Abnormal secretion of melatonin and cortisol in relation to sleep disturbances in children with Williams syndrome

Exploring the Association Between Sleep Patterns, Pubertal Health, and Phthalate Exposure-Preliminary Results from Slovakia

BACKGROUND

This study aims to explore the association between sleep patterns in children and their exposure to phthalates to assess potential health implications.

METHODS

Participants (n = 60) completed the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Consumer behavior scores (CBS) were calculated. The Tanner scale was used to monitor the stages of puberty. First-morning urine samples were analyzed by high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

The average sleep duration was 8 h and 44 min, with boys sleeping significantly longer (p = 0.01). Notably, 51.7% of participants reported sleeping less than 9 h. The nonlinear effects of phthalate metabolite in association with PSQI were observed for hydroxy-mono-isononyl phthalate (OH-MiNP, p = 0.003) and MnOP (p < 0.001), indicating that the relationship does not follow a simple linear pattern. Simple linear regression revealed a significant positive association between the Mono-n-octyl phthalate (MnOP) and PSQI scores (p = 0.016). After adjustment for place of residence, BMI, CBS, sex, and age, the significance of associations between phthalate metabolites and sleep quality diminished, necessitating cautious interpretation. No statistically significant associations between pubertal changes and the value of PSQI as well as phthalates were observed.

CONCLUSION

Our results provide preliminary evidence of potential nonlinear associations that require validation in a larger cohort. The findings highlight the importance of monitoring phthalate exposure in children, as it may influence sleep patterns and overall health.

Sleep and circadian disturbances in children with neurodevelopmental disorders

Sleep is essential for brain development and overall health, particularly in children with neurodevelopmental disorders (NDDs). Sleep disruptions can considerably impact brain structure and function, leading to dysfunction of neurotransmitter systems, metabolism, hormonal balance and inflammatory processes, potentially contributing to the pathophysiology of NDDs. This Review examines the prevalence, types and mechanisms of sleep disturbances in children with NDDs, including autism spectrum disorder, attention-deficit hyperactivity disorder and various genetic syndromes. Common sleep disorders in these populations include insomnia, hypersomnia, circadian rhythm disorders, sleep-related breathing disorders and parasomnias, with underlying factors often involving genetic, neurobiological, environmental and neurophysiological influences. Sleep problems such as insomnia, night awakenings and sleep fragmentation are closely linked to both internalizing symptoms such as anxiety and depression, and externalizing behaviours such as hyperactivity and aggression. Assessment of sleep in children with NDDs presents unique challenges owing to communication difficulties, comorbid conditions and altered sensory processing. The Review underscores the importance of further research to unravel the complex interactions between sleep and neurodevelopment, advocating for longitudinal studies and the identification of predictive biomarkers. Understanding and addressing sleep disturbances in NDDs is crucial for improving developmental outcomes and the overall quality of life for affected individuals and their families.

Fundamentals of sleep regulation: Model and benchmark values for fractal and oscillatory neurodynamics

Homeostatic, circadian and ultradian mechanisms play crucial roles in the regulation of sleep. Evidence suggests that ratios of low-to-high frequency power in the electroencephalogram (EEG) spectrum indicate the instantaneous level of sleep pressure, influenced by factors such as individual sleep-wake history, current sleep stage, age-related differences and brain topography characteristics. These effects are well captured and reflected in the spectral exponent, a composite measure of the constant low-to-high frequency ratio in the periodogram, which is scale-free and exhibits lower interindividual variability compared to slow wave activity, potentially serving as a suitable standardization and reference measure. Here we propose an index of sleep homeostasis based on the spectral exponent, reflecting the level of membrane hyperpolarization and/or network bistability in the central nervous system in humans. In addition, we advance the idea that the U-shaped overnight deceleration of oscillatory slow and fast sleep spindle frequencies marks the biological night, providing somnologists with an EEG-index of circadian sleep regulation. Evidence supporting this assertion comes from studies based on sleep replacement, forced desynchrony protocols and high-resolution analyses of sleep spindles. Finally, ultradian sleep regulatory mechanisms are indicated by the recurrent, abrupt shifts in dominant oscillatory frequencies, with spindle ranges signifying non-rapid eye movement and non-spindle oscillations - rapid eye movement phases of the sleep cycles. Reconsidering the indicators of fundamental sleep regulatory processes in the framework of the new Fractal and Oscillatory Adjustment Model (FOAM) offers an appealing opportunity to bridge the gap between the two-process model of sleep regulation and clinical somnology.

