Journal of Sleep Research

Article	Citations
Changes in sleep pattern, sense of time and digital media use during COVID‐19 lockdown in Italy	658
Dealing with sleep problems during home confinement due to the COVID‐19 outbreak: Practical recommendations from a task force of the European CBT‐I Academy	606
On the rise and fall of the apnea−hypopnea index: A historical review and critical appraisal	164
Covid‐19 health crisis and lockdown associated with high level of sleep complaints and hypnotic uptake at the population level	118
Sleep of preschoolers during the coronavirus disease 2019 (COVID‐19) outbreak	103
Profiles of sleep changes during the COVID‐19 pandemic: Demographic, behavioural and psychological factors	98
Insomnia disorder: State of the science and challenges for the future	74
Insomnia symptoms during pregnancy: A meta‐analysis	63
Gender‐specific estimates of sleep problems during the COVID‐19 pandemic: Systematic review and meta‐analysis	60
Maternal perceptions of sleep problems among children and mothers during the coronavirus disease 2019 (COVID‐19) pandemic in Israel	58
Sleeping under the waves: A longitudinal study across the contagion peaks of the COVID‐19 pandemic in Italy	55
Pandemic nightmares: Effects on dream activity of the COVID‐19 lockdown in Italy	54
Sleep, insomnia and mental health	53
Heart rate variability and obstructive sleep apnea: Current perspectives and novel technologies	47
COVID‐19 lockdown and poor sleep quality: Not the whole story	47
Sleep and circadian problems during the coronavirus disease 2019 (COVID‐19) pandemic: the International COVID‐19 Sleep Study (ICOSS)	46
European guideline and expert statements on the management of narcolepsy in adults and children	43
Pharmacological and non‐pharmacological interventions to enhance sleep in mild cognitive impairment and mild Alzheimer's disease: A systematic review	42
Obstructive sleep apnea: transition from pathophysiology to an integrative disease model	40
Severe effects of the COVID‐19 confinement on young children’s sleep: A longitudinal study identifying risk and protective factors	39
Research routes on improved sleep bruxism metrics: Toward a standardised approach	38
Insomnia as a mediating therapeutic target for depressive symptoms: A sub‐analysis of participant data from two large randomized controlled trials of a digital sleep intervention	37
Temporal associations between morningness/eveningness, problematic social media use, psychological distress and daytime sleepiness: Mediated roles of sleep quality and insomnia among young adults	37
Sleep structure in sleep bruxism: A polysomnographic study including bruxism activity phenotypes across sleep stages	35
Telehealth‐delivered CBT‐I programme enhanced by acceptance and commitment therapy for insomnia and hypnotic dependence: A pilot randomized controlled trial	35

The two‐process model of sleep regulation: Beginnings and outlook†	33
Maladaptive coping with the infodemic and sleep disturbance in the COVID‐19 pandemic	32
Adenosine, caffeine, and sleep–wake regulation: state of the science and perspectives	32
Actigraphy in sleep research with infants and young children: Current practices and future benefits of standardized reporting	32
Sleep patterns and insomnia in a large population‐based study of middle‐aged and older adults: The Tromsø study 2015–2016	30
Association between morningness‐eveningness, sleep duration, weekend catch‐up sleep and depression among Korean high‐school students	30
Shift work is associated with increased risk of COVID‐19: Findings from the UK Biobank cohort	29
Risk factors of excessive daytime sleepiness in a prospective population‐based cohort	28
Metabolic dysfunction in OSA: Is there something new under the sun?	28
Outdoor daylight exposure and longer sleep promote wellbeing under COVID‐19 mandated restrictions	28
Influence of one‐night CPAP therapy on the changes of HIF‐1α protein in OSA patients: A pilot study	27
Mindful larks and lonely owls: The relationship between chronotype, mental health, sleep quality, and social support in young adults	27
YouTube as a source of information for narcolepsy: A content‐quality and optimization analysis	26
Effects of the COVID‐19 pandemic on sleep quality in children and adolescents: A systematic review and meta‐analysis	26
Respiratory safety of lemborexant in healthy adult and elderly subjects with mild obstructive sleep apnea: A randomized, double‐blind, placebo‐controlled, crossover study	25
The orexin story, sleep and sleep disturbances	24
The circadian system, sleep, and the health/disease balance: a conceptual review	24
Sleep symptoms are essential features of long‐COVID– Comparing healthy controls withCOVID‐19 cases of different severity in the internationalCOVIDsleep study (ICO	24
