PURPOSE:Positional obstructive sleep apnea (POSA) is the most common phenotype of obstructive sleep apnea, yet patient selection for positional therapy (PT) remains suboptimal. With this analysis we aimed to clarify how many patients with POSA may not require PT because they do not habitually sleep supine at home, and how many fail vibrotactile PT despite appropriate indication. METHODS:We conducted a retrospective observational study of consecutive adults with POSA evaluated at a tertiary sleep center between 2021 and 2024. All patients underwent a home-based trial with a neck-based vibrotactile positional therapy device (Night Shift™), consisting of monitoring mode followed by therapy mode. Outcomes included the proportion of non-supine sleepers at home, failure rate of vibrotactile PT, device compliance and differences in supine sleep time between diagnostic testing and home monitoring. RESULTS:Of 92 screened patients, 74 met inclusion criteria (mean age 60.3 ± 13.2 years; mean AHI 22.9 ± 13.3 events/h). Fifteen percent (11/74) did not habitually sleep supine at home, indicating no clinical need for PT, and an additional 14.8% (11/74) failed vibrotactile PT. Overall, 30% of patients were either unlikely to benefit from PT or failed therapy. Non-response was frequently associated with psychotropic or sedative medication use and neurological or sleep-related comorbidities. CONCLUSION:A substantial proportion of patients diagnosed with POSA either do not require or fail vibrotactile treatment in real-world conditions. Incorporating a brief home monitoring and therapy trial into routine clinical practice may optimize patient selection, reduce unnecessary costs, and improve personalized management of POSA.

Excessive daytime sleepiness (EDS) is a frequent complaint in the general population. Other than being a common symptom associated with various sleep disorders, EDS may be a consequence of chronic sleep deprivation or the primary symptom of central disorders of hypersomnolence (CDH). In addition to narcolepsy type 1 (NT1), the other conditions within the CDH spectrum are less well-defined and share considerable clinical and neurophysiological similarities. Herein, we describe the clinical management of a complex case that highlights several challenges in the diagnostic process of a patient with EDS and a history of obsessive-compulsive disorder (OCD). In the absence of other sleep disorders, secondary structural causes, and orexin deficiency as possible causes for EDS, the patient was initially diagnosed with NT2 based on electrophysiological criteria. However, the clinical course, which showed only a partial response to various stimulant medications for subjective and objective daytime sleepiness, led us to question the diagnosis. A detailed psychiatric and neuropsychological assessment revealed, in addition to the previously identified severe OCD and anxiety, a diagnosis of attention deficit hyperactivity disorder (ADHD), subsequently leading to a revised diagnosis of hypersomnia associated with a psychiatric disorder (HPSY). The literature regarding OCD and sleep disorders remains scarce but the connection between ADHD and hypersomnia, as well as narcolepsy, is well-established. Our case report illustrates that a psychiatric and neuropsychological assessment should be considered mandatory for patients with objective EDS.

The international Swiss Primary Hypersomnolence and Narcolepsy Cohort Study (iSPHYNCS) is a multicentre study aimed at identifying novel biomarkers for central disorders of hypersomnolence (CDH). We analysed questionnaires and metadata to uncover distinct clusters of participants and explore phenotypic variability within CDH. Data were collected from 227 patients with CDH and 33 healthy controls. Participants completed validated clinical questionnaires and study-specific questions addressing CDH-related symptoms such as excessive daytime sleepiness, fatigue, cataplexy, disrupted sleep, and sleep paralysis. Demographic metadata (age, gender, BMI) were included. After excluding participants with missing over 30% of data (n = 40), missing values were imputed using a multiple random forest algorithm. A robust clustering pipeline was employed: (1) random sampling of 60% of the dataset, (2) dimensionality reduction via UMAP, (3) K-means clustering, and (4) consensus clustering across 500 iterations. Post hoc analysis was performed to identify biomarkers in data not used for clustering. We identified four distinct clusters. One predominantly comprised healthy controls, while another primarily contained individuals with narcolepsy type 1 (NT1). Two clusters represented predominantly the narcolepsy borderland group (NBL), with one distinctly characterised by higher symptom severity and psychiatric comorbidities. The clustering pipeline produced reproducible results, with the NT1 and healthy control clusters serving as internal validation. The differentiation between the two NBL clusters aligns with prior studies, suggesting a possible NBL subtype marked by increased fatigue and psychiatric comorbidities. These findings emphasise the phenotypic heterogeneity of CDH and the potential for cluster-based approaches in management. Trial Registration: ClinicalTrials.gov identifier: NCT04330963.