Sleep in people with and without intellectual disabilities: a systematic review and meta-analysis

BACKGROUND

Sleep problems are regularly reported in people with intellectual disabilities. Recent years have seen a substantial increase in studies comparing sleep in people with intellectual disabilities to control participants, with an increase in the use of validated, objective measures. Emerging patterns of differences in sleep time and sleep quality warrant pooled investigation.

METHODS

A systematic search was conducted across three databases (Ovid Embase, PsycInfo and Medline) and returned all papers comparing sleep in people with intellectual disabilities to a control group, published since the last meta-analysis on the topic. A quality framework was employed to rate the risk of bias across studies. Separate meta-analyses of sleep duration and sleep quality were conducted. Subgrouping compared findings for those studies with participants with genetic syndromes or neurodevelopmental conditions and those with heterogeneous intellectual disability.

RESULTS

Thirteen new papers were identified and combined with those from the previous meta-analysis to provide 34 papers in total. Quality of studies was generally rated highly, though sampling provided risk of bias and adaptive functioning was rarely measured. People with intellectual disability associated with genetic syndromes or neurodevelopmental conditions sleep for shorter time periods (standardised mean difference = .26) and experience worse sleep quality (standardised mean difference = .68) than their peers. People with intellectual disability of heterogeneous origin show no difference in sleep time but have poorer sleep quality. There was some evidence that age moderated these effects.

CONCLUSIONS

People with intellectual disability have poorer sleep than those without. Subtle patterns suggest that aetiology of intellectual disability moderates the topography of these difficulties, with further work needed to differentiate common and distinct mechanisms across groups.

Melatonin in Neurodevelopmental Disorders: A Critical Literature Review

The article presents a review of the relationships between melatonin and neurodevelopmental disorders. First, the antioxidant properties of melatonin and its physiological effects are considered to understand better the role of melatonin in typical and atypical neurodevelopment. Then, several neurodevelopmental disorders occurring during infancy, such as autism spectrum disorder or neurogenetic disorders associated with autism (including Smith-Magenis syndrome, Angelman syndrome, Rett's syndrome, Tuberous sclerosis, or Williams-Beuren syndrome) and neurodevelopmental disorders occurring later in adulthood like bipolar disorder and schizophrenia, are discussed with regard to impaired melatonin production and circadian rhythms, in particular, sleep-wake rhythms. This article addresses the issue of overlapping symptoms that are commonly observed within these different mental conditions and debates the role of abnormal melatonin production and altered circadian rhythms in the pathophysiology and behavioral expression of these neurodevelopmental disorders.

Short Report: Lack of Diurnal Variation in Salivary Cortisol Is Linked to Sleep Disturbances and Heightened Anxiety in Adolescents with Williams Syndrome

OBJECTIVE

The aim of the current study was to examine the potential relationship between sleep patterns, cortisol levels, and anxiety profiles in adolescents with Williams Syndrome (WS) compared to typically developing adolescents.

METHOD

Thirteen adolescents with WS and thirteen TD adolescents (age range 12-18 years) were recruited. Participants were provided with a "testing kit", containing instructions for collecting data through a sleep diary, MotionWare actigraphy, the Childhood Sleep Habits Questionnaire (CSHQ), and the Spence Children's Anxiety Scale, and a salivary cortisol collection kit.

