Genetics and epigenetics of rare hypersomnia.

Herein we focus on connections between genetics and some central disorders of hypersomnolence - narcolepsy types 1 and 2 (NT1, NT2), idiopathic hypersomnia (IH), and Kleine-Levin syndrome (KLS) - for a better understanding of their etiopathogenetic mechanisms and a better diagnostic and therapeutic definition. Gene pleiotropism influences neurological and sleep disorders such as hypersomnia; therefore, genetics allows us to uncover common pathways to different pathologies, with potential new therapeutic perspectives. An important body of evidence has accumulated on NT1 and IH, allowing a better understanding of etiopathogenesis, disease biomarkers, and possible new therapeutic approaches. Further studies are needed in the field of epigenetics, which has a potential role in the modulation of biological specific hypersomnia pathways.

Neuropsychological Changes in Isolated REM Sleep Behavior Disorder: A Systematic Review and Meta-analysis of Cross-sectional and Longitudinal Studies.

The aim of this meta-analysis is twofold: (a) to assess cognitive impairments in isolated rapid eye movement (REM) sleep behavior disorder (iRBD) patients compared to healthy controls (HC); (b) to quantitatively estimate the risk of developing a neurodegenerative disease in iRBD patients according to baseline cognitive assessment. To address the first aim, cross-sectional studies including polysomnography-confirmed iRBD patients, HC, and reporting neuropsychological testing were included. To address the second aim, longitudinal studies including polysomnography-confirmed iRBD patients, reporting baseline neuropsychological testing for converted and still isolated patients separately were included. The literature search was conducted based on PRISMA guidelines and the protocol was registered at PROSPERO (CRD42021253427). Cross-sectional and longitudinal studies were searched from PubMed, Web of Science, Scopus, and Embase databases. Publication bias and statistical heterogeneity were assessed respectively by funnel plot asymmetry and using I2. Finally, a random-effect model was performed to pool the included studies. 75 cross-sectional (2,398 HC and 2,460 iRBD patients) and 11 longitudinal (495 iRBD patients) studies were selected. Cross-sectional studies showed that iRBD patients performed significantly worse in cognitive screening scores (random-effects (RE) model = -0.69), memory (RE model = -0.64), and executive function (RE model = -0.50) domains compared to HC. The survival analyses conducted for longitudinal studies revealed that lower executive function and language performance, as well as the presence of mild cognitive impairment (MCI), at baseline were associated with an increased risk of conversion at follow-up. Our study underlines the importance of a comprehensive neuropsychological assessment in the context of iRBD.

Risk Factors for Phenoconversion in Rapid Eye Movement Sleep Behavior Disorder.

OBJECTIVE: This study was undertaken to follow up predictive factors for α-synuclein-related neurodegenerative diseases in a multicenter cohort of idiopathic/isolated rapid eye movement sleep behavior disorder (iRBD). METHODS: Patients with iRBD from 12 centers underwent a detailed assessment for potential environmental and lifestyle risk factors via a standardized questionnaire at baseline. Patients were then prospectively followed and received assessments for parkinsonism or dementia during follow-up. The cumulative incidence of parkinsonism or dementia was estimated with competing risk analysis. Cox regression analyses were used to evaluate the predictive value of environmental/lifestyle factors over a follow-up period of 11 years, adjusting for age, sex, and center. RESULTS: Of 319 patients who were free of parkinsonism or dementia, 281 provided follow-up information. After a mean follow-up of 5.8 years, 130 (46.3%) patients developed neurodegenerative disease. The overall phenoconversion rate was 24.2% after 3 years, 44.8% after 6 years, and 67.5% after 10 years. Patients with older age (adjusted hazard ratio [aHR] = 1.05) and nitrate derivative use (aHR = 2.18) were more likely to phenoconvert, whereas prior pesticide exposure (aHR = 0.21-0.64), rural living (aHR = 0.53), lipid-lowering medication use (aHR = 0.59), and respiratory medication use (aHR = 0.36) were associated with lower phenoconversion risk. Risk factors for those converting to primary dementia and parkinsonism were generally similar, with dementia-first converters having lower coffee intake and beta-blocker intake, and higher occurrence of family history of dementia. INTERPRETATION: Our findings elucidate the predictive values of environmental factors and comorbid conditions in identifying RBD patients at higher risk of phenoconversion. ANN NEUROL 2022;91:404-416.

