Effects of screen time on motor asymmetry in primary schoolchildren

Background. The modern model of hemispheric asymmetries includes genetic, environmental, and epigenetic factors. Therefore, this makes relevant the study of the effect of the academic environment on hemispheric asymmetries in schoolchildren. The paper aims to identify the effect of screen time on hand asymmetry among primary schoolchildren. Materials and methods. The study involved 2677 girls and 1528 boys of grades 1-4 from 66 schools in Moscow. The surveys were carried out twice a year (in October and March-April), all samples were independent. Psychomotor coordination was measured during motor tests by means of the movement measuring device, which allowed to identify movement speed and accuracy, as well as movement smoothness and response. The volume of school and out-of-school screen time was assessed by teachers based on relevant hygienic standards. Results. The results obtained show that screen time did not affect the asymmetry of speed indicators. Movement accuracy tests showed that groups with maximal screen time (3 or more times higher than that of hygienic standards) had increased left hand activity indicators in terms of flexor muscles by spring. In girls of the maximum screen time group, movement smoothness tests showed increased right hand activity indicators in spring tests. In boys, similar changes were found in the groups with both maximum and lower screen time. Similar results were obtained for reaction time (reaction to light). It is important that the use of computers within the limits of hygienic standards did not affect the indicators of motor asymmetry. Conclusion. The data obtained show that students of grades 3-4 with high levels of screen time developed a new motor skill by the end of the academic year. Such changes can be considered as an adaptive response to a computer-oriented educational environment.