Aujourd'hui, 90 millions de personnes dans le monde souffrent de lésions de la moelle épinière. Grâce aux progrès de la prise en charge des patients, leur espérance de vie est comparable à celle du reste de la population et la priorité de la recherche médicale est désormais consacrée à l'amélioration de leur qualité de vie. La stimulation électrique fonctionnelle (SEF) permet de restaurer les mouvements des membres paralysés et a des bénéfices thérapeutiques et fonctionnels. L'objectif de cette thèse est de proposer des solutions pour l'assistance au lever de chaise, au transfert d'une surface à une autre et à la station debout. Nous souhaitons trouver un compromis entre fonctionnalité et simplicité d'utilisation en termes de nombres de capteurs requis et de complexité calculatoire et donc favoriser l'application en environnement clinique et privé.

Background: Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects. However, vagus nerve branching has not yet been described in the context of vagus nerve stimulation. Materials and methods: Branching of the cervical vagus nerve was investigated macroscopically in 35 body donors (66 cervical sides) in the carotid sheath. After X-ray imaging for determining the vertebral levels of cervical vagus nerve branching, samples were removed to confirm histologically the nerve and to calculate cervical vagus nerve diameters and cross-sections. Results: Cervical vagus nerve branching was observed in 29%of all cases (26% unilaterally, 3% bilaterally) and proven histologically in all cases. Right-sided branching (22%) was more common than left-sided branching (12%) and occurred on the level of the fourth and fifth vertebra on the left and on the level of the second to fifth vertebra on the right side. Vagus nerves without branching were significantly larger than vagus nerves with branches, concerning their diameters (4.79mm vs. 3.78mm) and cross-sections (7.24 mm2 vs. 5.28mm2). Discussion: Cervical vagus nerve branching is considerably more frequent than described previously. The side-dependent differences of vagus nerve branching may be linked to the asymmetric effects of the vagus nerve. Cervical vagus nerve branching should be taken into account when identifying main trunk of the vagus nerve for implanting electrodes to minimize potential side effects or lacking therapeutic benefits of vagus nerve stimulation.

Abstract Aim: The main objective of this study was to compare electro mechanical delay (EMD) and rate of torque development (RTD) of the knee extensors 6 weeks after rehabilitation of anterior cruciate ligament reconstruction (ACLR) with or without neuromuscular electrical stimulation (NMES). Further the feasibility of the study was examined. Method: 10 participants were randomized into two groups, one neuromuscular electrical stimulation group (NMESG) and one training group (TG). The NMESG used a NMES-device as a complement to the ordinary rehabilitation protocol. Regular meetings with a physiotherapist were scheduled during the rehabilitation. Measurements of RTD and EMD during knee extension were made in an isokinetic dynamometer with electromyography recordings (EMG) from the knee extensors 6 weeks after surgery. Results: All participants completed the study. The NMESG went to see the physiotherapist 6.7 ± 2.5 times and the TG 6.8 ± 1.8 times. The participants in the NMESG used the NMES-apparatus 28 ± 1.7 times. Total number of training days for the NMESG was 25 ± 4 and for the TG 35 ± 1. RTD did not significantly differ between the groups. For the TG, RDT was 901.1, 941.2 and 531.0 Nm/s, over the first 50, 100 and 200 ms, respectively. For NMESG: RTD was 824.3, 966.2 and 529.0 Nm/s, over the first 50, 100 and 200 ms, respectively. No significant difference between the groups or interaction between group and muscle was found in EMD. For both groups EMD was significantly larger for vastus medialis as compared to the vastus lateralis and rectus femoris. Conclusions: The study was feasible to perform, and despite fewer training days for the NMESG, no significant group differences were found in RTD or EMD. A larger study population is needed to evaluate the efficacy of the intervention. / Abstrakt Syfte: Huvudsyftet med denna studie var att jämföra elektromekaniska fördröjning (EMD) och vridmoment utveckling (RTD) för knäextensorerna 6 veckor efter rehabilitering av främre korsbandsrekonstruktion (ACLR) med eller utan neuromuskulär elektrisk stimulering (NMES). Vidare undersöktes genomförbarheten av studien. Metod: 10 deltagare randomiseras in i två grupper, en neuromuskulär elektrisk stimulerings grupp (NMESG) och en träningsgrupp (TG). NMESG använde en NMES - enhet som ett komplement till ordinarie rehabiliteringsprotokoll. Regelbundna möten med sjukgymnast var inplanerad under rehabiliteringen. Mätningar av RTD och EMD under knäets extension gjordes i en isokinetisk dynamometer med elektromyografi inspelningar (EMG) från knäextensorerna 6 veckor efter operationen. Resultat: Alla deltagare fullföljde studien. NMESG träffade sjukgymnasten 6,7 ± 2,5 gånger och TG 6,8 ± 1,8 gånger. Deltagarna i NMESG använde NMES - apparaten 28 ± 1,7 gånger. Totalt antal träningsdagar för NMESG var 25 ± 4 och för TG 35 ± 1. RTD skiljde sig inte signifikant mellan grupperna. För TG var RDT 901,1, 941,2 och 531,0 Nm/s, under de respektive första 50, 100 och 200 ms. För NMESG var RTD 824,3, 966,2 och 529,0 Nm/s, under de respektive första 50, 100 och 200 ms. Inga signifikanta skillnader mellan grupperna eller samspel mellan grupp och muskler hittades i EMD. För båda grupperna var EMD signifikant större för vastus medialis jämfört vastus lateralis och rectus femoris. Slutsats: Studien var möjligt att utföra, och trots färre träningsdagar för NMESG sågs inga signifikanta skillnader mellan grupperna i RTD eller EMD. Det behövs en större studiepopulation för att utvärdera effekten av interventionen.

