Polysomnographic findings in Rett syndrome: a case-control study

The Efficacy of Noninvasive Ventilation in Patients Affected by Rett Syndrome With Hypoventilation

BACKGROUND

Rett syndrome is a progressive neurological disorder associated to several comorbidities that contribute significantly to impair lung function. Respiratory morbidity represents a major cause of death in this population. Little is known about the benefit of noninvasive ventilation.

METHODS

We retrospectively enrolled patients with Rett syndrome who underwent a pneumological evaluation combined with a cardiorespiratory polygraphy and/or a pulse oximetry and capnography from 2012 to 2022.

RESULTS

Medical records of 11 patients with Rett syndrome, mean age 13 ± 6 years, were evaluated. Most patients presented with both epilepsy and scoliosis. Five patients showed a pathologic sleep study and/or impaired night gas exchange: mean obstructive apnea-hypopnea index was 4 ± 3 events/hour; mean and minimal SpO2 were, respectively, 93% ± 2% and 83% ± 6%, while mean and maximal transcutaneous carbon dioxide monitoring (PtcCO2) were, respectively, 51 ± 5 mm Hg and 55 ± 8 mm Hg; and mean oxygen desaturation index was 13 ± 11 events/hour. These patients started noninvasive ventilation with clinical benefit and improved gas exchange mostly in terms of PtcCO2 (mean PtcCO2 51 ± 5 mm Hg before and 46 ± 6 mm Hg after noninvasive ventilation).

CONCLUSIONS

Noninvasive ventilation is a suitable option for patients with Rett syndrome.

A clinical-translational review of sleep problems in neurodevelopmental disabilities

Sleep disorders are very common across neurodevelopmental disorders and place a large burden on affected children, adolescents, and their families. Sleep disturbances seem to involve a complex interplay of genetic, neurobiological, and medical/environmental factors in neurodevelopmental disorders. In this review, we discuss animal models of sleep problems and characterize their presence in two single gene disorders, Rett Syndrome, and Angelman Syndrome and two more commonly occurring neurodevelopmental disorders, Down Syndrome, and autism spectrum disorders. We then discuss strategies for novel methods of assessment using wearable sensors more broadly for neurodevelopmental disorders in general, including the importance of analytical validation. An increased understanding of the mechanistic contributions and potential biomarkers of disordered sleep may offer quantifiable targets for interventions that improve overall quality of life for affected individuals and their families.

Management of respiratory issues in patients with Rett syndrome: Italian experts' consensus using a Delphi approach

BACKGROUND

Despite the publication of the 2020 guidelines on how to manage Rett Syndrome (RS), some fundamental topics are still open, in particular respiratory problems.

OBJECTIVE

Identification and reinforcement of current recommendations concerning the management of respiratory issues in RS patients.

MATERIALS AND METHODS

Using a Delphi approach, the leading group reviewed the literature and formulated 14 statements. A multidisciplinary panel of 29 experts were invited to score, for each statement, their agreement on a 1-5 scale. The cut-off level for consensus was 75%, obtained through multiple rounds.

RESULTS

The panel agreed that in all RS types, respiratory issues should be faced at an early stage, regardless of epilepsy onset. It is recommended to perform periodically sleep studies in all Congenital Rett Syndrome, and in selected cases with other RS types. Noninvasive ventilation should be considered in all RS subjects with sleep respiratory disorders and in those with hypotonia associated with hypercapnia. Chest physiotherapy should be performed in all RS patients with difficult management of the accumulation of respiratory secretions, using airway clearance techniques and devices (PEP-mask, AMBU bag, or cough machine), more appropriate and tolerated by the patients. The panel recommended individualized programs for the management of scoliosis, and to consider performing gastrostomy in patients at increased risk of ab ingestis pneumonia.

CONCLUSIONS

This consensus could support everyday clinical practice on respiratory issues in RS patients, complementary to existing recommendations by regulatory agencies and guidelines.

Sleep and the Social Profiles of Individuals With Rett Syndrome

BACKGROUND

This study investigates the distinctive social behaviors observed in individuals with Rett syndrome (RTT), characterized by the loss of spoken language, impaired eye gaze communication, gait abnormalities, and sleep issues. The research aims to identify social profiles in RTT and explore their correlation with sleep, sleep-disordered breathing (SDB), and daytime sleepiness.

METHODS

Standard overnight sleep macrostructure and respiratory parameters were assessed. Extracting 25 social-related items and one for daytime sleepiness from the Rett Syndrome Behavioral Questionnaire, factor analysis was applied to establish latent social profiles. These profiles were then correlated with sleep parameters. The nonparametric Mann-Whitney U test compared social profiles based on the presence of SDB (defined by an apnea-hypopnea index greater than one per hour) and daytime sleepiness.

RESULTS

The study involved 12 female subjects with confirmed RTT diagnoses and MECP2 mutations, aged 8.54 ± 5.30 years. The Rett Syndrome Behavioral Questionnaire revealed a total average score of 25.83 ± 12.34, indicating varying degrees of social impairments. Comprising 25 social-related items, factor analysis yielded four social profiles: "interactive motricity," "mood change," "anxiety/agitation," and "gazing." Longer sleep onset latency correlated with increased socio-behavioral impairments, particularly in interactive motricity reduction. Conversely, higher rapid eye movement sleep was associated with fewer interactive socio-motor behaviors. No significant differences in social profiles were found concerning the presence of SDB or daytime sleepiness.

CONCLUSIONS

The findings suggest four distinct social profiles in RTT individuals, hinting at shared disrupted circuits between sensorimotor functioning and sleep-related neuronal pathways. Despite the absence of differences in SDB or daytime sleepiness, the study highlights the relationship between sleep parameters, such as sleep onset latency and rapid eye movement sleep, and socio-behavioral outcomes in RTT with MECP2 mutations.

Natural Course of IQSEC2-Related Encephalopathy: An Italian National Structured Survey

Pathogenic loss-of-function variants in the IQ motif and SEC7 domain containing protein 2 (IQSEC2) gene cause intellectual disability with Rett syndrome (RTT)-like features. The aim of this study was to obtain systematic information on the natural history and extra-central nervous system (CNS) manifestations for the Italian IQSEC2 population (>90%) by using structured family interviews and semi-quantitative questionnaires. IQSEC2 encephalopathy prevalence estimate was 7.0 to 7.9 × 10-7. Criteria for typical RTT were met in 42.1% of the cases, although psychomotor regression was occasionally evidenced. Genetic diagnosis was occasionally achieved in infancy despite a clinical onset before the first 24 months of life. High severity in both the CNS and extra-CNS manifestations for the IQSEC2 patients was documented and related to a consistently adverse quality of life. Neurodevelopmental delay was diagnosed before the onset of epilepsy by 1.8 to 2.4 years. An earlier age at menarche in IQSEC2 female patients was reported. Sleep disturbance was highly prevalent (60 to 77.8%), with mandatory co-sleeping behavior (50% of the female patients) being related to de novo variant origin, younger age, taller height with underweight, better social interaction, and lower life quality impact for the family and friends area. In conclusion, the IQSEC2 encephalopathy is a rare and likely underdiagnosed developmental encephalopathy leading to an adverse life quality impact.

Inhibitory Synaptic Influences on Developmental Motor Disorders

During development, GABA and glycine play major trophic and synaptic roles in the establishment of the neuromotor system. In this review, we summarise the formation, function and maturation of GABAergic and glycinergic synapses within neuromotor circuits during development. We take special care to discuss the differences in limb and respiratory neuromotor control. We then investigate the influences that GABAergic and glycinergic neurotransmission has on two major developmental neuromotor disorders: Rett syndrome and spastic cerebral palsy. We present these two syndromes in order to contrast the approaches to disease mechanism and therapy. While both conditions have motor dysfunctions at their core, one condition Rett syndrome, despite having myriad symptoms, has scientists focused on the breathing abnormalities and their alleviation-to great clinical advances. By contrast, cerebral palsy remains a scientific quagmire or poor definitions, no widely adopted model and a lack of therapeutic focus. We conclude that the sheer abundance of diversity of inhibitory neurotransmitter targets should provide hope for intractable conditions, particularly those that exhibit broad spectra of dysfunction-such as spastic cerebral palsy and Rett syndrome.

