Neurophysiological features of the nervous system in young children with epileptic encephalopathies according to video EEG monitoring

Epileptic encephalopathies (EE) are a group of childhood disorders in which epileptic seizures and epileptiform activity on the electroencephalogram (EEG) directly contribute to the development of serious cognitive and behavioral disorders. The "gold standard" for the diagnosis of EE are video EEG monitoring during night sleep. Aim - to analyze the neurophysiological features of the nervous system of children of early and preschool age with EE according to EEG monitoring data, to determine the typical characteristics of the EEG in children with different forms of EE, with the purpose of improving the diagnostics of these conditions and improving the interaction between specialists of multidisciplinary teams that provide assistance to children with EE. Materials and methods. The work was performed based on the results of the examination of 157 children of early and preschool age. The children were divided into groups, depending on the age of onset of epileptic seizures: Group I - 75 children with EE who made their debut before the age of 1 year; Group II - 44 children with EE who made their debut at the age of 1 to 3 years; III Group (comparison) - 38 children with epileptiform and developmental encephalopathies (ERE). The average age of examined children of the Group I was 16.3 months, the Group II - 18.5 months, the Group III - 19.7±1.7 months. Results. Posterior dominant rhythm (PDR) was registered only in a third (66.7%) of children of the Group I. In more than half (60.0%) children, PDR was represented by alpha-like activity in the form of unstable diffuse groups of theta waves. Thus, in most children with EE, there was a complete absence of ADHD (Group I) or manifestations of its delayed formation (Group II). Beta activity in children with EE was reduced in most areas of the brain compared to age norms (93.3% - Group I; 90.9% - Group -II; 78.9% - Group III). Diffuse slowing of the main activity was noted in 85.3% children of the Group I, 77.7% children of the Group II, and 68.4% children of the Group III. During EEG monitoring of night sleep, focal epileptiform changes were recorded in 60.0% children of the Group I. Among children of the Group II, focal epileptiform changes during night sleep were noted in 54.5%. Based on the results of the assessment of the spike-wave activity index (SWI), it was found that 34.7% children of the Group I, 18.2% children of the Group II, and 15.8% children of the Group III had a SWI above 85%. Conclusions. Data on the neurophysiological features of the nervous system of children with EE were obtained and the diagnostic value of EEG monitoring of night sleep was clarified, which will contribute to its implementation for the purpose of more accurate diagnosis of this pathology and optimization of therapy. The research was carried out in accordance with the principles of the Declaration of Helsinki. The study protocol was approved by the Local Ethics Committees of the institutions indicated in the work. Informed consent of the child and child's parents was obtained for the research. No conflict of interest was declared by the authors.