Dependence of Brain-Computer Interface Control Training on Personality Traits.

Personality traits (PTs) are predictors of the success of control of brain-computer interfaces (BCIs); however, it is unknown how the PTs that are optimal for BCI control changes during training. The paper for the first time analyzes the correlations between PTs and the accuracy of the classification (AC) of brain states in imagining the movements of the hands, feet, and locomotion during 10-day training of ten volunteers in BCI control. In the first 3 days of training, the AC is higher for more stressed and anxious volunteers; in the last days, for calmer ones. In the middle of the training period, AC is higher in low-demonstrativeness persons, it is more pronounced when imagining foot movements. Correlations of low demonstrativeness, as well as of foresight and self-control with AC when imagining foot movements are revealed significantly more often than when imagining hand movements and locomotions. During almost the entire period of training, AC with locomotion imagination is higher in individualists. The results make it possible to propose individually-oriented recommendations for the use of BCI based on the imagination of movements for the rehabilitation of patients with motor disorders.

A New Technology for Recovery of Locomotion in Patients after a Stroke.

Neural networks in the spinal cord can generate the walking pattern and control posture in the absence of supraspinal influences. A technology using transcutaneous electrical spinal cord stimulation (tSCS) was created. During walking, tSCS activated spinal locomotor networks, as well as leg flexor/extensor motor pools in the swing/stance phases, respectively. It was assumed that the use of this technology in subjects with locomotion disorders would improve walking. Patients with hemiparesis were studied 3-11 months after stroke, the duration of the course was 2 weeks. Patients of the main and control groups received standard therapy and rehabilitation using the technology; in the control group, sham tSCS was used. After the course, minimal clinically important differences in walking parameters were achieved in the main group, in contrast to the control group. The developed technology is an effective means of restoring walking in patients with hemiparesis.

Interhemispheric Asymmetry and Personality Traits of Brain-Computer Interface Users in Hand Movement Imagination.

Personality traits of users can affect the success in controlling brain-computer interfaces (BCIs), and the activity of right and left brain structures may differ depending on personality traits. Earlier, it was not known, how the success of BCI control with different personality traits is associated with interhemispheric asymmetry. In this work, the dependence of the success of imagination of movements, estimated by the success of recognition of EEG signals during imagination of hand movements compared to rest state, on the user's personal characteristics was studied. It is shown that in single control of BCI by naive subjects, recognition success in imagining right-hand (RH) movements was higher in expressive sensitive extroverts, and in imagining left-hand movements (LH) it was higher in practical, reserved, skeptical, and not very sociable persons. It is suggested that this phenomenon may be based on interhemispheric differences in dopamine level and in the way of encoding movement information.

[Controlled sclerosing in the treatment of venous maxillofacial malformations]. / Primenenie metoda kontroliruemogo sklerozirovaniia v lechenii venoznykh mal'formatsii cheliustno-litsevoi oblasti.

The aim of the study was to assess the effectiveness of ultrasound-guided use of the foam form of ethoxysclerol for the treatment of venous malformations of the maxillofacial area. The study involved clinical and ultrasound examination data of 60 patient allowing to determine treatment tactics and optimal volume of injected foam sclerosant as well as the role of ultrasound for monitoring of the treatment. The results proved the efficacy of 3% foam ethoxysclerol for less invasive treatment of venous maxillofacial malformations.

[The distinctive features of EMG-activity in early age children with movement disorders].

The purpose of this work was the study of neuromuscular characteristics of healthy infants and infants with movement disorders by method of surface electromyography. 76 children at the age from 6 months till 3 years participated in the investigation: 61 with movement disorders (13--with ataxic form of cerebral palsy (CP), 48--with spastic form of CP) and 15 without movement disorders. Passive flexing and extending of knee and hip joints was conducted to the child in a recumbent position, EMG activity of the basic muscles groups of a hip and a shin was recorded. Characteristic properties of electromyographic activity were assessed with wavelet transform and subsequent analysis of obtained time dependencies. As a result of work the parameters connected with diagnosis of infants with movement disorders were revealed.

Prior history of FDI muscle contraction: different effect on MEP amplitude and muscle activity.

