Periodic Limb Movements During Sleep Research Articles

A Review of the Posttraumatic Stress Disorder and Sleep Disturbances

Post-traumatic stress disorder (PTSD) is characterized by intrusive emotional memory, alertness and avoidance after individuals suffer from one or more traumatic events. With the exception of manifestations, sleep disturbances are also considered to be the core symptoms of PTSD. This article mainly discussed insomnia, nightmares, obstructive sleep apnea (OSA), and periodic limb movement during sleep (PLMS) in patients with PTSD. Existing evidence suggested that insomnia is a predictor of the development of PTSD. Cognitive behavioral therapy for insomnia is an important research direction for treating insomnia in PTSD patients. Nightmares are also the core symptom of PTSD. Prazosin and image rehearsal therapy are effective therapies to treat post-traumatic nightmares. The co-occurrence of obstructive sleep apnea (OSA) is over 40% in patients with PTSD. Preliminary studies have shown that continuous positive airway pressure therapy can improve PTSD symptoms in patients with PTSD comorbid OSA. In the process of diagnosis and treatment of PTSD patients, it is important to firstly evaluate whether PTSD patient comorbid OSA or insomnia, and then clinicians could further develop an appropriate treatment plan for these patients.

Prospective associations of sleep apnea, periodic limb movements, and plasma fibrinogen level.

Our previous cross-sectional study showed that periodic limb movements during sleep (PLMS) were frequently found in patients with obstructive sleep apnea (OSA) and that both OSA and PLMS were associated with higher plasma fibrinogen levels. We explored the longitudinal relationships among these factors. Plasma fibrinogen levels were measured in 333 consecutive patients who underwent polysomnography to diagnose OSA. Patients who initiated continuous positive airway pressure (CPAP) underwent follow-up polysomnography after 3months of CPAP use. They were categorized into groups with good or poor adherence (% days with ≥ 4h/night of CPAP use ≥ 70% or < 70%, respectively). Changes in sleep parameters and plasma fibrinogen levels during the treatment period were compared between these groups. The cross-sectional analysis of all reviewed 333 patients indicated that fibrinogen levels were associated with the severities of OSA and PLMS. The 60 patients (27 good and 33 poor adherence) who underwent follow-up polysomnography were included in the longitudinal analysis. The median (interquartile range) periodic limb movement index did not change significantly from CPAP titration to the 3-month follow-up (good adherence: 10.5 (0-23.8) to 10.8 (0-70.2) events/h, p = 0.21; poor adherence: 1.2 (0-14.3) to 0.8 (0-15.7) events/h, p = 0.67). However, the plasma fibrinogen level significantly decreased only in the good adherence group (good adherence: baseline 275 ± 46 to follow-up 255 ± 47mg/dl, p < 0.01; poor adherence: 277 ± 52 to 284 ± 70mg/dl, p = 0.48). These results did not support a longitudinal association between PLMS and OSA. However, good adherence to CPAP could reduce plasma fibrinogen levels, thus ameliorating elevations in plasma fibrinogen as a risk factor for future cardiovascular events.

0805 Lack of Association Between Periodic Limb Movements of Sleep and Neuroimaging Signatures of Cerebral Small Vessel Disease in Stroke-Free Community-Dwelling Older Adults

