Enhancement of Robot-Assisted Rehabilitation Outcomes of Post-Stroke Patients Using Movement-Related Cortical Potential

Post-stroke rehabilitation is essential for stroke survivors to help them regain independence and to improve their quality of life. Among various rehabilitation strategies, robot-assisted rehabilitation is an efficient method that is utilized more and more in clinical practice for motor recovery of post-stroke patients. However, excessive assistance from robotic devices during rehabilitation sessions can make patients perform motor training passively with minimal outcome. Towards the development of an efficient rehabilitation strategy, it is necessary to ensure the active participation of subjects during training sessions. This thesis uses the Electroencephalography (EEG) signal to extract the Movement-Related Cortical Potential (MRCP) pattern to be used as an indicator of the active engagement of stroke patients during rehabilitation training sessions. The MRCP pattern is also utilized in designing an adaptive rehabilitation training strategy that maximizes patients’ engagement. This project focuses on the hand motor recovery of post-stroke patients using the AMADEO rehabilitation device (Tyromotion GmbH, Austria). AMADEO is specifically developed for patients with fingers and hand motor deficits. The variations in brain activity are analyzed by extracting the MRCP pattern from the acquired EEG data during training sessions. Whereas, physical improvement in hand motor abilities is determined by two methods. One is clinical tests namely Fugl-Meyer Assessment (FMA) and Motor Assessment Scale (MAS) which include FMA-wrist, FMA-hand, MAS-hand movements, and MAS-advanced hand movements’ tests. The other method is the measurement of hand-kinematic parameters using the AMADEO assessment tool which contains hand strength measurements during flexion (force-flexion), and extension (force-extension), and Hand Range of Movement (HROM)

INTERACTION OF CEREBRAL, CARDIAC AND MUSCULAR CHANGES INDUCED BY ACUTE ENDURANCE EXERCISE

Resting and premotor brain activity seems to be decisive for numerous motor behaviors. The literature has shown that acute endurance exercise may modulate the brain activity and reduce the motor performances. The aim of this thesis is to investigate the links between the modulations in resting and premotor electroencephalographic activity, and the knee-extensor neuromuscular function and the autonomic cardiovascular activity changes after an endurance exercise performed on an ergocycle. In parallel, this work aims to bring to the field of exercise sciences a new analysis method of the functional state of the resting brain, namely, the microstate analysis. In the first article, we reported a reduction in premotor potential amplitude and maximal voluntary contraction force after exercise. The decrease in premotor brain activity shows links with the neuromuscular function and suggests that mechanisms implicated in a voluntary contraction may reside at the premotor level, even before movement arises. In the second article, we reported a main effect of exercise on microstate C stability, which was characterized by an increase in its duration, time coverage and explained variance, and a greater percentage of transition towards this microstate. This study suggests that the modulations of microstate C may reflect a dominance of the salience resting-state network, likely under the influence of muscle afferents and endogenous stimuli, which could affect the voluntary motor command. In the third article, we showed that the increase in microstate C mean duration and the modulations in heart rate variability persist during the 1 hour after exercise. The modifications in microstate C temporal properties may reflect the adjustment of the autonomic cardiovascular activity and/or an increase in exercise-related cardiovascular arousal. By investigating the resting and premotor brain activity, the present thesis provides a better understanding of the motor response modulations after endurance exercise and opens up novel opportunities for exploring the interactions between the global functional state of the brain and the exercise-related physiological responses. -- L’activité cérébrale de repos et pré-motrice semble être déterminante pour de nombreux comportements moteurs. La littérature a montré qu’un exercice physique d’endurance aigu pouvait moduler l’activité cérébrale et réduire les performances motrices. Le but de cette thèse est d’investiguer les liens entre les modulations de l’activité électroencéphalographique de repos et pré-motrice, et les modifications de la fonction neuromusculaire des muscles extenseurs du genou et de l’activité cardiaque autonome à la suite d’un exercice d’endurance réalisé sur ergocycle. En parallèle, ce travail vise à apporter au champ des sciences de l’exercice une nouvelle méthode d’analyse de l’état fonctionnel global du cerveau au repos, à savoir l’analyse de micro-état. Dans le premier article, nous avons observé une réduction de l’amplitude du potentiel pré- moteur et de la force maximale volontaire après l’exercice. La réduction de l’activité cérébrale pré-motrice présente des liens avec les modulations de la fonction neuromusculaire, suggérant que des mécanismes impliqués dans une contraction volontaire pourraient résider au niveau pré-moteur, avant même que le mouvement soit produit. Dans le deuxième article, nous avons observé un effet principal de l’exercice sur la stabilité du micro-état C, caractérisé par une augmentation de sa durée, du temps couvert et de sa variance expliquée, ainsi qu’un pourcentage de transition vers ce micro-état plus important. Cette étude suggère que les modulations du micro-état C pourraient refléter une dominance du réseau de repos saillant, probablement sous l’influence d’afférences musculaires et de stimuli endogènes, qui exercerait une influence sur la commande motrice volontaire. Dans le troisième article, nous avons montré que l’augmentation de la durée moyenne du micro- état C persiste 1 heure après l’arrêt de l’exercice, tout comme les modulations de la variabilité de la fréquence cardiaque. Les modifications des propriétés temporelles du micro-état C pourraient refléter l’ajustement de l’activité cardiaque autonome et/ou une augmentation de l’éveil cardiovasculaire lié à l’exercice. En étudiant l’activité cérébrale de repos et pré-motrice, cette thèse fournit une meilleure compréhension des modulations de la réponse motrice à la suite d’un exercice physique d’endurance et ouvre de nouvelles opportunités pour explorer les interactions entre l’état fonctionnel global du cerveau au repos et les réponses physiologiques liées à l’exercice