The Sleep Revolution project: the concept and objectives	22
The impact of five nights of sleep restriction on emotional reactivity	22
Caring for the carers: Advice for dealing with sleep problems of hospital staff during the COVID‐19 outbreak	22
Subjective–objective sleep discrepancy in patients with insomnia during and after cognitive behavioural therapy: An actigraphy study	21
Cyclic alternating pattern in obstructive sleep apnea: A preliminary study	21
Sleepwalking, sleep terrors, sexsomnia and other disorders of arousal: the old and the new	21
The impact of the end of COVID confinement on pandemic dreams, as assessed by a weekly sleep diary: a longitudinal investigation in Italy	21
Adverse interaction effects of chronic and acute sleep deficits on spatial working memory but not on verbal working memory or declarative memory	21
Prevalence and management of chronic insomnia in Swiss primary care: Cross‐sectional data from the “Sentinella” practice‐based research network	21
Sleep in older adolescents. Results from a large cross‐sectional, population‐based study	20
Prenatal maternal sleep and trajectories of postpartum depression and anxiety symptoms	20
Validation of insomnia questionnaires in the general population: The Nord‐Trøndelag Health Study (HUNT)	20
Effects of sleep modulation during pregnancy in the mother and offspring: Evidences from preclinical research	20
Disturbances in sleep, circadian rhythms and daytime functioning in relation to coronavirus infection and Long‐COVID – A multinational ICOSS study	20
Psychological interventions to improve sleep in college students: A meta‐analysis of randomized controlled trials	20
ENIGMA‐Sleep: Challenges, opportunities, and the road map	19
Evidence against a large effect of sleep in protecting verbal memories from interference	19
A systematic review and meta‐analysis of wind turbine noise effects on sleep using validated objective and subjective sleep assessments	19
Impact of menstrual cycle phase and oral contraceptives on sleep and overnight memory consolidation	18
Narcolepsy	18
The multidimensionality of sleep in population‐based samples: a narrative review	18
Relationships of physical activity and sedentary behaviour with the previous and subsequent nights’ sleep in children and youth: A systematic review and meta‐analysis	18
Sleep and epilepsy: A snapshot of knowledge and future research lines	18
Altered frontal connectivity after sleep deprivation predicts sustained attentional impairment: A resting‐state functional magnetic resonance imaging study	18
Association of sleep spindle characteristics with executive functioning in healthy sedentary middle‐aged and older adults	18
Does observance of Ramadan affect sleep in athletes and physically active individuals? A systematic review and meta‐analysis	17
Self‐reported sleep quality is more closely associated with mental and physical health than chronotype and sleep duration in young adults: A multi‐instrument analysis	17
Sleep difficulties, incident dementia and all‐cause mortality among older adults across 8 years: Findings from the National Health and Aging Trends Study	17
Changes in dream features across the first and second waves of the Covid‐19 pandemic	17
Medical student education in sleep and its disorders is still meagre 20 years on: A cross‐sectional survey of UK undergraduate medical education	17
Sleep and circadian rhythm characteristics in individuals from the general population during the French COVID‐19 full lockdown	17
Insomnia symptoms and non‐suicidal self‐injury in adolescence: understanding temporal relations and mechanisms	17

Heart rate detection by Fitbit ChargeHR™: A validation study versus portable polysomnography	17
Multidimensional sleep health is associated with mental well‐being in Australian adults	16
Sleep problems and depressive symptoms in toddlers and 8‐year‐old children: A longitudinal study	16
Narcolepsy type 2: A rare, yet existing entity	16
Within‐person associations between racial microaggressions and sleep among African American and Latinx young adults	16
Revisiting nocturnal heart rate and heart rate variability in insomnia: A polysomnography‐based comparison of young self‐reported good and poor sleepers	15
Cognitive behavioural therapy for insomnia does not appear to have a substantial impact on early markers of cardiovascular disease: A preliminary randomized controlled trial	15
Influence of age and gender on sleep bruxism and snoring in non‐apneic snoring patients: A polysomnographic study	15
What about dreams? State of the art and open questions	15
Interventions to control children's screen use and their effect on sleep: A systematic review and meta‐analysis	15
