Movements In Healthy Subjects Research Articles

Physiological movements during sleep in healthy adults across all ages: a video-polysomnographic analysis of non-codified movements reveals sex differences and distinct motor patterns.

To define sleep-related movements in healthy adults according to sex and age. Sleep-related movements from 50 video-polysomnography (vPSG) recordings of 27 men and 23 women, from 20 to 70 years old, were classified according to International classification of sleep disorders (ICSD-3-TR) and American Academy of Sleep Medicine (AASM) criteria (codified movements); the remaining movements (non-codified movements) were described according to type (elementary movements-EMs or complex movements-CMs), topography (focal, segmental, multifocal or generalized) and, if present, were assigned to motor patterns (MPs). Of 4057 movements analyzed, 54.6% (2216/4057) were non-codified (1861 CMs, 355 EMs) and 1841 were codified. CMs were mainly generalized (70%) while EMs were multifocal (40%) or focal (30%). The median movement index (MI; movement/hour) was 11 and the median duration was 4 seconds. MI decreased from stages N1/REM > N2 > N3; men showed a higher MI. An MP was assigned to 2204 codified and non-codified movements, mainly stretching (50%) and scratching (30%). Stretching increased in REM sleep while food-carrying behaviors increased in N2. Men showed more food-carrying behaviors, changes of body positions, and comfort movements while stretching was more common in women. Younger participants exhibited more food-carrying behaviors, while scratching and stretching were more prevalent in the middle-aged group. Older participants showed more changes in body positions and comfort movements. In total, 54.6% of sleep-related movements in healthy participants were non-codified and characterized by motor sequences that can configure MPs. Our comprehensive classification method allows a detailed description of the physiological movements underlying differential motor control during sleep stages influenced by age and sex.

An Experiment Using Functional Near-Infrared Spectroscopy and Robot-Assisted Multi-Joint Pointing Movements of the Lower Limb.

Stroke affects approximately 17 million individuals worldwide each year and is a leading cause of long-term disability. Robotic therapy has shown promise in helping stroke patients regain lost motor functions. One potential avenue for increasing the understanding of how motor recovery occurs is to study brain activation during the movements that are targeted by therapy in healthy individuals. Functional Near-Infrared Spectroscopy (fNIRS) has emerged as a promising neuroimaging technique for examining neural underpinnings of motor function. This study aimed to investigate fNIRS neural correlates of complex lower limb movements in healthy subjects. Participants were asked to perform cycles of rest and movement for 6 min using a robotic device for motor rehabilitation. The task required coordinated knee and ankle joint movements to point to targets displayed on a computer screen. Two experimental conditions with different levels of movement assistance provided by the robot were explored. The results showed that the fNIRS protocol effectively detected brain regions associated with motor control during the task. Notably, all subjects exhibited greater activation in the contralateral premotor area during the no-assistance condition compared to the assisted condition. In conclusion, fNIRS appears to be a valuable approach for detecting changes in oxyhemoglobin concentration associated with multi-joint pointing movements of the lower limb. This research might contribute to the understanding of stroke motor recovery mechanisms and might pave the way for improved rehabilitation treatments for stroke patients. However, further research is needed to fully elucidate the potential of fNIRS in studying motor function and its applications in clinical settings.

Feasibility of Continuous Bronchoscopy During Exercise in the assessment of large airway movement in healthy subjects.

Excessive dynamic airway collapse (EDAC) is a recognized cause of exertional dyspnea arising due to invagination of the trachea and/ or main bronchi. EDAC is typically assessed by evaluating large airway movement with forced expiratory maneuvers. This differs from the respiratory response to exercise hyperpnea. We aimed to evaluate large airway movement during physical activity, with continuous bronchoscopy during exercise (CBE), in healthy subjects and compare findings with resting bronchoscopic maneuvers and imaging techniques. Twenty-eight individuals were recruited to complete two visits including treadmill-based CBE, to voluntary exhaustion and cine magnetic resonance imaging (MRI) with forced expiratory maneuvers at rest. 25 subjects (aged 29 (26 - 33) years, 52% female) completed the study (n=2 withdrew before bronchoscopy, and one was unable to tolerate insertion of bronchoscope). The majority (76%) achieved a peak heart rate of >90% predicted during CBE. The procedure was prematurely terminated in five subjects (n=3; elevated blood pressure and n=2; minor oxygen desaturation). The CBE assessment enabled adequate tracheal visualization in all cases. Excessive dynamic airway collapse (tracheal collapse ≥50%) was identified in 16 subjects (64%) on MRI, and in 6 (24%) individuals during resting bronchoscopy, but in no cases with CBE. No serious adverse events were reported, but minor adverse events were evident. The CBE procedure permits visualization of large airway movement during physical activity. In healthy subjects, there was no evidence of EDAC during strenuous exercise, despite evidence during forced maneuvers on imaging, thus challenging conventional approaches to diagnosis.