BACKGROUND:The cyclic alternating pattern (CAP) is a key marker of NREM sleep microstructure, reflecting the balance between sleep-protective (A1) and arousal-promoting (A2/A3) processes. However, normative spectral and topographic data for CAP subtypes during development are limited, and high-density EEG (HD-EEG) mapping in children is lacking. This study aimed to characterize the scalp topography and spectral properties of CAP A subtypes in typically developing children and to assess their overnight dynamics. METHODS:Nineteen typically developing children (mean age 10.2 years, range 8-13.7; 10 females) underwent overnight video-polysomnography with 256-channel HD-EEG. Power spectral density was estimated using Welch's method for CAP A1 (0.5-2.5 Hz), A2-low (0.5-2.5 Hz), A2-high (11-14 Hz), and A3 (11-14 Hz). Topographic distributions were computed across the night and compared between early and late NREM sleep using linear mixed-effects models with permutation-based TFCE correction. RESULTS:A1 and A2-low activity showed maximal power over fronto-central and centro-parietal midline regions and was significantly higher during early compared to late night. In contrast, A2-high and A3 activity displayed a predominantly frontal distribution and increased during the late night. High-frequency components of A2 and A3 peaked within the 11-14 Hz range, differing from the alpha-band activity typically reported in adults. CONCLUSIONS:This exploratory study characterises the scalp topography and spectral properties of CAP A subtypes in typically developing children using HD-EEG. Slow-frequency CAP activity declined across the night, consistent with homeostatic processes, whereas faster components showed a frontal predominance and a late-night increase. These findings highlight developmental differences in CAP organization and provide preliminary reference data for paediatric sleep research, which require confirmation in larger, multicentre cohorts.

STUDY OBJECTIVES:To characterize source-level cortical oscillatory dynamics before and during disorders of arousal (DoA) compared with physiological motor arousals in children and adults. MATERIALS AND METHODS:Nineteen children (10.9 ± 3.0 years) and 22 adults (30.3 ± 5.2 years) with DoA underwent 256-channel high-density EEG with video-polysomnography. Source-space spectral analysis in delta (0.5-4 Hz) and beta (18-30 Hz) bands was computed during stable slow-wave-sleep (-3 to -2 minutes before movement onset) and from -5 seconds to +15 seconds around movement onset for 84 DoA episodes and 146 physiological motor arousals. Linear mixed-effects models with permutation-based cluster correction were applied. RESULTS:Four reproducible cortical hallmarks emerged across age groups: (1) a widespread pre-onset increase in beta and delta relative to slow-wave-sleep; (2) sustained frontal delta enhancement over anterior cingulate, dorsomedial and ventromedial prefrontal, frontopolar, and orbitofrontal cortices; (3) concurrent centro-parietal delta suppression spanning posterior cingulate, precuneus, superior parietal, sensorimotor, and supplementary motor regions; and (4) persistent bilateral beta enhancement. Compared with physiological arousals, DoA arose from a "sleepier" background (higher delta, lower beta) and displayed greater beta coexisting with frontal delta persistence. Children showed broader pre-onset delta effects and more diffuse post-onset persistence, whereas adults exhibited a more anteriorly confined pattern. CONCLUSION:DoA display a reproducible, age-invariant cortical signature, consistent with a spatially organized failure of arousal integration: posterior sensorimotor and awareness circuits partially reactivate, while anterior executive and emotion-regulatory regions remain sleep-like. These spatiotemporal fingerprints position hd-EEG source analysis as a translational tool for mechanistically informed diagnostic and therapeutic development.

