Psychophysiological Status of Schoolchildren with Social and Visual Deprivation

Popova Tat'yana Vladimirovna ORCID: 0000-0002-5060-8132 Doctor of Biology Professor, Researcher at the Institute of Additional Education, South Ural State University 454080g.Chelyabinsk, Lenin Ave.,76, Russia, Chelyabinsk city, 454080, Lenin Ave., 76, of. 454080 tati.popova2010@yandex.ru Voloshina Irina Anatol'evna ORCID: 0000-0002-6635-0236 PhD in Technical Science Director of the Institute of Additional Education of the South Ural State University 454080, Russia, 454080, Chelyabinsk, ul. Lenin Ave., 76, office 454080 voloshinaia@susu.ru

Kourova Ol'ga Germanovna ORCID: 0000-0002-7996-1191 PhD in Biology Candidate of Biological Sciences, Associate Professor of the Department of Ecology and Chemical Technologies of the South Ural State University 454080, Russia, 454080, Chelyabinsk, ul. Lenin Ave., 76, office 454080 kourovaog@susu.ru

Setting the task. Literature review. Cognitive disorders in children are one of the most important problems worldwide. According to the World Health Organization, 15% of children have noticeable intellectual disabilities. Published data show that cognitive impairment occurs in at least 20% of children and adolescents ^[1]. To a large extent, this applies to children left without parental care ^[2] and children with sensory impairments ^[3]. In the social sphere of many countries, the problem is solved with the help of social centers (SC), special educational institutions, foster and foster families, etc.

        The nature of the development of such children attracts the attention of teachers, doctors, and psychologists, but there is not enough data in the literature on the peculiarities of their psychophysiological functions. The results of electrophysiological studies of the brain are currently the most informative in the analysis of both neurophysiological and psychophysiological human functions. Electroencephalogram (EEG) parameters, for example, the power density spectrum (SPM) of the main rhythms, spatial synchronization indicators are informative for evaluating integrative processes ^{[4, 5]}.

The alpha rhythm is the most studied in the rhythmic activity of the EEG.  Its high correlation with intelligence is shown ^[6]. Recently, more and more data has been accumulating that even short-term fluctuations in the EEG, especially in the alpha band of its frequency spectrum, in many cases reflect fluctuations in the level of the functional state of the brain, which determines, in particular, the effectiveness of sensorimotor activity and some aspects of mental activity ^[7]. The relationship of attention indicators with the amplitude of alpha, delta and theta rhythms in children aged 5-9 years, as well as the relationship between the cognitive development of young children and the nature of EEG rhythms was also revealed ^[8].

It is known that the lag in the development of cognitive functions of children is often noted in pupils of social and special educational institutions, which hinders the self-realization of the individual. In children with developmental delays, the ability to social interaction, learning, and flexibility of behavior decreases, and inadequate reactions to adverse effects are often observed. Therefore, a detailed study of the relationship between the individual characteristics of bioelectric brain processes and the level of cognitive development in children who find themselves in special conditions of psychosocial development is an urgent area of pedagogy and pedagogical sociology. Knowledge of the individual characteristics of the psychophysiological functions of such children is necessary for the competent justification of programs for their psychophysical correction in the process of studying at school.

            The aim of the study was to identify differences in the characteristics of bioelectric brain processes and cognitive functions in children left without parental care and children with visual impairments.      

Materials and methods examined boys aged 7-10 years (23 subjects), pupils of the social center (SC – group I); group II consisted of boys, students of a kindergarten school for children with visual impairment (NC – 18 people). Healthy schoolchildren of the same age, secondary school students living in their families (K – III group, 25 people) were examined as a control group. Refractive errors (myopia, hyperopia, astigmatism) prevailed among the visually impaired subjects, some children suffered from strabismus, amblyopia.

All the subjects were trained according to regular school curricula and had all the conditions for preparing school lessons, as well as for physical education, rehabilitation and cultural leisure. The present study corresponded to the ethical principles of the Helsinki Declaration of 1964 and was approved by the Ethics Committee of South Ural State University.

Bioelectric activity was recorded in accordance with the international 10-20 c system of projection regions of the frontal (F3, F4), central (C3, C4), parietal (P3, P4), occipital (O1, O2), posterior (T5, T6), anterior (T3, T4) regions of the left and right hemispheres. A combined ear electrode was used as a reference. The EEG was recorded at rest (background) for 15 minutes and during functional tests for 5-10 minutes: tests with opening (OG) and closing of the eyes (HR). The frequency step was 0.25 Hz. Records that did not contain pronounced artifacts were analyzed.