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects

Functional gastric disorders entail chronic or recurrent symptoms, high prevalence and a significant financial burden. These disorders do not always involve structural abnormalities and since they cannot be diagnosed by routine procedures, electrogastrography (EGG) has been proposed as a diagnostic alternative. However, the method still has not been transferred to clinical practice due to the difficulty of identifying gastric activity because of the low-frequency interference caused by skin–electrode contact potential in obtaining spatiotemporal information by simple procedures. This work attempted to robustly identify the gastric slow wave (SW) main components by applying multivariate variational mode decomposition (MVMD) to the multichannel EGG. Another aim was to obtain the 2D SW vectorgastrogram VGGSW from 4 electrodes perpendicularly arranged in a T-shape and analyse its dynamic trajectory and recurrence quantification (RQA) to assess slow wave vector movement in healthy subjects. The results revealed that MVMD can reliably identify the gastric SW, with detection rates over 91% in fasting postprandial subjects and a frequency instability of less than 5.3%, statistically increasing its amplitude and frequency after ingestion. The VGGSW dynamic trajectory showed a statistically higher predominance of vertical displacement after ingestion. RQA metrics (recurrence ratio, average length, entropy, and trapping time) showed a postprandial statistical increase, suggesting that gastric SW became more intense and coordinated with a less complex VGGSW and higher periodicity. The results support the VGGSW as a simple technique that can provide relevant information on the “global” spatial pattern of gastric slow wave propagation that could help diagnose gastric pathologies.

Evaluation of cognition with the eyelink: Saccadic eye movements in healthy subjects

AbstractBackgroundThe aim of this study is to determine the normative data of eye movements models for healthy individuals between the ages of 18‐77.Method76 healthy subjects were included in 3 age groups as 18‐44, 45‐59, 60+. Neuropsychological assessment with five cognitive domains, was applied. EyeLink 1000 Plus was used to record and pro‐saccade and anti‐saccade eye movement paradigms. Amplitude, latency, anticipatory saccades, express saccades, correct saccade response, corrected saccade and uncorrected saccade responses were analyzed.ResultIn antisaccade results, correct saccade response, latency, amplitude, anticipatory saccade, express saccade, corrected saccade response, uncorrected saccade were significantly different between the groups (p<0.05). Significant difference was also found in prosaccade latency (p<0.001). In the 18‐44 age group, executive functions were highly negatively correlated with antisaccade latency (r = ‐0.744, p = 0.000), and language was meanly negatively correlated with latency (r = ‐0.514, p = ‐0.010). In the 45‐59 age group, a medium level of negative correlation was observed between executive functions and latency (r = ‐0.501, p = 0.025). Language and express saccade (r = ‐0.515, p = 0.020) were meanly negatively correlated in the 45‐59 year age group. In the 60+ age group, a medium level of negative correlation was found between attention and latency (r = ‐0.414, p = 0.021). In this age group, executive functions and uncorrected saccade (r = ‐0.396, p = 0.027) were weakly negatively correlated.ConclusionDecline in cognitive functions that occur with aging might affect eye movements. The relationship between antisaccades and cognitive functions in our preliminary study may attract attention to antisaccades in evaluation of cognition.

Cutaneous silent period modulation by tooth clenching, tonic and phasic limb movements in healthy subjects.