Motor evoked potentials (MEPs) in the right first dorsal interosseous (FDI) muscle elicited by transcranial magnetic stimulation of left motor cortex were assessed in ten healthy subjects during maintenance of a fixed FDI contraction level. Subjects maintained an integrated EMG (IEMG) level with visual feedback and reproduced this level by memory afterwards in the following tasks: stationary FDI muscle contraction at the level of 40 ± 5 % of its maximum voluntary contraction (MVC; 40 % task), at the level of 20 ± 5 % MVC (20 % task), and also when 20 % MVC was preceded by either no contraction (0-20 task), by stronger muscle contraction (40-20 task) or by no contraction with a previous strong contraction (40-0-20 task). The results show that the IEMG level was within the prescribed limits when 20 and 40 % stationary tasks were executed with and without visual feedback. In 0-20, 40-20, and 40-0-20 tasks, 20 % IEMG level was precisely controlled in the presence of visual feedback, but without visual feedback the IEMG and force during 20 % IEMG maintenance were significantly higher in the 40-0-20 task than those in 0-20 and 40-20 tasks. That is, without visual feedback, there were significant variations in muscle activity due to different prehistory of contraction. In stationary tasks, MEP amplitudes in 40 % task were higher than in 20 % task. MEPs did not differ significantly during maintenance of the 20 % level in tasks with different prehistory of muscle contraction with and without visual feedback. Thus, in spite of variations in muscle background activity due to different prehistory of contraction MEPs did not vary significantly. This dissociation suggests that the voluntary maintenance of IEMG level is determined not only by cortical mechanisms, as reflected by corticospinal excitability, but also by lower levels of CNS, where afferent signals and influences from other brain structures and spinal cord are convergent.

[Interlimb interactions during cyclic in-phase and antiphased movements of arms and legs and their dependence on afferent influences].

Coordinated movements of arms and legs suppose the neural interaction between the generators of the rhythmics of the upper and lower extremities. In the lying position in 10 healthy subjects activity of the muscles of the upper and lower extremities was recorded when separate and joint cyclic movements of the arms and legs with different phase relationships between the movements of the limbs were performed, and under various conditions of the motor task. Antiphased active arm movements were characterized by increased muscle activity than during in-phase mode. The activity of the arm muscles under passive movements, imposed by experimenter, was significantly less than their activity when passive movements of the arms were imposed by the other arm. When loading one arm the muscle activity in the other passively moving arm increased independently from the synergy of arm movements. During motor tasks, implementing joint antiphased movements as the upper and lower extremities, compared to motor task, implementing their joint in-phase movements, there has been a significant increase in activity in the biceps brahii muscle, the tibialis anterior muscle and biceps femoris muscle. Loading of arms in these motor tasks has been accompanied by increased activity in some of the leg muscles. Increasing of frequency of rhythmic movements resulted in a significant growth of the muscle activity of the arms and legs with their cooperative movements with greater rate of rise of flexor muscles activity for arms and legs during joint antiphased movements. Thus, the spatial organization of movements and kind of afferent influences are significant factors of interlimb interaction, which, in turn, determine the type of neural interconnections that are involved in the regulation of movements.

Plasticity and modular control of locomotor patterns in neurological disorders with motor deficits.

Human locomotor movements exhibit considerable variability and are highly complex in terms of both neural activation and biomechanical output. The building blocks with which the central nervous system constructs these motor patterns can be preserved in patients with various sensory-motor disorders. In particular, several studies highlighted a modular burst-like organization of the muscle activity. Here we review and discuss this issue with a particular emphasis on the various examples of adaptation of locomotor patterns in patients (with large fiber neuropathy, amputees, stroke and spinal cord injury). The results highlight plasticity and different solutions to reorganize muscle patterns in both peripheral and central nervous system lesions. The findings are discussed in a general context of compensatory gait mechanisms, spatiotemporal architecture and modularity of the locomotor program.

[Abnormalities in mutual influences of upper and lower limbs in patients with stroke].

