.13-6.05).

CONCLUSIONS

PLMS with (but not without) arousals are temporally associated with a greater than twofold higher odds of subsequent NSVT episodes. PLMS-related arousals may be physiologically important ventricular arrhythmia triggers.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT00070681.

Moderate to severe but not mild RLS is associated with greater sleep-related sympathetic autonomic activation than healthy adults without RLS

INTRODUCTION

Restless legs syndrome (RLS) patients have been found to have high rates of transitory increases in the activity of the sympathetic autonomic nervous system with increases in heart rate and blood pressure. These were identified by evaluating heart rate or blood pressure changes independent of any leg movement analyses. There has been an implicit assumption this high rate of sympathetic activations is abnormal, but there has been no direct comparison for similar measures with a healthy population free of RLS. Thus, it is not known if during sleep the rates of sympathetic nervous system activation are greater for RLS than for a healthy population. The objectives of this study were to determine if: (1) RLS patients compared to healthy controls have a greater frequency of sympathetic nervous system activation (significant heart rate increases) with a higher percentage of leg movements associated with these activations; (2) the sympathetic activation frequency and its relation to leg movements correlate significantly with RLS severity in RLS patients; and (3) there is some minimum threshold for RLS severity defining an RLS population where most (eg 85%) have abnormally high rates of sympathetic activation.

METHODS

Sleep data on 32 RLS patients and 21 matched healthy controls were obtained from a prior study. All leg movements during sleep (LMS) and periodic leg movements in sleep (PLMS) were identified following the new WASM criteria; LMS that were not PLMS were considered isolated leg movements in sleep (ILMS). All episodes with significant heart rate increases were identified following procedures established by Cassel et al., (2016, see further on for citation) ie a slope of linear regression ≥2.5 beats per minute over five consecutive heartbeats. Severity of RLS was evaluated using the International Restless Legs Study Group Scale (IRLS).

RESULTS

RLS patients had significantly more heart rate increases than controls (67.88/hr vs. 9.87/hr). RLS patients had a significantly greater percentage of both LMS and PLMS occurring with heart rate increases than controls (44% vs. 30%; 48% vs. 18%, respectively). These measures correlated significantly with IRLS and also PLMS/hr. 85% of the RLS patients with IRLS scores >22 or PLMS >50/hr had rates of sympathetic activation that were >90th percentile for the healthy controls.

CONCLUSION

This is the first paper documenting that RLS patients showed clearly increased sympathetic activation when identified independent of PLMS. This, however, occurs for more severe RLS and not milder RLS. It has been proposed that the abnormally high rate of sympathetic activation for RLS patients relates to development of adverse cardiovascular health consequences observed in some studies. Thus, these data may provide a basic standard for possible use in epidemiological studies to identify the level of RLS severity more likely to have adverse health consequences (eg, cardiovascular disease). Since two-thirds of RLS patients have mild to even intermittent disease, including all RLS is likely to miss the potential health consequences of RLS.

Prognostic Impact of Restless Legs Syndrome on Patients with Heart Failure

The restless legs syndrome (RLS) is a neurological disorder characterized by an irresistible urge to move the legs or arms for relief of uncomfortable or unpleasant sensations. Prevalence and prognostic impact of RLS on patients with heart failure (HF) remain unclear. We aimed to investigate the clinical characteristics and prognostic impact of RLS on HF patients.Consecutive 338 HF patients were evaluated for RLS and divided into two groups on the basis of presence of RLS: HF patients with RLS (RLS group, n = 29) and HF patients without RLS (non-RLS group, n = 309). We compared clinical characteristics, parameters of laboratory data and echocardiography, and rate of follow-up cardiac events including worsening HF and cardiac death between the two groups. Compared with the non-RLS group, the RLS group had higher prevalence of anemia (65.5% versus 40.8%, P = 0.010), higher usage of inotropic agents (31.0% versus 15.2%, P = 0.028), higher levels of B-type natriuretic peptide (570.8 versus 215.8 pg/mL, P = 0.018), and lower levels of left ventricular ejection fraction (40.4% versus 48.4%, P = 0.019). By contrast, age, gender, prevalence of other co-morbidities and medications were comparable between the groups. In the Kaplan-Meier analysis, the cardiac event rate was significantly higher in the RLS group than in the non-RLS group (log-rank P = 0.034). In the Cox proportional hazard analysis, RLS was a predictor for cardiac events in HF patients (hazard ratio: 1.783, 95% confidence interval: 1.038-3.063).RLS is associated with adverse prognosis in HF patients.

Diagnostic Criteria, Differential Diagnosis, and Treatment of Minor Motor Activity and Less Well-Known Movement Disorders of Sleep

Purpose of review

Sleep-related movement disorders (SRMD) include several different motor activities during sleep. Few of them are well known and well classified, whereas others are minor motor disorders of sleep which are neither thoroughly characterized and classified nor have been extensively investigated to clarify their pathogenesis and clinical relevance. This review will focus on those minor sleep-related movement disorders.

Recent findings

Before diagnosing periodic limb movement (PLM) disorder in patients with PLM during polysomnography, other disorders associated with PLM need to be excluded, namely restless legs syndrome (RLS), narcolepsy, REM sleep behavior disorder (RBD), and sleep-related breathing disorder. For the diagnosis of propriospinal myoclonus at sleep-onset, multi-channel surface electromyography recording during polysomnography is required and a possible psychogenic origin of the movement disorder has to be considered. Excessive fragmentary myoclonus (EFM) does not require symptomatic treatment, but further evaluation is suggested as electrophysiological abnormalities are present in 50% of cases. Nine percent of healthy sleepers meet the criteria for EFM, raising the question if current, arbitrarily defined, cutoffs are valid. Hypnagogic foot tremor, rhythmic feet movements, alternating leg muscle activation, and high-frequency leg movements are somewhat overlapping minor motor activities during sleep which may exist on their own or represent stereotyped movements to relieve RLS-like symptoms. Neck myoclonus is probably a physiological phenomenon related to REM twitching. RBD is formally a parasomnia but a relevant differential diagnosis when evaluating sleep-related movement disorders. In particular, prodromal RBD is characterized by electromyographic and behavioral findings on video-polysomnography which needs to be differentiated by minor sleep-related movement disorders.