TMS application in both health and disease

Transcranial magnetic stimulation (TMS) can be useful for therapeutic purposes for a variety of clinical conditions. Numerous studies have indicated the potential of this noninvasive brain stimulation technique to recover brain function and to study physiological mechanisms. Following this line, the articles contemplated in this Research Topic show that this field of knowledge is rapidly expanding and considerable advances have been made in the last few years. There are clinical protocols already approved for Depression (and anxiety comorbid with major depressive disorder), Obsessive compulsive Disorder (OCD), migraine headache with aura, and smoking cessation treatment but many studies are concentrating their efforts on extending its application to other diseases, e.g., as a treatment adjuvant. In this Research Topic we have the example of using TMS for pain, post-stroke depression, or smoking cessation, but other diseases/injuries of the central nervous system need attention (e.g., tinnitus or the surprising epilepsy). Further, the potential of TMS in health is being explored, in particular regarding memory enhancement or the mapping of motor control regions, which might also have implications for several diseases. TMS is a non-invasive brain stimulation technique that can be used for modulating brain activation or to study connectivity between brain regions. It has proven efficacy against neurological and neuropsychiatric illnesses but the response to this stimulation is still highly variable. Research works devoted to studying the response variability to TMS, as well as large-scale studies demonstrating its efficacy in different sub-populations, are therefore of utmost importance. In this editorial, we summarize the main findings and viewpoints detailed within each of the 12 contributing articles using TMS for health and/or disease applications.publishe

Eye quietness and quiet eye in expert and novice golf performance: an electrooculographic analysis

Quiet eye (QE) is the final ocular fixation on the target of an action (e.g., the ball in golf putting). Camerabased eye-tracking studies have consistently found longer QE durations in experts than novices; however, mechanisms underlying QE are not known. To offer a new perspective we examined the feasibility of measuring the QE using electrooculography (EOG) and developed an index to assess ocular activity across time: eye quietness (EQ). Ten expert and ten novice golfers putted 60 balls to a 2.4 m distant hole. Horizontal EOG (2ms resolution) was recorded from two electrodes placed on the outer sides of the eyes. QE duration was measured using a EOG voltage threshold and comprised the sum of the pre-movement and post-movement initiation components. EQ was computed as the standard deviation of the EOG in 0.5 s bins from –4 to +2 s, relative to backswing initiation: lower values indicate less movement of the eyes, hence greater quietness. Finally, we measured club-ball address and swing durations. T-tests showed that total QE did not differ between groups (p = .31); however, experts had marginally shorter pre-movement QE (p = .08) and longer post-movement QE (p < .001) than novices. A group × time ANOVA revealed that experts had less EQ before backswing initiation and greater EQ after backswing initiation (p = .002). QE durations were inversely correlated with EQ from –1.5 to 1 s (rs = –.48 - –.90, ps = .03 - .001). Experts had longer swing durations than novices (p = .01) and, importantly, swing durations correlated positively with post-movement QE (r = .52, p = .02) and negatively with EQ from 0.5 to 1s (r = –.63, p = .003). This study demonstrates the feasibility of measuring ocular activity using EOG and validates EQ as an index of ocular activity. Its findings challenge the dominant perspective on QE and provide new evidence that expert-novice differences in ocular activity may reflect differences in the kinematics of how experts and novices execute skills

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 388)

This bibliography lists 132 reports, articles and other documents introduced into the NASA Scientific and Technical Information Database. Subject coverage includes: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Muscle activation patterns in shoulder impingement patients

Introduction: Shoulder impingement is one of the most common presentations of shoulder joint problems 1. It appears to be caused by a reduction in the sub-acromial space as the humerus abducts between 60o -120o – the 'painful arc'. Structures between the humeral head and the acromion are thus pinched causing pain and further pathology 2. Shoulder muscle activity can influence this joint space but it is unclear whether this is a cause or effect in impingement patients. This study aimed to observe muscle activation patterns in normal and impingement shoulder patients and determine if there were any significant differences. Method: 19 adult subjects were asked to perform shoulder abduction in their symptomatic arm and non-symptomatic. 10 of these subjects (age 47.9 ± 11.2) were screened for shoulder impingement, and 9 subjects (age 38.9 ± 14.3) had no history of shoulder pathology. Surface EMG was used to collect data for 6 shoulder muscles (Upper, middle and lower trapezius, serratus anterior, infraspinatus, middle deltoids) which was then filtered and fully rectified. Subjects performed 3 smooth unilateral abduction movements at a cadence of 16 beats of a metronome set at 60bpm, and the mean of their results was recorded. T-tests were used to indicate any statistical significance in the data sets. Significance was set at P<0.05. Results: There was a significant difference in muscle activation with serratus anterior in particular showing a very low level of activation throughout the range when compared to normal shoulder activation patterns (<30%). Middle deltoid recruitment was significantly reduced between 60-90o in the impingement group (30:58%).Trends were noted in other muscles with upper trapezius and infraspinatus activating more rapidly and erratically (63:25%; 60:27% respectively), and lower trapezius with less recruitment (13:30%) in the patient group, although these did not quite reach significance. Conclusion: There appears to be some interesting alterations in muscle recruitment patterns in impingement shoulder patients when compared against their own unaffected shoulders and the control group. In particular changes in scapula control (serratus anterior and trapezius) and lateral rotation (infraspinatus), which have direct influence on the sub-acromial space, should be noted. It is still not clear whether these alterations are causative or reactionary, but this finding gives a clear indication to the importance of addressing muscle reeducation as part of a rehabilitation programme in shoulder impingement patients