[Rehabilitation of patients with post-stroke cognitive impairment using the P300-based brain-computer interface: results of a randomized controlled trial]. / Reabilitatsiya patsientov s postinsul'tnymi kognitivnymi narusheniyami s ispol'zovaniem interfeisa «mozg­komp'yuter¼ na volne P300: rezul'taty randomizirovannogo kontroliruemogo issledovaniya.

OBJECTIVE: To study the effects of a 10-day cognitive training using the brain-computer interface (BCI) technology at the P300 wavelength on the recovery of cognitive functions in poststroke patients. MATERIAL AND METHODS: The study included 30 patients, aged 22-82 years, with ischemic stroke less than 3 months old and moderate cognitive impairment (<26 points on the Montreal Cognitive Assessment Scale (MoCA)). All patients underwent neuropsychological testing, assessment of the presence of depression, assessment of activity in daily life. Patients were randomized into two groups: patients of group 1 (main) underwent a 10-day course of cognitive rehabilitation in the form of daily exercises in the BCI environment at the P300 wave equipped with a headset for recording an electroencephalogram (EEG). Patients of group 2 (control) received a standard set of rehabilitation measures. RESULTS: There was an increase in the mean score of the MoCA «Attention¼ domain in the main group of patients (2.3±1.24 to 5.2±1.16 points) compared with the control group (5.9±1.00 to 4.2±0.94 points, p<0.05). The results of covariance analysis with repeated measures, taking into account the factors «Visit¼ and «Group¼, the covariate «Depression¼ and «Number of training sessions¼ revealed significant effects for the MoCA domains «Naming¼ (p<0.05), «Attention¼ (p<0.05), «Abstraction¼ (p<0.05). By the end of the 10-day cognitive training using BCI, patients of the main group showed a significant increase in the number of entered letters (20.8±2.01 to 25.9±1.7 characters (p=0.02) compared with the control group (21.9±1.9 to 23.1±1.8, p=0.06). When comparing the number of words entered by patients after 10 days, a significant difference was found between the main and control groups (p<0.05). CONCLUSION: Rehabilitation of patients with post-stroke cognitive impairment using P300 BCI has a significant positive effect on the restoration of cognitive functions, primarily attention.

Intracortical Directed Connectivity for Information Retention in Visual-Spatial Working Memory.

A group of 27 healthy young adults solved a task involving the working memory (WM) activation, consisting of the comparison between the spatial orientations of two sequentially presented square-wave luminance gratings. We investigated the effective (directed) connectivity patterns between the frontal and postcentral cortical regions related to the visual system. The connectivity was assessed using vector autoregression modeling of EEG. It was shown that the strength of the top-down right-hemispheric connectivity patterns directed from the frontal cortex to the visual areas in θ frequency was significantly lower at the stage of stimulus retention in the WM than at the stage of stimulus anticipation. On the contrary, in the α band the descending influences were slightly more intense. The results of the study showed the frequency-dependent dynamics of the descending influences of the frontal cortex on visual areas and confirm that the frontal cortex plays the role of a controlling and modulating center in the brain system underlying WM.