Challenging subjective excessive daytime sleepiness as an insomnia symptom: a retrospective study.

Diagnostic manuals describe insomnia disorder (ID) characterised by fatigue and sleepiness as diurnal consequences of nocturnal symptoms. However, patients with ID do not frequently report sleepiness in the clinical setting. The present study aimed to investigate subjective sleepiness in ID measured through the Epworth Sleepiness Scale (ESS) and its independence towards daytime functioning and fatigue, and to evaluate cognitive behavioural therapy for insomnia (CBT-I) improvement in daytime consequences and their relationship to sleepiness and fatigue. We retrospectively collected the ESS evaluation in a large sample of 105 healthy controls (HCs), 671 patients with ID, and 602 patients with sleep disorders characterised by excessive daytime sleepiness (EDS). Moreover, we conducted a pre-post evaluation of the ESS in a sub-sample of patients with ID who underwent CBT-I. Component 2 of the Insomnia Severity Index and Profile of Mood States-Fatigue Inertia Scale was used to evaluate daytime functioning and fatigue. Patients with ID reported ESS levels comparable to that observed in HCs and significantly lower than the EDS group. No significant correlation arose between ESS and the diurnal impact of the disorder, suggesting the independence between daytime functioning and sleepiness in ID. Contrarily, insomnia severity and diurnal impact significantly correlated with fatigue. Data showed a statistically significant increase in sleepiness after CBT-I, despite significantly improving daytime consequences and fatigue. Although diagnostic manuals report sleepiness and fatigue as daytime consequences of sleep symptoms in patients with ID, these retrospective data indicate a dissociation between these entities. This evidence aligns with the core feature of ID: the hyperarousal status that pervades patients also during wakefulness.

Sleep medicine catalogue of knowledge and skills - Revision.

The 'catalogue of knowledge and skills' for sleep medicine presents the blueprint for a curriculum, a textbook, and an examination on sleep medicine. The first catalogue of knowledge and skills was presented by the European Sleep Research Society in 2014. It was developed following a formal Delphi procedure. A revised version was needed in order to incorporate changes that have occurred in the meantime in the International Classification of Sleep Disorders, updates in the manual for scoring sleep and associated events, and, most important, new knowledge in sleep physiology and pathophysiology. In addition, another major change can be observed in sleep medicine: a paradigm shift in sleep medicine has taken place. Sleep medicine is no longer a small interdisciplinary field in medicine. Sleep medicine has increased in terms of recognition and importance in medical care. Consequently, major medical fields (e.g. pneumology, cardiology, neurology, psychiatry, otorhinolaryngology, paediatrics) recognise that sleep disorders become a necessity for education and for diagnostic assessment in their discipline. This paradigm change is considered in the catalogue of knowledge and skills revision by the addition of new chapters.

Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study.

