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Dynamic postural stability

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https://www.readbyqxmd.com/read/28226432/reinforcement-learning-for-stabilizing-an-inverted-pendulum-naturally-leads-to-intermittent-feedback-control-as-in-human-quiet-standing
#1
Kenjiro Michimoto, Yasuyuki Suzuki, Ken Kiyono, Yasushi Kobayashi, Pietro Morasso, Taishin Nomura, Kenjiro Michimoto, Yasuyuki Suzuki, Ken Kiyono, Yasushi Kobayashi, Pietro Morasso, Taishin Nomura, Ken Kiyono, Pietro Morasso, Kenjiro Michimoto, Yasushi Kobayashi, Yasuyuki Suzuki, Taishin Nomura
Intermittent feedback control for stabilizing human upright stance is a promising strategy, alternative to the standard time-continuous stiffness control. Here we show that such an intermittent controller can be established naturally through reinforcement learning. To this end, we used a single inverted pendulum model of the upright posture and a very simple reward function that gives a certain amount of punishments when the inverted pendulum falls or changes its position in the state space. We found that the acquired feedback controller exhibits hallmarks of the intermittent feedback control strategy, namely the action of the feedback controller is switched-off intermittently when the state of the pendulum is located near the stable manifold of the unstable saddle-type upright equilibrium of the inverted pendulum with no active control: this action provides an opportunity to exploit transiently converging dynamics toward the unstable upright position with no help of the active feedback control...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226425/the-brain-can-mix-different-control-strategies-in-a-task-oriented-and-multi-referential-manner-a-simulation-study
#2
Pietro Morasso, Taishin Nomura, Yasuyuki Suzuki, Jacopo Zenzeri, Pietro Morasso, Taishin Nomura, Yasuyuki Suzuki, Jacopo Zenzeri, Jacopo Zenzeri, Taishin Nomura, Yasuyuki Suzuki, Pietro Morasso
In everyday life the brain must adapt to variable situations that may require a mixture of approaches including anticipatory synergy formation, through an internal body schema, and different control strategies. Unstable tasks are particularly challenging because deteriorate the predictive power of internal models and further enhance the instability potential of delayed sensory feedback. We explore this issue by means of three simulation studies: A) The hybrid control of a double inverted pendulum model, B) The bimanual stabilization of a saddle-like instability, C) Whole-body focal-postural dynamics...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28218341/influence-of-hip-and-knee-osteoarthritis-on-dynamic-postural-control-parameters-among-older-fallers
#3
Sumaiyah Mat, Chin Teck Ng, Maw Pin Tan
OBJECTIVE: To compare the relationship between postural control and knee and hip osteoarthritis in older adults with and without a history of falls. METHODS: Fallers were those with ≥ 2 falls or 1 injurious fall over 12 months. Non-fallers were volunteers with no falls in the past year. Radiological evidence of osteoarthritis with no reported symptoms was considered "asymptomatic osteoarthritis", while "symptomatic osteoarthritis" was defined as radiographic osteoarthritis with pain or stiffness...
February 16, 2017: Journal of Rehabilitation Medicine
https://www.readbyqxmd.com/read/28217106/effect-of-noisy-galvanic-vestibular-stimulation-on-ocular-vestibular-evoked-myogenic-potentials-to-bone-conducted-vibration
#4
Shinichi Iwasaki, Shotaro Karino, Teru Kamogashira, Fumiharu Togo, Chisato Fujimoto, Yoshiharu Yamamoto, Tatsuya Yamasoba
OBJECTIVE: Galvanic vestibular stimulation (GVS) delivered as zero-mean current noise (noisy GVS) has been shown to improve static and dynamic postural stability probably by enhancing vestibular information. The purpose of this study was to examine the effect of an imperceptible level noisy GVS on ocular vestibular-evoked myogenic potentials (oVEMPs) in response to bone-conducted vibration (BCV). MATERIALS AND METHODS: oVEMPs to BCV were measured during the application of white noise GVS with an amplitude ranging from 0 to 300 µA [in root mean square (RMS)] in 20 healthy subjects...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28210066/effects-of-interactive-metronome-training-on-postural-stability-and-upper-extremity-function-in-parkinson-s-disease-a-case-study
#5
Arim Kim, Hye-Sun Lee, Chiang-Soon Song
[Purpose] The purpose of this study was to examine the effects of interactive metronome training on the postural stability and upper extremity function of an individual with Parkinson's disease. [Subject and Methods] The participant of this case study was a 75-year-old female with Parkinson's disease diagnosed 7 years prior. This study was a single-subject research with an A-B-A design. She received IM training during the treatment phase (B phase) for 40 minutes per session. She was assessed pretest and posttest using the Berg balance scale and Wolf motor function test, and at baseline and the treatment phase using the measured box-and-block test and a Tetrax system...
