Sleep Problems in Children With Agenesis of the Corpus Callosum

BMAL1 loss in oligodendroglia contributes to abnormal myelination and sleep

Myelination depends on the maintenance of oligodendrocytes that arise from oligodendrocyte precursor cells (OPCs). We show that OPC-specific proliferation, morphology, and BMAL1 are time-of-day dependent. Knockout of Bmal1 in mouse OPCs during development disrupts the expression of genes associated with circadian rhythms, proliferation, density, morphology, and migration, leading to changes in OPC dynamics in a spatiotemporal manner. Furthermore, these deficits translate into thinner myelin, dysregulated cognitive and motor functions, and sleep fragmentation. OPC-specific Bmal1 loss in adulthood does not alter OPC density at baseline but impairs the remyelination of a demyelinated lesion driven by changes in OPC morphology and migration. Lastly, we show that sleep fragmentation is associated with increased prevalence of the demyelinating disorder multiple sclerosis (MS), suggesting a link between MS and sleep that requires further investigation. These findings have broad mechanistic and therapeutic implications for brain disorders that include both myelin and sleep phenotypes.

Genetic heterogeneity in corpus callosum agenesis

The corpus callosum is the largest white matter structure connecting the two cerebral hemispheres. Agenesis of the corpus callosum (ACC), complete or partial, is one of the most common cerebral malformations in humans with a reported incidence ranging between 1.8 per 10,000 livebirths to 230–600 per 10,000 in children and its presence is associated with neurodevelopmental disability. ACC may occur as an isolated anomaly or as a component of a complex disorder, caused by genetic changes, teratogenic exposures or vascular factors. Genetic causes are complex and include complete or partial chromosomal anomalies, autosomal dominant, autosomal recessive or X-linked monogenic disorders, which can be either de novo or inherited. The extreme genetic heterogeneity, illustrated by the large number of syndromes associated with ACC, highlight the underlying complexity of corpus callosum development. ACC is associated with a wide spectrum of clinical manifestations ranging from asymptomatic to neonatal death. The most common features are epilepsy, motor impairment and intellectual disability. The understanding of the genetic heterogeneity of ACC may be essential for the diagnosis, developing early intervention strategies, and informed family planning. This review summarizes our current understanding of the genetic heterogeneity in ACC and discusses latest discoveries.

Nighttime Sleep Characteristics and White Matter Integrity in Young Adults

PURPOSE

Sleep is essential for life and plays a key role for optimal physiology, brain functioning, and health. Evidence suggests a relation between sleep and cerebral white matter integrity. Human studies report that sleep duration shows a U-shaped association with brain functioning. We hypothesized that participants with longer or shorter sleep time in the nighttime period show altered microstructural white matter integrity.

PARTICIPANTS AND METHODS

Seventy-three young adult participants were evaluated. Sleep-wake cycle parameters were assessed objectively using actigraphy. Diffusion tensor imaging studies were performed to assess white matter integrity using fractional anisotropy and mean, axial, and radial diffusivities. Relations between white matter microstructure indexes and sleep parameters were investigated through tract-based spatial statistics. Participants were grouped according to their nocturnal total sleep time: 27 in the Reference sleep group (6.5-8.0 h), 23 in the Short sleep group (<6.5 h) and 23 in the Long sleep group (>8.0 h).

RESULTS

Compared with the Reference sleep group, participants in the Long sleep group showed lower fractional anisotropy (p < 0.05) and higher radial diffusivity (p < 0.05) values in white matter tracts linked to sleep regulation (corona radiata, body of the corpus callosum, superior longitudinal fasciculus, and anterior thalamic radiation).

CONCLUSION

This pattern of reduced fractional anisotropy and increased radial diffusivity in the Long sleep group indicates an association between sleep duration and lower integrity of myelin sheaths. Because myelin is continuously remodeled in the brain, nighttime sleep characteristics appear to be a key player for its quality and maintenance.

Social-emotional, sleep and feeding problems in young patients with agenesis of the corpus callosum and the life quality of their parents

Agenesis of the corpus callosum (ACC) is a common congenital brain malformation. Most patients with no combined abnormalities have a good prognosis, but impairments have been observed in their sleep, feeding, and higher-order cognitive functions. Sixty-three Chinese ACC patients, aged 0-3 years, were included in our cross-sectional online research. The Chinese version of Infant-Toddler Social and Emotional Assessment (ITESA), the Brief Infant Sleep Questionnaire (BISQ), and the Montreal Children's Hospital Feeding Scale (MCH-FS) were used to assess these patients. We also used the brief version of the World Health Organization's Quality of Life Instrument (WHOQOL-BREF) to evaluate their parents. 43% of patients had ITESA domain problem: 10% in Externalizing, 7% in Internalizing, 3% in Dysregulation, and 30% in Competence. 52% of the patients were rated by their parents as having a sleep problem. Feeding difficulties occurred in 23% of patients. Patients' sleep and feeding problems were significantly correlated with their social and emotional performance, which influenced the life quality of their parents. Patients with intracranial abnormalities had more internalizing problems. In conclusion, sleep and feeding problems in young ACC patients might indicate their social-emotional problems. The problems in ACC patients were correlated with the life quality of their parents.

Sleep in Children with Congenital Malformations of the Central Nervous System

PURPOSE OF REVIEW

Congenital malformations of the central nervous system may be seen in isolation or in association with syndromes that have multiorgan involvement. Among the potential health challenges these children may face, sleep concerns are frequent and may include chronic insomnia, sleep-related breathing disorders, and circadian rhythm disorders.

RECENT FINDINGS

In this review, we describe recent research into sleep disorders affecting children with congenital malformations of the CNS including visual impairment, septo-optic dysplasia, agenesis of the corpus callosum, Aicardi syndrome, Chiari malformation, spina bifida, achondroplasia, Joubert syndrome, fetal alcohol spectrum disorders, and congenital Zika syndrome. In many cases, the sleep disturbance can be directly related to observed anatomical differences in the brain (such as in apnea due to Chiari malformation), but in most syndromes, a complete understanding of the underlying pathophysiology connecting the malformation with sleep problem is still being elucidated. Our review provides a synthesis of available evidence for clinicians who treat this patient population, in whom appropriate diagnosis and management of sleep problems may improve the quality of life for both patient and caregiver.

A Sleep Questionnaire for Children with Severe Psychomotor Impairment (SNAKE)-Concordance with a Global Rating of Sleep Quality

Sleep problems are a common and serious issue in children with life-limiting conditions (LLCs) and severe psychomotor impairment (SPMI). The “Sleep Questionnaire for Children with Severe Psychomotor Impairment” (Schlaffragebogen für Kinder mit Neurologischen und Anderen Komplexen Erkrankungen, SNAKE) was developed for this unique patient group. In a proxy rating, the SNAKE assesses five different dimensions of sleep(-associated) problems (disturbances going to sleep, disturbances remaining asleep, arousal and breathing disorders, daytime sleepiness, and daytime behavior disorders). It has been tested with respect to construct validity and some aspects of criterion validity. The present study examined whether the five SNAKE scales are consistent with parents’ or other caregivers’ global ratings of a child’s sleep quality. Data from a comprehensive dataset of children and adolescents with LLCs and SPMI were analyzed through correlation coefficients and Mann–Whitney U testing. The results confirmed the consistency of both sources of information. The highest levels of agreements with the global rating were achieved for disturbances in terms of going to sleep and disturbances with respect to remaining asleep. The results demonstrate that the scales and therefore the SNAKE itself is well-suited for gathering information on different sleep(-associated) problems in this vulnerable population.