The clinical and sleep manifestations in children with FOXG1 syndrome

FOXG1 syndrome is a rare neurodevelopmental disorder associated with severe cognitive dysfunction, autistic behavior, and early-onset hyperkinetic movement disorders. Patients have also been reported to experience sleep disturbances. However, these findings are mainly based on subjective caregivers' reports, and limited by small case numbers. Moreover, no studies using objective evaluation tools, such as actigraphy, have been reported. We analyzed the clinical and sleep manifestations of children with FOXG1 syndrome registered in the International FOXG1 Research Foundation registry database. A total of 258 individuals with FOXG1 syndrome were included in this research. 132 (51.16%) had sleep disturbances. The more impaired of language acquisitions (absence of speech, OR: 3.99, 95%CI = 1.69-9.42, p = 0.002), hyperkinetic movement disorders (OR: 2.64, 95%CI = 1.34-5.20 p = 0.005) and feeding difficulties (OR: 2.81, 95% CI = 1.52-5.19, p = 0.001) were significantly associated with an increase in odds of sleep disturbance after adjusting for age, sex, and antiepileptic drugs. We also performed sleep studies on six individuals with FOXG1 syndrome using The Children's Sleep Habits Questionnaire (CSHQ), the Sleep Disturbance Scale for Children (SDSC), and 7-day data from Actiwatch. The Pittsburgh Sleep Quality Index (PSQI) and 7-day data from Actiwatch were also used to evaluate the sleep condition of their parents. The CSHQ scores revealed bedtime resistance, sleep onset delay, sleep duration, sleep anxiety, night-waking, and parasomnia. Sleep-wake transition disorders and disorders of initiating and maintaining sleep were also suggested by the SDSC scores. The children's actigraphy revealed short sleep durations, impaired sleep efficiency, longer wake after sleep onset, and frequent night-waking. All caregivers reported significantly higher PSQI scores, mildly declined sleep efficiency, and shorter total sleep duration. Sleep disturbances, especially in initiating and maintaining sleep, are common in individuals with FOXG1 syndrome and their caregivers. Sleep disorders in patients with FOXG1 syndrome and their caregivers should be investigated.

Long time polysomnographic sleep and breathing evaluations in children with CDKL5 deficiency disorder

STUDY OBJECTIVES

CDKL5 deficiency disorder (CDD) is a rare developmental and epileptic encephalopathy, developing in the first months of life, caused by a mutation in the cyclin-dependent kinase-like 5 (CDKL5) gene. Children with CDD often have sleep (90%) and breathing disorders in wake (50%). Sleep disorders may have a significant impact emotional wellbeing and quality of life of caregivers of children with CDD and are challenging to treat. The outcomes of these features are unknown in children with CDD.

METHODS

We retrospectively evaluated sleep and respiratory function changes over 5-10 years in a small cohort of Dutch children with CDD, using video-EEG and/or polysomnography (3 × 24 h) and a parental questionnaire, the Sleep Disturbance Scale for Children (SDSC). The present study is a follow-up sleep and PSG study to evaluate if sleep and breathing disturbances persist in children with CDD previously studied.

RESULTS

Sleep disturbances persisted during the study period (5.5-10 years). All five individuals had long sleep latency (SL, range 32-174.5 min) and frequent arousals and awakenings (14-50/night), unrelated to apneas/seizures, corresponding to the SDSC findings. Low sleep efficiency (SE, 41-80%) was present and did not improve. In our participants, total sleep time (TST, 3h52min-7h52min) was short and remained so. Time in bed (TIB) was typical for children aged 2-8 years, but did not adjust with ageing. Low duration (4.8-17.4%) or even absent REM sleep persisted over time. No sleep apneas were noted. Central apneas due to episodic hyperventilation were reported during wakefulness in two of the five.

CONCLUSION

Sleep disturbances were present and persisted in all. The decreased REM sleep and sporadic breathing disturbances in wake may indicate failure of brainstem nuclei. Sleep disturbances can severely affect the emotional wellbeing and quality of life of the caregivers and the individuals with CDD and are challenging to treat. Hopefully our polysomnographic sleep data contribute to find the optimal treatment of the sleep problems in CDD patients.

An investigation of the sleep macrostructure of girls with Rett syndrome

OBJECTIVE/BACKGROUND

Methyl-CpG-binding protein 2 (MeCP2) is of utmost importance in neuronal function. We aim to characterize phenotypic traits in the sleep of individuals with Rett Syndrome (RTT, OMIM # 312750), a rare disorder predominantly caused by mutations of the MECP2 gene.

PATIENTS/METHODS

An overnight polysomnographic recording was performed. Outcomes investigated were parameters of nocturnal sleep macrostructure, and sample stratification per genetic and clinical characteristics, and six key features of clinical severity was applied.

RESULTS

The sleep of our 21 RTT female subjects with a mutant MECP2 gene, aged 8.8 ± 5.4 years, showed no significant differences within strata. However, compared to a normative dataset, we found longer duration of wake time after sleep onset and total sleep time (TST) but shorter sleep onset latency, in RTT. Regarding the proportion of sleep stages per TST, higher stage N3 (%) with lower stage N2 (%) and REM (%) were generally seen. Such abnormalities became more uniformly expressed at the severe level of clinical features, particularly for hand functioning and walking.

CONCLUSIONS

RTT girls with MECP2 mutations in our study demonstrated an increased deep sleep and reduced rapid eye movement sleep proportion, which is mostly allied with their hand dysfunction severity. Poor sleep-on/off switching in RTT since embryogenesis is possibly linked to (psycho)motor impairment in the cases with MECP2 mutations.

Feasibility of wearable devices and machine learning for sleep classification in children with Rett syndrome: A pilot study

Sleep is vital to many processes involved in the well-being and health of children; however, it is estimated that 80% of children with Rett syndrome suffer from sleep disorders. Caregiver reports and questionnaires, which are the current method of studying sleep, are prone to observer bias and missed information. Polysomnography is considered the gold standard for sleep analysis but is labor and cost-intensive and limits the frequency of data collection for sleep disorder studies. Wearable digital health technologies, such as actigraphy devices, have shown potential and feasibility as a method for sleep analysis in Rett syndrome, but have not been validated against polysomnography. Furthermore, the collected accelerometer data has limitations due to the rigidity, periodic limb movement, and involuntary muscle contractions prevalent in Rett syndrome. Heart rate and electrodermal activity, along with other physiological signals, have been linked to sleep stages and can be utilized with machine learning to provide better resistance to noise and false positives than actigraphy. This research aims to address the gap in Rett syndrome sleep analysis by comparing the performance of a machine learning model utilizing both accelerometer data and physiological data features to the gold-standard polysomnography for sleep analysis in Rett syndrome. Our analytical validation pilot study (n = 7) found that using physiological and accelerometer features, our machine learning models can differentiate between awake, non-rapid eye movement sleep, and rapid eye movement sleep in Rett syndrome children with an accuracy of 85.1% when using an individual model. Additionally, this work demonstrates that it is feasible to use digital health technologies in Rett syndrome, even at a young age, without data loss or interference from repetitive movements that are characteristic of Rett syndrome.

Sleep Respiratory Disturbances in Girls with Rett Syndrome

Individuals with Rett Syndrome (RTT), a rare neurodevelopmental disorder, present disordered breathing during wakefulness. Whilst findings on breathing during sleep are contradictory, the relation between sleep breathing and their clinical features, genetic characteristics, age, and sleep phase is rarely investigated, which is the objective of this study. Overnight polysomnography (PSG) was performed. Sleep macrostructure parameters were compared between the RTT subjects with and without sleep-disordered breathing (SDB). The association between the apnea-hypopnea index (AHI) with age at PSG was tested. Particularly for RTT subjects with SDB, the respiratory indexes in REM and NREM sleep were compared. Stratified analyses per clinical characteristics, genetic characteristics, and clinical features' severity were performed. Non-parametric statistics were applied. A sample of 11 female RTT subjects, aged 8.69 ± 5.29 years with ten confirmed with MECP2 mutations, were studied. The average AHI was 3.94 ± 1.19/h TST, of which eight (72.73%) had obstructive sleep apnea, i.e., six in 1/h TST ≤ AHI ≤ 5/h TST, and two in AHI > 5/h TST. The mean SpO₂% was 81.00 ± 35.15%. The AHI was not significantly correlated with their age at PSG (r_s = -0.15, p = 0.67). Sleep macrostructure in SDB-absent and SDB-present groups was not different. Respiratory indexes in those with obstructive sleep apnea showed no difference between REM and NREM sleep nor any of the strata. In our clinical sample, more than half of the RTT subjects with MECP2 mutations had obstructive sleep apnea in both NREM and REM sleep which was unrelated to their clinical features. Our results also indicated hypoxemia throughout nocturnal sleep in RTT. To conclude, our results suggest that disordered breathing during sleep is prevalently present in RTT as an independent clinical feature.