RESULTS

Adolescents in the WS group did not show diurnal variation in salivary cortisol. Significantly higher scores were reported for two CSHQ subsections, night wakings and parasomnias, in the WS group. Regarding the actigraphy, only significantly longer sleep latency was observed in the WS group. In comparison to the TD group, the WS group had significantly higher anxiety. As expected, the TD group showed typical diurnal variation in cortisol, whereas the WS group showed a flattened cortisol profile throughout the day.

CONCLUSIONS

From the developmental perspective, this study provides new data supporting the conclusion that sleep problems are not transient but continue to persist into adolescence in WS. Future studies ought to consider examining the role of cortisol and its interplay with anxiety levels and sleep problems across the lifespan in individuals with WS.

An integrated perspective for the diagnosis and therapy of neurodevelopmental disorders - From an engineering point of view

Neurodevelopmental disorders (NDDs) are complex conditions with largely unknown pathophysiology. While many NDD symptoms are familiar, the cause of these disorders remains unclear and may involve a combination of genetic, biological, psychosocial, and environmental risk factors. Current diagnosis relies heavily on behaviorally defined criteria, which may be biased by the clinical team's professional and cultural expectations, thus a push for new biological-based biomarkers for NDDs diagnosis is underway. Emerging new research technologies offer an unprecedented view into the electrical, chemical, and physiological activity in the brain and with further development in humans may provide clinically relevant diagnoses. These could also be extended to new treatment options, which can start to address the underlying physiological issues. When combined with current speech, language, occupational therapy, and pharmacological treatment these could greatly improve patient outcomes. The current review will discuss the latest technologies that are being used or may be used for NDDs diagnosis and treatment. The aim is to provide an inspiring and forward-looking view for future research in the field.

Children with neurodevelopmental disorders: how do they sleep?

PURPOSE OF REVIEW

In this review we summarized the available evidence on sleep disorders in children with neurodevelopmental disorders (NDDs) in particular: intellectual disability (including some genetic conditions such as Prader-Willi Syndrome, Smith-Magenis Syndrome), Autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD), Developmental Coordination Disorder, language disorders, and specific learning disorders.

RECENT FINDINGS

Children with NDDs frequently suffer from sleep disturbances, with a higher prevalence than that of the general pediatric population.

SUMMARY

These problems tend to be chronic and may cause additional cognitive and behavioral difficulties, often affecting the whole family's well-being. Sleep behaviors are also related to other important developmental skills, such as attention and listening. Investigating sleep disorders in children with NDDs is therefore crucial in clinical practice. For a systematic approach in clinical practice, we propose the use of a short and easy to remember sleep screening tool.

Exploring the relationship of sleep, cognition, and cortisol in sickle cell disease

Background

Neurocognitive impairment is common in people with Sickle Cell Disease (SCD) and evidence is accumulating that sleep disturbances play a role. The interaction between cortisol and sleep in the general population is associated with cognition as well as general wellbeing but there are few data in SCD. We aimed to understand the relationship between cortisol and sleep in individuals with SCD and explored associations with cognition.

Methods

Forty-five participants of black heritage (SCD: N = 27, 9–29 years, 16 females; Controls: N = 18, 11–25 years, 13 females) were recruited from the community between 2018 - 2020. Participants completed standardized questionnaires about their sleep behaviour and wore actigraphy MotionWatch8 for 7 nights to assess nocturnal sleep patterns. Salivary cortisol samples were taken on wakening and 3 times after 14:00. Cognition was assessed using the Wechsler Intelligence Scales for children and adults.

Results

People with SCD took longer to fall asleep and experienced greater wake bouts, mobile minutes and fragmented sleep compared to controls. Although non-significant, people with SCD experienced lower morning cortisol, with a flattened diurnal cortisol ratio compared to controls. Interestingly, SCD participants, but not controls, with low diurnal variation scored lowest on processing speed (PSI) and perceptual reasoning index (PRI). A moderator analysis revealed that the effect of morning cortisol and diurnal cortisol ratio on PRI by group health (i.e., SCD and healthy controls) depended on sleep quality.