Abstract Introduction Evidence of the relationship between periodic limb movements during sleep (PLMS) and cerebral small vessel disease (cSVD) is limited and inconsistent. Here, we aimed to assess the independent association between PLMS and the different neuroimaging signatures of cSVD. Methods Community dwelling adults aged ≥60 years enrolled in the Atahualpa Project undergoing PSG and MRI with time intervals ≤6 months were included. MRI readings focused on white matter hyperintensities (WMH) of presumed vascular origin, deep cerebral microbleeds (CMB), silent lacunar infarcts (LI), and &amp;gt;10 enlarged basal ganglia-perivascular spaces (BG-PVS). Data from single-night polysomnograms were interpreted according to recommendations of the American Academy of Sleep Medicine. Associations between the PLMS index and neuroimaging signatures of cSVD (as dependent variables) were assessed by means of logistic regression models, adjusted for relevant confounders. Results A total of 146 individuals (mean age: 71.4 ± 7.5 years; 64% women) were included. A PLMS index ≥15/hour were noted in 48 (33%) participants. Moderate-to-severe WMH were present in 33 individuals (23%), deep CMB in 9 (6%), silent LI in 16 (11%), and &amp;gt;10 BG-PVS in 44 (30%). In univariate analyses, silent LI (p=0.035) and the presence of &amp;gt;10 enlarged BG-PVS (p=0.034) were significantly higher among participants with a PLMS index ≥15/hour. However, fully-adjusted multivariate models showed no significant association between PLMS index ≥15/hour and any of the neuroimaging signatures of cSVD. Conclusion This study shows no independent association between the PLMS index and neuroimaging signatures of cSVD in stroke-free community-dwelling older adults. Support This study was supported by Universidad Espíritu Santo - Ecuador.

CSF and serum ferritin levels in narcolepsy type 1 comorbid with restless legs syndrome.

ObjectivesTo investigate whether cerebrospinal fluid (CSF) and serum ferritin levels differ between patients with narcolepsy type 1 (NT1) comorbid with restless legs syndrome (RLS) or periodic leg movements during sleep (PLMS), and patients with NT1 or controls without comorbid RLS or PLMS.MethodsSixty‐six drug‐free patients with NT1 (44 males, age 38.5 years [14–81]) were enrolled, including 20 with RLS, 18 with PLMS index ≥15/h (six with both RLS and PLMS). Thirty‐eight drug‐free patients (12 males, age 22.5 years [12–61]) referred for sleepiness complaint, but without central hypersomnia, RLS, PLMS were included as controls. Clinical, electrophysiological and biological (CSF/serum ferritin, orexin [ORX]) data were quantified.ResultsNT1 patients with and without RLS did not differ for age, gender, and body mass index (BMI). No between‐group differences were found for CSF ferritin, ORX, and serum ferritin levels. No CSF ferritin, ORX, and serum ferritin level differences were found between NT1 patients with and without PLMS, or with RLS or PLMS versus not. CSF‐ferritin levels were not different between NT1 and controls in adjusted analyses. CSF‐ferritin levels in the whole population correlated positively with age, serum‐ferritin, BMI, negatively with ORX, but not with PLMS index. In NT1, CSF‐ferritin levels correlated with age and serum‐ferritin but not with PLMS.ConclusionThe absence of CSF ferritin deficiency in NT1 with comorbid RLS or PLMS indicates normal brain iron levels in that condition. This result suggests that the frequent association between RLS, PLMS, and NT1 is not based on alterations in brain iron metabolism, a pathophysiological mechanism involved in primary RLS.

Association of periodic limb movements during sleep and tinnitus in humans

Both of periodic limb movements during sleep (PLMS) and tinnitus were related with dopaminergic system dysfunction. However, it was still unclear whether PLMS, one kind of sleep disturbances, was associated with chronic tinnitus or not. Thus, we aimed to investigate this issue in humans. Clinical and overnight polysomnographic data of 2849 adults from a community hospital during Nov. 2011 to Jun 2017 in Taiwan was collected retrospectively. The association of PLMS and chronic tinnitus was analyzed by Student’s t-test, Pearson’s Chi-Square test, and multivariate logistic regression. The results showed that the mean age was 50.6 years old (standard deviation, SD = 13.3, range = 18~91) for all subjects. There were 1886 subjects without tinnitus and 963 subjects with tinnitus in this study. The PLMS was not significantly different between subjects without tinnitus (mean = 1.0/h, SD = 3.5/h) and subjects with tinnitus mean = 1.1/h, SD = 3.4/h) by Student’s t-test. The severity of PLMS was not significantly between non-tinnitus and tinnitus subjects by Pearson’s Chi-Square test. Multivariate logistic regression also showed that PLMS was not significantly associated with tinnitus after adjusting age, sex, subjective hearing loss, Parkinson’s disease, and insomnia. In conclusion, PLMS was not associated with chronic tinnitus in humans.