A meta-review of standard polysomnography parameters in Rett Syndrome

Rett Syndrome (RTT, OMIM 312750), a unique rare neurodevelopmental disorder, mostly affects females and causes severe multi-disabilities including poor sleep. This meta-analysis systematically reviewed the polysomnographic (PSG) data of individuals with RTT on both sleep macrostructure and sleep respiratory indexes and compared them to literature normative values. Studies were collected from PubMed, Web of Science, PsycINFO, Ebsco, Scopus, and Cochrane Library till 26 April 2022. Across 13 included studies, the 134 selected RTT cases were mostly females being MECP2 (n = 41) and CDKL5 (n = 4) positive. They were further stratified by gene, age, and clinical features. Findings of comparison with literature normative values suggested shorter total sleep time (TST) and sleep onset latency (SOL), twice as long wake after sleep onset (WASO) with lower sleep efficiency (SEI) in RTT, as well as increased non-rapid eye movement stage 3 (stage N3) and decreased rapid eye movement sleep. Based on limited data per stratifications, we found in RTT cases <5 years old lower stage N3, and in RTT cases >5 years old less WASO and more WASO in the epileptic strata. However, meta-results generated from studies designed with comparison groups only showed lower stage N1 in RTT than in healthy comparison, together with similar SEI and stage N3 to primary snoring subjects. For sleep respiratory indexes, severe disordered sleep breathing was confirmed across roughly all RTT strata. We are the first study to meta-analyze PSG data of subjects with RTT, illustrating shorter TST and aberrant sleep staging in RTT that may vary with age or the presence of epilepsy. Severe nocturnal hypoxemia with apneic events was also demonstrated. More studies are needed to explore and elucidate the pathophysiological mechanisms of these sleep findings in the future.

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.

Breathing Abnormalities During Sleep and Wakefulness in Rett Syndrome: Clinical Relevance and Paradoxical Relationship With Circulating Pro-oxidant Markers

Background

Breathing abnormalities are common in Rett syndrome (RTT), a pervasive neurodevelopmental disorder almost exclusively affecting females. RTT is linked to mutations in the methyl-CpG-binding protein 2 (MeCP2) gene. Our aim was to assess the clinical relevance of apneas during sleep-wakefulness cycle in a population with RTT and the possible impact of apneas on circulating oxidative stress markers.

Methods

Female patients with a clinical diagnosis of typical RTT (n = 66), MECP2 gene mutation, and apneas were enrolled (mean age: 12.5 years). Baseline clinical severity, arterial blood gas analysis, and red blood cell count were assessed. Breathing was monitored during the wakefulness and sleep states (average recording time: 13 ± 0.5 h) with a portable polygraphic screening device. According to prevalence of breath holdings, the population was categorized into the wakefulness apnea (WA) and sleep apnea (SA) groups, and apnea-hypopnea index (AHI) was calculated. The impact of respiratory events on oxidative stress was assessed by plasma and intra-erythrocyte non-protein-bound iron (P-NPBI and IE-NPBI, respectively), and plasma F2-isoprostane (F2-IsoP) assays.

Results

Significant prevalence of obstructive apneas with values of AHI &gt; 15 was present in 69.7% of the population with RTT. The group with SA showed significantly increased AHI values &gt; 15 (p = 0.0032), total breath holding episodes (p = 0.007), and average SpO2 (p = 0.0001) as well as lower nadir SpO2 (p = 0.0004) compared with the patients with WAs. The subgroups of patients with WA and SA showed no significant differences in arterial blood gas analysis variables (p &gt; 0.089). Decreased mean cell hemoglobin (MCH) (p = 0.038) was observed in the group with WAs. P-NPBI levels were significantly higher in the group with WA than in that with SAs (p = 0.0001). Stepwise multiple linear regression models showed WA being related to nadir SpO2, average SpO2, and P-NPBI (adjusted R2 = 0.613, multiple correlation coefficient = 0.795 p &lt; 0.0001), and P-NPBI being related to average SpO2, blood PaCO2, red blood cell mean corpuscular volume (MCV), age, and topiramate treatment (adjusted R2 = 0.551, multiple correlation coefficient = 0.765, p &lt; 0.0001).

Conclusion

Our findings indicate that the impact of apneas in RTT is uneven according to the sleep-wakefulness cycle, and that plasma redox active iron represents a potential novel therapeutic target.

Sleep Disorders in Rett Syndrome and Rett-Related Disorders: A Narrative Review

Rett Syndrome (RTT) is a rare and severe X-linked developmental brain disorder that occurs primarily in females, with a ratio of 1:10.000. De novo mutations in the Methyl-CpG Binding protein 2 (MECP2) gene on the long arm of X chromosome are responsible for more than 95% cases of classical Rett. In the remaining cases (atypical Rett), other genes are involved such as the cyclin-dependent kinase-like 5 (CDKL5) and the forkhead box G1 (FOXG1). Duplications of the MECP2 locus cause MECP2 duplication syndrome (MDS) which concerns about 1% of male patients with intellectual disability. Sleep disorders are common in individuals with intellectual disability, while the prevalence in children is between 16 and 42%. Over 80% of individuals affected by RTT show sleep problems, with a higher prevalence in the first 7 years of life and some degree of variability in correlation to age and genotype. Abnormalities in circadian rhythm and loss of glutamate homeostasis play a key role in the development of these disorders. Sleep disorders, epilepsy, gastrointestinal problems characterize CDKL5 Deficiency Disorder (CDD). Sleep impairment is an area of overlap between RTT and MECP2 duplication syndrome along with epilepsy, regression and others. Sleep dysfunction and epilepsy are deeply linked. Sleep deprivation could be an aggravating factor of epilepsy and anti-comitial therapy could interfere in sleep structure. Epilepsy prevalence in atypical Rett syndrome with severe clinical phenotype is higher than in classical Rett syndrome. However, RTT present a significant lifetime risk of epilepsy too. Sleep disturbances impact on child's development and patients' families and the evidence for its management is still limited. The aim of this review is to analyze pathophysiology, clinical features, the impact on other comorbidities and the management of sleep disorders in Rett syndrome and Rett-related syndrome.

Literature Cases Summarized Based on Their Polysomnographic Findings in Rett Syndrome

Rett syndrome (RTT) is a severe and rare neurodevelopmental disorder affecting mostly girls. In RTT, an impaired sleep pattern is a supportive criterion for the diagnosis, yet little is known regarding the sleep structure and sleep respiratory events. Aiming to delineate sleep by aggregating RTT case (series) data from published polysomnographic studies, seventy-four RTT cases were collected from eleven studies up until 6 February 2022 (PROSPERO: CRD 42020198099). We compared the polysomnographic data within RTT stratifications and to a typically developing population. MECP2 cases demonstrated shortened total sleep time (TST) with increased stage N3 and decreased REM sleep. In cases with CDKL5 mutations, TST was longer and they spent more time in stage N1 but less in stage N3 than those cases affected by MECP2 mutations and a typically developing population. Sleep-disordered breathing was confirmed by the abnormal apnea/hypopnea index of 11.92 ± 23.67/h TST in these aggregated cases. No association of sleep structure with chronological age was found. In RTT, the sleep macrostructure of MECP2 versus CDKL5 cases showed differences, particularly regarding sleep stage N3. A severe REM sleep propensity reduction was found. Aberrant sleep cycling, possibly characterized by a poor REM ‘on switch’ and preponderance in slow and high-voltage sleep, is proposed.