Discussion

Sleep and cortisol may play a crucial role in the expression of cognitive difficulties seen in SCD. This should be considered for the development of interventions to optimise cognitive functioning and sleep. This, in turn, could positively impact on secretion of cortisol and general health in SCD.

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We examined sleep patterns, cortisol and cognition in 27 participants with Sickle Cell Disease (SCD) and 18 healthy controls.

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People with SCD had lower cognitive scores compared to healthy controls.

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People with SCD took longer to fall asleep, had greater wake bouts, mobile minutes, and fragmented sleep.

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People with SCD experienced a flattened diurnal cortisol profile.

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Sleep disturbances might interfere with diurnal cortisol rhythm and contribute to lower cognitive scores .

Hair glucocorticoids in adults with intellectual disabilities and depressive symptoms pre- and post-bright light therapy: First explorations

BACKGROUND

Depressive symptoms and stress are common in adults with intellectual disabilities. Our aim was to explore long-term biological stress levels, assessed by hair cortisol (HairF) and cortisone (HairE) concentrations, in adults with intellectual disabilities and depressive symptoms and to investigate the effects of bright light therapy (BLT) on hair glucocorticoids.

METHOD

Scalp hair samples (n = 14) were retrospectively examined at baseline and post-BLT (10.000 and 300 lux). Liquid chromatography-tandem mass spectrometry was used to measure hair glucocorticoids.

RESULTS

A significant correlation was found between baseline HairF and depression scores (r = .605, p = .028). Post-intervention HairE levels were significantly increased ([95% CI: 11.2-17.4 pg/mg], p = .003), in particular after dim light (300 lux) ([95% CI: 10.0-18.3 pg/mg], p = .020).

CONCLUSIONS

This study showed that retrospectively examining biological levels of stress in adults with intellectual disabilities seems a potentially promising and objective method to gain insight in the stress level of adults with intellectual disabilities.

Sleep-related learning in Williams Syndrome and Down's Syndrome

This chapter addresses sleep research challenges for the study of neurodevelopmental disorders drawing upon two disorders such as Down Syndrome and Williams syndrome. General sleep problems are outlined here, however particular consideration is given to the syndrome-specific issues or challenges that may be crucial to advancing our understanding of sleep-related cognitive and behavioral issues.

Sleep's role in memory consolidation: What can we learn from atypical development?

Research conducted over the last century has suggested a role for sleep in the processes guiding healthy cognition and development, including memory consolidation. Children with intellectual and developmental disabilities (IDDs) tend to have higher rates of sleep disturbances, which could relate to behavior issues, developmental delays, and learning difficulties. While several studies examine whether sleep exacerbates daytime difficulties and attention deficits in children with IDDs, this chapter focuses on the current state of knowledge regarding sleep and memory consolidation in typically developing (TD) groups and those at risk for learning difficulties. In particular, this chapter summarizes the current literature on sleep-dependent learning across developmental disabilities, including Down syndrome, Williams syndrome, Autism Spectrum Disorder, and Learning Disabilities (Attention-Deficit/Hyperactivity Disorder and Dyslexia). We also highlight the gaps in the current literature and identify challenges in studying sleep-dependent memory in children with different IDDs. This burgeoning new field highlights the importance of considering the role of sleep in memory retention across long delays when evaluating children's memory processes. Further, an understanding of typical and atypical development can mutually inform recent theories of sleep's role in memory.