Intermittent hypoxia and sleep disruption in obstructive sleep apnea increase serum tau and amyloid‐beta levels	15
Effect of the novel dual orexin receptor antagonist daridorexant on night‐time respiratory function and sleep in patients with moderate chronic obstructive pulmonary disease	15
Interhemispheric sleep depth coherence predicts driving safety in sleep apnea	15
Sleep‐related hypermotor epilepsy and non‐rapid eye movement parasomnias: Differences in the periodic and aperiodic component of the electroencephalographic power spectra	15
The European Insomnia Guideline: An update on the diagnosis and treatment of insomnia 2023	15
A polysomnography study examining the association between sleep and postoperative delirium in older hospitalized cardiac surgical patients	14
How many hours do you sleep? A comparison of subjective and objective sleep duration measures in a sample of insomnia patients and good sleepers	14
Mechanisms of intermittent hypoxia‐mediated macrophage activation – potential therapeutic targets for obstructive sleep apnoea	14
Sleep apnea and the risk of dementia: A systematic review and meta‐analysis	14
Nightmare content during the COVID‐19 pandemic: Influence of COVID‐related stress and sleep disruption in the United States	14
Daytime and nighttime smartphone use: A study of associations between multidimensional smartphone behaviours and sleep among 24,856 Danish adults	14
Imagery rehearsal therapy and/or mianserin in treatment of refugees diagnosed with PTSD: Results from a randomized controlled trial	14
Maternal perinatal depression and infant sleep problems at 1 year of age: Subjective and actigraphy data from a population‐based birth cohort study	14
Effect of cognitive behavioural therapy on sleep and opioid medication use in adults with fibromyalgia and insomnia	14
Social jetlag, a novel predictor for high cardiovascular risk in blue‐collar workers following permanent atypical work schedules	14
The acute effects of sleep restriction therapy for insomnia on circadian timing and vigilance	13
Two years after lockdown: Longitudinal trajectories of sleep disturbances and mental health over the COVID‐19 pandemic, and the effects of age, gender and chronotype	13
Testing the theory of Differential Susceptibility to nightmares: The interaction of Sensory Processing Sensitivity with the relationship of low mental wellbeing to nightmare frequency and nightmare di	13
Bidirectional association between light exposure and sleep in adolescents	13
Sleep quality is associated with emotion experience and adaptive regulation of positive emotion: An experience sampling study	13
Relationship between sleep efficacy endpoints and measures of functional status and health‐related quality of life in participants with narcolepsy or obstructive sleep apnea treated for excessive dayt	13
How does cessation of work affect sleep? Prospective analyses of sleep duration, timing and efficiency from the Swedish Retirement Study	13
Maintaining normal sleep patterns, lifestyles and emotion during the COVID‐19 pandemic: The stabilizing effect of daytime napping	13
Insomnia and circadian sleep disorders in ovarian cancer: Evaluation and management of underestimated modifiable factors potentially contributing to morbidity	13
The association of co‐morbid insomnia and sleep apnea with prevalent cardiovascular disease and incident cardiovascular events	13
Unfair police treatment and sleep problems among a national sample of adults	13
Unidirectional and bidirectional links between maternal depression symptoms and infant sleep problems	13
Temporal association between objectively measured smartphone usage, sleep quality and physical activity among Chinese adolescents and young adults	13
The European Portuguese version of the insomnia severity index	13
Assessment of sleep‐disordered‐breathing: Quest for a metric or search for meaning?	12
Physiological sleep measures predict time to 15‐year mortality in community adults: Application of a novel machine learning framework	12
Determinants of sleep problems in children with intellectual disability	12
Central apnea and periodic breathing in children with underlying conditions	12
Depressed mood and repetitive negative thinking in Delayed Sleep–Wake Phase Disorder: Treatment effects and a comparison with good sleepers	12
Sleep differentially impacts involuntary intrusions and voluntary recognitions of lab‐analogue traumatic memories	12
Association between sleep disorders and osteoarthritis: A case–control study of 351,932 adults in the UK	12
Understanding the association between sleep, shift work and COVID‐19 vaccine immune response efficacy: Protocol of the S‐CORE study	12