Idiopathic REM sleep behaviour disorder (iRBD) is a powerful early sign of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. This provides an unprecedented opportunity to directly observe prodromal neurodegenerative states, and potentially intervene with neuroprotective therapy. For future neuroprotective trials, it is essential to accurately estimate phenoconversion rate and identify potential predictors of phenoconversion. This study assessed the neurodegenerative disease risk and predictors of neurodegeneration in a large multicentre cohort of iRBD. We combined prospective follow-up data from 24 centres of the International RBD Study Group. At baseline, patients with polysomnographically-confirmed iRBD without parkinsonism or dementia underwent sleep, motor, cognitive, autonomic and special sensory testing. Patients were then prospectively followed, during which risk of dementia and parkinsonsim were assessed. The risk of dementia and parkinsonism was estimated with Kaplan-Meier analysis. Predictors of phenoconversion were assessed with Cox proportional hazards analysis, adjusting for age, sex, and centre. Sample size estimates for disease-modifying trials were calculated using a time-to-event analysis. Overall, 1280 patients were recruited. The average age was 66.3 ± 8.4 and 82.5% were male. Average follow-up was 4.6 years (range = 1-19 years). The overall conversion rate from iRBD to an overt neurodegenerative syndrome was 6.3% per year, with 73.5% converting after 12-year follow-up. The rate of phenoconversion was significantly increased with abnormal quantitative motor testing [hazard ratio (HR) = 3.16], objective motor examination (HR = 3.03), olfactory deficit (HR = 2.62), mild cognitive impairment (HR = 1.91-2.37), erectile dysfunction (HR = 2.13), motor symptoms (HR = 2.11), an abnormal DAT scan (HR = 1.98), colour vision abnormalities (HR = 1.69), constipation (HR = 1.67), REM atonia loss (HR = 1.54), and age (HR = 1.54). There was no significant predictive value of sex, daytime somnolence, insomnia, restless legs syndrome, sleep apnoea, urinary dysfunction, orthostatic symptoms, depression, anxiety, or hyperechogenicity on substantia nigra ultrasound. Among predictive markers, only cognitive variables were different at baseline between those converting to primary dementia versus parkinsonism. Sample size estimates for definitive neuroprotective trials ranged from 142 to 366 patients per arm. This large multicentre study documents the high phenoconversion rate from iRBD to an overt neurodegenerative syndrome. Our findings provide estimates of the relative predictive value of prodromal markers, which can be used to stratify patients for neuroprotective trials.

The association between emotional dysregulation and REM sleep features in insomnia disorder.

Rapid Eye Movement (REM) sleep is involved in nightly emotional processing; therefore, its disruption might be associated with an impaired ability of emotional regulation during daytime. Accordingly, the aim of the present study was to evaluate the presence of emotional dysregulation in insomnia patients and to test its correlation with REM sleep features. Forty-six subjects (23 insomnia patients and 23 healthy controls) were enrolled. All subjects underwent an assessment for the evaluation of emotion dysregulation (Difficulties in Emotion Regulation Scale, DERS), sleep quality, insomnia severity, excessive daytime sleepiness, worry, rumination, depressive and anxious symptomatology. Insomnia patients underwent a nocturnal polysomnographic recording to characterize sleep macrostructure and REM sleep microstructure variables. Insomnia patients reported increased values of emotional dysregulation. REM sleep percentage and REM sleep latency significantly correlated with DERS total score, and with the subscales "Lack of Confidence in Emotional Regulation Skills", "Difficulties in Behavioral Control" and "Difficulty in recognizing emotions". Furthermore, positive correlations between REM arousal index and emotion dysregulation were found, whereas REM density negatively correlated with DERS. Our results suggest the presence of a relationship between REM sleep and emotional regulation in insomnia patients.

Insomnia Patients With Subjective Short Total Sleep Time Have a Boosted Response to Cognitive Behavioral Therapy for Insomnia Despite Residual Symptoms.

Background: Two distinct insomnia disorder (ID) phenotypes have been proposed, distinguished on the basis of an objective total sleep time less or more than 6 hr. In particular, it has been recently reported that patients with objective short sleep duration have a blunted response to cognitive behavioral therapy for insomnia (CBT-I). The aim of this study was to investigate the differences of CBT-I response in two groups of ID patients subdivided according to total sleep time. Methods: Two hundred forty-six ID patients were subdivided into two groups, depending on their reported total sleep time (TST) assessed by sleep diaries. Patients with a TST greater than 6 hr were classified as "normal sleepers" (NS), while those with a total sleep time less than 6 hr were classified as "short sleepers" (SS). Results: The delta between Insomnia Severity Index scores and sleep efficiency at the beginning as compared to the end of the treatment was significantly higher for SS in comparison to NS, even if they still exhibit more insomnia symptoms. No difference was found between groups in terms of remitters; however, more responders were observed in the SS group in comparison to the NS group. Conclusions: Our results demonstrate that ID patients with reported short total sleep time had a beneficial response to CBT-I of greater magnitude in comparison to NS. However, these patients may still experience the presence of residual insomnia symptoms after treatment.

Impaired visual processing in patients with insomnia disorder revealed by a dissociation in visual search.

