Reactivity of the autonomic nervous system in children of younger school age with mental retardation

Abstract

Introduction. The functioning of the autonomic nervous system (ANS) to some extent affects various aspects of human health and general well-being. One of the main ANS functions is to ensure adaptation to the factors of the external and internal environment, carried out by the coordinated activity of the sympathetic and parasympathetic links. Determining the predominant type of ANS reactivity according to the characteristics of the heart rhythm makes it possible to predict the adaptive capabilities of the child’s body in the learning process in a personalized way. 
 The aim of the study was to study the trend in heart rate variability in children with special health conditions associated with disorders of the intellectual development, which characterizes the implementation of mechanisms for adapting the body to the conditions of schooling.
 Materials and methods. We examined one hundred sixty eight 7–11 years children of primary school age, including 54 children with special health abilities (SHA) (F70, F71), and 114 mentally healthy children. The study of heart rate variability was carried out using the hardware-software complex “ORTO Valeo”. There was analyzed TP, HF, LF, VLF, LF / HF; RMSSD, SDNN, Mo, AMo, ΔX, IN, AMo / Mo, Amo / ΔX; type of vegetative regulation.
 Results. In SHA children of primary school age, the LF, VLF, LF / HF indices are increased and HF is decreased relative to the control group, which indicates the predominance of the sympathetic link of the autonomic nervous system over the parasympathetic. When analyzing the spectral components in SHA children of primary school age, VLF (40.6%) and low HF (19.6%) dominate. According to the types of autonomic regulation in SHA children, the following ratio was found 50: 4: 33: 13, the central type of cardiac regulation dominates (type I).
 Limitations. The limitation of the study is due to the specifics of the individuals in the observation group – children of primary school age (7–11 years) with special health opportunities associated with mental retardation.
 Conclusion. SHA children of primary school age have high activity of sympathetic modulation, reduced resistance to stress, high tension of adaptive responses with the dominance of the central type of regulation of the cardiac activity. The revealed imbalance of the parameters of autonomic regulation in SHA children without corrective measures (including correction of physical status, psychoemotional and educational loads) threatens the development of a breakdown of adaptive responses to the effects of various internal and external factors, contributing to asthenization of regulatory systems.