Previously, in healthy subjects the common pattern of muscle activation and specifics of interlimb neuron connections during performance of rhythmic separate and simultaneous movements of arms and legs in the lying position, which reflect functional meaningful of interlimb interactions, were shown. The aim of this research was to investigate such mutual influences of upper and lower limbs during the execution of similar motor tasks by patients with stroke. In sixteen poststroke patients with different stage of hemiparesis arms movements together with or without legs movements were performed, while lying supine. It was demonstrated that the common pattern of muscle activity distribution under the execution of voluntary cyclic movements by both arms was disordered. Passive rhythmic movements of each arm caused the phased EMG activity in shoulder muscles in patients with mild hemiparesis, but no activation was observed in patients with severe paresis. The loading of nonparetic arm resulted in an increasing of activity in shoulder flexor muscles of paretic arm in patients with weak paresis (which was typical for healthy subjects), while it not exerted essential influences in patients with severe paresis. Under connecting the cyclic movements of arms with stepping movements of legs in diagonal synergy the activity in proximal muscles of both arms was decreased irrespective of the paresis degree, as it was seeing in healthy subjects. Simultaneous arms and legs movements did not change the muscle activity in non-paretic leg in both groups of patients, but in some muscles of paretic leg the activity even decreased. The results obtained revealed important features of poststroke motor disturbances, which caused the changes of interlimb interaction and in great degree depended on the level of paresis. The data of investigation can be of a great importance for developing the new methods for rehabilitative procedure in patients with stroke.

[Control of different electromyogram levels of M. abductor pollicis brevis by means of visual feedback in healthy subjects].

We studied voluntary control of integrated electromyogram (IEMG) in the range of 20 +/- 5% and 40 +/- 5% of the IEMG of m. abductor pollicis brevis during its maximum voluntary contraction with and without visual feedback. Healthy subjects performed IEMG control with visual feedback in 5 trials; IEMG control with visual feedback in 5 trials for 5 days, and the reproduction of memorized IEMG value without visual feedback after 5 trials of IEMG under the visual control. The accuracy of IEMG control was estimated by the following parameters: time of IEMG being out of the required 10% range (ERROR); IEMG variability (VARIABILITY), and the bias of IEMG mean level (BIAS) during 30-sec trials. The IEMG control in the range of 20 +/- 5% with visual feedback improved in all subjects over the course of 5 trials. Within 5-day training, ERROR and VARIABILITY reduced on the first day only; during the last 4 days there was no accuracy increase. ERROR increased more than twice when the 20% IEMG level was reproduced without vision. The IEMG control in the range of 40 +/- 5% improved neither during 5 trials, nor during 5 days of training with visual feedback. ERROR increased for about 1.5 times when the 40% IEMG level was reproduced without vision. It was concluded that the motor system, particularly the motor cortex, could control the given level of muscle activity using the visual feedback.

[Mutual influences of upper and lower extrimities during cyclic movements].

The possibility of muscle activation of passive arm during its cyclic movements, imposed by active movements of contralateral arm or by experimenter was studied, as well as the influence of lower extremities cyclic movements onto arm muscles activity. In addition to that the activity of legs muscles was estimated in dependence on motor task condition for arms. Ten healthy supine subjects carried out opposite movements of arms with and without stepping-like movements of both legs. The experiment included three conditions for arm movements: 1) the active movements of both arms; 2) the active movements of one arm, when other entirely passive arm participated in the movement by force; 3) passive arm movement caused by experimenter. In the condition 2) additional load on active arm was applied (30 N and 60 N). In all three conditions the experiment was carried out with arms movements only or together with legs movements. The capability of passive moving arm muscles activation depended on increasing afferent inflow from muscles of contralateral arm was demonstrated. Emerging electrical activity was modulated in the arms movements cycle and depended on the degree of active arm loading. During combined active movements of arms and legs the reduction of activity in the flexor muscles of shoulder and forearm was observed. Concomitant arms movements increased the magnitude ofelectromiographic bursts during passive stepping-like movements in the most of recorded muscles, and the same increasing was only observed in biceps femoris and tibialis anterior muscles during active legs movement. The increasing of loading of one arm caused essential augmentation of EMG-activity in the majority of recording legs muscles. The data obtained are the additional proof of existence of functionally significant neuronal interaction both between arms and between upper and lower extremities, which is evidently depend on the intraspinal neuronal connections.

Assisted leg displacements and progressive loading by a tilt table combined with FES promote gait recovery in acute stroke.