Some parameters of the subjects' cognitive functions were also analyzed. The indicators of mental performance, thinking and attention were evaluated according to ^[9]. Indicators of anxiety and the level of aggression according to Eysenck were also studied ^[10].

Statistical data processing was performed using standard IBM SPSS Statistics 22 programs. The EEG spectral power parameters were calculated over the entire frequency range (0-40 Hz). The nonparametric Wilcoxon criterion was used to identify inter-level differences in the EEG power spectrum.

The representativeness of the samples allowed for the statistical processing of other results to apply a parametric analysis of the calculation of confidence intervals using a 95% confidence probability and the Student's t criterion.

            The results of the study and their discussion. The features of EEG indicators in all groups of subjects were revealed.Thus, in children from the social center (SC) in the right hemisphere, the amplitude of the ?-rhythm was slightly lower than in the left, as in the control group (K), and the frequency was higher; the amplitude of the ?–rhythm was lower, unlike K (Table. 1); ?–rhythm dominates in their parietal and occipital leads, and 70% have an interhemispheric asymmetry of the ?-rhythm in amplitude; ?–waves dominate in the frontal leads.

Table 1 - Amplitude-frequency characteristics of ? and ? EEG rhythms in children aged 7-10 years

Notation: ? h – low-frequency ?–rhythm (14-20 Hz); ? b - high-frequency ?-rhythm (20-35 Hz); * – reliability of differences with the control group (P <0.05)

In half of the examined pupils, the alpha rhythm dominated in the central parietal leads, in 4 of them in the frontal and only two in the occipital, unlike children of the control groups, in whom alpha activity prevailed in the occipital leads.

In younger schoolchildren with visual impairment (NC) at rest, the amplitude of both the ?- and ?-rhythm, unlike schoolchildren K and SC, is higher above the right hemisphere. The alpha rhythm dominates the right hemisphere in the temporal leads, and the left hemisphere in the central leads, and the ? rhythm in the central, temporal and occipital leads.

In 60-70% of schoolchildren with visual impairment, ? activity was observed over both hemispheres, as well as in healthy (K) and children of the SC groups (Fig.1), mainly in the frontal, central and occipital leads. In 70% of children above the left hemisphere, as well as in healthy children, slow theta waves are observed in the central and occipital leads.

In the control groups, the nature of the electroencephalograms corresponded to the data obtained earlier also in healthy children^[11]. Our data indicate that with age there is a natural flattening of the ?-rhythm and an increase in its frequency, as well as a decrease in the amplitude of the ?-rhythm, especially in the left hemisphere. In 70% of the examined children, ?-activity with an average amplitude of 63 Mv was noted in the occipital, parietal and frontal leads. (Fig. 2). In this case, the amplitude of the ?-waves is higher above the right hemisphere than above the left. At rest, single ? waves in the frontal and central leads are also observed above the right hemisphere.

  a) b)

 Fig. 1. The spectrum of EEG wave activity (K-V. SC, 10 years old), in the initial state (a) and when closing the eyes (b), 414 s – 393 s; M:2; notation of leads in the text.

The dominance of the ?-rhythm in the majority of subjects in the control group was observed in the frontal leads, in 3 of them in the parietal and in 2 in the occipital (Fig.2). It is characteristic that slow rhythms of the ? and ?-range were less common in them than in peers of the SC and NC groups, however, the amplitude (82.9 and 71 MV) and the power of the wave spectrum in this range were much higher. Changes in the ?-rhythm during functional tests were more pronounced in them than in children with SC and NC.

                                        a) b)

     Fig. 2. The spectrum of EEG wave activity (P-va. 9 years old, K) in the initial state (a) and with the eyes closed (b).

The alpha rhythm dominated the right hemisphere in the frontal and central leads, and the left hemisphere in the occipital ones. In 50% of healthy children, an interhemispheric asymmetry of the alpha rhythm in amplitude and in 20% in amplitude and frequency was revealed. 

Table 2 - Mental performance of adolescents living in various conditions

 Notes: * - reliability of differences with the control group;

The study of mental performance showed that all its parameters in children of the same age living in the usual conditions of their native family (K) were higher than in children of the SC and NC groups (Table 2). Between age groups, the advantage in older children was revealed in terms of stability of attention, thinking and memory,

and also with regard to the generalized assessment of mental performance. It is characteristic that no significant age differences were found in relation to the distribution of attention.