Beyond the AHI–pulse wave analysis during sleep for recognition of cardiovascular risk in sleep apnea patients	12
Cumulative incidence and relative risk of sleep problems among children and adolescents with newly diagnosed neurodevelopmental disorders: A nationwide register‐based study	12
Acceptance of virtual agents in a homecare context: Evaluation of excessive daytime sleepiness in apneic patients during interventions by continuous positive airway pressure (CPAP) providers	12
Behavioural sleep in two species of buccal pumping sharks (Heterodontus portusjacksoni and Cephaloscyllium isabellum)	12
Age and chronotype influenced sleep timing changes during the first wave of the COVID‐19 pandemic	12
Worry about COVID‐19 as a predictor of future insomnia	12
Multimodal phenotypic labelling using drug‐induced sleep endoscopy, awake nasendoscopy and computational fluid dynamics for the prediction of mandibular advancement device treatment outcome: a prospec	11
Sleep extension and metabolic health in male overweight/obese short sleepers: A randomised controlled trial	11
Rapid eye movement sleep behaviour disorder: Past, present, and future	11
Relationship between sleep characteristics and markers of inflammation in Swedish women from the general population	11
Insomnia—A risk factor for mental disorders	11
Correlates of excessive daytime sleepiness in obstructive sleep apnea: Results from the nationwide SESAR cohort including 34,684 patients	11
Behavioural and emotional profiles of children and adolescents with disorders of arousal	11
Sleep during COVID‐19‐related school lockdown, a longitudinal study among high school students	11
Changes in sleep pattern and dream activity across and after the COVID‐19 lockdown in Italy: A longitudinal observational study	11
Ageing shift workers’ sleep and working‐hour characteristics after implementing ergonomic shift‐scheduling rules	11
Sleep slow oscillations favour local cortical plasticity underlying the consolidation of reinforced procedural learning in human sleep	11
Long‐term changes in self‐reported sleep quality and risk of chronic musculoskeletal pain: The HUNT Study	11
Association of rotating shift work schedules and the use of prescribed sleep medication: A prospective cohort study	11
Self‐rated sleep quality predicts incident suicide ideation in US military veterans: Results from a 7‐year, nationally representative, prospective cohort study	10
The Swiss Primary Hypersomnolence and Narcolepsy Cohort study (SPHYNCS): Study protocol for a prospective, multicentre cohort observational study	10
Smartphone‐based virtual agents and insomnia management: A proof‐of‐concept study for new methods of autonomous screening and management of insomnia symptoms in the general population	10
Potential genetic and epigenetic mechanisms in insomnia: A systematic review	10
Standard procedures for the diagnostic pathway of sleep‐related epilepsies and comorbid sleep disorders: A European Academy of Neurology, European Sleep Research Society and International League again	10
Do sleep changes mediate the anti‐depressive and anti‐suicidal response of intravenous ketamine in treatment‐resistant depression?	10
Restless legs syndrome: Over 50 years of European contribution	10
Targeted memory reactivation has a sleep stage‐specific delayed effect on dream content	10
Usefulness of sleep events detection using a wrist worn peripheral arterial tone signal device (WatchPAT™) in a population at low risk of obstructive sleep apnea	10
The orexin story and orexin receptor antagonists for the treatment of insomnia	10
Sleep macroarchitecture but not obstructive sleep apnea is independently associated with cognitive function in only older men of a population‐based cohort	10
Child maltreatment and sleep: Two pathways explaining the link	10
How much does sleep vary from night‐to‐night? A quantitative summary of intraindividual variability in sleep by age, gender, and racial/ethnic identity across eight‐pooled datasets	10
The impact of acoustic stimulation during sleep on memory and sleep architecture: A meta‐analysis	10

Health‐related quality of life in narcolepsy: A systematic review and meta‐analysis	10
Menstrual regularity and bleeding is associated with sleep duration, sleep quality and fatigue in a community sample	10
Validation of the Munich Actimetry Sleep Detection Algorithm for estimating sleep–wake patterns from activity recordings	10
Association of social jetlag and eating patterns with sleep quality and daytime sleepiness in Japanese high school students	10
Test–retest reliability of the Epworth Sleepiness Scale in clinical trial settings	10
Sleep, substance misuse and addictions: a nationwide observational survey on smoking, alcohol, cannabis and sleep in 12,637 adults	10