Insomnia disorder is associated with both subjective and objective daytime impairments. In particular, cognitive impairments are frequently reported. However, little is known about the effects of this pathology on perceptual processes. In this study we aim at evaluating the effect of insomnia disorder on visual processing by employing a visual search paradigm. Twenty-three patients with insomnia disorder and 20 healthy age- and sex-matched control subjects participated in the study. After a polysomnographic recording night patients performed a visual search task in which they had to respond to the presence/absence of a target (letter T) embedded into a set of distractors (letters Os, Xs or Ls). Target's salience and distractors' numerosity were manipulated, while accuracy and reaction times were recorded as dependent variables. The results mainly confirmed the typical effects of a visual search task. An overall delay in performing the task was observed for patients with insomnia disorder. However, distinguishing the reaction times to stimuli containing the target from reaction times to stimuli in which the target was absent, the clinical group differed from controls solely in the condition of target absent. The performance (reaction times) of the subjects correlated with the age in the control group, whereas no correlation between reaction times and age, disease duration and quality of sleep was found in patients with insomnia disorder. These results experimentally demonstrate the presence of a daytime impairment in patients with insomnia disorder revealed by a dissociation in visual search, and are discussed in the light of the hyperarousal concept of insomnia.

Short-interval leg movements during sleep entail greater cardiac activation than periodic leg movements during sleep in restless legs syndrome patients.

Periodic leg movements during sleep (PLMS) are sequences of ≥4 motor events with intermovement intervals (IMI) of 10-90 s. PLMS are a supportive diagnostic criterion for restless legs syndrome (RLS) and entail cardiac activation, particularly when associated with arousal. RLS patients also over-express short-interval leg movements during sleep (SILMS), which have IMI <10 s and are organized mainly in sequences of two movements (doublets). We tested whether the cardiac activation associated with SILMS doublets differs from that associated with PLMS in a sample of 25 RLS patients. We analysed time-series of R-R intervals synchronized to the onset of SILMS doublets or PLMS that entailed an arousal during non-rapid eye movement (NREM) sleep. We assessed cardiac activation based on the R-R interval decrease with respect to baseline during NREM sleep without leg movements. We found that the duration of the R-R interval decrease with SILMS doublets was significantly longer than that with PLMS, whereas the maximal decrease in R-R interval was similar. Scoring SILMS in RLS patients may therefore be relevant from a cardiac autonomic perspective.

Sequence analysis of leg movements during sleep with different intervals (<10, 10-90 and >90 s) in restless legs syndrome.

The aim of this study was to define the time structure of leg movements during sleep occurring with an intermovement interval (onset-to-onset) shorter than 10 s in patients with restless legs syndrome and controls, and to compare it to the structure of movements with intervals of 10-90 s or >90 s. Polysomnographic recordings of 141 untreated patients and 68 age-matched normal controls were analysed. All movements were detected and classified into three categories, separated by intervals of <10, 10-90 or >90 s. The number of movements included in each category was significantly higher in patients than in controls. The movements with an interval of >90 s occurred steadily during the night, whereas the hourly distribution of movements with intervals of <10 or 10-90 s was decreasing or bell-shaped in patients or controls, respectively. Movements with an interval of <10 s tended to have a shorter duration and constituted shorter sequences than movements with intervals of 10-90 or >90 s. The time structure features of the three categories of movements considered in this study were found to be clearly different. This, together with previous observations on the differential effects of dopamine agonists on movements with different intervals, suggests that movements with intervals of <10 and >90 s are regulated by neurotransmitter mechanisms different from those modulating movements with an interval of 10-90 s.

Risk factors for neurodegeneration in idiopathic rapid eye movement sleep behavior disorder: a multicenter study.

