Peculiarities of interhemispheric functional asymmetry of the frontal region in 4–7 year-old children with mental development and speech development delay

This work is an attempt to evaluate the ratio of sustainable potentials in the frontal region of the right and left hemispheres in children of 4–7 years of age with speech dysphasia (SD) and light mental problems of cerebral-organic genesis (LMP). The survey was administered to 30 children (20 boys and 10 girls) aged 4 to 7 years (5,5 ± 1,1 years); 15 children had been diagnosed with General Speech Underdevelopment (GSU) in the 2nd or 3rd degree, and the other 15 children had been diagnosed with both SD and LMP. To confirm the diagnoses all the children were examined by a neurologist and a speech therapist. The data obtained during the neurological examination determined the presence of changes on the brainstem, pyramidal and extrapyramidal levels. In turn, the speech therapist determined the degrees of SD caused by a primary disorder of cortical mechanisms. The dynamics of sustainable potential (SP) of the brain in symmetrical prefrontal leads of the left and right hemispheres, corresponding to the projection of the F9 Brodmann area, was evaluated by means of applying miniature liquid non-polarisable silver chloride electrodes. For children with the 2nd and 3rd degree SD in a state of rest a high level of activity coordination in the frontal areas of the right and left hemispheres was detected, whereas a shift to a functional state entailed a reduction in the level of such coordination. In children with a combination of the SD and the LMP there was no change in the level of activity coordination in the hemispheres during the transition from one functional state to another. A higher level of activity in the right hemisphere was revealed in children with a combination of the SD and the LMP in comparison with children with the 2nd and 3rd degree SD only.