Endogenous melatonin and sleep in individuals with Rare Genetic Neurodevelopmental Disorders (RGND): A systematic review

Individuals with Rare Genetic Neurodevelopmental Disorders (RGND) present with significant sleep problems and circadian rhythm abnormalities of uncertain aetiology. Abnormal melatonin secretion may play a role in sleep disturbance in individuals with higher incidence developmental disabilities, however, RGND research is limited. This review compared the melatonin profiles in a range of RGND with that of the general population and considered the impact of any differences on sleep. A systematic search identified 19 studies that met inclusion criteria. Each study was examined to extract data relating to the study design, participant characteristics, objectives, sleep measures and results, and melatonin measures and findings. Studies were evaluated using the BIOCROSS quality appraisal tool. Nine studies focussed on Smith-Magenis syndrome (SMS), the rest included individuals with Angelman (AS), Fragile-X (FXS), Prader-Willi (PWS), septo-optic dysplasia, PAX6/WAGR and Williams (WS) syndromes (N = 349). Individuals with RGND present with a range of sleep problems, particularly dyssomnias. The melatonin profile varied within and between RGND, with low nocturnal melatonin levels commonly reported. Understanding the relationship between specific sleep and melatonin parameters within RGND may help inform sleep intervention.

Neurodevelopmental Disorders Commonly Presenting with Sleep Disturbances

There are multiple disorders of neurodevelopment that present with co-occurring sleep disturbances. Many of these neurodevelopmental disorders (NDD) include sleep disturbances in their diagnostic criteria. Neurobiological, genetic, and environmental factors overlap to cause different sleep disorders in individuals with NDD. Caregivers often present reporting either insomnia or hypersomnia, and based on the clinical history and findings from diagnostic tests, an appropriate diagnosis can be made. It is crucial that clinicians understand the different presentations of sleep disturbances in individuals with NDD.

Sleep characteristics and problems of 2-year-olds with Williams syndrome: relations with language and behavior

Background

Sleep problems have been shown to have a negative impact on language development and behavior for both typically developing children and children with a range of neurodevelopmental disorders. The relation of sleep characteristics and problems to language and behavior for children with Williams syndrome (WS) is unclear. The goal of this study was to address these relations for 2-year-olds with WS. Associations of nonverbal reasoning ability, nighttime sleep duration, and excessive daytime sleepiness with language ability and behavior problems were considered.

Method

Ninety-six 2-year-olds with genetically confirmed classic-length WS deletions participated. Parents completed the Pediatric Sleep Questionnaire, which includes a Sleep-Related Breathing Disorder (SRBD) scale with a subscale measuring excessive daytime sleepiness, to assess sleep characteristics and problems. Parents also completed the Child Behavior Checklist (CBCL) and the MacArthur-Bates Communicative Development Inventory: Words and Sentences to assess behavior problems and expressive vocabulary, respectively. Children completed the Mullen Scales of Early Learning to measure nonverbal reasoning and language abilities.

Results

Parents indicated that children slept an average of 10.36 h per night (SD = 1.09, range 7.3–13.3), not differing significantly from the mean reported by Bell and Zimmerman (2010) for typically developing toddlers (p = .787). Sixteen percent of participants screened positive for SRBD and 30% for excessive daytime sleepiness. Children who screened positive for SRBD had significantly more behavior problems on all CBCL scales than children who screened negative. Children with excessive daytime sleepiness had significantly more attention/hyperactivity, stress, and externalizing problems than those who did not have daytime sleepiness. Individual differences in parent-reported nighttime sleep duration and directly measured nonverbal reasoning abilities accounted for unique variance in expressive language, receptive language, and internalizing problems. Individual differences in parent-reported daytime sleepiness accounted for unique variance in externalizing problems.

Conclusions

The relations of nighttime sleep duration, positive screens for SRBD, and excessive daytime sleepiness to language and behavior in toddlers with WS parallel prior findings for typically developing toddlers. These results highlight the importance of screening young children with WS for sleep problems. Studies investigating the efficacy of behavioral strategies for improving sleep in children with WS are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-020-09336-z.