OBJECTIVE: To assess whether risk factors for Parkinson disease and dementia with Lewy bodies increase rate of defined neurodegenerative disease in idiopathic rapid eye movement (REM) sleep behavior disorder (RBD). METHODS: Twelve centers administered a detailed questionnaire assessing risk factors for neurodegenerative synucleinopathy to patients with idiopathic RBD. Variables included demographics, lifestyle factors, pesticide exposures, occupation, comorbid conditions, medication use, family history, and autonomic/motor symptoms. After 4 years of follow-up, patients were assessed for dementia or parkinsonism. Disease risk was assessed with Kaplan-Meier analysis, and epidemiologic variables were compared between convertors and those still idiopathic using logistic regression. RESULTS: Of 305 patients, follow-up information was available for 279, of whom 93 (33.3%) developed defined neurodegenerative disease. Disease risk was 25% at 3 years and 41% after 5 years. Patients who converted were older (difference = 4.5 years, p < 0.001), with similar sex distribution. Neither caffeine, smoking, nor alcohol exposure predicted conversion. Although occupation was similar between groups, those who converted had a lower likelihood of pesticide exposure (occupational insecticide = 2.3% vs 9.0%). Convertors were more likely to report family history of dementia (odds ratio [OR] = 2.09), without significant differences in Parkinson disease or sleep disorders. Medication exposures and medical history were similar between groups. Autonomic and motor symptoms were more common among those who converted. Risk factors for primary dementia and parkinsonism were generally similar, except for a notably higher clonazepam use in dementia convertors (OR = 2.6). INTERPRETATION: Patients with idiopathic RBD are at very high risk of neurodegenerative synucleinopathy. Risk factor profiles between convertors and nonconvertors have both important commonalities and differences.

The effects of Transcranial Direct Current Stimulation (tDCS) on Idiopathic Hypersomnia: a pilot study.

Idiopathic Hypersomnia (IH) is a rare sleep disorder characterised by excessive daytime sleepiness (EDS) that leads to invalidating daytime consequences. Till now the treatment of IH has mirrored that of sleepiness in narcolepsy, and it is mainly focused on symptoms' management. We employed an anodal transcranic Direct Current Stimulation (tDCS) treatment in order to induce a shift toward arousal in IH patients' cortex during the day. Every patients underwent a 4 weeks treatment (3 stimulations per week, for a total of 12 stimulations over a period of 28 days) with an assessment at the baseline and after treatment aimed to the evaluation of subjective daytime sleepiness, neurocognitive functions, and attentional domain tested by means of the Attentional Network Task (ANT). The dependent variables of the ANT are accuracy and reaction times, which represent the objective outcome of our study. A significant effect of tDCS' treatment in reducing EDS was found. Besides the amelioration in subjective EDS,  an objective improvement in RTs in all conditions of the ANT, in particular in the more difficult component, was observed. Our results indicate that tDCS may foster the management of EDS in IH, improving also the attentional domain.

Restless legs syndrome/Willis Ekbom disease: new diagnostic criteria according to different nosology.

Restless Legs Syndrome/Willis Ekbom Disease (RLS/WED) is a common neurological disorder characterized by uncomfortable and unpleasant sensations in the legs, with an urge to move. The symptoms typically begin or worsen during periods of rest, in particular during the evening and at night, while the activity may typically relieve them. The majority of patients complains of poor sleep. Recent studies reported the prevalence is ranging from 5 to 10%. RLS/WED can be divided into primary (patients without associated conditions that may explain the symptoms) and secondary forms (mostly iron deficiency). RLS/WED is typically a chronic condition. The clinical course varies according to the age of onset. A great load of accumulating research and clinical data have led to an extended consensus for a need to enhance the diagnostic criteria. The aim of this paper is to provide a critical comparison among different diagnostic criteria, taking into account respectively the International Classification of Sleep Disorders (ICSD), the International RLS Study Group (IRLSSG) and the Diagnostic and Statistical Manual of Mental Disorders (DSM). There are several remarkable distinctions between the IRLSSG revised criteria, ICSD-3 and DSM-V. Contrary to the DSM-V criteria, ICSD-3 diagnostic criteria are more aligned to the IRLSSG ones. In fact, the five essential criteria of the IRLSSG are also required for the diagnosis of RLS/WED according to ICSD-3. The new IRLSSG criteria provide a more rigorous approach to case ascertainment and a better characterization of patients by specifying clinical significance and course. Future ascertainment of correct diagnosis should include documentation that all five diagnostic criteria are considered.

Obstructive sleep apnea in Prader-Willi syndrome: risks and advantages of adenotonsillectomy.