Multimodal Neuroimaging in Rett Syndrome With MECP2 Mutation

Rett syndrome (RTT) is a rare neurodevelopmental disorder characterized by severe cognitive, social, and physical impairments resulting from de novo mutations in the X-chromosomal methyl-CpG binding protein gene 2 (MECP2). While there is still no cure for RTT, exploring up-to date neurofunctional diagnostic markers, discovering new potential therapeutic targets, and searching for novel drug efficacy evaluation indicators are fundamental. Multiple neuroimaging studies on brain structure and function have been carried out in RTT-linked gene mutation carriers to unravel disease-specific imaging features and explore genotype-phenotype associations. Here, we reviewed the neuroimaging literature on this disorder. MRI morphologic studies have shown global atrophy of gray matter (GM) and white matter (WM) and regional variations in brain maturation. Diffusion tensor imaging (DTI) studies have demonstrated reduced fractional anisotropy (FA) in left peripheral WM areas, left major WM tracts, and cingulum bilaterally, and WM microstructural/network topology changes have been further found to be correlated with behavioral abnormalities in RTT. Cerebral blood perfusion imaging studies using single-photon emission CT (SPECT) or PET have evidenced a decreased global cerebral blood flow (CBF), particularly in prefrontal and temporoparietal areas, while magnetic resonance spectroscopy (MRS) and PET studies have contributed to unraveling metabolic alterations in patients with RTT. The results obtained from the available reports confirm that multimodal neuroimaging can provide new insights into a complex interplay between genes, neurotransmitter pathway abnormalities, disease-related behaviors, and clinical severity. However, common limitations related to the available studies include small sample sizes and hypothesis-based and region-specific approaches. We, therefore, conclude that this field is still in its early development phase and that multimodal/multisequence studies with improved post-processing technologies as well as combined PET–MRI approaches are urgently needed to further explore RTT brain alterations.

Evaluating Sleep Disturbances in Children With Rare Genetic Neurodevelopmental Syndromes

BACKGROUND

Adequate sleep is important for proper neurodevelopment and positive health outcomes. Sleep disturbances are more prevalent in children with genetically determined neurodevelopmental syndromes compared with typically developing counterparts. We characterize sleep behavior in Rett (RTT), Angelman (AS), and Prader-Willi (PWS) syndromes to identify effective approaches for treating sleep problems in these populations. We compared sleep-related symptoms across individuals with these different syndromes with each other, and with typically developing controls.

METHODS

Children were recruited from the Rare Diseases Clinical Research Network consortium registries; unaffected siblings were enrolled as related controls. For each participant, a parent completed multiple sleep questionnaires including Pediatric Sleep Questionnaire (Sleep-Disordered Breathing), Children's Sleep Habits Questionnaire (CSHQ), and Pediatric Daytime Sleepiness Scale.

RESULTS

Sleep data were analyzed from 714 participants, aged two to 18 years. Young children with AS had more reported sleep problems than children with RTT or PWS. Older children with RTT had more reported daytime sleepiness than those with AS or PWS. Finally, all individuals with RTT had more evidence of sleep-disordered breathing when compared with individuals with PWS. Notably, typically developing siblings were also reported to have sleep problems, except for sleep-related breathing disturbances, which were associated with each of the genetic syndromes.

CONCLUSIONS

Individuals with RTT, AS, and PWS frequently experience sleep problems, including sleep-disordered breathing. Screening for sleep problems in individuals with these and other neurogenetic disorders should be included in clinical assessment and managements. These data may also be useful in developing treatment strategies and in clinical trials.

Reviewing Evidence for the Relationship of EEG Abnormalities and RTT Phenotype Paralleled by Insights from Animal Studies

Rett syndrome (RTT) is a rare neurodevelopmental disorder that is usually caused by mutations of the MECP2 gene. Patients with RTT suffer from severe deficits in motor, perceptual and cognitive domains. Electroencephalogram (EEG) has provided useful information to clinicians and scientists, from the very first descriptions of RTT, and yet no reliable neurophysiological biomarkers related to the pathophysiology of the disorder or symptom severity have been identified to date. To identify consistently observed and potentially informative EEG characteristics of RTT pathophysiology, and ascertain areas most worthy of further systematic investigation, here we review the literature for EEG abnormalities reported in patients with RTT and in its disease models. While pointing to some promising potential EEG biomarkers of RTT, our review identify areas of need to realize the potential of EEG including (1) quantitative investigation of promising clinical-EEG observations in RTT, e.g., shift of mu rhythm frequency and EEG during sleep; (2) closer alignment of approaches between patients with RTT and its animal models to strengthen the translational significance of the work (e.g., EEG measurements and behavioral states); (3) establishment of large-scale consortium research, to provide adequate Ns to investigate age and genotype effects.

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.

Protective role of mirtazapine in adult female Mecp2+/- mice and patients with Rett syndrome

BACKGROUND

Rett syndrome (RTT), an X-linked neurodevelopmental rare disease mainly caused by MECP2-gene mutations, is a prototypic intellectual disability disorder. Reversibility of RTT-like phenotypes in an adult mouse model lacking the Mecp2-gene has given hope of treating the disease at any age. However, adult RTT patients still urge for new treatments. Given the relationship between RTT and monoamine deficiency, we investigated mirtazapine (MTZ), a noradrenergic and specific-serotonergic antidepressant, as a potential treatment.

METHODS

Adult heterozygous-Mecp2 (HET) female mice (6-months old) were treated for 30 days with 10 mg/kg MTZ and assessed for general health, motor skills, motor learning, and anxiety. Motor cortex, somatosensory cortex, and amygdala were analyzed for parvalbumin expression. Eighty RTT adult female patients harboring a pathogenic MECP2 mutation were randomly assigned to treatment to MTZ for insomnia and mood disorders (mean age = 23.1 ± 7.5 years, range = 16-47 years; mean MTZ-treatment duration = 1.64 ± 1.0 years, range = 0.08-5.0 years). Rett clinical severity scale (RCSS) and motor behavior assessment scale (MBAS) were retrospectively analyzed.

RESULTS

In HET mice, MTZ preserved motor learning from deterioration and normalized parvalbumin levels in the primary motor cortex. Moreover, MTZ rescued the aberrant open-arm preference behavior observed in HET mice in the elevated plus-maze (EPM) and normalized parvalbumin expression in the barrel cortex. Since whisker clipping also abolished the EPM-related phenotype, we propose it is due to sensory hypersensitivity. In patients, MTZ slowed disease progression or induced significant improvements for 10/16 MBAS-items of the M1 social behavior area: 4/7 items of the M2 oro-facial/respiratory area and 8/14 items of the M3 motor/physical signs area.

CONCLUSIONS

This study provides the first evidence that long-term treatment of adult female heterozygous Mecp2^tm1.1Bird mice and adult Rett patients with the antidepressant mirtazapine is well tolerated and that it protects from disease progression and improves motor, sensory, and behavioral symptoms.

Sleep problems in Rett syndrome animal models: A systematic review

Due to the discovery of Rett Syndrome (RTT) genetic mutations, animal models have been developed. Sleep research in RTT animal models may unravel novel neural mechanisms for this severe neurodevelopmental heritable rare disease. In this systematic literature review we summarize the findings on sleep research of 13 studies in animal models of RTT. We found disturbed efficacy and continuity of sleep in all genetically mutated models of mice, cynomolgus monkeys, and Drosophila. Models presented highly fragmented sleep with distinct differences in 24-hr sleep/wake cyclicity and circadian arrhythmicity. Overall, animal models mimic sleep complaints reported in individuals with RTT. However, contrary to human studies, in mutant mice, attenuated sleep delta waves, and sleep apneas in non-rapid eye movement sleep were reported. Future studies may focus on sleep structure and EEG alterations, potential central mechanisms involved in sleep fragmentation and the occurrence of sleep apnea across different sleep stages. Given that locomotor dysfunction is characteristic of individuals with RTT, studies may consider to integrate its potential impact on the behavioral analysis of sleep.

Neurochemistry of the Kölliker-Fuse nucleus from a respiratory perspective

The Kölliker-Fuse nucleus (KF) is a functionally distinct component of the parabrachial complex, located in the dorsolateral pons of mammals. The KF has a major role in respiration and upper airway control. A comprehensive understanding of the KF and its contributions to respiratory function and dysfunction requires an appreciation for its neurochemical characteristics. The goal of this review is to summarize the diverse neurochemical composition of the KF, focusing on the neurotransmitters, neuromodulators, and neuropeptides present. We also include a description of the receptors expressed on KF neurons and transporters involved in each system, as well as their putative roles in respiratory physiology. Finally, we provide a short section reviewing the literature regarding neurochemical changes in the KF in the context of respiratory dysfunction observed in SIDS and Rett syndrome. By over-viewing the current literature on the neurochemical composition of the KF, this review will serve to aid a wide range of topics in the future research into the neural control of respiration in health and disease.

Sleep-Disordered Breathing in Pediatric Patients With Rett Syndrome

STUDY OBJECTIVES

Although respiratory abnormalities occurring during wakefulness are well recognized in patients with Rett syndrome (RS), less has been reported regarding sleep-disordered breathing (SDB) in this population. This study aims to characterize the presenting complaints, types and severity of SDB, and treatment modalities of patients with RS and sleep concerns.