Early manifestation of sleep problems in toddlers with Williams Syndrome using a mixed method longitudinal approach

Children with neurodevelopmental disorders commonly experience sleep problems. Williams Syndrome (WS), a rare genetic disorder characterised by a complex, uneven cognitive profile, is no exception. Compared with children with typical development (TD), school-aged children with WS experience significant sleep disruption: shorter sleep duration, more night wakings, greater bedtime resistance and excessive daytime tiredness. In children with TD, sleep problems impede optimal daytime functioning. In WS, this could compound existing difficulties. Few studies have examined sleep in very young children with WS and little is known about the early emergence of sleep problems in this population. To date, studies have been based on parent-report and no studies have objectively assessed sleep patterns using longitudinal approach in toddlers with WS. Thus, the current study sought to objectively explore sleep patterns in toddlers with WS. Parents of 38 children (13 WS, 25 TD) completed the Brief Infant Screening Questionnaire and the Medical and Demographics Questionnaire and sleep patterns were assessed using actigraphy. Data were collected longitudinally at ages 18, 24 and 30 months. Significant sleep disturbances were present in WS from 18 months old. Sleep duration, as measured by actigraphy, was significantly shorter in WS at all ages and, furthermore, parents of children with WS reported more night wakings, longer settling times and high levels of parental involvement. Crucially, whereas actigraphy showed developmental improvements in sleep quality in TD, no longitudinal changes were found in WS. Findings could be instrumental in working towards instigating appropriate, timely sleep management in this group, thus improving outcomes for children and their families.

Sleep is atypical across neurodevelopmental disorders in infants and toddlers: A cross-syndrome study

This cross-syndrome study focuses on sleep and its relationship with language development. Children with neurodevelopmental disorders present with language delay. Typical language development is constrained by numerous factors including sleep. Sleep is often disrupted in adolescents/adults with neurodevelopmental disorders. We therefore hypothesised that sleep may be disrupted, and correlate with language development, in infants/toddlers with neurodevelopmental disorders. To test our hypothesis, we obtained sleep and vocabulary size data from 75 infants/toddlers with one of three neurodevelopmental disorders (Down syndrome [DS], fragile X syndrome [FXS], Williams syndrome [WS]). Sleep was indeed disrupted in these children. It was also positively associated with receptive vocabulary size in the infants/toddlers with DS and WS (we could not test the relationship between sleep and language in FXS due to lack of power). We argue that disrupted sleep may be a common occurrence in very young children with neurodevelopmental disorders, and it may relate to their ability to acquire their first language.

Health Care Supervision for Children With Williams Syndrome

This set of recommendations is designed to assist the pediatrician in caring for children with Williams syndrome (WS) who were diagnosed by using clinical features and with chromosome 7 microdeletion confirmed by fluorescence in situ hybridization, chromosome microarray, or multiplex ligation-dependent probe amplification. The recommendations in this report reflect review of the current literature, including previously peer-reviewed and published management suggestions for WS, as well as the consensus of physicians and psychologists with expertise in the care of individuals with WS. These general recommendations for the syndrome do not replace individualized medical assessment and treatment.

A Cross-Syndrome Comparison of Sleep-Dependent Learning on a Cognitive Procedural Task

Sleep plays a key role in the consolidation of newly acquired information and skills into long term memory. Children with Down syndrome (DS) and Williams syndrome (WS) frequently experience sleep problems, abnormal sleep architecture, and difficulties with learning; thus, we predicted that children from these clinical populations would demonstrate impairments in sleep-dependent memory consolidation relative to children with typical development (TD) on a cognitive procedural task: The Tower of Hanoi. Children with DS (n = 17), WS (n = 22) and TD (n = 34) completed the Tower of Hanoi task. They were trained on the task either in the morning or evening, then completed it again following counterbalanced retention intervals of daytime wake and night time sleep. Children with TD and with WS benefitted from sleep for enhanced memory consolidation and improved their performance on the task by reducing the number of moves taken to completion, and by making fewer rule violations. We did not find any large effects of sleep on learning in children with DS, suggesting that these children are not only delayed, but atypical in their learning strategies. Importantly, our findings have implications for educational strategies for all children, specifically considering circadian influences on new learning and the role of children's night time sleep as an aid to learning.

