Introduction:
Recently, school maladjustment that is associated with the cognitive decline in children with minor central nervous system disorders has become one of the topical issues.

Aim:
The aim of this research was a retrospective analysis of changes concerning neurophysiological and neuropsychological parameters in children with psychic development disorders after treatment employing the transcranial direct current stimulation (tDCS) technique.

Material and methods:
Study data of 128 children with learning disorders and 48 children with mild mental retardation, aged 8–12 years old, who had undergone a course of tDCS, were analyzed. The data of neuropsychological testing and electroencephalography (EEG) of 22 healthy children and 42 children with psychic development disorders who had undergone conventional treatment, aged 8–12 years old, were used as a control. For tDCS procedures 60–120 µA direct current was used, the stimulating electrodes area ranged from 2.5 cm² to 6.25 cm². Treatment session duration (ranging from 25 min to 45 min), as well as stimulating electrodes localization onto the scalp and the time of the procedure, depended on clinical goals, age, and the severity of disorders. The entire treatment course duration lasted 4–5 weeks: 5–9 procedures with 2–3 day intervals.

Results:
A neuropsychological study revealed statistically significant improvement of higher mental functions in patients undergoing tDCS compared to control groups. Verbal functions improvement was observed in 80.0% of children with such disorders. In patients with dysgraphia, after tDCS the rate of mistakes in writing reduced 3-fold, the process of writing quickened. The ability to fulfill tasks requiring visual spatial analysis and synthesis also considerably improved. After the course of tDCS no cases of negative changes of EEG parameters were noted. On the contrary, the improvement of EEG parameters, showing their approaching the age norms, was observed.

Discussion:
The study results indicate that tDCS enables one to not only change directionally the functional status of brain areas lying under electrodes, but also to influence actively the functional status of deep regulatory brain systems through the changing of modulatory cortical areas status.

Conclusions:
Having practically no adverse effects, tDCS appears to be an effective correction technique with respect to higher psychic disorders for children with psychic development disorders.