Insufficient sleep syndrome (ISS) and narcolepsy type 1 (NT1) both feature excessive daytime sleepiness (EDS), yet they differ in etiology and nighttime sleep architecture. We compared clinical characteristics, video-polysomnography (v-PSG), Multiple Sleep Latency Test (MSLT), and actigraphy in ISS and NT1, to better define ISS and differentiate the two disorders. We retrospectively screened patients from a Sleep Medicine Unit who had a confirmed diagnosis of ISS (n = 23) or NT1 (n = 9) and underwent v-PSG, MSLT, and actigraphy. All patients were drug-free, and those with comorbid sleep disorders were excluded. Clinical data were collected through structured interviews, sleep diaries, and standardized questionnaires. Subjective EDS, reported by both ISS and NT1 groups, was similar in severity. MSLT showed that nearly one-third of ISS patients exhibited sleep-onset REM periods (SOREMPs), highlighting the risk of overlap with NT1. In v-PSG, ISS was characterized by high sleep efficiency and a low arousal index; no major differences in sleep parameters emerged between ISS and NT1. Actigraphy provided relevant data: ISS displayed weekday sleep restriction with weekend compensation, whereas NT1 showed fragmented but prolonged nighttime sleep and more frequent daytime naps. Overall, the variability in sleep patterns (time in bed and total sleep time) was more pronounced in ISS on weekends, whereas NT1's hallmark was nighttime fragmentation. While ISS and NT1 overlap in EDS, they differ in the organization of sleep-wake rhythms. Actigraphy, highlighting weekday-weekend changes in ISS and fragmented nighttime sleep in NT1, may be pivotal for differential diagnosis.

Disorders of arousal (DoA), a group of Non-Rapid Eye Movement parasomnias—including sleepwalking, night terrors, and confusional arousals—arise from incomplete awakenings during slow-wave sleep, yet their neural signatures remain poorly defined. Using high-density EEG and source-space spectral analysis in both children and adults, we mapped cortical dynamics in the seconds before and after DoA onset and compared them to physiological motor arousals. Across ages, DoA episodes emerged from a globally less activated cortical state, with pre-onset surges in delta and beta power peaking in premotor, orbitofrontal, and anterior cingulate cortices. After onset, episodes showed widespread beta enhancement and focal delta suppression in sensorimotor and parietal associative regions relative to stable slow-wave sleep, alongside sustained frontal delta and beta activity compared with physiological motor arousals. These age-invariant spatial patterns identify a stable neurophysiological signature of DoA, supporting the concept of local sleep–wake dissociation. Our findings provide a framework for mechanistic models and potential biomarkers to modulate, predict, and differentiate DoA from other nocturnal events. ### Competing Interest Statement The authors have declared no competing interest. EOC Young Researchers Grant 2023

The aim of the present study was to examine gender and age-specific effects on subjective daytime sleepiness (as measured by the Epworth Sleepiness Scale), body weight and eating behaviour in patients with central disorders of hypersomnolence. Based on the European Narcolepsy Network database, we compared 1035 patients with narcolepsy type I and 505 patients with other central disorders of hypersomnolence ("narcoleptic borderland"), including narcolepsy type II (N = 308) and idiopathic hypersomnia (N = 174), using logistic regression and general linear models. In the entire study population, the Epworth Sleepiness Scale was higher in women (N = 735, mean age = 30 years, mean Epworth Sleepiness Scale = 16.6 +/- SD 3.9) than in men (N = 805, mean age = 32 years, mean Epworth Sleepiness Scale = 15.8 +/- SD 4.4). In women with narcolepsy type I (N = 475), both Epworth Sleepiness Scale and body mass index increased in parallel with age. In women of the narcoleptic borderland (N = 260), the Epworth Sleepiness Scale markedly peaked in their early 30s, while body mass index only started to rise at that age. This rise in body mass index following the Epworth Sleepiness Scale peak cannot be explained by sleepiness-induced uncontrolled eating, as self-reported uncontrolled eating was negatively associated with the Epworth Sleepiness Scale in this group. We propose that the narcoleptic borderland harbours a unique cluster of women in their fertile years with an unexplored aetiology requiring further investigation towards tailored interventions.