OBJECTIVE: Here we developed and tested a novel system for early motor rehabilitation in acute stroke when patients are unable to stand and walk without assistance. Stepping performance may be largely facilitated by providing treatment in the supine position on a tilt table using step-synchronized functional electrical stimulation (FES) with assisted leg movements and progressive limb loading. METHODS: Sixty-one individuals with acute stroke were randomly assigned to two groups, experimental and control. The first group received both a conventional therapy and FES-therapy combined with progressive limb loading, whereas the control group received a conventional therapy only. Changes after treatment were assessed using clinical scores and neurophysiological measurements of movement performance. RESULTS: After treatment, there was an improvement of the clinical scores, muscle forces and everyday life activity performance in both groups, however, significantly higher in the experimental group. Active rhythmic movements of the non paretic leg often provoked muscle activity in the paretic leg as well as there was a reduction of the contralateral leg muscle contraction during paretic leg movements. CONCLUSION: The developed FES and leg displacement-assisted therapy facilitates a smooth transition to walking in the vertical position and increases the patient's functional abilities and the effectiveness of rehabilitation.

[The investigation of control mechanisms of stepping rhythm in human in the air-stepping conditions during passive and voluntary leg movements].

In unloading condition the degree of activation of the central stepping program was investigated during passive leg movements in healthy subjects, as well as the excitability of spinal motoneurons during passive and voluntary stepping movement. Passive stepping movements with characteristics maximally approximated to those during voluntary stepping were accomplished by experimenter. The comparison of the muscle activity bursts during voluntary and imposed movements was made. In addition to that the influence of artificially created loading onto the foot to the leg movement characteristics was analyzed. Spinal motoneuron excitability was estimated by means of evaluation of amplitude modulation of the soleus H-reflex. The changes of H-reflexes under the fixation of knee or hip joints were also studied. In majority of subjects the passive movements were accompanied by bursts of EMG activity of hip muscles (and sometimes of knee muscles), which timing during step cycle was coincided with burst timing of voluntary step cycle. In many cases the bursts of EMG activity during passive movements exceeded activity in homonymous muscles during voluntary stepping. The foot loading imitation exerted essential influence on distal parts of moving extremity during voluntary as well passive movements, that was expressed in the appearance of movements in the ankle joint and accompanied by emergence and increasing of phasic EMG activity of shank muscles. The excitability of motoneurons during passive movements was greater then during voluntary ones. The changes and modulation of H-reflex throughout the step cycle without restriction of joint mobility and during exclusion of hip joint mobility were similar. The knee joint fixation exerted the greater influence. It is supposed that imposed movements activate the same mechanisms of rhythm generation as a supraspinal commands during voluntary movements. In the conditions of passive movements the presynaptic inhibition depend on afferent influences from moving leg in the most degree then on central commands. It seems that afferent inputs from pressure receptors of foot in the condition of "air-stepping" actively interact with central program of stepping and, irrespective of type of the performing movements (voluntary or passive), form the final pattern activity.

[Application of "tachocomb" preparation in pediatric surgery].

The efficacy of preparation "Tachocomb" application in 224 children, ageing from 1 day to 18 years old, was studied up. The spectrum of the preparation studying had included the investigation of its properties, which secure an additional isolation for the intestinal and vascular walls defects, and hemostatic effect in the hemorrhage area as well. The data obtained trust the safety and efficacy of "Tachocomb" platelets application in pediatric surgery and permit to recommend them for improvement of the surgical treatment results.

[Early motor rehabilitation with the help of a software/hardware complex "Vertical" in acute period of stroke].

The purpose of our study was the investigation of effectiveness of restoration of lost motor functions in acute period of stroke with the help of software/hardware complex "Vertical". This complex includes a functional bed-trainer for leg movements with phase-dependent functional electrical myostimulation (FES). Fifty-five subjects (mean age 64 +/-1.5 years) were assigned randomly to two groups receiving standard rehabilitation (a control group--27 subjects) and standard rehabilitation combined with the treatment by the "Vertical" complex (FES group--28 subjects). The treatment course was started on average 9 +/- 4 days after stroke and consisted of 30 min sessions 5 days per week during 2 weeks. Outcome was assessed by a battery of scales, everyday movement abilities and biomechanical parameters before and after treatment. No significant differences were found in baseline measurements. After the treatment, there was a positive dynamics in both groups with significant improvement in scores in the FES group. Most of patients of this group (67%) had hemiparesis of mild degree compared to the control group (7%, p < 0.05) to the end of treatment. Also 89% of subjects in the FES group were able to walk without assistance after treatment as compared to the control group (p < 0.05). There was a significant improvement in ankle flexors and extensors force of the paretic leg as well as in ankle joint movements of voluntary "walking" in the supine position in the FES group (p < 0.05).