Psychometric properties of the Patient‐Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance and Sleep‐Related Impairment item banks in adolescents	10
Dynamic tongue area measurements in ultrasound images for adults with obstructive sleep apnea	10
Association between daytime napping and stroke: A dose–response meta‐analysis	10
Current models of insomnia disorder: a theoretical review on the potential role of the orexinergic pathway with implications for insomnia treatment	10
Accounting for automatic processes in sleep health	10
Association of occupational stress, period circadian regulator 3 (PER3) gene polymorphism and their interaction with poor sleep quality	9
Sleep deprivation reduces the density of individual spine subtypes in a branch‐specific fashion in CA1 neurons	9
Association between proteomics and obstructive sleep apnea phenotypes in a community‐based cohort of women	9
Effects of insomnia symptoms and objective short sleep duration on memory performance in youths	9
The role of sleep and dreams in long‐COVID	9
Sleep‐spindle frequency: Overnight dynamics, afternoon nap effects, and possible circadian modulation	9
Poor sleep accelerates hippocampal and posterior cingulate volume loss in cognitively normal healthy older adults	9
Do non‐pharmacological sleep interventions affect anxiety symptoms? A meta‐analysis	9
How to deal with sleep problems during heatwaves: practical recommendations from the European Insomnia Network	9
Self‐reported sleep and sleep deficiency: Results from a large initiative of sailors attached to U.S. Navy warships	9
Worldwide estimation of restless legs syndrome: a systematic review and meta‐analysis of prevalence in the general adult population	9
New‐onset and exacerbated insomnia symptoms during the COVID‐19 pandemic in US military veterans: A nationally representative, prospective cohort study	9
Associations between sleep disturbances, diabetes and mortality in the UK Biobank cohort: A prospective population‐based study	9
Altered structure and functional connectivity of the central autonomic network in idiopathic rapid eye movement sleep behaviour disorder	9
Pilot evaluation of a consumer wearable device to assess sleep in a clinical polysomnography trial of suvorexant for treating insomnia in patients with Alzheimer's disease	9
Disrupting ripples: Methods, results, and caveats in closed‐loop approaches in rodents	9
Sleep medicine catalogue of knowledge and skills – Revision	9
The contribution of dispositional optimism to understanding insomnia symptomatology: Findings from a cross‐sectional population study in Austria	9
Influence of head flexion and rotation on obstructive sleep apnea severity during supine sleep	9
Patient and caregiver perspectives on sleep in dialysis	9
Sleep and affect in adolescents: Bidirectional daily associations over 28‐day ecological momentary assessment	9
High sleep fragmentation parallels poor subjective sleep quality during the third wave of the Covid‐19 pandemic: An actigraphic study	9
Telephone‐guided imagery rehearsal therapy for nightmares: Efficacy and mediator of change	9
Hypothalamic–pituitary–adrenal (HPA) axis response to exogenous corticotropin‐releasing hormone (CRH) is attenuated in men with chronic insomnia	9
The impact of short sleep on food reward processes in adolescents	9
Rise and shine: The use of polychromatic short‐wavelength‐enriched light to mitigate sleep inertia at night following awakening from slow‐wave sleep	9
Digital cognitive behaviour therapy for insomnia (dCBT‐I): Chronotype moderation on intervention outcomes	8
Factors associated with insomnia symptoms: A cross‐sectional study during a Covid‐19 fully restrictive lockdown	8
Revisiting the Psychobiological Inhibition Model: a conceptual framework for understanding and treating insomnia using cognitive and behavioural therapeutics (CBTx)	8
Trends in the use of medications with insomnia side effects and the implications for insomnia among US adults	8
Prospective relations between sleep in preschool years and academic achievement at school entry	8
Validity of chronotype questionnaires in adolescents: Correlations with actigraphy	8
The ‘5 principles’ of good sleep health	8
Obstructive sleep apnea is associated with coronary microvascular dysfunction: A systematic review from a clinical perspective	8
Acute sleep deprivation elevates brain and body temperature in rats	8
The effects of sleep deprivation and obstructive sleep apnea syndrome on male reproductive function: a multi‐arm randomised trial	8
Daily and average associations of physical activity, social media use, and sleep among adolescent girls during the COVID‐19 pandemic	8
No perfect sleep! A systematic review of the link between multidimensional perfectionism and sleep disturbance	8