METHODS

Retrospective chart review of pediatric patients with RS referred to our academic tertiary care institution from January 2007 to July 2017.

RESULTS

Thirteen patients were identified, 11 female (84.6%); mean age at polysomnography (PSG) was 10.3 years (standard deviation 4.94). Eleven were white (84.6%), 2 were black (15.4%). The most common presenting symptoms were snoring (10/13, 77%) and witnessed apnea (7/13, 53.8%). On baseline PSG, all patients (100%) exhibited hyperapneas followed by a central apnea during wake. Nine (69.2%) had obstructive sleep apnea (OSA) (obstructive apnea-hypopnea index (oAHI) > 1); four had severe OSA (oAHI ≥ 10). One had central sleep apnea (central apnea index > 5) and severe OSA. No patients exhibited hypoventilation on baseline PSG. Mean AHI of all patients was 8.77 ± 8.82 (oAHI 6.51 ± 6.91) events/h. Mean oxyhemoglobin nadir was 88.52 ± 5.6%. Treatment modalities included observation: 5 (38%), acetazolamide: 2 (15%), nasal mometasone: 1 (7.7%), adenotonsillectomy: 3 (23.1%), and positive airway pressure: 2 (15%).

CONCLUSIONS

Regarding patients with RS referred to the sleep medicine clinic, snoring and witnessed apneas were the most common presenting complaints. In addition to breathing abnormalities during wake, OSA was very common in our cohort. Further studies are needed to examine the pathogenesis of OSA in RS and relationships between disease genotype and respiratory abnormality phenotype.

Polysomnographic findings in Rett syndrome

INTRODUCTION

Rett syndrome (RS) is a severe neurodevelopment disorder associated with abnormal breathing during wakefulness and disturbed nocturnal behaviour. Breathing abnormalities during daytime have been extensively reported but polysomnographic (PSG) findings have been poorly studied.

MATERIALS AND METHODS

Consecutive patients with RS carrying distinct mutations in MECP2 gene, who underwent a PSG between October 2014 and January 2018, were included in the study. Clinical and PSG data were collected.

RESULTS

Seventeen RS girls, mean age 9.5 ± 2.8 years, were included in the study. Mean total sleep time was 366 ± 102 min. Mean sleep efficiency was reduced (66 ± 19%) with only 3 girls presenting a sleep efficiency above 80%. Wake after sleep onset was increased (33 ± 20%) with an arousal index of 7 ± 6 events/hour. Sleep stages were altered with a normal N1 (2 ± 3%), a decreased N2 (34 ± 20%), an increase of N3 (51 ± 23%) and a decrease of REM sleep (12 ± 9%). Mean apnea hypopnea index (AHI) was increased at 19 ± 37 events/hour, with a predominance of obstructive events. Thirteen patients had an AHI > 1.5 event/hour. Four patients had an obstructive AHI >10 events/hour with one patient having associated tonsillar hypertrophy. Two patients had predominant severe central apneas (central AHI 53 and 132 events/hour) which resolved with noninvasive ventilation and nocturnal oxygen therapy respectively.

CONCLUSION

Girls with RS have poor sleep quality with alterations in slow wave and REM sleep stages. Obstructive respiratory events are uncommon in patients without adenotonsillar hypertrophy. Central respiratory events are rare. Longitudinal studies should help understanding the natural history of sleep disturbances in RS and their relationship with the neurocognitive decline.

Sleep disturbances in Rett syndrome: Impact and management including use of sleep hygiene practices

Sleep disturbances are debilitating for individuals with Rett syndrome (RTT) and their families yet the evidence base for management is poor. We investigated management strategies and their relationships with sleep problems. Data were provided by 364/461 (79%) families with a child with RTT and registered with the International RTT Phenotype Database. Logistic regression models were used to investigate relationships between impacts of sleep problems on the child and family with age group, mutation type, medication type, and sleep hygiene score. Linear regression models were used to estimate the association of disorders of initiating and maintaining sleep (DIMS) with age group, mutation type, medication type, and sleep hygiene. Among those who ever had difficulty falling asleep or night waking, use of any medication was associated with higher odds of moderate/major impact sleep problems (relative to minor/no impact) for the affected child and the family, as well as higher DIMS scores, when compared with the no treatment/nonmedication group accounting for the effects of age, mutation type, and sleep hygiene score. Better use of sleep hygiene practices was associated with lower odds of moderate/major impact on the family (odds ratio 0.60, 95% confidence intervals [CIs] 0.37, 0.98) and lower DIMS scores (geometric mean ratio 0.86, 95%CI 0.80, 0.92) compared with poorer use after adjusting for covariates. Attention to sleep hygiene remains an important management strategy for sleep problems in RTT. Further prospective research is required to investigate efficacy of pharmaceutical treatments.

The feasibility of using actigraphy to characterize sleep in Rett syndrome

BACKGROUND

Rett syndrome (RTT) is a neurodevelopmental disorder primarily caused by mutations in the MECP2 gene. Sleep problems are reported by the majority of caregivers of individuals with RTT.

METHODS

The present study aimed to replicate and extend previous work about the feasibility of measuring sleep with an actigraph device in a sample of girls with clinically diagnosed RTT (N = 13, mean age = 9 years, 5 months). Participants wore an actigraph device day and night for seven consecutive days. Materials also included a parent-completed sleep diary to measure bedtime, duration of nighttime sleep, and daytime sleep, and the Child Sleep Habit's Questionnaire (CSHQ).

RESULTS

The means for the sample as measured by actigraphy were 492.3 min (SD = 47.3) of total night sleep (TNS), 76.0% (SD = 6.7) sleep efficiency, 86.0 min (SD = 34.2) of wake after sleep onset, and 46.1 min (50.8) of sleep when parents reported a nap occurring. Parents reported 589.7 min (SD = 53.6) of TNS, 15.9 min (SD = 12.0) of WASO, and 93.6 min (SD = 66.8) of daytime sleep according to sleep diaries, with all parents reporting at least one nap during the week. Relations were found between sleep characteristics and seizure status and CSHQ total scores. No age-related changes were observed for any sleep characteristic, regardless of collection method. Five of nine participants above the cutoff score on the CSHQ indicate the need for further evaluation for a sleep disorder.

CONCLUSIONS

Overall, actigraphy was feasible in this community-based sample of girls with RTT. The results replicated some aspects of previous studies of sleep in RTT (e.g., no age-related changes in total nighttime sleep or efficiency). Some participants met the American Academy of Sleep Medicine guidelines for recommended total sleep time, with others showing too much or too little sleep. Each of the three methods for describing sleep presented its own advantages and challenges. Future work should be prospectively designed, validate the use of actigraphy in this population, and include a typically developing comparison sample to improve the precision of our understanding of sleep in RTT.

Visual-spatial training efficacy in children affected by migraine without aura: a multicenter study

Routinely in the clinical practice, children affected by migraine without aura (MwA) tend to exhibit severe and persistent difficulties within cognitive processes such as attention, memory, and visual-motor integration (VMI) skills. The aim of this study was to assess the visual-spatial and visual-motor abilities among a sample of children with MwA and the effects of a specific computerized training. The study population was composed of 84 patients affected by MwA (39 girls and 45 boys; mean age: 8.91±2.46 years), and they were randomly divided into two groups (group A and group B) comparable for age (P=0.581), gender (P=0.826), socioeconomic status (SES), migraine frequency (P=0.415), and intensity (P=0.323). At baseline (T0), the two groups were comparable for movement assessment battery for children (M-ABC) and VMI performances. After 6 months of treatment (T1), group A showed lower scores in the dexterity item of M-ABC test (P<0.001) and higher scores in M-ABC global performance centile (P<0.001) and total (P<0.001), visual (P=0.017), and motor (P<0.001) tasks of VMI test than group B. Moreover, at T1, group A showed higher scores in total (P<0.001) and motor (P<0.001) tasks of VMI test and in M-ABC global performance centile (P<0.001) and lower scores in the dexterity item of M-ABC test (P<0.001) than at T0. Group B showed, at T1, performances comparable to T0 for all evaluations. As reported by recent studies about alteration MwA among children in motor abilities, our study confirmed these difficulties and the efficacy of a specific software training, suggesting a new rehabilitative proposal in childhood.