BACKGROUND:Insufficient sleep syndrome (ISS) represents an emerging health concern but remains poorly defined as a diagnostic entity, though included in the international classification of sleep disorders. In the present study, we aimed to clarify the longitudinal course of ISS and to identify prognostic factors by comparing remitting and non-remitting patients. METHODS:A chart-review was realized, retrieving fifty-five patients with ISS (aged 39.8 ± 16.6 years, with 44.6 % of women) who underwent a comprehensive clinical evaluation at baseline and during a follow-up visit after 3-6 months. This evaluation included sleep symptoms, sleep logs, medications, and comorbidities. Additionally, actigraphy, video-polysomnography, and a multiple sleep latency test were conducted at baseline, and at the same moment standard psychoeducation on sleep was provided. RESULTS:During the follow-up visit, 69 % of patients still met the criteria for a clinical diagnosis of ISS, experiencing symptoms such as daytime sleepiness, disrupted nighttime sleep, unrefreshing sleep, and sleep attacks. Comparing sleep patterns of remitters and non-remitters based on sleep diaries, we observed that remission is associated with not only an increase in total sleep time but also a more regular sleep schedule. This regularity includes a reduction in napping and a lesser difference in sleep timings between weekdays and weekends. However, comparing baseline clinical and instrumental data between remitters and non-remitters revealed no significant differences, hindering the use of these features as prognostic factors. CONCLUSIONS:Given the low remission rate with standard treatment (i.e. psychoeducation on sleep), we propose the following: (1) Criterion E (extension of total sleep time results in resolution of the symptoms of sleepiness) should be considered as a therapeutic advice, and supportive rather than necessary for the diagnosis; (2) specific cognitive-behavioral therapy protocols targeting the cognitive factors underlying sleep-depriving behaviors are required, as single routine behavioral interventions are insufficient.

The Swiss Primary Hypersomnolence and Narcolepsy Cohort Study (SPHYNCS) is a multicenter research initiative to identify new biomarkers in central disorders of hypersomnolence (CDH). Whereas narcolepsy type 1 (NT1) is well characterized, other CDH disorders lack precise biomarkers. In SPHYNCS, we utilized Fitbit smartwatches to monitor physical activity, heart rate, and sleep parameters over one year. We examined the feasibility of long-term ambulatory monitoring using the wearable device. We then explored digital biomarkers differentiating patients with NT1 from healthy controls (HC). A total of 115 participants received a Fitbit smartwatch. Using a compliance metric to evaluate the usability of the wearable device, we found an overall compliance rate of 80% over one year. We calculated daily physical activity, heart rate, and sleep parameters from two weeks of greatest compliance to compare NT1 (n=20) and HC (n=9) subjects. Compared to controls, NT1 patients demonstrated findings consistent with increased sleep fragmentation, including significantly greater wake-after-sleep onset (p=0.007) and awakening index (p=0.025), as well as standard deviation of time in bed (p=0.044). Moreover, NT1 patients exhibited a significantly shorter REM latency (p=0.019), and sleep latency (p=0.001), as well as a lower peak heart rate (p=0.008), heart rate standard deviation (p=0.039) and high-intensity activity (p=0.009) compared to HC. This ongoing study demonstrates the feasibility of long-term monitoring with wearable technology in patients with CDH and potentially identifies a digital biomarker profile for NT1. While further validation is needed in larger datasets, these data suggest that long-term wearable technology may play a future role in diagnosing and managing narcolepsy.