At the beginning of this project it was known that functional electrical stimulation (FES) rowing was technically feasible, but no studies on health benefits had been conducted and it was unclear what levels of fitness could be reliably attained by spinal cord injured (SCI) users. This thesis shows that training with the first-generation of the FES-rowing system (RowStim II), seven paraplegics achieved high V02peak values (21.0 - 27.9 ml-kg-1-min-1) and a significant (10%) increase in V02peak. This was also found to significantly improve insulin sensitivity and leptin levels but it had no significant effect on lipid profiles or body composition, possibly caused by technological limitations of the RowStim 11. However, training volumes were positively correlated with improvements in lipid profile and body composition. This motivated further technical development of the RowStim to enable paraplegics to train harder and longer. The development included a more stable seat configuration with redesigned trunk retaining straps, a rigid low friction carriage/brake system, improved leg stabiliser, improved stimulation control and a gravity-assisted return phase. This RowStim III has enabled paraplegics to participate in the British (2004, 2005 and 2006) and World Indoor Rowing Championships (2006). The rowers have achieved higher exercise intensities (26.8 -31.0 ml. kg- I .min-1) and increased exercise volumes (1,150 kcal-week-1) with the RowStim III. Such levels of physical activity, which are difficult to achieve for paraplegics using traditional exercises, are correlated with significant health benefits in the able-bodied. Preliminary results suggest that perfusion of the quadriceps muscle during FES-rowing might limit the exercise time in novice rowers. Other preliminary data from pressure mapping indicate that there is a dynamic pattern during FES-rowing, which might reduce the risk for pressure sores during FES-rowing. This thesis shows that FES-rowing is now a rapidly developing exercise modality, which has been shown to enable safe and well-tolerated exercise for individuals with SCI. It can offer unprecedented levels of cardiovascular fitness, competitive challenges and potentially important health benefits.

