Behavioral-state development and sleep-state differentiation during early ontogenesis

International audienceSleep is a key process in neurodevelopment and essential for the maturation of fundamental brain functions. Premature birth can disturb the initial steps of sleep maturation, which may contribute to the impairment of neurodevelopment. It is thus fundamental to understand the maturation of the various sleep states and the quality of cerebral function in each vigilance state, as well as the development of sleep cyclicity, in at-risk neonatal infants, particularly those born premature. The objective of this review is to provide a precise description of sleep states and cycles and their rhythmic organization in premature and term newborns according to their gestational age. Technical aspects of polysomnography, which requires a high level of expertise in neonates, are also described. Principles of the visual interpretation of polysomnography, including the simultaneous analysis of behavioral (spontaneous motricity and eye movements), polysomnographic parameters (electro-oculogram, electrocardiogram, respiration), and electroencephalography patterns are presented. The neurophysiology of sleep ontogenesis and its interaction with brain maturation are discussed, highlighting the crucial-role of sleep states and their duration in premature newborns. In particular, the involvement of myoclonic twitches in functional connectivity in sensorimotor development is discussed. Indeed, sleep quality, determined by combined polysomnographic parameters, reflects either normal or pathological developmental processes during the neonatal period. The fundamental place of neurophysiological explorations in the early detection of sleep disorders is discussed, as well as their potential consequences on neurodevelopmental care to improve the prevention of neurodevelopmental impairment. (C) 2020 Elsevier Masson SAS. All rights reserved

Normal EEG during the neonatal period: maturational aspects from premature to full-term newborns

International audienceElectroencephalography (EEG) is the reference tool for the analysis of brain function, reflecting normal and pathological neuronal network activity. During the neonatal period, EEG patterns evolve weekly, according to gestational age. The first analytical criteria for the various maturational stages and standardized neonatal EEG terminology were published by a group of French neurophysiologists training in Paris (France) in 1999. These criteria, defined from analog EEG, were completed in 2010 with digital EEG analysis. Since then, this work has continued, aided by the technical progress in EEG acquisition, the improvement of knowledge on the maturating processes of neuronal networks, and the evolution of critical care. In this review, we present an exhaustive and didactic overview of EEG characteristics from extremely premature to full-term infants. This update is based on the scientific literature, enhanced by the study of normal EEGs of extremely premature infants by our group of neurophysiologists. For educational purposes, particular attention has been paid to illustrations using new digital tools. (C) 2020 Elsevier Masson SAS. All rights reserved

Early onset Huntington disease: a neuronal degeneration syndrome.

Huntington disease (HD) is an autosomal dominant, lethal neurodegenerative disorder of the central nervous system, caused by an uncontrolled expansion of a CAG dynamic mutation in the coding region of the IT15gene. Although a majority of patients have a midlife onset of the disease, in a small number of patients the disease manifests before 20 years of age. In adults, HD is mainly characterised by involuntary movements, personality changes and dementia. By contrast, in children a dominant picture of bradykinesia, rigidity, dystonia and epileptic seizures is noticed. The earlier onset is often associated with a paternal transmission of the disease allele to the offspring. We report here a rather unusual infantile onset of the disease in a little girl who presented with a history of seizures and psychomotor regression starting at the age of 3 years. A progressive cortical-subcortical atrophy, progressive cerebellar atrophy and lesions in the basal ganglia were found on MRI. An important expansion, of 214 triplet numbers, of the CAG repeat size associated with HD, was observed.info:eu-repo/semantics/publishe

Reduction of seizure frequency after epilepsy surgery in a patient with STXBP1 encephalopathy and clinical description of six novel mutation carriers

Mutations in STXBP1 have been identified in a subset of patients with early onset epileptic encephalopathy (EE), but the full phenotypic spectrum remains to be delineated. Therefore, we screened a cohort of 160 patients with an unexplained EE, including patients with early myoclonic encephalopathy (EME), Ohtahara syndrome, West syndrome, nonsyndromic EE with onset in the first year, and Lennox-Gastaut syndrome (LGS). We found six de novo mutations in six patients presenting as Ohtahara syndrome (2/6, 33%), West syndrome (1/65, 2%), and nonsyndromic early onset EE (3/64, 5%). No mutations were found in LGS or EME. Only two of four mutation carriers with neonatal seizures had Ohtahara syndrome. Epileptic spasms were present in five of six patients. One patient with normal magnetic resonance imaging (MRI) but focal seizures underwent epilepsy surgery and seizure frequency dropped drastically. Neuropathology showed a focal cortical dysplasia type 1a. There is a need for additional neuropathologic studies to explore whether STXBP1 mutations can lead to structural brain abnormalities