We aimed to examine the modulation of the cutaneous silent period (CSP) by tooth clenching and contralateral tonic dorsiflexion of lower limb and phasic voluntary movements of upper limb. In 18 healthy subjects, we recorded CSP on right thenar muscle after painful stimulation of index finger during mild contraction at six conditions: baseline, maximum tooth clenching, contralateral tonic dorsiflexion of foot, as well as at the beginning (RT1), in the middle (RT2) and at last part (RT3) of the contralateral phasic wrist extension. We measured latency and duration and calculated suppression indices. During tooth clenching, the suppression index of second inhibitory phase (I2) was significantly higher than that at baseline condition. The suppression index of first inhibitory phase (I1) was reduced in tonic dorsiflexion. The I2 durations in RT2 and RT3 were longer than that at baseline. The I2 suppression indices during RT1, RT2, and RT3 were significantly higher than that at baseline condition (p < 0.05). The tooth clenching has an inhibitory effect on CSP. The contralateral phasic hand movements caused higher suppression index. The CSP is modulated by remote influences differently depending on the type of muscle contraction (tonic vs. phasic) and/or where it is realized (tooth, upper or lower limb).

Exploring EEG spectral and temporal dynamics underlying a hand grasp movement.

For brain-computer interfaces, resolving the differences between pre-movement and movement requires decoding neural ensemble activity in the motor cortex's functional regions and behavioural patterns. Here, we explored the underlying neural activity and mechanisms concerning a grasped motor task by recording electroencephalography (EEG) signals during the execution of hand movements in healthy subjects. The grasped movement included different tasks; reaching the target, grasping the target, lifting the object upwards, and moving the object in the left or right directions. 163 trials of EEG data were acquired from 30 healthy participants who performed the grasped movement tasks. Rhythmic EEG activity was analysed during the premovement (alert task) condition and compared against grasped movement tasks while the arm was moved towards the left or right directions. The short positive to negative deflection that initiated around -0.5ms as a wave before the onset of movement cue can be used as a potential biomarker to differentiate movement initiation and movement. A rebound increment of 14% of beta oscillations and 26% gamma oscillations in the central regions was observed and could be used to distinguish pre-movement and grasped movement tasks. Comparing movement initiation to grasp showed a decrease of 10% in beta oscillations and 13% in gamma oscillations, and there was a rebound increment 4% beta and 3% gamma from grasp to grasped movement. We also investigated the combination MRCPs and spectral estimates of α, β, and γ oscillations as features for machine learning classifiers that could categorize movement conditions. Support vector machines with 3rd order polynomial kernel yielded 70% accuracy. Pruning the ranked features to 5 leaf nodes reduced the error rate by 16%. For decoding grasped movement and in the context of BCI applications, this study identifies potential biomarkers, including the spatio-temporal characteristics of MRCPs, spectral information, and choice of classifiers for optimally distinguishing initiation and grasped movement.

Effects of experimental pain on the cervical spine reposition errors

BackgroundHealthy subjects showed normal variance of cervical spine reposition errors of approximately 2 degrees. Effects of experimental pain on cervical spine reposition errors were unknown; thus, the purpose of this study was to investigate the effects of experimental pain on cervical spine reposition errors.MethodsA repeated measured study design was applied. Thirty healthy subjects (12 males) were recruited. Reposition errors were extracted from upright cervical positions before and after cervical flexion movement in healthy subjects before and during experimental neck pain. Cervical spine reposition errors were calculated based on anatomical landmarks of each cervical joint. Reposition errors were extracted in degrees as constant errors and absolute errors for further statistical analysis. Repeated measures analysis of variance (RM-ANOVA) was applied to analyse experimental pain effects on either constant errors or absolute errors of different cervical joints.ResultsThe cervical spine showed non-significant difference in reposition errors regarding the constant errors (P>0.05) while larger reposition errors regarding the absolute errors during experimental pain compared to before experimental pain (P<0.001). In addition, the pain level joint (C4/C5) and its adjacent joints (C3/C4 and C5/C6) indicated larger reposition errors regarding absolute errors (P=0.035, P=0.329 and P=0.103, respectively).ConclusionsThis study firstly investigated the cervical spine reposition errors in experimental neck pain and further found the joints adjacent to the pain level showed larger errors compared to the distant joints regarding absolute errors. It may imply that the larger reposition errors in specific cervical joint indicate probable injury or pain existed adjacent to the joints.