Po priekinio kryžminio raiščio (PKR) rekonstrukcijos fizinio aktyvumo atgavimas trunka nuo 3 iki 12 mėnesių. Siekiant greitesnio kelio sąnario funkcijos atkūrimo, šiame darbe vertinamas dviejų skirtingų metodikų efektyvumas. Darbo tikslas – palyginti raumenų elektrostimuliacijos (RES), taikomos kineziterapijos metu ir prieš kineziterapijos procedūrą, poveikį kelio sąnario funkcijos atkūrimui po priekinio kryžminio raiščio rekonstrukcinės operacijos. Apžvelgus mokslinę literatūrą numatytą mokslinio darbo tikslą pasiekti buvo iškelti 3 uždaviniai. Pirmuoju uždaviniu siekiama įvertinti kelio sąnario funkcijos kitimą po priekinio kryžminio raiščio rekonstrukcinės operacijos taikant raumenų elektrostimuliaciją prieš kineziterapijos procedūras. Antrasis uždavinys skirtas įvertinti kelio sąnario funkcijos kitimą po priekinio kryžminio raiščio rekonstrukcinės operacijos taikant raumenų elektrostimuliaciją kineziterapijos procedūros metu. Trečiuoju uždaviniu siekiama palyginti kelio sąnario funkcijos atkūrimo pokytį po priekinio kryžminio raiščio rekonstrukcinės operacijos taikant raumenų elektrostimuliaciją kineziterapijos metu ir prieš kineziterapijos procedūrą. Tyrimo metodai: 1. Judesių amplitudė per kelio sąnarį vertinta goniometrijos metodu. 2. Blauzdą lenkiančių ir tiesiančių raumenų jėga vertinta Medicininių tyrimų tarnybos skale. 3. Skausmo intensyvumui vertinti naudota Skaičių analoginė skausmo skalė. 4. Kelio sąnario funkcinė būklė vertinta Lysholm klausimynu. 5. Operuotos... [toliau žr. visą tekstą] / After anterior cruciate ligament (ACL) reconstruction physical activity recovery lasts from 3 to 12 months. Seeking more rapid knee joint function recovery the effectiveness of two different methods are estimated in this research. The aim of the research is to compare the effectiveness of neuromuscular electrical stimulation (NMES) applied before and during physiotherapy procedure, as well as the effect of the knee joint function recovery after anterior cruciate ligament reconstruction. After review of scholarly literature there were 3 tasks set to reach the aim of the research. The first task is to estimate the changes in the knee joint function after anterior cruciate ligament reconstruction applying neuromuscular electrical stimulation before physiotherapy procedures. The second task is to estimate the changes in the knee joint function after anterior cruciate ligament reconstruction applying neuromuscular electrical stimulation during physiotherapy procedures. The third task is to compare the changes in the knee joint function applying neuromuscular electrical stimulation during physiotherapy and before physiotherapy procedure. The methods of the research: 1. The amplitude of the knee joint movements is estimated by goniometry method. 2. The force of the calf flexor and extensor muscles is estimated by Medical Research Council scale. 3. The intensity of the pain is estimated by Numeric Rating Scale. 4. The knee joint function is assessed by Lysholm knee questionnaire. 5... [to full text]

The restoration of arm-free standing in paraplegic individuals can be accomplished with the help of functional electrical stimulation (FES). The key component of such a system is a controller that can modulate FES induced muscle contractions in real-time, such that artificially produced forces in the legs and abdominal muscles are able to generate stable standing posture. A 57 year-old individual with chronic ASIA-A (American Spinal Injury Association), T3/4 level spinal cord injury (SCI) participated in this study. The objective was to determine if a proportional-derivative (PD) or proportional-integral-derivative (PID) controller could be used to regulate FES induced muscle contractions in the ankle joint to allow it to maintain balance of the entire body during quiet standing, while exhibiting physiological dynamics seen in able-bodied individuals while doing so.

Individuals with stroke often demonstrate impaired ankle-foot function, commonly termed dropped foot that affects their ability to walk safely at home and within their community. While interventions are available to improve gait function, they have inconsistency demonstrated positive effects due to the lack of evidence-based practice guidelines and a limited understanding of the mechanisms leading to dropped foot. The aim of this dissertation was to 1) determine the relationship between dropped foot gait deviations and impaired sensorimotor control, 2) compare gait biomechanics between stroke survivors with and without dropped foot impairment, and 3) evaluate the immediate effects of an ankle-foot orthotic (AFO) and functional electrical stimulation (FES) device among stroke survivors with dropped foot impairment. Our evaluation combined standardized clinical measures of ankle-foot function (i.e. sensorimotor control, strength, spasticity and range of motion) and gait analysis using advanced laboratory techniques (i.e. electromyography and electrical goniometers) to quantify mechanisms of dropped foot impairment. Fifty-five stroke survivors completed the assessment prior to discharge from inpatient rehabilitation. Individuals with poor generation of isometric dorsiflexor force and reduced passive ankle range of motion were likely to demonstrate greater plantarflexion in swing and limited stance phase ankle joint excursion, respectively. Results from the gait analysis revealed a delayed onset and reduced activation time of the ankle dorsiflexors, and decreased co-activation time in the stance phase as possible mechanisms leading to dropped foot. A detailed case series was performed with four stroke survivors with dropped foot currently using an AFO. Application of an AFO immediately improved peak dorsiflexion in the swing phase and limited ankle range of motion during stance. When walking with the FES device, individuals with moderate dorsiflexor muscle weakness improved their ankle position at initial contact and increased peak dorsiflexion during stance, while no significant changes were observed among individuals with greater impairment. Overall, the results highlighted individual differences in response to interventions aimed at improving dropped foot gait deviations. These findings contribute to a greater understanding of gait dysfunction post stroke, and may lead to the development of a more effective clinical assessment and intervention strategies to improve dropped foot impairment.