Presence of psychiatric comorbidities is well documented in narcolepsy type-1 (NT1) but there are limited data on patients with 'other central disorders of hypersomnolence' (OCH). This study aimed to investigate frequency of psychiatric comorbidities in patients with NT1 and OCH, and to evaluate their impact on quality of life and sleep as an additive factor in combination with hypersomnolence-related symptoms. This study was conducted within the scope of the international Swiss Primary Hypersomnolence and Narcolepsy Cohort Study (iSPHYNCS), which aims to find new biomarkers in central disorders of hypersomnolence (CDH). Study participants underwent Mini International Neuropsychiatric Interview and completed questionnaires related to quality of life and sleep. Comparative analysis was conducted to investigate group differences, and multivariable regression models were used to reveal the impact of psychiatric comorbidities. Among a total of 90 patients, 26 were diagnosed with NT1 and 64 with OCH. In all, 38 patients showed at least one psychiatric disorder, 27% of NT1 and 48% of OCH, with female dominance (50% in females versus 23% in males, p < 0.02). Major depressive episodes (n = 29) were most common, followed by suicidality (n = 13). Patients with a psychiatric diagnosis were more fatigued (beta = 0.70, p < 0.05), apathic (beta = -5.41, p < 0.002), had more disturbed sleep (beta = 0.55, p < 0.02), worse sleep (beta = 1.89, p < 0.001) and general health (beta = -12.55, p < 0.02) quality. Comorbid psychiatric disorders are frequent in patients with CDH and worsen the impact of hypersomnolence-related symptoms on daily activities regardless of the type of CDH. Psychiatric comorbidities may create a vicious circle with fatigue and avoidance of physical activities, which aggravates hypersomnolence-related symptoms.

Introduction Narcolepsy and obstructive sleep apnea syndrome (OSA) are relevant causes of excessive daytime sleepiness (EDS); although different for etiopathogenesis and symptoms, differential diagnosis is sometimes difficult, and guidelines are lacking concerning their management when coexisting in a same patient. Methods A narrative review of the literature was realized including PubMed, Scopus and Embase, aimed to regroup studies and case reports evaluating epidemiology, clinical and instrumental features and treatment of patients presenting comorbid NT1 and OSA. Moreover, a snowball search on the pathophysiology underpinnings of the association of the two disorder was realized. Results For adults, the prevalence of OSA in NT1 ranged from 24.8% to 51.4%. No studies were found concerning the treatment of EDS in double-diagnosis patients, but only case reports; these latter and the experience on patients with either NT or OSA suggest that modafinil, methylphenidate, pitolisant and solriamfetol are effective. Discussion Adults with NT1 showed a higher prevalence of OSA compared to the general population, but the reach of the results reviewed here is limited by the retrospective design of most of the studies and by the inhomogeneous utilization of diagnostic criteria. The association with OSA is likely to be explained by the involvement of orexin in hypercapnic-hypoxic responses: a deficit of orexin may promote obstructive events during sleep. Open questions warrant further investigation, especially orexin’s involvement in other sleep disorders associated with EDS, and the more appropriate treatment for the OSA-narcolepsy comorbidity.