Annual Research Review: Sleep problems in childhood psychiatric disorders--a review of the latest science

BACKGROUND

Hippocrates flagged the value of sleep for good health. Nonetheless, historically, researchers with an interest in developmental psychopathology have largely ignored a possible role for atypical sleep. Recently, however, there has been a surge of interest in this area, perhaps reflecting increased evidence that disturbed or insufficient sleep can result in poor functioning in numerous domains. This review outlines what is known about sleep in the psychiatric diagnoses most relevant to children and for which associations with sleep are beginning to be understood. While based on a comprehensive survey of the literature, the focus of the current review is on the latest science (largely from 2010). There is a description of both concurrent and longitudinal links as well as possible mechanisms underlying associations. Preliminary treatment research is also considered which suggests that treating sleep difficulties may result in improvements in behavioural areas beyond sleep quality.

FINDINGS

To maximise progress in this field, there now needs to be: (a) greater attention to the assessment of sleep in children; (b) sleep research on a wider range of psychiatric disorders; (c) a greater focus on and examination of mechanisms underlying associations; (d) a clearer consideration of developmental questions and (e) large-scale well-designed treatment studies.

CONCLUSIONS

While sleep problems may sometimes be missed by parents and healthcare providers; hence constituting a hidden risk for other psychopathologies - knowing about these difficulties creates unique opportunities. The current excitement in this field from experts in diverse areas including developmental psychology, clinical psychology, genetics and neuropsychology should make these opportunities a reality.

Deficiency of GABAergic synaptic inhibition in the Kölliker-Fuse area underlies respiratory dysrhythmia in a mouse model of Rett syndrome

KEY POINTS

Life threatening breathing irregularity and central apnoeas are highly prevalent in children suffering from Rett syndrome. Abnormalities in inhibitory synaptic transmission have been associated with the physiopathology of this syndrome, and may underlie the respiratory disorder. In a mouse model of Rett syndrome, GABAergic terminal projections are markedly reduced in the Kölliker-Fuse nucleus (KF) in the dorsolateral pons, an important centre for control of respiratory rhythm regularity. Administration of a drug that augments endogenous GABA localized to this region of the pons reduced the incidence of apnoea and the respiratory irregularity of Rett female mice. Conversely, the respiratory disorder was recapitulated by blocking GABAergic transmission in the KF area of healthy rats. This study helps us understand the mechanism for generation of respiratory abnormality in Rett syndrome, pinpoints a brain site responsible and provides a clear anatomical target for the development of a translatable drug treatment. Central apnoeas and respiratory irregularity are a common feature in Rett syndrome (RTT), a neurodevelopmental disorder most often caused by mutations in the methyl-CpG-binding protein 2 gene (MECP2). We used a MECP2 deficient mouse model of RTT as a strategy to obtain insights into the neurobiology of the disease and into mechanisms essential for respiratory rhythmicity during normal breathing. Previously, we showed that, systemic administration of a GABA reuptake blocker in MECP2 deficient mice markedly reduced the occurrence of central apnoeas. Further, we found that, during central apnoeas, post-inspiratory drive (adductor motor) to the upper airways was enhanced in amplitude and duration in Mecp2 heterozygous female mice. Since the pontine Kölliker-Fuse area (KF) drives post-inspiration, suppresses inspiration, and can reset the respiratory oscillator phase, we hypothesized that synaptic inhibition in this area is essential for respiratory rhythm regularity. In this study, we found that: (i) Mecp2 heterozygous mice showed deficiency of GABA perisomatic bouton-like puncta and processes in the KF nucleus; (ii) blockade of GABA reuptake in the KF of RTT mice reduced breathing irregularity; (iii) conversely, blockade of GABAA receptors in the KF of healthy rats mimicked the RTT respiratory phenotype of recurrent central apnoeas and prolonged post-inspiratory activity. Our results show that reductions in synaptic inhibition within the KF induce rhythm irregularity whereas boosting GABA transmission reduces respiratory arrhythmia in a murine model of RTT. Our data suggest that manipulation of synaptic inhibition in KF may be a clinically important strategy for alleviating the life threatening respiratory disorders in RTT.

Heightened Delta Power during Slow-Wave-Sleep in Patients with Rett Syndrome Associated with Poor Sleep Efficiency

Sleep problems are commonly reported in Rett syndrome (RTT); however the electroencephalographic (EEG) biomarkers underlying sleep dysfunction are poorly understood. The aim of this study was to analyze the temporal evolution of quantitative EEG (qEEG) biomarkers in overnight EEGs recorded from girls (2-9 yrs. old) diagnosed with RTT using a non-traditional automated protocol. In this study, EEG spectral analysis identified high delta power cycles representing slow wave sleep (SWS) in 8-9h overnight sleep EEGs from the frontal, central and occipital leads (AP axis), comparing age-matched girls with and without RTT. Automated algorithms quantitated the area under the curve (AUC) within identified SWS cycles for each spectral frequency wave form. Both age-matched RTT and control EEGs showed similar increasing trends for recorded delta wave power in the EEG leads along the antero-posterior (AP). RTT EEGs had significantly fewer numbers of SWS sleep cycles; therefore, the overall time spent in SWS was also significantly lower in RTT. In contrast, the AUC for delta power within each SWS cycle was significantly heightened in RTT and remained heightened over consecutive cycles unlike control EEGs that showed an overnight decrement of delta power in consecutive cycles. Gamma wave power associated with these SWS cycles was similar to controls. However, the negative correlation of gamma power with age (r = -.59; p<0.01) detected in controls (2-5 yrs. vs. 6-9 yrs.) was lost in RTT. Poor % SWS (i.e., time spent in SWS overnight) in RTT was also driven by the younger age-group. Incidence of seizures in RTT was associated with significantly lower number of SWS cycles. Therefore, qEEG biomarkers of SWS in RTT evolved temporally and correlated significantly with clinical severity.

Impaired CO2 sensitivity of astrocytes in a mouse model of Rett syndrome

Rett syndrome, a prototypical neurological disorder caused by loss of function of the transcriptional regulator methyl-CpG-binding protein 2 (MeCP2) gene, is associated with a severely disordered breathing pattern and reduced ventilatory CO2 sensitivity. In a mouse model of Rett syndrome (MeCP2 knockout), re-introduction of the MeCP2 gene selectively in astrocytes rescues normal respiratory phenotype. In the present study we determined whether the metabolic and/or signalling functions of astrocytes are affected by testing the hypotheses that in conditions of MeCP2 deficiency, medullary astrocytes are unable to produce/release appropriate amounts of lactate or detect changes in PCO2/[H(+) ], or both. No differences in tonic or hypoxia-induced release of lactate from the ventral surface of the medulla oblongata or cerebral cortex in brain slices of MeCP2-knockout and wild-type mice were found. In brainstem slices of wild-type mice, respiratory acidosis triggered robust elevations in [Ca(2+) ]i in astrocytes residing near the ventral surface of the medulla oblongata. The magnitude of CO2 -induced [Ca(2+) ]i responses in medullary astrocytes was markedly reduced in conditions of MeCP2 deficiency, whereas [Ca(2+) ]i responses to ATP were unaffected. These data suggest that (i) metabolic function of astrocytes in releasing lactate into the extracellular space is not affected by MeCP2 deficiency, and (ii) MeCP2 deficiency impairs the ability of medullary astrocytes to sense changes in PCO2/[H(+) ]. Taken together with the evidence of severely blunted ventilatory sensitivity to CO2 in mice with conditional MeCP2 deletion in astroglia, these data support the hypothesis of an important role played by astrocytes in central respiratory CO2 /pH chemosensitivity.

Circadian rhythm disruption in a mouse model of Rett syndrome circadian disruption in RTT

Disturbances in the sleep/wake cycle are prevalent in patients with Rett syndrome (RTT). We sought to determine whether the circadian system is disrupted in a RTT model, Mecp2(-/y) mice. We found that MeCP2 mutants showed decreased strength and precision of daily rhythms of activity coupled with extremely fragmented sleep. The central circadian clock (suprachiasmatic nucleus) exhibited significant reduction in the number of neurons expressing vasoactive intestinal peptide (VIP) as well as compromised spontaneous neural activity. The molecular clockwork was disrupted both centrally in the SCN and in peripheral organs, indicating a general disorganization of the circadian system. Disruption of the molecular clockwork was observed in fibroblasts of RTT patients. Finally, MeCP2 mutant mice were vulnerable to circadian disruption as chronic jet lag accelerated mortality. Our finds suggest an integral role of MeCP2 in the circadian timing system and provides a possible mechanistic explanation for the sleep/wake distrubances observed in RTT patients. The work raises the possibility that RTT patients may benefit from a temporally structured environment.

