Postural control during turn on the light task assisted by functional electrical stimulation in post stroke subjects

Postural control mechanisms have a determinant role in reaching tasks and are typically impaired in post-stroke patients. Functional electrical stimulation (FES) has been demonstrated to be a promising therapy for improving upper limb (UL) function. However, according to our knowledge, no study has evaluated FES infuence on postural control. This study aims to evaluate the infuence of FES UL assistance, during turning on the light task, in the related postural control mechanisms. An observational study involving ten post-stroke subjects with UL dysfunction was performed. Early and anticipatory postural adjustments (EPAs and APAs, respectively), the weight shift, the center of pressure and the center of mass (CoM) displacement were analyzed during the turning on the light task with and without the FES assistance. FES parameters were adjusted to improve UL function according to a consensus between physiotherapists’ and patients’ perspectives. The ANOVA repeated measures, Paired sample t and McNemar tests were used to compare postural control between the assisted and non-assisted conditions. When the task was assisted by FES, the number of participants that presented APAs increased (p= 0.031). UL FES assistance during turning on the light task can improve postural control in neurological patients with UL impairments.info:eu-repo/semantics/publishedVersio

Effect of Stance Symmetry on Perturbation-Induced Protective Stepping in Persons Poststroke and Controls

Problem Statement: Stepping is a common strategy after a perturbation. Stroke survivors display a predilection for stepping with non-paretic leg. Insight into induced stepping between stroke survivors and age-matched control may guide our understanding for reactive postural control training post stroke. Purpose: To investigate the difference in perturbation-induced stepping between chronic stroke survivors and age-matched controls at three phases of the stepping response: preparation, execution, and landing and association with clinical outcome measures. Procedure: Twenty-one community-dwelling chronic stroke survivors (mean age 59y/o ±13yrs) and 17 age- and gender-matched controls (mean age 54.4y/o ±17yrs) completed this study. Clinical measures of gait, balance, range, sensation, and motor control were assessed. A mechanical weight drop of 10% body weight (BW) was used to create the anterior waist pull perturbation during three stance symmetry positions: equal stance (EQ) and two asymmetrical stance (70% BW on dominant leg and 70% BW on nondominant leg). Ten perturbation trials plus two catch trials at 2% BW were given in a standard randomly order at the three stance positions. Kinematic and kinetic data was collected for perturbation steps. Results: The asymmetrical trials resulted in two types of stepping response, steps with the leg bearing 70% BW (loaded steps – LS) and steps with the leg that had 30% BW (unloaded steps – ULS). All subjects initiated steps more often with their unloaded leg (ULS) in the asymmetrical stance trials. In the stroke group the ULS increased paretic leg stepping compared to EQ (p=0.001) and LS (p=0.001). The stroke group had significantly earlier APA onset with both non-paretic leg (p=0.003) and paretic leg (p=0.028), took significantly more steps with paretic (p=0.01) and non-paretic (p=0.07), shorter step length (paretic, p=0.025 and non-paretic p=0.003), and less change in momentum at landing with paretic leg (p=0.01) compared to controls. Conclusion: Reacting to a perturbation is more challenging for chronic stroke survivors than age- and gender-matched control subjects in the preparation, execution, and landing phase of the stepping response regardless of the leg used. Perturbation training should include stepping with both non-paretic and paretic leg

Posture and Movement Estimation Based on Reduced Information. Application to the Context of FES-based Control of Lower-Limbs

International audienc

A novel behavioural paradigm for characterising anticipatory postural adjustments in mice

Daily we use purposeful, voluntary movements to interact with our environment. These movements demand and cause our body to experience a weight redistribution, i.e., anticipatory postural adjustments (APAs), and it’s the appropriate employment of these APAs that allows us to complete said voluntary movements without falling over or losing our equilibrium. The literature suggests that for humans, monkeys, and several quadrupeds, APAs are crucial at initiation and during movement. However, research has been somewhat limited due to the lack of behavioural paradigms that would allow for a better understanding into the neural circuitry involved with APAs. Given the widespread availability of genetic tools and advanced viral techniques in mice I focused my efforts in developing a novel behavioral paradigm for this species. The first chapters detail the reasoning behind the development of this novel behavioural paradigm while also providing a complete description of the different components and their functions. Later chapters use the custom-designed setup to characterise mouse APAs, incorporating various recording approaches designed to quantify APAs and compare them to those described in prior work, highlighting possible interspecifies similarities and differences. Additionally, I briefly discuss the potential neural circuitry of APAs informed by my own data and research that has been done in different animals, providing a comprehensive overview of APAs in mice

Anticipatory postural adjustments in the shoulder girdle in the reach movement performed in standing by post-stroke subjects