            Thus, the majority of subjects from the SC and NC, compared with healthy schoolchildren, revealed the following differences in the bioelectric activity of the large hemispheres:

– More pronounced rhythm activity in the alpha range;

– Interhemispheric asymmetry in the alpha rhythm is less common (in fewer subjects);

– Alpha rhythm dominance is observed in the frontal and central leads, not in the occipital;

– The amplitude of the high-frequency beta rhythm is higher;

– The amplitude of the low-frequency beta rhythm is slightly lower;

– Slow rhythms in the delta and theta ranges are less common in children with NC than in the SC group.

The data of bioelectric processes in the tested groups of SC and NC suggest a high readiness for cognitive activity. The highest rates of personal anxiety and aggressiveness were noted in children living in social centers (SC) and with visual impairment (NC) (Table 3). It can be noted that these indicators change unevenly with age.

Table 3 – Indicators of the psychoemotional state of the subjects living in different conditions

Notes: *– reliability of differences with the control group;

It is characteristic that the data obtained indicate the presence of varying degrees of functional stress in all examined children, the lowest in children of the control group.

Discussion of the results. The results of our study revealed differences in the bioelectric processes of the brain and the functional state of the central nervous system in children developing in different conditions.

The study data confirmed that the alpha rhythm was the most informative indicator on electroencephalograms (EEG).    The data of our study coincide with those obtained by Farber, differing in children of the control groups with a slightly higher frequency of the alpha rhythm in the right hemisphere. Scientists ^[12] also believe that the right hemisphere is the leading one for the alpha rhythm. When comparing the control group of schoolchildren with children with behavioral disorders, an increase in the phase difference between the two occipital regions was revealed ^[13].

            The pupils of the social center, for the most part, had a greater alpha rhythm power than healthy peers and its spread to the anterior hemispheres, displacement from the occipital zones. In children with NC, the alpha rhythm dominated in the temporal leads on the right and in the central ones on the left, and the ? rhythm dominated in the central, temporal and occipital leads.

Morphofunctional transformations in the cerebral cortex can be continuously reconstructed throughout life ^[14], therefore, during the period of human growth and development, a competent approach to the development of cognitive functions is especially important.

In general, the results of our study suggest that SC pupils, and especially children with NC, in comparison with healthy peers from native families, have changes in the bioelectric activity of the brain, indicating a functional tension of the central nervous system. On the other hand, we can talk about suppressed hypothalamic activity as a sign of compensatory inhibition of cortical processes.

At the same time, EEG data are the basis for the assumption of sufficiently high compensatory capabilities of such children. Thus, the subjects we examined did not have the features of bioelectric brain activity identified in children with attention deficit disorder, in whom an increase in the theta rhythm of the EEG was observed in hyperactivity conditions against the background of a decrease in the alpha rhythm ^[15].

The results of the study of mental performance showed that in conditions of social and sensory deprivation, cognitive function is insufficiently activated, as evidenced by slower age-related development, compared with healthy children living in their families.

            It can also not be excluded that the functional tension in the central nervous system, confirmed by the data of electroencephalograms in all children, in the absence of corrective measures, may be the cause of the development of decompensation mechanisms for reducing mental performance.

Therefore, the introduction of correctional and wellness programs for schoolchildren of the surveyed groups is a necessary condition for the harmonization of their psychophysical development. In this regard, research is being conducted to study and introduce into the educational process methods for developing students' emotional intelligence, communication skills, development of non-cognitive skills, self-control, and psychophysical technologies of self-regulation ^[16-18]. The accumulated experience of introducing such programs into the school education process according to domestic ^[18] and foreign studies indicates their beneficial effect on the psychophysical state of children and adolescents. Thus, the authors ^[19] showed the role of "socio–emotional learning" in ensuring the psychological safety of U.S. schoolchildren, due to favorable changes in psychophysical development

Conclusion

Thus, the features of bioelectric activity of the brain revealed by us in children with insufficiently adequate conditions of psychosocial development allow us to conclude about the high potential of their cognitive abilities. It can be assumed that if at this age the social environmental friendliness of the conditions of psychophysical development is increased (creation of motivation, special developmental programs, individual approach to learning, adequate methods of encouragement), their psychosocial adaptation can be accelerated. On the contrary, the absence of such an approach, combined with less favorable conditions for age-related development, may contribute to inhibition of maturation of cognitive functions. The presence of signs of functional stress in children of this age is the basis for recommendations on the introduction of correctional and wellness programs in educational centers..

Further research is needed on the impact of health-improving and correctional programs on the psychophysical state of schoolchildren of different ages, gender and social status.