Comparison of village dog and wolf genomes highlights the role of the neural crest in dog domestication

BACKGROUND

Domesticated from gray wolves between 10 and 40 kya in Eurasia, dogs display a vast array of phenotypes that differ from their ancestors, yet mirror other domesticated animal species, a phenomenon known as the domestication syndrome. Here, we use signatures persisting in dog genomes to identify genes and pathways possibly altered by the selective pressures of domestication.

RESULTS

Whole-genome SNP analyses of 43 globally distributed village dogs and 10 wolves differentiated signatures resulting from domestication rather than breed formation. We identified 246 candidate domestication regions containing 10.8 Mb of genome sequence and 429 genes. The regions share haplotypes with ancient dogs, suggesting that the detected signals are not the result of recent selection. Gene enrichments highlight numerous genes linked to neural crest and central nervous system development as well as neurological function. Read depth analysis suggests that copy number variation played a minor role in dog domestication.

CONCLUSIONS

Our results identify genes that act early in embryogenesis and can confer phenotypes distinguishing domesticated dogs from wolves, such as tameness, smaller jaws, floppy ears, and diminished craniofacial development as the targets of selection during domestication. These differences reflect the phenotypes of the domestication syndrome, which can be explained by alterations in the migration or activity of neural crest cells during development. We propose that initial selection during early dog domestication was for behavior, a trait influenced by genes which act in the neural crest, which secondarily gave rise to the phenotypes of modern dogs.

Use and Effectiveness of Sleep Medications by Parent Report in Individuals with Williams Syndrome

OBJECTIVE

Sleep disorders are common in individuals with Williams syndrome (WS), and sleep disturbance has a significant negative effect on attention, learning, and behavior. The use of sleep-inducing medicine in individuals with WS has not been widely investigated. The objective of this study was to evaluate the use and effectiveness of sleep medications among a large sample of individuals with WS by parent survey.

METHODS

A survey of the use and effectiveness of sleep medications was completed by 513 (of 2846) members of the Williams Syndrome Association. The online survey asked for the age at initiation, degree of effectiveness (helpful, somewhat helpful, and not helpful), and side effects.

RESULTS

One hundred thirty participants (25%) indicated that their family member with WS had taken medication to help with sleep. Melatonin was the most commonly reported medication taken for sleep, with 91% of parents reporting that it was "helpful" or "somewhat helpful" for their child with WS. Those who reported taking melatonin reported very few, if any, side effects.

CONCLUSION

This parent-completed survey is a preliminary study showing the positive benefit of melatonin for individuals with WS who have disrupted sleep. The findings support the need for further study of the use of melatonin, in addition to behavioral sleep aids, given evidence that sleep disturbance negatively influences cognition and behavior.

Analysis of Different Melatonin Secretion Patterns in Children With Sleep Disorders: Melatonin Secretion Patterns in Children

The objective of this study was to analyze circadian patterns of urinary 6-sulphatoxymelatonin (aMT6s) excretion in children with primary sleep disorders in comparison with healthy controls. A total of 124 control children and 124 patients (aged 4-14 years) diagnosed with diverse primary sleep disorders were recruited. aMT6s concentrations were measured in diurnal and nocturnal urine, as well as in 24-hour urine. aMT6s levels were significantly higher and showed significantly more evident circadian variations in the control group ( P < .001). Four different melatonin (aMT) production and excretion patterns were distinguished in the group with sleep disorders: (1) standard aMT production pattern, (2) low aMT production pattern, (3) aMT production pattern with absence of circadian variation, and (4) aMT hyperproduction pattern. This study highlights the importance of analyzing specific alterations of aMT secretion in each sleep disorder and provides evidences to explain why not all children with sleep disturbances do respond to aMT treatment.