After a stroke in middle cerebral artery territory, there is a high probability of dysfunction of the ventromedial pathways, mainly related with postural control mechanisms such as the anticipatory postural adjustments (APAs). According to neuroanatomical knowledge, these pathways have a predominant ipsilesional disposition, which justifies a bilateral postural control dysfunction, often neglected in rehabilitation. In order to assess this bilateral postural control dysfunction, electromyography activity was assessed in eight post-stroke and 10 healthy individuals in the anterior deltoids, the superior and lower trapezius, and the latissimus dorsi as they reached for a bottle with both upper limbs separately at a self-selected velocity and fast velocity while standing associated with trunk kinematics analysis. Through this analysis it was possible to compare the timing of APAs in scapular muscles between sides in post-stroke and with healthy individuals, and to verify if there is a relation between the timing and the displacement of the trunk in the temporal window of the APAs. Indeed, post-stroke individuals show a delayed activation of APAs on scapular girdle muscles on both ipsilesional and contralesional sides, which were not reflected in the trunk displacement.info:eu-repo/semantics/publishedVersio

Inconsistent anticipatory postural adjustments (APAs) in rugby players : a source of injuries ?

Background: We are developing since 2010 with Thales and the Fédération Française de Rugby (FFR) M-Rex, a new kind of rugby scrum simulator. The study questioned whether it could improve safety and protect players from injury by using it as a tool for training/coaching the packs. Aim: To explore the anticipatory postural adjustments (APAs) during the engagement of the ruck, because these predictive neck and back muscles contractions protect the spinal cord at the time of impacts, which is crucial to prevent injuries. Methods: We quantified the kinematics and the EMG activities in high-level front row players during their initial engagement, when scrummaging with M-Rex. All studies were performed with one player interacting with the robot, at first, and then with the three players acting together. Results: For most of the tested high-level players, the APA latencies were highly variable from trial to trial even though the engagement resulted in similar impacts. At time, the onset of the electromyography activity in the neck and back muscles showed latencies inferior to 50 ms or even close to zero prior to the impact, which rendered muscle contractions inefficient as APAs. We were also unable to identify clear muscular synergies underlying the APAs because of their great variability on a trial-to-trial basis. Finally, the APAs were not related to the amplitude of the ensuing impact and were asymmetric in most trials. All these characteristics held true, whether the player was playing alone or with two other frontline players. Conclusion: Our result suggest that APAs should be systematically tested in high-level rugby players as well as in any high-level sport men at risk of neck and back injuries. Because APAs can be efficiently trained, our study paves the way to design individual position-specific injury prevention programme.This study was funded by Fédération Française de Rugb

Comparative analysis of postural balance by posturography in patients with isolated vertigo or associated with hearing loss

Purpose: To perform a comparative analysis of the balance of subjects with isolated vertigo and dizziness associated with hearing loss. Methods: The sample consisted of 29 patients with peripheral vertigo diagnosis selected by non-probabilistic sampling and convenience aged between 45 and 64 years. The diagnostic survey to hearing evaluation consisted of audiological anamnesis and assessment of postural balance; it was made in force platform, in the bipedal and semi tandem positions with open eyes. The analyzed balance parameters were: ellipse area, center of pressure in square centimeters, average speed in centimeters per second and average frequency, in Hertz, of swaying in both directions of movement: anteroposterior and mediolateral. Results: As for the population in general, the comparison between individuals with and without hearing loss has not shown to be there any damage to the maintenance of postural balance. There was difference in women in the speed parameter in mediolateral direction. Conclusion: Although no differences have been found which might have characterized a correlation between hearing loss and balance in patients, there was a worse performance in postural balance of women with vertigo associated with hearing loss in the mediolateral parameter. Objetivo: Realizar uma análise comparativa do equilíbrio de sujeitos com vertigem isolada e com vertigem associada à perda auditiva. Métodos: A amostra foi constituída por 29 pacientes com diagnóstico de vertigem periférica, selecionados pelo método de amostragem não probabilística e por conveniência, com idade entre 45 e 64 anos, sendo 9 do gênero masculino e 20 do gênero feminino. A pesquisa diagnóstica para avaliação da audição consistiu de anamnese audiológica e audiometria tonal liminar. A avaliação do equilíbrio postural foi feita em Plataforma de Força, nas posições bipodal e semi-tandem, com os olhos abertos. Os parâmetros de equilíbrio analisados foram: área elipse, centro de pressão em centímetros quadrados, velocidade média em centímetros por segundo e frequência média, em Hertz, de oscilações do centro de pressão, em ambas as direções dos movimentos: anteroposterior e mediolateral. Resultados: Na população geral, a comparação dos dados estabilométricos entre indivíduos com e sem perda auditiva não demonstrou prejuízo da manutenção do equilíbrio postural. Houve diferença no gênero feminino, em relação ao parâmetro velocidade, na direção mediolateral. Conclusão: Embora não tenham sido encontradas diferenças que possam caracterizar correlação entre perda auditiva e equilíbrio entre os pacientes, houve pior desempenho no equilíbrio postural das mulheres com vertigem associada à perda auditiva, no parâmetro mediolateral