Periodic limb movements during sleep may reduce excessive daytime sleepiness in men with obstructive sleep apnea.

The impact of periodic limb movements during sleep (PLMS) on excessive daytime sleepiness (EDS) is controversial. We investigated the relationship between PLMS and EDS in men with obstructive sleep apnea (OSA). This was a cross-sectional study of men with OSA. PLMS parameters were a PLM index (PLMI) > 15 per hour of sleep and a PLM-arousal index (PLMAI) > 5 per hour of sleep. The Epworth Sleepiness Scale (ESS) and the Beck Depression Inventory were used. EDS was defined as an ESS score ≥ 11. Multivariate logistic regression analysis was performed with adjustments for several covariates. Of 1111 men with OSA, 14.0% (n = 156) had a PLMI > 15/h, and 3.7% (n = 41) had a PLMAI > 5/h. EDS was noted in 39.5% (n = 439) of men. Men with a PLMI > 15/h were less likely to have EDS (odd ratio [OR], 0.598; 95% confidence interval [CI], 0.414-0.864; p = 0.006). This association remained significant after controlling for age, body mass index, depressive symptoms, total sleep time, and severity of OSA (OR, 0.675; 95% CI, 0.456-0.999; p = 0.049). Men with a PLMAI > 5/h were less likely to have EDS, but this result did not reach statistical significance (OR, 0.550; 95% CI, 0.273-1.109; p = 0.095). PLMS defined as PLMI > 15/h are significantly and inversely associated with EDS in men with OSA, even after controlling for several confounding variables.

Brain regions associated with periodic leg movements during sleep in restless legs syndrome

The neural substrates related to periodic leg movements during sleep (PLMS) remain uncertain, and the specific brain regions involved in PLMS have not been evaluated. We investigated the brain regions associated with PLMS and their severity using the electroencephalographic (EEG) source localization method. Polysomnographic data, including electromyographic, electrocardiographic, and 19-channel EEG signals, of 15 patients with restless legs syndrome were analyzed. We first identified the source locations of delta-band (2–4 Hz) spectral power prior to the onset of PLMS using a standardized low-resolution brain electromagnetic tomography method. Next, correlation analysis was conducted between current densities and PLMS index. Delta power initially and most prominently increased before leg movement (LM) onset in the PLMS series. Sources of delta power at −4~−3 seconds were located in the right pericentral, bilateral dorsolateral prefrontal, and cingulate regions. PLMS index was correlated with current densities at the right inferior parietal, temporoparietal junction, and middle frontal regions. In conclusion, our results suggest that the brain regions activated before periodic LM onset or associated with their severity are the large-scale motor network and provide insight into the cortical contribution of PLMS pathomechanism.

Sleep Disorders and Risk of Ischemic Stroke.

Sleep is a highly coordinated physiologic state, which is essential for functional integrity of the neurons and brain. It is crucial for survival. Non rapid eye movement sleep (NREM) vagal dominance enables neural/cardiovascular axis to regenerate homeostasis after periods of stress or fatigue during wakefulness. Any reasons of sleep interruption or deprivation like periodic limb movements during sleep (PLMS), insomnia, shift work and obstructive sleep apnea have negative effect on cardiovascular homeostasis and restoration. Sleep disorders have a fundamental contribution in cerebrovascular and other cardiovascular diseases. The aim of this review is to highlight the role of sleep disorders in the risk of cerebrovascular ischemic stroke and help both neurologists and our community to realize the great value of diagnosis and management of sleep disorders for effective prevention of ischemic stroke and proper care. Further attention and care should be given to the early identification of sleep disorders in risky patients to avoid major cerebrovascular and cardiovascular events.