Obstructive sleep apnea is a well-known clinical manifestation of Prader-Willi syndrome. The aim of our study is to evaluate the efficacy of adenotonsillectomy for the treatment of the disorder as well as the improvement of their post-operative quality of life. Five patients with moderate to severe obstructive sleep apneas and adenotonsillar hypertrophy of grade III-IV underwent adenotonsillectomy. Pre- and postoperative apneas and Quality of Life were assessed respectively with a polysomnography with multi-sleep latency test and with the pediatric Quality of Life questionnaire, performed before and 6 months after surgery. A decrease of apnea/hypopnea index values has been detected between pre- and post-surgery (t=2.64, P=0.005), as well as oxygen desaturation index values (t=5.51, P=0.005), multi-sleep latency test (t=4.54, P=0.01), and of the values of pediatric Quality of Life questionnaire. No correlation has been detected between body mass index and apnea/hypopnea index, oxygen desaturation index and multi-sleep latency test values pre- and post-adenotonsillectomy. A correlation has been found between multi-sleep latency test and oxygen desaturation index values post-surgery (P=0.04). No post-operative complications were observed. Our data underline the efficacy of surgery in Prader-Willi patients with adenotonsillar hypertrophy in order to improve their quality of life.

Catalogue of knowledge and skills for sleep medicine.

Sleep medicine is evolving globally into a medical subspeciality in its own right, and in parallel, behavioural sleep medicine and sleep technology are expanding rapidly. Educational programmes are being implemented at different levels in many European countries. However, these programmes would benefit from a common, interdisciplinary curriculum. This 'catalogue of knowledge and skills' for sleep medicine is proposed, therefore, as a template for developing more standardized curricula across Europe. The Board and The Sleep Medicine Committee of the European Sleep Research Society (ESRS) have compiled the catalogue based on textbooks, standard of practice publications, systematic reviews and professional experience, validated subsequently by an online survey completed by 110 delegates specialized in sleep medicine from different European countries. The catalogue comprises 10 chapters covering physiology, pathology, diagnostic and treatment procedures to societal and organizational aspects of sleep medicine. Required levels of knowledge and skills are defined, as is a proposed workload of 60 points according to the European Credit Transfer System (ECTS). The catalogue is intended to be a basis for sleep medicine education, for sleep medicine courses and for sleep medicine examinations, serving not only physicians with a medical speciality degree, but also PhD and MSc health professionals such as clinical psychologists and scientists, technologists and nurses, all of whom may be involved professionally in sleep medicine. In the future, the catalogue will be revised in accordance with advances in the field of sleep medicine.

Neurophysiological Parameters Influencing Sleep-Wake Discrepancy in Insomnia Disorder: A Preliminary Analysis on Alpha Rhythm during Sleep Onset.

Sleep state misperception (SSM) is a common issue in insomnia disorder (ID), causing a discrepancy between objective and subjective sleep/wake time estimation and increased daytime impairments. In this context, the hyperarousal theory assumes that sustained central nervous system activation contributes to the SSM. This study investigates factors influencing SSM during sleep latency (SL) and total sleep time (TST). Objective polysomnographic sleep variables (the alpha density index, latency-to-sleep stages and the first K-complex, and Rapid Eye Movement (REM) arousal density) and subjective sleep indices, taken from sleep diaries, were analyzed in 16 ID patients. Correlation analyses revealed a positive association between the degree of SL misperception (SLm) and the percentage of epochs that contained a visually scored stereotyped alpha rhythm during objective SL. A regression analysis showed that the REM arousal density and alpha density index significantly predicted TST misperception (TSTm). Furthermore, the degree of SLm was associated with an increased probability of transitioning from stage 1 of non-REM sleep to wakefulness during subjective SL. These findings support the role of hyperarousal in SSM and highlight the importance of alpha activity in unravelling the heterogeneous underpinnings of SSM.

Boosting obstructive sleep apnea therapy by non-pharmacological approaches: A network meta-analysis.