Dream‐enactment behaviours during the COVID‐19 pandemic: an international COVID‐19 sleep study	8
Improved sleep efficiency is associated with reduced cardio‐metabolic risk: Findings from the MODERN trial	8
Medicinal cannabis improves sleep in adults with insomnia: a randomised double‐blind placebo‐controlled crossover study	8
Can exercise training promote better sleep and reduced fatigue in people with chronic stroke? A systematic review	8
Feasibility, acceptability and affective consequences of at‐home sleep extension in young women with depressive symptoms: A pilot study	8
B‐waves are present in patients without intracranial pressure disturbances	8
Validation of an automated sleep detection algorithm using data from multiple accelerometer brands	8
Grumpy face during adult sleep: A clue to negative emotion during sleep?	8
Perceived risk of COVID‐19 exposure and poor COVID‐19 prognosis impair sleep: The mediating and moderating roles of COVID‐19‐related anxiety and knowledge	8
Negative social jetlag – Special consideration of leisure activities and evidence from birdwatchers	8
Interleukin 6 as a marker of depression in women with sleep apnea	8
Short‐ and long‐term mortality following hypnotic use	8
Cross‐sectional case‐control study of the relationships between pharyngeal compliance and heart rate variability indices in childhood obstructive sleep apnoea	8
Mothers’ and fathers’ sleep: Is there a difference between first‐time and experienced parents of 6‐month‐olds?	8
Extending sleep to confirm insufficient sleep syndrome is challenging	8
Home nocturnal infrared video to record non‐rapid eye movement sleep parasomnias	8
The association between social jetlag and parameters of metabolic syndrome and type 2 diabetes: a systematic review and meta‐analysis	8
Severe paediatric obesity and sleep: A mutual interactive relationship!	8
The importance of social zeitgeber in paediatric type 1 narcolepsy: What we can learn from the COVID‐19 restrictions adopted in Italy?	8
Hyperarousal in insomnia disorder: Current evidence and potential mechanisms	8
The promise of portable remote auditory stimulation tools to enhance slow‐wave sleep and prevent cognitive decline	8
Prevalence and predictors of mood disturbances in idiopathic REM sleep behaviour disorder	8
Normal values for respiratory sleep polygraphy in children aged 4 to 9 years at 2,560 m above sea level	8
Orexin 2 receptor‐selective agonist danavorexton (TAK‐925) promotes wakefulness in non‐human primates and healthy individuals	8
Impact factor rankings for sleep research journals between 2005 and 2018	8
Altered brain activity related to inhibitory processing in youth with insomnia	8
Adolescents’ preference for later school start times	8
The history of sleep research and sleep medicine in Europe	8
Help for insomnia from the app store? A standardized rating of mobile health applications claiming to target insomnia	8
Prevalence of insomnia and poor sleep quality in the prison population: A systematic review	8
Why could sleep medicine never do without polysomnography?	8
Light therapy in insomnia disorder: A systematic review and meta‐analysis	8
The association between sleep and empathy in young preschoolers: A population study	7
Cross‐sectional and prospective associations between self‐reported sleep characteristics and cognitive function in men and women: The Midlife in the United States study	7
No familiarization or ‘first‐night effect’ evident when monitoring sleep using wrist actigraphy	7
The impact of COVID‐19 on Italian adolescents’ sleep and its association with psychological factors	7
Subjective and objective sleep in young people with borderline personality disorder features	7
Effect of 12 weeks continuous positive airway pressure on day and night arterial stiffness and blood pressure in patients with type 2 diabetes and obstructive sleep apnea: A randomized controlled tria	7
Shift‐work‐related sleep disruption and the risk of decline in cognitive function: The CRUISE Study	7
The mediating role of perceived social support in the relationship between morningness–eveningness and subjective well‐being	7
Association of sleep duration and quality with immunological response after vaccination against severe acute respiratory syndrome coronavirus‐2 infection	7
Effects of N6‐(4‐hydroxybenzyl) adenine riboside in stress‐induced insomnia in rodents	7
Low test–retest reliability of the Epworth Sleepiness Scale within a substantial short time frame	7
Co‐ordination of brain and heart oscillations during non‐rapid eye movement sleep	7
The hypnagogic state: A brief update	7
Cardiac autonomic control during non‐REM and REM sleep stages in paediatric patients with Prader‐Willi syndrome	7