The manifestations of chronic insomnia undergo age-related changes. In younger infants and children, behavioral insomnia emerges as the most prevalent form and typically responds to behavioral interventions. However, distinct clusters of clinical presentations suggest the presence of various phenotypes, potentially implicating the primary involvement of specific neurotransmitters. These conceptualizations, coupled with genetic studies on pleiotropy and polygenicity, may aid in identifying individuals at risk of persistent insomnia into adulthood and shed light on novel treatment options. In school-age children, the predominant presentation is sleep-onset insomnia, often linked with nighttime fears, anxiety symptoms, poor sleep hygiene, limit-setting issues, and inadequate sleep duration. The manifestations of insomnia in adolescence correlate with the profound changes occurring in sleep architecture, circadian rhythms, and homeostatic processes. The primary symptoms during adolescence include delayed sleep onset, sleep misperception, persistent negative thoughts about sleep, and physiological hyperarousal—paralleling features observed in adult insomnia. An approach centered on distinct presentations may provide a framework for precision-based treatment options. Enhanced comprehension of insomnia’s manifestations across diverse developmental stages can facilitate accurate assessment. Efforts to subtype insomnia in childhood align with this objective, potentially guiding the selection of appropriate treatments tailored to individual neurobiological, clinical, and familial features.

Attention deficit hyperactivity disorder (ADHD) is a widespread neurodevelopmental disorder. Currently, the diagnosis and treatment of ADHD in children and adolescents is primarily centred on daytime functioning and the associated impairment of academic performance, although disrupted and restless sleep have been frequently reported in individuals with ADHD. Further, it has been recognised that sleep disorders not only intensify existing ADHD symptoms but in some cases can also mimic ADHD symptoms in the paediatric population with primary sleep disorders. Under the title ‘The blind spot: sleep as a child’s right issue?’, professionals from diverse disciplines, including medicine and social sciences as well as individuals with an interest in ADHD and sleep medicine, including laypeople, have initiated a unifying discourse. The objective of this discourse is to improve our understanding of the diagnosis and treatment of ADHD and disruptive behaviours and to develop personalised and precision medicine. Research has shown that the existing, primarily descriptive and categorical diagnostic systems do not capture the heterogeneous nature of youth with attentional and behavioural difficulties and the phenotypic expressions thereof, including nighttime behaviours and sleep. New strategies for clinical phenotyping and the exploration of patient-reported behaviours are necessary to expand our understanding and develop personalised treatment approaches. In this position paper, we outline gaps in the clinical care of ADHD and related sleep disturbances, review strategies for closing these gaps to meet the needs of individuals with ADHD, and suggest a roadmap for escaping the one-size-fits-all approach that has characterised ADHD treatment algorithms to date.

Introduction and aims: Narcolepsy type 1 (NT1) is a central disorder of hypersomnolence (CDH) characterized by excessive daytime sleepiness and cataplexy. The Swiss Narcolepsy Scale (SNS), which includes the updated and short (sSNS) versions, has recently been introduced as a reliable diagnostic tool for identifying NT1. This study aims to assess the validity of the SNS scales in a new cohort of patients with CDH, while also introducing the French and Italian versions of the SNS and providing a summary of the existing literature on SNS. Materials and methods: The current study is based on the international Swiss Primary Hypersomnolence and Narcolepsy Cohort Study (iSPHYNCS) which aims to identify new biomarkers for CDH. Diagnostic accuracy of the SNS was assessed by calculating sensitivity, specificity, positive predictive value, and negative predictive value. Results: In our population, 108 participants with suspected CDH (including 28 NT1 patients) and 14 healthy controls completed the scale. Original SNS, updated SNS and sSNS scores showed a high sensitivity (86%, 89% and 79%, respectively) and high specificity (96%, 90% and 95%, respectively) for diagnosing NT1 compared to other CDH. The French version was completed by 5 participants, and the Italian version by 8 participants. Regarding previous studies, the SNS has now been assessed in six different populations, involving a total of 1247 subjects (including 326 with narcolepsy with cataplexy/NT1), suggesting high sensitivity (85–100%) and specificity (86–100%) of the SNS for the diagnosis of NT1. Conclusion: The SNS is a simple screening tool validated in seven languages (German, English, French, Italian, Dutch, Turkish and Japanese), demonstrating high sensitivity and specificity for the diagnosis of NT1.