James Waldo Lance 1926–2019

James W. Lance was a clinical neurologist who created the first university-based department of neurology in Australia. He championed academic enquiry and the scientific basis of clinical practice, and his research had two major themes, motor control and headache. After his doctoral studies on the pyramidal tract of the cat, he became a pioneer of the new field of motor control studied in human subjects, making seminal contributions on the control of muscle tone, reflexes and movement in healthy subjects and the pathophysiology of movement disorders in patients. At the same time he developed a clinical research program into the mechanisms and management of headache, in particular migraine. These studies evolved into parallel experiments in human subjects, cats and monkeys, probing the control of the cerebral circulation and the mechanisms underlying craniofacial pain, for which he received international acclaim in both fields. He received international and Australian honours and was the first practising clinician to be elected a fellow of the Australian Academy of Science. He is rightfully credited with leading the development of academic neurology in Australia and overseas.

Visuomotor Integration for Coupled Hand Movements in Healthy Subjects and Patients With Stroke.

Many studies have investigated the bilateral upper limb coordination during movements under different motor and visual conditions. Bilateral training has also been proposed as an effective rehabilitative protocol for patients with stroke. However, the factors influencing in-phase vs. anti-phase coupling have not yet been fully explored. In this study, we used a motion capture device based on two infrared distance sensors to assess whether the up and down oscillation of the less functional hand (the non-dominant one in healthy younger and older subjects and the paretic one in patients with stroke) could be influenced by in-phase or anti-phase coupling of the more functional hand and by visual feedback. Similar patterns were found between single hand movements and in-phase coupled movements, whereas anti-phase coupled movements were less ample, less sinusoidal, but more frequent. These features were particularly evident for patients with stroke who showed a reduced waveform similarity of bilateral movements in all conditions but especially for anti-phase movements under visual control. These results indicate that visuomotor integration in patients with stroke could be less effective than in healthy subjects, probably because of the attentional overload required when moving the two limbs in an alternating fashion.

In Vitro Utilization Characteristics of Maltobionic Acid and Its Effects on Bowel Movements in Healthy Subjects.

We examined the in vitro digestibility of maltobionic acid, obtained from enzymatic oxidation of maltose, its utilization by intestinal bacteria, and its biological effects on the bowel movements in healthy subjects. We found that maltobionic acid is not digested in vitro by saliva, gastric juice, or pancreatic juice. Moreover, it is digested only to a small extent by small intestinal enzymes. Among the 24 strains of intestinal bacteria, maltobionic acid was selectively utilized by Bifidobacterium dentium and Bi. adolescentis. We also evaluated the influence of long-term ingestion of maltobionic acid calcium salt on bowel movements in healthy Japanese women by a randomized, double-blind, placebo-controlled, crossover trial. Thirty-four subjects completed the study, and no adverse events related to the test food were observed. Ten subjects were excluded prior to the efficacy analysis because of conflict with the control criteria; the remaining 24 subjects were analyzed. Intake of test food containing 4 g maltobionic acid for 4 weeks caused a significant increase in the stool frequency, significant improvement in stool form scale and CAS-MT total scores as compared with the placebo group. These results suggest that maltobionic acid is an indigestible carbohydrate and is a promising therapeutic agent for improving the intestinal environment.

Comparison of Objective Indicators of Proprioception of Single–joint Arm Movements in Healthy Subjects and Post–Stroke Patients in Sitting and Lying Positions

Testing of sensory-motor performance and motor rehabilitation training in post-stroke patients are often executed in lying position. At the same time, influence of the body position on proprioceptive perception is poorly studied. In this study, we have investigated proprioceptive perception of single-joint arm movements in 10 healthy subjects and 17 post-stroke patients with unilateral arm paresis in the sitting and lying positions using the method we developed. Movements of flexion–extension in shoulder, elbow and wrist joints and abduction–adduction in shoulder and wrist joints were tested. The subjects were made to perform a series of the passive single-joint movements with the eyes closed and had to copy these movements simultaneously by active movements of another arm. We recorded the angles at the tested joint and the homonymous joint of the other arm, and the status of proprioceptive sensitivity was evaluated basing on the degree of similarity of these “passive” and “active” movements. Qualitative and quantitative indicators were used to assess the similarity. It was found that healthy subjects reproduce the passive movements without rough qualitative errors in both the sitting and lying positions. The movement reproduction was less accurate in the lying position by values of some quantitative indicators, however only 3% of trails did not match the conventional criterion for proprioceptive sensitivity intactness. On the contrary, the movement reproduction in almost half of tests in the group of post-stroke patients was performed with qualitative and quantitative errors and did not match the requirements of the conventional criterion. A deficit of proprioception was observed in 1 to 5 different test-movements in 88% of patients in the sitting position and 71% of patients in the lying position. Most frequent and rough errors in the movement reproduction were observed in distal segments of the paretic arm. It was found that the body position could have different effects on the proprioceptive perception of the same test-movement in patients: the proprioceptive perception was evaluated as intact in the sitting position and as distorted in the lying position in 14% of all test trials and vice versa it was evaluated as distorted in sitting position and as intact in lying positions in 17% of trials. Such individual differences must be considered when choosing conditions for motor rehabilitation procedures in patients with paresis of the arm.