[Rehabilitation of patients after total endoprosthesis replacement of hip joint by the method of functional electrostimulation].

Patients after total endoprosthesis replacement of hip joint underwent method of functional electrostimulation (FES) with the purpose to recovery correct walking stereotype, to increase leisured muscle strength, to prevent secondary coxarthrosis development via stimulation or relaxation of muscles, and for analgesia of joints and pain zones at walking. Results of treatment of 143 patients received rehabilitation course of FES (15 procedures of 30 minutes) were compared with results of treatment of 54 patients received traditional methods. It is shown that FES is effective method of rehabilitation because it makes possible to improve muscle strength significantly, to eliminate or reduce motor deficit, to decrease pain syndrome, to form correct walking stereotype, and to perform early prophylaxis of secondary coxarthrosis on contralateral side. The main advantage of proposed method of nonmedicamental influence is better clinic-biomechanical result without use of drugs.

Asymmetric leg loading during sit-to-stand, walking and quiet standing in patients after unilateral total hip replacement surgery.

BACKGROUND: Asymmetric limb loading persists well after unilateral total hip replacement surgery and represents a risk of the development of osteoarthritis in the non-operated leg. Here we studied bilateral limb loading in hip arthroplasty patients for a variety of everyday activities. METHODS: Twenty-seven patients and 27 healthy age-matched control subjects participated in the study. They were asked to stand up from a chair, to stand quietly, to perform isometric maximal voluntary contractions and to walk along a 10 m path at a natural and fast speed. Two force platforms measured vertical forces under each foot during quiet standing and sit-to-stand maneuver. Temporal variables of gait were measured using footswitches. FINDINGS: In all tasks patients tended to preferentially load the non-operated limb, though the amount of asymmetry depended on the task being most prominent during standing up (inter-limb weight bearing difference exceeded 20%, independent of speed or visual conditions). In contrast, when performing maximal voluntary contractions, or during walking and quiet standing, the inter-limb difference in the maximal force production, stance/swing phase durations or weight bearing was typically less than 10%. INTERPRETATION: The results suggest that the amount of asymmetry might not be necessarily the same for different tasks. Asymmetric leg loading in patients can be critical during sit-to-stand maneuver in comparison with quiet standing and walking, and visual information seems to play only a minor role in the control of the weight-bearing ability. The proposed asymmetry indices might be clinically significant for development of post-surgical rehabilitation.

Involvement of the motor cortex in the bimanual unloading reaction: a transcranial magnetic stimulation study.

The responses of the biceps brachii muscle of the upper arm to magnetic stimulation of the motor cortex during the postural pretuning and forearm unloading tasks were studied in humans. On active unloading, the amplitude of the evoked response decreased in parallel with a decrease in muscle activity. During stationary holding of the load, the muscle response changed in proportion to the load. When, on the background of stationary holding of the load, the other arm took on the same load, the amplitude of the evoked response in the biceps muscle of the arm holding the load decreased without any change in the muscle activity. Passive unloading was accompanied by similar changes in the response evoked by magnetic stimulation as seen with active unloading. The question of whether the decrease in muscle activity (postural pretuning) in active unloading may be associated with both direct corticospinal influences and influences mediated via subcortical structures is discussed.

[Participation of the motor cortex in the bimanual unloading task: a study by transcranial magnetic stimulation]. / Uchastie motornoi kory v bimanual'noi reaktsii razgruzki: issledovanie s pomoshch'iu transkranial'noi magnitnoi stimuliatsii.

Motor potentials of m. biceps brachii evoked by transcranial magnetic stimulation of the contralateral motor cortex have been recorded in postural adjustment during arm unloading in humans. During active unloading, the amplitude of the motor evoked potential decreases simultaneously with the decreasing of the muscle activity. During load keeping, the muscle response changes simultaneously with the load changes. When the other arm has lifted the other load during load keeping, the amplitude of the motor evoked potential decreases in the m. biceps of the keeping arm without muscle activity changes. Passive unloading results in the same changes of the motor evoked potential as active unloading. A possible role of the direct corticospinal volley and the motor command mediated by some subcortical structures in the decrease of the muscle activity preceding active unloading (postural adjustment) is discussed.