Electrical Brain Activity of Adolescents with Visual Dysfunction in Rasring State

Redka I. V.

PHYSIOLOGY

Scentific article

The aim of this article was to determine features of the functional state of the brain of adolescents with congenital visual dysfunction. Data and methods. 29 adolescents with congenital visual dysfunction and 42 sighted adolescents at 12.5-16 years were studied by EEG method in a resting state with eyes closed. EEG fragments without artifacts (35-45 second) were analyzed by spectral analysis with the value of the step 0,001 Hz. Five frequency bands were detected in the EEG: delta (0. 5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta-1 (13-20 Hz) and beta-2 (20-30 Hz) bands. Absolute spectral power (ASP), relative spectral power (RSP) and peak frequency (PF) of five EEG band were studied. results. A lower (P > 0. 05) values of ASP in theta, alpha and beta-1 bands and higher values (P > 0. 05) of ASP in the beta-2 band was observed in most areas of the brain convexital surface in adolescents with congenital visual dysfunction in contrast with healthy adolescents. A higher (P > 0.05) values of ASP in delta band was founded in boys with visual dysfunction, but a lower (P > 0. 05) values of ASP in delta band was founded in girls. Significant dif- ferences (Р 2264 > 0.05) were observed for alpha-, beta-1 and beta-2 bands. Established that slightly (P > 0.05) lower values of PF in the theta and alpha bands were observed in most areas of the brain convexital surface in adolescents with visual dysfunction. Gender differences were founded for the PF in the delta, beta-1 and beta-2 bands. Significant differences (Р 2264 > 0.05) in PF were more prevalent in girls with visual dysfunction. EEG structure in adolescents with visual dysfunction was changed: the level of delta-and beta-2 activity was increased in all sites, and the contribution of theta activity was increases only in the caudal areas. The power of the alpha-band was generalized reduced. The most significant changes in the electrical activity of the brain under the influence of chronic restriction of the visual afferentation exposed to males. The vast majority of differences between girls with vision dysfunction and sighted girls were detected by the values of the peak frequency. These may indicate a transition to another level of functioning of neural networks allows keeping the relative balance between activating and deactivating brain systems. Topographically significant differences were recorded in girls with visual dysfunction recorded in caudal regions of the cerebral cortex, indicating functional changes at the level of stem structures. conclusion. Visual dysfunction accompanied with the formation of a functional failure thalamo-cortical system. The activity of stem-reticular structures and limbico-reticular complex was increased in boys with visual dysfunctions. The neuronal networks of brain system of girls with visual dysfunctions were transited to another functional level compared with sighted girls. the girls with vision dysfunction were characterized by functional changes at the level of stem structures. The most significant changes in the electrical activity of the brain under the influence of chronic restriction of the visual afferentation exposed to males.

electroencephalogram, spectral analysis, adolescents with visual dysfunction.

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