Effects of Combined Exercise Training on Balance of Hemiparetic Stroke patients

INTRODUCTION: A stroke occurs as a result of brain damage caused by cerebral infarction or hemorrhage. The majority, 73~88%, of cerebral infarction patients have impaired sensory motor ability on the side opposite to the brain damage appearing as hemiplegia of the arms and legs or either. Most survivors of stroke have decreased capacity to perform activities of daily living (ADL) because of a combination of sensory, motor, cognitive and emotional impairments. Of all the possible sensorimotor deficits of stroke, damaged postural control has the greatest impact on ADL independence and gait. Hemiplegic patients have decreased balance control ability. Especially, the postural sway in static positions is more than twice that of healthy subjects of the same age group, which consequences for safety4. Balance is described as the ability to maintain equilibrium in a gravitational field by keeping or returning the center of body mass over its base of support5. Dynamic balance is a voluntary response which maintains the position in response to an external perturbation. AIM OF THE STUDY: To find the effectiveness of combined exercises which consists of aerobic training and functional strengthening exercise over conventional exercises which consists of balance,posture control exercise and gait training in improving balance in hemiparetic stroke patients. OBJECTIVES: 1. To find the effectiveness of combined exercises (functional strengthening exercise and aerobic) in improving the balance in hemiparetic stroke patients. 2. To find the effectiveness of conventional exercises (balance exercise,posture exercise and gait training) in improving balance in hemiparetic stroke patients. 3. To compare the effectiveness of combined exercise versus conventional exercises training in improving balance in hemiparetic stroke patients. MATERIALS AND METHODLOGY: RESEARCH DESIGN: A Pretest-Posttest experimental study consisting of 30 stroke patients were undertaken to investigate the balance of the hemiparetic stroke patients. There are two experimental groups. SELECTION CRITERIA: Inclusion Criteria: 1. Patients with stroke involving in lower extremity. 2. Patient within 6 months of post stroke period. 3. Both sexes. 4. Age group between 35-50 years. 5. Patient who can stand independently without any assistive devices at least for a minute. Exclusion Criteria: 1. Haemodynamically unstable. 2. Patient could not perform functional exercise due to arthritis. 3. Low back pain, with radiating pain and numbness over legs. 4. Cardiovascular and Respiratory conditions impairing aerobic training. 5. Patient who have uncontrolled hypertension. 6. Patients who could not follow instructions due to low perceptive abilities, cognitive disorder. 7. Hearing impairment. SAMPLE SIZE AND SAMPLING: Purposive sampling of thirty samples was adopted in this study. A group of 30 subjects who had satisfied the inclusion criteria and exclusion criteria were selected and they were purposively divided into two groups. Group 1 - received combined exercises with aerobics and functional strengthening exercise, Group 2 - received conventional exercises. Setting of Study: Narayana Health, Multi speciality Hospital, Bangalore-99. Duration of the Study: It was an experimental study with the duration of 4 weeks of treatment per subject. RESULTS: As the calculated value is greater than the t table value. Null hypothesis 1 (Ho1) is rejected and research hypothesis 1 (H11) is accepted. As the calculated value is greater than the t table value. Null hypothesis 2 (H02) is rejected and research hypothesis 2 (H12) is accepted. As the calculated value is greater than the t table value. Null hypothesis 1 (H03) is rejected and research hypothesis 3 (H13) is accepted. SUMMARY: In this study, totally 30 subjects of the hemiparetic stroke patients are taken into two experimental groups equally into Combined exercises group (aerobic and functional strengthening exercises) group 1 and conventional exercises group (balance exercises, posture exercises and gait training) group 2 in improving the static and dynamic balance by using the Berg Balance Scale (BBS) and Timed Up and Go test (TUG) as the outcome measuring scale. Based on the results found in this study there are improvements in both the combined exercises, group 1 and conventional exercises, group 2. But, there are significant better improvement in the combined exercises, group 1 than the conventional exercises, group 2. So, the results found are published. CONCLUSIONS: Based on this study combined exercises given to group 1 has shown the improvement in both the static and dynamic balance scores in the hemiparetic stroke patients. Based on this study conventional exercises given to group 2 has shown the improvement in both the static and dynamic balance scores in the hemiparetic stroke patients. Based on this study combined exercise of group 1 had shown the marked improvement in both the static and dynamic balance than the conventional exercises of group 2 in the hemiparetic stroke patients. This suggests that combined exercise training can be prescribed for stroke patients to reduce their risk of falls and lead to independent ADL