Lack of Association between Periodic Limb Movements during Sleep and Neuroimaging Signatures of Cerebral Small Vessel Disease in Stroke-Free Community-Dwelling Older Adults. The Atahualpa Project

Evidence of the relationship between periodic limb movements during sleep (PLMS) and cerebral small vessel disease (cSVD) is limited and inconsistent. Here, we aimed to assess the independent association between PLMS and the different neuroimaging signatures of cSVD. Atahualpa residents aged more than or equal to 60 years enrolled in the Atahualpa Project undergoing polysomnography and MRI with time intervals less than or equal to 6 months were included. MRI readings focused on white matter hyperintensities (WMH) of presumed vascular origin, deep cerebral microbleeds (CMB), silent lacunar infarcts (LI), and more than 10 enlarged basal ganglia-perivascular spaces (BG-PVS). Data from single-night polysomnograms were interpreted according to recommendations of the American Academy of Sleep Medicine. Associations between the PLMS index and neuroimaging signatures of cSVD (as dependent variables) were assessed by means of logistic regression models, adjusted for relevant confounders. A total of 146 individuals (mean age: 71.4 ± 7.5 years; 64% women) were included. A PLMS index more than or equal to 15 per hour were noted in 48 (33%) participants. Moderate-to-severe WMH were present in 33 individuals (23%), deep CMB in 9 (6%), silent LI in 16 (11%), and more than 10 BG-PVS in 44 (30%). In univariate analyses, silent LI (P = .035) and the presence of more than 10 enlarged BG-PVS (P = .034) were significantly higher among participants with a PLMS index more than or equal to 15 per hour. However, fully-adjusted multivariate models showed no significant association between PLMS index more than or equal to 15 per hour and any of the neuroimaging signatures of cSVD. This study shows no independent association between the PLMS index and neuroimaging signatures of cSVD in stroke-free community-dwelling older adults.

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.

Limb movements during sleep in children: effects of age, sex, and iron status in more than 1,000 patients referred to a pediatric sleep center.

Limb movements during sleep (LMS) and periodic limb movements during sleep (PLMS) have been shown to vary by age in children. In the current study, we examined this relationship in more detail in a large clinically referred sample adjusting for iron status and sex. Retrospective data analysis was done on a large pediatric population who underwent an overnight sleep study and had ferritin levels measured within 30 days of sleep study between May 2013 and October 2017 at pediatric sleep center. Patients with obstructive or central sleep apneas were excluded. A total of 1,070 patients were included in the study, with 60% males. Younger age and male sex were associated with increased PLMS and LMS. In addition, there was an increase in PLMS and LMS during adolescence that subsided at a later age, independent of sex. These associations remained significant in models controlling for ferritin level. Ferritin level, in contrast, was not a significant predictor of PLMS or LMS when controlling for sex and age. Age and sex may need to be considered when interpreting limb movement indices in pediatric sleep patients regardless of ferritin level.

Blood pressure profile and endothelial function in restless legs syndrome

Restless legs syndrome (RLS) is frequently comorbid with hypertension and cardiovascular diseases; however this relationship and underlying mechanisms remain controversial. After clinical evaluation, 84 drug-free patients with primary RLS (53 women; mean age 55.1 ± 12.3 years) and 76 controls (47 women; mean age 52.2 ± 15.3 years) underwent 24-hour ambulatory blood pressure (BP) and polysomnographic monitoring, and peripheral arterial tonometry to assess endothelial function for 61 patients and 69 controls. Hypertension was diagnosed in 11.9% of patients with RLS based on office measurement, and in 46.4% on the 24 h recording, with nighttime hypertension, two times more frequent than daytime hypertension. Periodic limb movement during sleep (PLMS), markers of sleep fragmentation, and systolic and mean BP non-dipping profile were more frequent among patients. BP non-dipping status was associated with older age, later RLS onset and diagnosis, RLS severity and higher sleep fragmentation. The mean 24-hour, daytime and nighttime BP values, the frequency of hypertension and the endothelial function were comparable between groups. However, both systolic and diastolic BP trajectories over a 24-hour period differed between groups. In conclusion, patients with RLS exhibit a 24-hour BP deregulation with increased frequency of systolic non-dipping profiles that could worsen the risk for CVD morbidity and mortality.

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

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. 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. 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). 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. ClinicalTrials.gov, NCT00070681.