This thesis describes experiments designed to investigate the effects of neuromuscular electrical stimulation (NMES) on corticospinal (CS) excitability in humans. NMES delivered at 100 Hz was more effective for increasing CS excitability than 10-, 50-, or 200-Hz NMES. CS excitability increases occurred after 24 min of 100-Hz NMES, were strongest in the stimulated muscle, and were mediated primarily at a supraspinal level. NMES of the common peroneal nerve of the leg increased CS excitability in multiple leg muscles, whereas NMES of the median nerve of the hand increased CS excitability in only the muscle innervated by that nerve. Additionally, CS excitability for the hand increased after 40 min of relatively high intensity and frequency NMES but not after 2 h of lower intensity and frequency NMES. These results have implications for identifying optimal NMES parameters to augment CS excitability for rehabilitation after central nervous system injury.

In this thesis sensorimotor integration in the human spinal cord was investigated in the intact (Chapters 2 and 3) and injured nervous systems (Chapter 4-stroke; Chapter 5-spinal cord injury (SCI)). In Chapter 2, I characterized a short-latency reflex pathway between sensory receptors of the lower leg and the erector spinae (ES) muscles of the lower back that may play a role in the maintenance of posture and balance. The ES reflexes were evoked bilaterally by taps applied to the Achilles tendon and were modulated by task. Furthermore, these reflexes involved a larger contribution from cutaneous receptors in the lower limb, rather than muscle spindles. In Chapter 3, I investigated changes in reflex transmission along the H-reflex pathway throughout 10 s trains of neuromuscular electrical stimulation (NMES) using physiologically relevant frequencies (5-20 Hz) and during functionally relevant tasks (sitting and standing) and background contraction amplitudes (up to 20% MVC). The results of this study revealed strong post-activation depression of reflex amplitudes, followed by significant recovery during the stimulation, both of which were influenced by stimulation frequency and background contraction amplitude, but not task. During 10 Hz stimulation, reflex amplitudes showed complete recovery (i.e. back to their initial values), and at times, complete recovery occurred by the third reflex in the train. These results demonstrate that transmission along the H-reflex pathway is modulated continuously during periods of repetitive input. In Chapters 4 and 5, I studied the extent to which a novel stimulation protocol that incorporated wide pulse widths (1 ms) and high frequencies (up to 100 Hz) (wide-pulse NMES; WP-NMES), could enhance electrically-evoked contractions through a central contribution in individuals with stroke or SCI. This central effect arises from the electrical activation of sensory axons, which in turn, reflexively recruit motoneurons in the spinal cord. After stroke, contractions evoked by WP-NMES were larger in the paretic arm than the non-paretic arm. After SCI, transmission along the H-reflex pathway was observed throughout trains of WP-NMES; direct evidence of a central contribution. These results suggest that maximizing the central contribution during WP-NMES may be useful for maintaining muscle quality after neurological injury.

Functional electrical stimulation (FES) is a rehabilitative technology that can be used to improve walking in individuals with mobility impairments due to neurologic injury or disease. Feedback is essential for efficient FES-assisted walking. The overall goal of my project was to investigate external sensors to provide feedback for FES-assisted walking. The current study evaluated accelerometers, force sensitive resistors, segment orientation angles, and segment angular velocities to determine which were appropriate for determining the activation and deactivation of six major muscles used for walking. The results demonstrated that the segment orientation angles were the most appropriate sensors. Using the segment angle of the thigh, shank, and foot, the activation and deactivation times of the six muscles investigated could be determined within 6% of the step cycle. The shank segment angle performed the best for determining the activation and deactivation times when only one sensor was desired.