Why do seizures occur when they do? Situations perceived to be associated with increased or decreased seizure likelihood in people with epilepsy and intellectual disability

Seizure precipitants are commonly reported in the general population of people with epilepsy. However, there has been little research in this area in people with epilepsy and intellectual disability (ID). We conducted a survey of the situations associated with increased or decreased seizure likelihood in this population. The aim of the research was to identify situations of increased seizure likelihood (SISLs) and situations of decreased seizure likelihood (SDSLs) reported by carers of people with an ID and epilepsy. Three study groups were investigated: two groups comprising individuals with ID associated with a specific genetic diagnosis - Rett syndrome or fragile X syndrome - and one group consisting of individuals with a range of other etiologies. Responses relating to 100 people were received: 44 relating to people with Rett syndrome, 25 to people with fragile X syndrome, and 31 to people whose ID had some other etiologies. Ninety-eight percent of the respondents reported at least one SISL, and 60% reported at least one SDSL. Having more seizure types and greater seizure frequency were associated with a higher number of SISLs reported. The most commonly reported SISLs and SDSLs for each of the three groups are presented. The most common SISL overall was illness, which was reported as an SISL by 71% of the respondents. There was less consensus with regard to SDSLs. These findings provide a greater understanding of when seizures occur in those with ID and epilepsy, with possible implications for adjunctive behavioral management of seizures in those with treatment-refractory epilepsy.

Alterations in the cholinergic system of brain stem neurons in a mouse model of Rett syndrome

Rett syndrome is an autism-spectrum disorder resulting from mutations to the X-linked gene, methyl-CpG binding protein 2 (MeCP2), which causes abnormalities in many systems. It is possible that the body may develop certain compensatory mechanisms to alleviate the abnormalities. The norepinephrine system originating mainly in the locus coeruleus (LC) is defective in Rett syndrome and Mecp2-null mice. LC neurons are subject to modulation by GABA, glutamate, and acetylcholine (ACh), providing an ideal system to test the compensatory hypothesis. Here we show evidence for potential compensatory modulation of LC neurons by post- and presynaptic ACh inputs. We found that the postsynaptic currents of nicotinic ACh receptors (nAChR) were smaller in amplitude and longer in decay time in the Mecp2-null mice than in the wild type. Single-cell PCR analysis showed a decrease in the expression of α3-, α4-, α7-, and β3-subunits and an increase in the α5- and α6-subunits in the mutant mice. The α5-subunit was present in many of the LC neurons with slow-decay nAChR currents. The nicotinic modulation of spontaneous GABAA-ergic inhibitory postsynaptic currents in LC neurons was enhanced in Mecp2-null mice. In contrast, the nAChR manipulation of glutamatergic input to LC neurons was unaffected in both groups of mice. Our current-clamp studies showed that the modulation of LC neurons by ACh input was reduced moderately in Mecp2-null mice, despite the major decrease in nAChR currents, suggesting possible compensatory processes may take place, thus reducing the defects to a lesser extent in LC neurons.

Sleep alterations in children with refractory epileptic encephalopathies: a polysomnographic study

Data on the relationship between sleep disturbances and refractory epileptic encephalopathies (EEs) are scarce. Our aim was to assess, by means of nocturnal polysomnography, if children with EEs present with objective alterations in sleep organization. Twenty-three children with EEs (12 males; mean age: 8.7±1.4years) and 40 healthy controls (22 males; mean age: 8.8±1.1years) underwent an overnight full polysomnography (PSG). Relative to controls, children with EEs showed a significant reduction in all PSG parameters related to sleep duration time in bed (TIB-min p<0.001), total sleep time (TST-min p<0.001), and sleep percentage (SPT-min p<0.001), as well as significantly higher REM latency (FRL-min p<0.001), rate in stage shifting (p=0.005), and number of awakenings/hour (p=0.002). Relative to controls, children with EEs also showed significant differences in respiratory parameters (AHI/h p<0.001, ODI/h p<0.001, SpO2% p<0.001, SpO2 nadir% p<0.001) and a higher rate of periodic limb movements (PLMs% p<0.001). Our findings suggest that sleep evaluation could be considered mandatory in children with refractory epileptic encephalopathy in order to improve the clinical management and the therapeutic strategies.

Pinpointing brainstem mechanisms responsible for autonomic dysfunction in Rett syndrome: therapeutic perspectives for 5-HT1A agonists

Rett syndrome is a neurological disorder caused by loss of function of methyl-CpG-binding protein 2 (MeCP2). Reduced function of this ubiquitous transcriptional regulator has a devastating effect on the central nervous system. One of the most severe and life-threatening presentations of this syndrome is brainstem dysfunction, which results in autonomic disturbances such as breathing deficits, typified by episodes of breathing cessation intercalated with episodes of hyperventilation or irregular breathing. Defects in numerous neurotransmitter systems have been observed in Rett syndrome both in animal models and patients. Here we dedicate special attention to serotonin due to its role in promoting regular breathing, increasing vagal tone, regulating mood, alleviating Parkinsonian-like symptoms and potential for therapeutic translation. A promising new symptomatic strategy currently focuses on regulation of serotonergic function using highly selective serotonin type 1A (5-HT_1A) “biased agonists.” We address this newly emerging therapy for respiratory brainstem dysfunction and challenges for translation with a holistic perspective of Rett syndrome, considering potential mood and motor effects.

Intellectual disabilities and power spectra analysis during sleep: a new perspective on borderline intellectual functioning

BACKGROUND

The role of sleep in cognitive processes has been confirmed by a growing number of reports for all ages of life. Analysing sleep electroencephalogram (EEG) spectra may be useful to study cortical organisation in individuals with Borderline Intellectual Functioning (BIF), as seen in other disturbances even if it is not considered a disease. The aim of this study was to determine if the sleep EEG power spectra in children with BIF could be different from typically developing children.

METHODS

Eighteen BIF (12 males) (mean age 11.04; SD ± 1.07) and 24 typical developing children (14 men) (mean age 10.98; SD ± 1.76; P = 0.899) underwent an overnight polysomnography (PSG) recording in the Sleep Laboratory of the Clinic of Child and Adolescent Neuropsychiatry, after one adaptation night. Sleep was subdivided into 30-s epochs and sleep stages were scored according to the standard criteria and the power spectra were calculated for the Cz-A2 channel using the sleep analysis software Hypnolab 1.2 (SWS Soft, Italy) by means of the Fast Fourier Transform and the power spectrum was calculated for frequencies between 0.5 and 60 Hz with a frequency step of 1 Hz and then averaged across the following bands delta (0.5-4 Hz), theta (5-7 Hz), alpha (8-11 Hz), sigma (11-15 Hz), and beta (16-30 Hz), gamma (30-60 Hz) for S2, SWS and REM (Rapid Eye Movement) sleep stages.

RESULTS

BIF have a reduced sleep duration (total sleep time; P < 0.001), and an increased rate of stage shifts (P < 0.001) and awakenings (P < 0.001) and WASO (wakefulness after sleep onset) % (P < 0.001); the stage 2% (P < 0.001), and REM% (P < 0.001) were lower and slow-wave sleep percentage was slightly higher (P < 0.001). All children with BIF had an AHI (apnoea-hypopnea index) less than 1 (mean AHI = 0.691 ± 0.236) with a mean oxygen saturation of 97.6% and a periodic leg movement index (PLMI) less than 5 (mean PLMI = 2.94 ± 1.56). All sleep stages had a significant reduction in gamma frequency (30-60 Hz) (P < 0.001) and an increased delta frequency (0.5-4.0 Hz) (P < 0.001) power in BIF subjects compared with typically developing children.

CONCLUSION

Our findings shed light on the importance of sleep for cognition processes particularly in cognitive borderline dysfunction and the role of EEG spectral power analysis to recognize sleep characteristics in BIF children.

Orthodontic treatment need for adolescents in the Campania region: the malocclusion impact on self-concept

BACKGROUND

Dental malocclusions can be considered not only as an oral health problem, because they are linked to quality of life perception. Many factors related to malocclusion have strong influences on the perception of facial esthetics (eg, anterior tooth alignment, tooth shape and position, lip thickness, symmetric gingival or tooth contour, lip profile, and overjet). Many reports have shown that the perception of facial esthetics can influence psychological development from early childhood to adulthood. The aim of this study is to investigate the effect of dental malocclusion on self-esteem in a sample of adolescents.