Investigation on the effect of noisy galvanic vestibular stimulation on fine motor skills during a visuomotor task in healthy participants.

Noisy galvanic vestibular stimulation (nGVS) has been shown to improve dynamic walking stability, affect postural responses, enhance balance in healthy subjects, and influence motor performance in individuals with Parkinson’s disease. Although the studies to fully characterize the effect of nGVS are still ongoing, stochastic resonance theory which states that the addition of noisy signal may enhance a weak sensory input signals transmission in a non-linear system may provide a possible explanation for the observed positive effects of nGVS. This study explores the effect of nGVS on fine tracking behavior in healthy subjects. Ten healthy participants performed a computer-based visuomotor task by controlling an object with a joystick to follow an amplitude-modulated signal path while simultaneously receiving a sham or pink noise nGVS. The stimulation was generated to have a zero-mean, linearly detrended 1/f-type power spectrum, Gaussian distribution within 0.1–10 Hz range, and a standard deviation (SD) set to 90% based on each participant’s cutaneous threshold value. Results show that simultaneous nGVS delivery statistically improved the tracking performance with a decreased root-mean-squared error of 5.71±6.20% (mean±SD), a decreased time delay of 11.88±9.66% (mean±SD), and an increased signal-to-noise ratio of 2.93% (median, interquartile range (IQR) 3.31%). This study showed evidence that nGVS may be beneficial in improving sensorimotor performance during a fine motor tracking task requiring fine wrist movement in healthy subjects. Further research with a more comprehensive subset of tasks is required to fully characterize the effects of nGVS on fine motor skills.

P 106 - Intra- and inter-operator reliability of a novel hand protocol during grip movement in healthy subjects

Variability in gait speed is influenced by age and health status. However, no study has investigated the effects of different instructions on gait speed.This study investigated how walking prompts contributed to variability in gait speed.Participants walked on a pressurized walkway. Gait speed variability was assessed using multilevel modeling.61% of the variance in gait speed was due to instruction, while 14% was due to individual differences.Reference values for gait speed across a number of prompts will be highly useful for assessing gait performance in young adults. Further, the instruction given produces a large amount of variability in selected walking speed. This finding urges researchers to maintain consistency when delivering walking instructions.

FMRI Reactions in Motor Tasks Performed by Patients with Traumatic Brain Injury

The study included 22 healthy right-handed subjects (age 25.1 ± 3.9) and 9 patients with traumatic brain injury (TBI) (age 27.9 ± 7.3) without hemiparesis and local lesions in the sensorimotor cortex. The hemodynamical brain reactions were analyzed using functional magnetic resonance imaging (fMRI) during right- and left-hand movements. It was shown that reactive changes of responses have larger interindividual variability of the main topographic activation areas during left-hand movements as compared with right-hand movements in healthy subjects. In the TBI patients, the diffuse component of reactive changes was increased and involved a larger number of brain structures, both cortex areas and subcortical formations, including areas nonspecific for the motor analyzer. These changes were most clearly expressed in the dominant hemisphere (during movement of the right hand).

P 106 - Intra- and inter-operator reliability of a novel hand protocol during grip movement in healthy subjects

Quantitative and qualitative measures of human movement can be two important features for clinical decision making. The purpose of this study is to evaluate the Intra-and inter- operator reliability of a novel hand protocol during grip movement. The experimental protocol required the positioning of 8 optoelectronic cameras and 24 markers. 5 healthy subjects have been recruited. Each subject received 2 markerizations by two different operators (A and B) and they carried out 3 tests at a time T0 and at a time T1 (a week after) for each markerization. Results have shown that Test-retest reliability of the markers positions measurements was good (test: 0,893, p < 0.001; retest: 0,773, p < 0.01) and intra-operator reliability was excellent (A: 0.983, p < 0.001; B: 0.993 p < 0.001). Overall, these results suggest that this protocol is reliable in order to develop future studies for its application in clinical practice.