Risk of resistant hypertension associated with restless legs syndrome and periodic limb movements during sleep: a study on 673 treated hypertensive individuals

ObjectiveGiven the limited data available in the literature, the aim of this study was to examine the risk of resistant hypertension (RHT) associated with restless legs syndrome (RLS) and periodic limb movements during sleep (PLMS) in a large sample of treated hypertensive individuals. MethodsDemographic and polysomnographic (PSG) data from 673 treated hypertensive individuals recruited from the research database of the sleep laboratory of Erasme Hospital were analysed. After exclusion of the main causes of pseudo-resistance and secondary hypertension, RHT status was defined by the presence of an uncontrolled hypertension despite treatment with at least three antihypertensive agents (including a diuretic) from different classes in correct combination and at the highest tolerated doses or by the presence of controlled hypertension requiring the use of at least four antihypertensive agents. Logistic regression analyses were conducted to examine the risk of RHT associated with RLS and PLMS in treated hypertensive individuals. ResultsAfter adjustment for major confounding factors associated with RHT, multivariate logistic regression analysis revealed that frequent RLS (≥2 episodes/week) combined with PLMS index ≥26/h [odds ratio (OR) 2.20; 95% confidence interval (CI) 1.35–3.61, p = 0.021] was a significant risk factor of RHT in treated hypertensive individuals. ConclusionIn treated hypertensive individuals, frequent RLS combined with PLMS index ≥26/h is associated with higher risk of RHT which suggests that this pathology may be a secondary cause of RHT (eg, obstructive sleep apnoea syndrome and insomnia with short sleep duration) justifying the establishment of effective treatments in this particular subpopulation.

External validation of a data-driven algorithm for muscular activity identification during sleep.

Several automated methods for scoring periodic limb movements during sleep (PLMS) and rapid eye movement (REM) sleep without atonia (RSWA) have been proposed, but most of them were developed and validated on data recorded in the same clinic, thus they may be biased. This work aims to validate our data-driven algorithm for muscular activity detection during sleep, originally developed based on data recorded and manually scored at the Danish Center for Sleep Medicine. The validation was carried out on a cohort of 240 participants, including de novo Parkinson's disease (PD) patients and neurologically healthy controls, whose sleep data were recorded and manually evaluated at Paracelsus-Elena Klinik, Kassel, Germany. In the German cohort, the algorithm showed generally good agreement between manual and automated PLMS indices, and identified with 88.75% accuracy participants with PLMS index above 15 PLMS per hour of sleep, and with 84.17% accuracy patients suffering from REM sleep behaviour disorder (RBD) showing RSWA. By comparing the algorithm performances in the Danish and German cohorts, we hypothesized that inter-clinical differences may exist in the way limb movements are manually scored and how healthy controls are defined. Finally, the algorithm performed worse in PD patients, probably as a result of increased artefacts caused by abnormal motor events related to neurodegeneration. Our algorithm can identify, with reasonable performance, participants with RBD and increased PLMS index from data recorded in different centres, and its application may reveal inter clinical differences, which can be overcome in the future by applying automated methods.

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

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. 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. 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. 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.

Frequency of cardiovascular diseases in the patients with restless legs syndrome

Background: Restless Legs Syndrome (RLS) is a sensory-motor neurological disease characterized by discomfort, unpleasant sensations, an urge to move the legs. There are a lot of studies showing the association between Restless Legs Syndrome (RLS), Cardiovascular Diseases (CVD), Hypertension (HT) and Body Mass Index (BMI). The potential underlying mechanism of an increased risk of CVD in RLS is not clear but may involve hypertension, as Periodic Limb Movements during Sleep (PLMS) were shown to be related to blood pressure increases. These studies were inconsistent. The aim of this case control study was to show the prevalence of CVD in the patients with RLS compared with a control group.Methods: A total of 37 newly diagnosed patients with RLS (group 1) who were applied to neurology polyclinic of Sakarya University Hospital between March 2016 and May 2017 and 37 control subjects (group 2) were included in this case control study. RLS was diagnosed using the criteria of the International RLS Study Group. Both groups were screened for HT, dyslipidemia, coronary artery diseases, atrial fibrillation. 24hour Ambulatory Blood Pressure Monitoring (ABPM) were enrolled for both groups. Interventricular septum was measured with echocardiography by cardiologist for diagnosis of left ventricular hypertrophy.Results: There were no significant differences in sex (p:0.11) and age (p:0.33) between the two groups. Hypertension (p:0.001) and non-dipper hypertension (p:0.004), BMI (p:0.004), left ventricular hypertrophy (p:0,002) were found statistically significantly higher than the control group. There were no differences in atrial fibrillation (p:1) and hyperlipidemia (p:0.69) between two groups.Conclusions: Patients with RLS should be followed closely for cardiovascular diseases.