Capacity to improve fine motor skills in Williams syndrome

BACKGROUND

Individuals with Williams syndrome (WS) are known to have difficulties in carrying out fine motor movements; however, a detailed behavioural profile of WS in this domain is still missing. It is also unknown how great the capacity to improve these skills with focused and extensive practice is.

METHOD

We studied initial performance and learning capacity in a sequential finger tapping (FT) task in WS and in typical development. Improvement in the FT task has been shown to be sleep dependent. WS subjects participating in the current study have also participated in earlier polysomnography studies, although not directly related to learning.

RESULTS

WS participants presented with great individual variability. In addition to generally poor initial performance, learning capacity was also greatly limited in WS. We found indications that reduced sleep efficiency might contribute to this limitation.

CONCLUSIONS

Estimating motor learning capacity and the depth of sleep disorder in a larger sample of WS individuals might reveal important relationships between sleep and learning, and contribute to efficient intervention methods improving skill acquisition in WS.

Management of sleep disorders in neurodevelopmental disorders and genetic syndromes

PURPOSE OF REVIEW

Sleep disorders in individuals with developmental difficulties continue to be a significant challenge for families, carers, and therapists with a major impact on individuals and carers alike. This review is designed to update the reader on recent developments in this area.

RECENT FINDINGS

A systematic search identified a variety of studies illustrating advances in the regulation of circadian rhythm and sleep disturbance in neurodevelopmental disorders. Specific advances are likely to lead in some disorders to targeted therapies. There is strong evidence that behavioural and sleep hygiene measures should be first line therapy; however, studies are still limited in this area. Nonpharmacological measures such as exercise, sensory interventions, and behavioural are reported. Behavioural regulation and sleep hygiene demonstrate the best evidence for improved sleep parameters in individuals with neurodisability.

SUMMARY

Although the mainstay of management of children with sleep problems and neurodevelopmental disability is similar to that of typically developing children, there is emerging evidence of behavioural strategies being successful in large-scale trials and the promise of more targeted therapies for more specific resistant disorders.

A cross-syndrome study of the differential effects of sleep on declarative memory consolidation in children with neurodevelopmental disorders

Sleep plays an active role in memory consolidation. Because children with Down syndrome (DS) and Williams syndrome (WS) experience significant problems with sleep and also with learning, we predicted that sleep‐dependent memory consolidation would be impaired in these children when compared to typically developing (TD) children. This is the first study to provide a cross‐syndrome comparison of sleep‐dependent learning in school‐aged children. Children with DS (n = 20) and WS (n = 22) and TD children (n = 33) were trained on the novel Animal Names task where they were taught pseudo‐words as the personal names of ten farm and domestic animals, e.g. Basco the cat, with the aid of animal picture flashcards. They were retested following counterbalanced retention intervals of wake and sleep. Overall, TD children remembered significantly more words than both the DS and WS groups. In addition, their performance improved following night‐time sleep, whereas performance over the wake retention interval remained stable, indicating an active role of sleep for memory consolidation. Task performance of children with DS did not significantly change following wake or sleep periods. However, children with DS who were initially trained in the morning continued to improve on the task at the following retests, so that performance on the final test was greater for children who had initially trained in the morning than those who trained in the evening. Children with WS improved on the task between training and the first retest, regardless of whether sleep or wake occurred during the retention interval. This suggests time‐dependent rather than sleep‐dependent learning in children with WS, or tiredness at the end of the first session and better performance once refreshed at the start of the second session, irrespective of the time of day. Contrary to expectations, sleep‐dependent learning was not related to baseline level of performance. The findings have significant implications for educational strategies, and suggest that children with DS should be taught more important or difficult information in the morning when they are better able to learn, whilst children with WS should be allowed a time delay between learning phases to allow for time‐dependent memory consolidation, and frequent breaks from learning so that they are refreshed and able to perform at their best.