Brain activity region during kinesthetic illusion induced by visual stimulation of ankle joint

Kinesthetic illusion induced by visual stimulation (KiNvis) is a novel method that produces kinesthetic perception through observation of a person's physical exercise on a computer screen. KiNvis enhances lower limb corticomotor excitability in healthy subjects. However, it is not clear which regions of the brain are activated during KiNvis. The purpose of this study was to investigate the regions of brain activity during KiNvis in the ankle dorsiflexion movement. We examined the left lower limbs of 17 healthy subjects (mean age, 24.1 ± 5.3 years; 12 males and 5 females). We randomly applied two conditions to the left lower limbs. Condition 1 (observation condition) was to observe the image of ankle. Condition 2 (KiNvis condition) was to observe the video and induced the KiNvis. The video of ankle dorsiflexion movement on the right side filmed in first-person perspective was flipped horizontally and then shown on a computer screen. A computer was placed over the left side foot. Subjects observed the video that recorded the ankle dorsiflexion movement to induce KiNvis. The two conditions were measured using a rest-task-rest block design. Cerebral blood flow during rest and task (in the two conditions) were recorded using functional near infrared spectroscopy (fNIRS). Effective size of the two conditions were calculated and compared. During the KiNvis condition, A visual analogue scale (VAS) was measured to evaluate the degree of kinesthetic illusion. VAS was found to be 66.9 ± 12.5 mm (mean). Cerebral blood flow in the right premotor area was significantly increased during the KiNvis condition compared with that during the observation condition. Our results demonstrate that cerebral blood flow in the premotor area increases with KiNvis of the ankle dorsiflexion movement in healthy subjects.

A novel fluoroscopic method for multidimensional evaluation of swallowing function

ObjectiveDynamic videofluoroscopic swallow study (VFSS) is used to investigate swallowing movements. However, it requires prolonged radiation exposure and mainly provides qualitative information. Herein, we present a multi-dimensional method for analyzing swallowing based on a pulsed, low-dose fluoroscopy technique that uses serial-shot images and evaluates the size, position, and temporal profile of the bolus to obtain a more comprehensive and realistic analysis of swallowing movements. MethodsFifteen healthy adults drank two liquids: 20mL of pure water followed by 20mL of contrast medium mixture in a fluoroscopic study. Data were recorded in serial-shot images (7.5 frames/second, 1024×1024-pixel resolution, DICOM format). The images from the water and contrast swallows were inverted, synchronized, and subtracted to visualize the bolus in each frame. The pathway of the bolus was divided into 15 parts traversing the oropharynx, hypopharynx, and upper esophagus, and the total gray value was measured in each section. The results were presented as contour graphs. ResultsThe contour graphs allowed for information on the size, anatomical location, and temporal location of the bolus during swallowing to be displayed simultaneously. Two distinct swallowing patterns were observed in the subjects. The bolus showed two peaks—one in the hypopharynx and one in the upper esophagus—in all subjects. However, in nine of the 15 subjects, the two peaks were in different frames, whereas in six of the subjects, the two peaks were in the same frame. ConclusionWe developed a new method for quantitatively evaluating swallowing. The technique allows for multidimensional assessment of the size, position, and temporal profile of the movement of the bolus across the pharynx. This method evaluates the swallowing movements using sharp, high-resolution images obtained by serial-shot, pulsed fluoroscopy with low radiation exposure. Additional studies are required to further clarify the variability of swallowing patterns and their clinical relevance in the evaluation of swallowing movements in healthy subjects and in patients with swallowing disorders.