MATERIALS AND METHODS

The study population was composed of 516 orthodontically untreated subjects (256 males) mean ages 13.75±1.977 years recruited from schools in the Campania region of Italy between January 2011 and July 2011. To evaluate the self-esteem grade in our population, all subjects filled out the Multidimensional Self Concept Scale questionnaire and attended an orthodontic clinical evaluation to estimate dental occlusal aspects.

RESULTS

Pearson's analysis shows the relationship in our sample between some occlusal characteristics (crossbite and dental crowding) and aspects of self-concept evaluation (social, competence, academic, physical, and global score) of the Multidimensional Self Concept Scale questionnaire. Moreover, logistic regression analysis shows the potential role of dental crowding (odds ratio 5.359; 95% confidence interval 3.492-8.225) and crossbite (odds ratio 6.153; 95% confidence interval 3.545-10.678) as risk factors for development of global self-concept score abnormalities.

CONCLUSION

Our findings confirm the relationship between psychosocial well-being, self-esteem, and dental malocclusion among adolescents.

Inflammatory lung disease in Rett syndrome

Rett syndrome (RTT) is a pervasive neurodevelopmental disorder mainly linked to mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Respiratory dysfunction, historically credited to brainstem immaturity, represents a major challenge in RTT. Our aim was to characterize the relationships between pulmonary gas exchange abnormality (GEA), upper airway obstruction, and redox status in patients with typical RTT (n = 228) and to examine lung histology in a Mecp2-null mouse model of the disease. GEA was detectable in ~80% (184/228) of patients versus ~18% of healthy controls, with “high” (39.8%) and “low” (34.8%) patterns dominating over “mixed” (19.6%) and “simple mismatch” (5.9%) types. Increased plasma levels of non-protein-bound iron (NPBI), F₂-isoprostanes (F₂-IsoPs), intraerythrocyte NPBI (IE-NPBI), and reduced and oxidized glutathione (i.e., GSH and GSSG) were evidenced in RTT with consequently decreased GSH/GSSG ratios. Apnea frequency/severity was positively correlated with IE-NPBI, F₂-IsoPs, and GSSG and negatively with GSH/GSSG ratio. A diffuse inflammatory infiltrate of the terminal bronchioles and alveoli was evidenced in half of the examined Mecp2-mutant mice, well fitting with the radiological findings previously observed in RTT patients. Our findings indicate that GEA is a key feature of RTT and that terminal bronchioles are a likely major target of the disease.

Sleep, plasticity and the pathophysiology of neurodevelopmental disorders: the potential roles of protein synthesis and other cellular processes

Sleep is important for neural plasticity, and plasticity underlies sleep-dependent memory consolidation. It is widely appreciated that protein synthesis plays an essential role in neural plasticity. Studies of sleep-dependent memory and sleep-dependent plasticity have begun to examine alterations in these functions in populations with neurological and psychiatric disorders. Such an approach acknowledges that disordered sleep may have functional consequences during wakefulness. Although neurodevelopmental disorders are not considered to be sleep disorders per se, recent data has revealed that sleep abnormalities are among the most prevalent and common symptoms and may contribute to the progression of these disorders. The main goal of this review is to highlight the role of disordered sleep in the pathology of neurodevelopmental disorders and to examine some potential mechanisms by which sleep-dependent plasticity may be altered. We will also briefly attempt to extend the same logic to the other end of the developmental spectrum and describe a potential role of disordered sleep in the pathology of neurodegenerative diseases. We conclude by discussing ongoing studies that might provide a more integrative approach to the study of sleep, plasticity, and neurodevelopmental disorders.

Quantification of functional abilities in Rett syndrome: a comparison between stages III and IV

We aimed to evaluate the functional abilities of persons with Rett syndrome (RTT) in stages III and IV. The group consisted of 60 females who had been diagnosed with RTT: 38 in stage III, mean age (years) of 9.14, with a standard deviation of 5.84 (minimum 2.2/maximum 26.4); and 22 in stage IV, mean age of 12.45, with a standard deviation of 6.17 (minimum 5.3/maximum 26.9). The evaluation was made using the Pediatric Evaluation of Disability Inventory, which has 197 items in the areas of self-care, mobility, and social function. The results showed that in the area of self-care, stage III and stage IV RTT persons had a level of 24.12 and 18.36 (P=0.002), respectively. In the area of mobility, stage III had 37.22 and stage IV had 14.64 (P<0.001), while in the area of social function, stage III had 17.72 and stage IV had 12.14 (P=0.016). In conclusion, although persons with stage III RTT have better functional abilities when compared with stage IV, the areas of mobility, self-care, and social function are quite affected, which shows a great functional dependency and need for help in basic activities of daily life.

Migraine and periodic limb movement disorders in sleep in children: a preliminary case-control study

BACKGROUND

The relationships between sleep and headaches are complex and manifold. About the variety of phenomena that can disrupt the sleep macrostructure and can impact its restorative function, the periodic limb movements disorder (PLMd) can be considered as the most powerful.No studies are known about the role of PLMd in the pathophysiology of migraine in children.Aim of study is to assess the prevalence of PLMd and migraine and their relationship with disability and pain intensity in a pediatric sample, referred for migraine without aura by pediatricians.

METHODS

After a preliminary sleep habits screening with the Sleep Disturbances Scale for Children, 34 migraine subjects affected by migraine without aura (20 M, 14 F) (mean age 9.08; SD ± 2.28) and 51 volunteers healthy children (28 M, 23 F) (mean age 9.37; SD ± 1.81) accepted to underwent overnight PSG recordings in the Sleep Laboratory of the Clinic of Child and Adolescent Neuropsychiatry, in order to define the macrostructural sleep characteristics and the prevalence of PLMd. Subsequently, the migraineurs sample was studied in order to define the relationship between disability, pain intensity, therapeutical responsiveness and the presence of PLMd.

RESULTS

In the migraineurs children group, the individuals with PLM pathological index (PLMI ≥ 5) represent the 26.47% of sample and present higher frequency (p < 0.001), intensity (p < 0.001), duration (p = 0.006) and life impairment as scored in the PedMIDAS (p < 0.001) of headache and lower efficacy of prophylactic (p = 0.001) and acute (p = 0.006) pharmacological treatment than MoA children without PLM pathological index.

CONCLUSIONS

This preliminary study indicates the potential value of the determination of the PLMd signs, and the importance of the PSG evaluation in children affected by migraine, particularly when the clinical and pharmacological management tend to fail in the attacks control.

Sturge-weber syndrome: a report of 14 cases

Sturge-Weber-Krabe syndrome (SWS), also known as encephalotrigeminalangiomatosis and named the forthfacomatosis, recall the names of the authors who first describedit in its basic clinical, radiological andanatomopathological aspects. We report here 14 cases of Sturge-Weber disease. In 6 of these, despite what had been previously described in literature, an extension of the angioma has been noted in other parts of the body. The study of these subjects stresses not only the need for a pharmacological/neuropsychomotor intervention, but alsothe need of a psychotherapeutic approach, for the emotional and affective implications thatcould derive from this syndrome. The reported cases are similar to those presented in literature for their main features. In particular, two elements are interesting: i) the exceptional diffusion of the red nevousto the whole hemicorpo; and ii) the evaluation of the way the patients live the disease, which has not beenpreviously considered in literature. We can conclude that SWS is a multisystem disorder that requires the neurologist to be aware of the possible endocrine, psychiatric, ophthalmological, and other medical issues that can arise and impact on the neurological status of the patients.

Acupressure therapy for insomnia in adolescents: a polysomnographic study

BACKGROUND

The purpose of this study was to assess the efficacy of acupressure therapy in a sample of adolescents with insomnia using a standard polysomnographic evaluation.

METHODS

For this study, 25 adolescents affected by psychophysiological insomnia (mean age 15.04 ± 1.18 years, 12 boys) were enrolled. A device known as the Sea-Band(®) was used by the patients in order to improve their symptoms related to difficulty in falling asleep. All subjects enrolled underwent two sets of consecutive overnight polysomnographic studies in the Sleep Laboratory of the Clinic of Child and Adolescent Neuropsychiatry, comprising two studies at baseline (before treatment) and another two studies at the end of 6 months of treatment.

RESULTS

At the end of 6 months of treatment, there was a significant increase in all macrostructural parameters of sleep duration, and a reduction in sleep onset latency, wake after sleep onset, and stage 2 sleep. Moreover, the study group showed a significant increase in percent sleep efficiency (P < 0.001) and in slow wave sleep representation.

CONCLUSION

Acupressure is a noninvasive, safe, and effective method for the management of insomnia in adolescents, with good compliance and no adverse effects.