Quetiapine-induced behavioral disorder during sleep.

Quetiapine-induced behavioral disorder during sleep.

Sleep and Tibialis Anterior Muscle Activity in Mice With Mild Hypoxia and Iron Deficiency: Implications for the Restless Legs Syndrome.

Restless legs syndrome (RLS) is a neurological disorder that entails an urge to move with a circadian pattern during the evening/night. RLS may be accompanied by decreased sleep time and increased occurrence of periodic leg movements during sleep (PLMS), which involve bursts of tibialis anterior (TA) muscle electromyogram (EMG). Mild hypoxia and non-anemic iron deficiency, a highly prevalent nutritional deficiency, are relatively unexplored factors in RLS pathophysiology. We tested whether mice exposed to mild hypoxia, alone or in combination with non-anemic iron deficiency, show decreased sleep time particularly in the light (rest) period and increased occurrence of TA EMG phasic events similar to human PLMS. Female C57BL/6J mice were fed diets with low or normal iron for 6 months from weaning and instrumented with electrodes to record the electroencephalogram and the EMG of both TA muscles. Mice were recorded in a whole-body plethysmograph while breathing a normoxic or mildly hypoxic (15% O2) gas mixture for 48 h. Hypoxia increased minute ventilation during sleep. The low-iron diet decreased liver and serum iron, leaving blood hemoglobin and brainstem iron levels unaffected. Hypoxia, either alone or in combination with non-anemic iron deficiency, decreased non-rapid-eye-movement (non-REM) sleep time, but this occurred irrespective of the light/dark period and was not associated with increased occurrence of TA EMG events during non-REM sleep. These results do not support the hypothesis that mild hypoxia is sufficient to cause signs of RLS, either alone or in combination with non-anemic iron deficiency, pointing to the necessity of further susceptibility factors.

Video polysomnographic findings in non-rapid eye movement parasomnia.

Although video polysomnography (vPSG) is not routinely recommended for the evaluation of typical cases of non‐rapid eye movement (NREM) parasomnias, it can aid diagnosis of unusual cases, other sleep disorders and complicated cases with REM behaviour disorder (RBD), and in differentiating parasomnias from epilepsy. In this study, we aimed to assess vPSG findings in consecutive patients with a clinical diagnosis of NREM‐parasomnia covering the whole phenotypic spectrum. Five hundred and twelve patients with a final diagnosis of NREM parasomnia who had undergone vPSG were retrospectively identified. vPSGs were analysed for features of NREM parasomnia and for the presence of other sleep disorders. Two hundred and six (40.0%) patients were clinically diagnosed with sleepwalking, 72 (14.1%) with sleep terrors, 39 (7.6%) with confusional arousals, 15 (2.9%) with sexsomnia, seven (1.4%) with sleep‐related eating disorder, 122 (23.8%) with mixed phenotype, and 51 (10.0%) with parasomnia overlap disorder (POD). The vPSG supported the diagnosis of NREM parasomnia in 64.4% of the patients and of POD in 98%. In 28.9% of the patients, obstructive sleep apnea (OSA) or/and periodic limb movements during sleep (PLMS) were identified, most commonly in older, male, sleepy and obese patients. vPSG has a high diagnostic yield in patients with NREM parasomnia and should be routinely performed when there is diagnostic doubt, or in patients where there is a suspicion of OSA and PLMS.