F191. Electrophysiological brain activity during motor imagery enhanced by brain–computer interface in healthy volunteers and post-stroke patients

Introduction Motor imagery (MI) has been shown to be an effective tool in rehabilitation of post-stroke patients. MI can be enhanced by kinesthetic feedback provided by brain-computer-exoskeleton interfaces. Description and analysis of brain activity during the kinesthetic imagery of movements in healthy subjects and post-stroke patients with the subcortical location of the damage was performed in the current study. Methods Seven right-handed healthy volunteers (age 29 [22.0; 35.0] years) and nine post-stroke patients (age 52.0 [36.0; 58.0] years, time since stroke 6.0 [4.0; 13.0] months) were enrolled. They were trained in kinesthetic motor imagery using brain-computer interface (BCI) and a controllable exoskeleton. All participants had 20 training sessions with a duration of up to 15 min. The BCI was controlled using a Bayessian classifier, which was preset to recognize the imagery of left or right hand extension and the rest state. Processing of EEG recordings was performed using the independent component analysis. The digitization of EEG-electrode positions for obtaining their coordinates in the MRI-related system was made using an NBS Eximia Nexstim device for navigational transcranial magnetic stimulation. This study used the AMICA method to find the sources of electrophysiological brain activity during motor imagery. For each component determined, the EEG inverse problem was solved according to the sLORETA method. Results Components that are most frequently identified by the AMICA method were revealed in the same areas in both groups: SIL (the primary somatosensory left cortex), SIR (the primary somatosensory right cortex), PRC (the precuneus), PRM (the premotor left cortex), and SMA (the supplementary motor area). There were differences in the activity characteristics when comparing healthy controls and patients: the μ -rhythm in the somatosensory area was characterized by a lower frequency in the studied poststroke patients than in the healthy subjects; it had a poorly pronounced peak in all mental states and was only slightly suppressed during contralateral hand motor imagery. The rhythm in the α -band was also characterized by a low frequency with a poorly pronounced peak in the precuneus and premotor area; however, unlike in the healthy subjects, this rhythm increased, i.e., was synchronized, during motor imagery. Conclusion This study is an extension of previous investigations of EEGs during motor imagery in healthy subjects. Only two symmetrical sources in the primary somatosensory cortex were previously discussed. This study revealed three more sources: the premotor area, precuneus, and supplementary motor area. The characteristics of the EEG sources during motor imagery are fundamentally different in post-stroke patients comparing to healthy controls. Funding was provided by grant RFMEF N I60715X0128.

The effect of transcranial direct current stimulation (tDCS) on locomotion and balance in patients with chronic stroke: study protocol for a randomised controlled trial

BackgroundFollowing stroke, patients are often left with hemiparesis that reduces balance and gait capacity. A recent, non-invasive technique, transcranial direct current stimulation, can be used to modify cortical excitability when used in an anodal configuration. It also increases the excitability of spinal neuronal circuits involved in movement in healthy subjects. Many studies in patients with stroke have shown that this technique can improve motor, sensory and cognitive function. For example, anodal tDCS has been shown to improve motor performance of the lower limbs in patients with stroke, such as voluntary quadriceps strength, toe-pinch force and reaction time. Nevertheless, studies of motor function have been limited to simple tasks. Surprisingly, the effects of tDCS on the locomotion and balance of patients with chronic stroke have never been evaluated. In this study, we hypothesise that anodal tDCS will improve balance and gait parameters in patients with chronic stroke-related hemiparesis through its effects at cortical and spinal level.Methods/designThis is a prospective, randomised, placebo-controlled, double-blinded, single-centre, cross-over study over 36 months. Forty patients with chronic stroke will be included. Each patient will participate in three visits: an inclusion visit, and two visits during which they will all undergo either one 30-min session of transcranial direct current stimulation or one 30-min session of placebo stimulation in a randomised order. Evaluations will be carried out before, during and twice after stimulation. The primary outcome is the variability of the displacement of the centre of mass during gait and a static-balance task. Secondary outcomes include clinical and functional measures before and after stimulation. A three-dimensional gait analysis, and evaluation of static balance on a force platform will be also conducted before, during and after stimulation.DiscussionThese results should constitute a useful database to determine the aspects of complex motor function that are the most improved by transcranial direct current stimulation in patients with hemiparesis. It is the first essential step towards validating this technique as a treatment, coupled with task-oriented training.Trial registrationClinicalTrials.gov, ID: NCT02134158. First received on 18 December 2013; last updated on 14 September 2016. Other study ID numbers: P120135 / AOM12126, 2013-A00952-43.