Summary

Minor SRMD beyond the well-known main motor disorders of sleep should be correctly diagnosed, distinguished from differential diagnosis, and understood in their potential clinical relevance, in order also to start an appropriate treatment if needed.

Periodic limb movements in sleep: Prevalence and associated sleepiness in the Wisconsin Sleep Cohort

OBJECTIVES

Periodic limb movements in sleep (PLMS) are thought to be prevalent in elderly populations, but their impact on quality of life remains unclear. We examined the prevalence of PLMS, impact of age on prevalence, and association between PLMS and sleepiness.

METHODS

We identified limb movements in 2335 Wisconsin Sleep Cohort polysomnograms collected over 12 years. Prevalence of periodic limb movement index (PLMI) ≥15 was calculated at baseline (n = 1084). McNemar's test assessed changes in prevalence over time. Association of sleepiness and PLMS evaluated using linear mixed modeling and generalized estimating equations. Models adjusted for confounders.

RESULTS

Prevalence of PLMI ≥15 at baseline was 25.3%. Longitudinal prevalence increased significantly with age (p = 2.97 × 10^-14). Sleepiness did not differ significantly between PLMI groups unless stratified by restless legs syndrome (RLS) symptoms. The RLS+/PLM+ group was sleepier than the RLS+/PLM- group. Multiple Sleep Latency Test trended towards increased alertness in the RLS-/PLM+ group compared to RLS-/PLM-.

CONCLUSIONS

A significant number of adults have PLMS and prevalence increased with age. No noteworthy association between PLMI category and sleepiness unless stratified by RLS symptoms.

SIGNIFICANCE

Our results indicate that RLS and PLMS may have distinct clinical consequences and interactions that can help guide treatment approach.

Impact on Clinical Outcomes of Periodic Leg Movements During Sleep in Hospitalized Patients Following Acute Decompensated Heart Failure

BACKGROUND

Periodic leg movements during sleep (PLM) are characterized by regularly recurring movement of the legs during sleep. Although PLM is common and a predictor of death in patients with chronic heart failure, the clinical significance of PLM in hospitalized patients with a reduced left ventricular ejection fraction (LVEF) following acute decompensated heart failure (ADHF) remains unknown.Methods and Results:After initial improvement of acute signs and symptoms of ADHF, 94 consecutive patients with reduced LVEF who underwent polysomnography were enrolled. They were divided into 2 groups based on the presence or absence of severe PLM defined as PLM index ≥30. The risks for clinical events, composite of all-cause death and rehospitalization, were assessed using a stepwise multivariable Cox proportional model including variables showing P<0.10 in univariate analyses. Severe PLM was observed in 21 patients (22%). At a median follow-up of 5.2 months, 30 patients experienced clinical events (32%). In the multivariable analysis, the presence of severe PLM was significantly associated with increasing clinical events (hazard ratio, 2.16; 95% confidence interval, 1.03-4.54; P=0.042) independent of hemoglobin level and the severity of sleep-disordered breathing.

CONCLUSIONS

In hospitalized patients with systolic dysfunction following ADHF, severe PLM was prevalent and significantly associated with increased risk of death and/or rehospitalization.

Longitudinal relationships of periodic limb movements during sleep and incident atrial fibrillation

OBJECTIVES

This study aimed to examine relationship between periodic limb movements during sleep (PLMS) and incident atrial fibrillation/flutter (AF).

METHODS

Prospective multicenter cohort (n = 2273: adjudicated AF group; n = 843: self-reported AF group) of community-dwelling men without prevalent AF were followed for an average of 8.3 years (adjudicated) and 6.5 years (self-reported). PLMS index (PLMI, <5 (ref), ≥5 to <30, ≥30) and PLM arousal index (PLMAI, <1 (ref), ≥1 to <5, ≥5) were measured by polysomnography. Incident adjudicated and self-reported AF were analyzed by Cox proportional hazards and logistic regression, respectively, and adjusted for age, clinic, race, body mass index (BMI), alcohol use, cholesterol level, cardiac medications, pacemaker, apnea-hypopnea index, renal function, and cardiac risk. The interaction of age and PLMS was examined.

RESULTS

In this primarily Caucasian (89.8%) cohort of older men (mean age 76.1 ± 5.5 years) with BMI of 27.2 ± 3.7, there were 261 cases (11.5%) of adjudicated and 85 cases (10.1%) of self-reported incident AF. In the overall cohort, PLMI and PLMAI were not associated with adjudicated or self-reported AF. There was some evidence of an interaction of age and PLMI (p = 0.08, adjudicated AF) and PLMAI (p ≤ 0.06, both outcomes). Among men aged ≥76 years, the highest PLMI tertile was at increased risk of adjudicated AF (≥30 vs. <5; hazard ratio (HR) = 1.63, 1.01-2.63) and the middle PLMAI tertile predicted increased risk of both outcomes (1 to <5 vs. <1; adjudicated, HR = 1.65, 1.05-2.58; self-reported HR = 5.76, 1.76-18.84). No such associations were found in men aged <76 years.

CONCLUSIONS

Although PLMS do not predict AF incidence in the overall cohort, the findings suggest PLMS increases incident AF risk in the older subgroup.