INTRODUCTION: Obstructive sleep apnea (OSA) is the most common breathing-related sleep disorder with a considerable economic burden, low diagnosis and treatment rates. Continuous positive airway pressure (CPAP/PAP) is the principal therapy for OSA treatment; nevertheless, effectiveness is often limited by suboptimal adherence. The present network meta-analysis aims to systematically summarize and quantify different interventions' effects on CPAP/PAP adherence (such as mean usage CPAP or PAP in hours per night) in OSA patients, comparing Behavioral, Educational, Supportive and Mixed interventions in Randomized Control Trials (RCT). METHODS: We conducted a computer-based search using the electronic databases of Pubmed, Psycinfo, Scopus, Embase, Chinal and Medline until August 2022, selecting 50 RCT. RESULTS: By means of a random effect model network meta-analysis, results suggested that the most effective treatment in improving CPAP/PAP adherence was the Supportive approach followed by Behavioral Therapy focused on OSA treatment adherence. CONCLUSION: This network meta-analysis might encourage the most experienced clinicians and researchers in the field to collaborate and implement treatments for improving CPAP/PAP treatment adherence. Moreover, these results support the importance of multidisciplinary approaches for OSA treatment, which should be framed within a biopsychological model.

Periodic limb movement disorder in children: A systematic review.

This systematic review evaluates the scientific literature on pediatric periodic limb movement disorder (PLMD), adhering to PRISMA guidelines and utilizing PICOS criteria. The search across PubMed, EMBASE, and Scopus yielded 331 articles, with 17 meeting inclusion criteria. Diagnostic criteria evolved, with polysomnography and PLMS index ≥5 required since 2003. Also, PLMD diagnosis mandates clinical consequences like insomnia, hypersomnia, and fatigue, excluding comorbidities causing sleep disruption. Prevalence in children is low (0.3%), emphasizing the need for meticulous investigation. Comorbidities, particularly the bidirectional relationship with ADHD, were explored. Challenges in diagnosis and understanding arise from overlapping conditions such as sleep disordered breathing, psychotropic medication, and criteria non-adherence. Despite generally good study quality, weaknesses include sample size justification and biases. The periodic leg movement index shows high sensitivity but low specificity, underscoring strict diagnostic criteria adherence. Diverse metrics for symptoms necessitate standardized approaches. Family history of RLS in children with PLMD suggests unexplored aspects. Treatment, mainly iron supplementation, lacks standardized assessment metrics. The review emphasizes diagnostic and treatment challenges, recommending unbiased studies with precise techniques. Comprehensive research, quantifying PLMS and objectively assessing sleep parameters, is crucial for advancing understanding in pediatric PLMD. PROSPERO REGISTRATION NUMBER: CRD42021251406.

Dissociation of periodic leg movements from arousals in restless legs syndrome.

OBJECTIVE: The purpose of this study was to characterize the nature of the relation between periodic leg movements during sleep (PLMS) and cortical arousals to contribute to the debate on the clinical significance and treatment of PLMS. METHODS: A prospective, placebo-controlled, single-blind, parallel group study was carried out including 46 drug-naive patients with idiopathic restless legs syndrome (RLS). Each patient underwent 2 consecutive full-night polysomnographic studies. The first night was the baseline night. Prior to the second night, 1 group received a single oral dose of 0.25mg pramipexole, whereas a second group received a single oral dose of 0.5mg clonazepam, and the remaining patients received placebo. Sleep stages, cyclic alternating pattern (CAP), and leg movement activity were scored following standard criteria; symptoms of RLS were also assessed. RESULTS: Pramipexole suppressed PLMS without affecting electroencephalographic (EEG) instability (CAP) and arousals (corresponding to CAP A3 and, partially, A2 subtypes), whereas clonazepam did the opposite, reducing non-rapid eye movement sleep EEG instability without effects on PLMS. Both drugs were effective on sensory RLS symptoms. INTERPRETATION: This study demonstrates that a selective pharmacological approach can disconnect PLMS from arousal events, suggesting an indirect relation between each other. These results might weaken the hypothesis of a direct pathological role of PLMS in sleep disruption and can be important for the discussion on the existence of a distinct entity called periodic limb movements disorder. Moreover, the study opens the doors to the possibility of a joint treatment for RLS targeting sensory and motor symptoms, as well as sleep instability.