January 2017: Journal of Physical Therapy Science
https://www.readbyqxmd.com/read/28194100/head-stability-and-head-trunk-coordination-in-horseback-riders-the-contribution-of-visual-information-according-to-expertise
#6
Agnès Olivier, Elise Faugloire, Laure Lejeune, Sophie Biau, Brice Isableu
Maintaining equilibrium while riding a horse is a challenging task that involves complex sensorimotor processes. We evaluated the relative contribution of visual information (static or dynamic) to horseback riders' postural stability (measured from the variability of segment position in space) and the coordination modes they adopted to regulate balance according to their level of expertise. Riders' perceptual typologies and their possible relation to postural stability were also assessed. Our main assumption was that the contribution of visual information to postural control would be reduced among expert riders in favor of vestibular and somesthetic reliance...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28192831/training-effects-of-the-fifa-11-and-harmoknee-on-several-neuromuscular-parameters-of-physical-performance-measures
#7
Francisco Ayala, Carlos Pomares-Noguera, Francisco Javier Robles-Palazón, Maria Del Pilar García-Vaquero, Ignacio Ruiz-Pérez, Sergio Hernández-Sánchez, Mark De Ste Croix
The main purpose of this study was to analyse the training effects of the FIFA 11+ and Harmoknee on several parameters of physical performance measures in youth amateur football players. 41 adolescent players were randomised within each team into 2 groups (team 1: control vs. FIFA 11+; team 2: control vs. Harmoknee). The FIFA 11+ and Harmoknee groups performed the program 3 times a week for 4 weeks; the control groups completed their usual warm-up routines. 13 physical performance measures (joint range of motion, dynamic postural control, single legged hop limb symmetry, sprint time, jumping height and agility) were assessed...
February 13, 2017: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/28187057/improvements-in-gait-with-hearing-aids-and-cochlear-implants
#8
Corey S Shayman, Gammon M Earhart, Timothy E Hullar
OBJECTIVE: To evaluate whether wearing auditory assistive devices can improve gait and dynamic balance. PATIENTS: Three adult users of bilateral hearing assistive devices: one with cytomegalovirus exposure wearing cochlear implants, one with Ménière's disease wearing hearing aids, and one with presbystasis wearing hearing aids. INTERVENTION: Rehabilitative intervention involved participants performing gait and dynamic posture tasks with and without their hearing assistive devices...
February 9, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28157620/dynamic-head-neck-stabilization-in-cervical-dystonia
#9
Patrick A Forbes, Edo de Bruijn, Sebastiaan W R Nijmeijer, Johannes H T M Koelman, Frans C T van der Helm, Alfred C Schouten, Marina A J Tijssen, Riender Happee
BACKGROUND: Effective sensorimotor integration is essential to modulate (adapt) neck stabilization strategies in response to varying tasks and disturbances. This study evaluates the hypothesis that relative to healthy controls cervical dystonia patients have an impaired ability to modulate afferent feedback for neck stabilization with changes in the frequency content of mechanical perturbations. METHODS: We applied anterior-posterior displacement perturbations (110s) on the torso of seated subjects, while recording head-neck kinematics and muscular activity...
January 16, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28153459/total-hip-arthroplasty-in-the-spinal-deformity-population-does-degree-of-sagittal-deformity-affect-rates-of-safe-zone-placement-instability-or-revision
#10
Edward M DelSole, Jonathan M Vigdorchik, Ran Schwarzkopf, Thomas J Errico, Aaron J Buckland
BACKGROUND: Changes in spinal alignment and pelvic tilt alter acetabular orientation in predictable ways, which may have implications on stability of total hip arthroplasty (THA). Patients with sagittal spinal deformity represent a subset of patients who may be at particularly high risk of THA instability because of postural compensation for abnormal spinal alignment. METHODS: Using standing stereoradiography, we evaluated the spinopelvic parameters, acetabular cup anteversion, and inclination of 139 THAs in 107 patients with sagittal spinal deformity...
December 27, 2016: Journal of Arthroplasty
https://www.readbyqxmd.com/read/28148513/no-association-between-static-and-dynamic-postural-control-and-acl-injury-risk-among-female-elite-handball-and-football-players-a-prospective-study-of-838-players
#11
Kathrin Steffen, Agnethe Nilstad, Tron Krosshaug, Kati Pasanen, Aleksander Killingmo, Roald Bahr
BACKGROUND: Research on balance measures as potential risk factors for ACL injury is limited. OBJECTIVE: To assess whether postural control was associated with an increased risk for ACL injuries in female elite handball and football players. METHOD: Premier league players were tested in the preseason and followed prospectively for ACL injury risk from 2007 through 2015. At baseline, we recorded player demographics, playing experience, ACL and ankle injury history...
February 2017: British Journal of Sports Medicine
https://www.readbyqxmd.com/read/28119877/effects-of-pilates-core-stability-exercises-on-the-balance-abilities-of-archers
#12
Jeong-Min Park, Gwang-Suk Hyun, Yong-Seok Jee
This study aimed to provide fundamental data contributing to archery performance improvement and stabilization of shooting posture in archers by examining the influence of Pilates core stability (PCS) exercises on dynamic and static balance. The study was conducted from December 2015 to March 2016 on high school archers who were registered as archers in the Korea Archery Association with 5 or more years of archery experience. Twenty voluntary subjects (exercise group n=10; control group n=10) with an understanding toward the aims of this study were selected and their body composition, static and dynamic balance abilities, before and after the PCS program, were measured...
December 2016: Journal of Exercise Rehabilitation
https://www.readbyqxmd.com/read/28095106/gender-differences-in-static-and-dynamic-postural-stability-of-soldiers-of-the-army-s-101st-airborne-division-air-assault
#13
Timothy C Sell, Mita T Lovalekar, Takashi Nagai, Michael D Wirt, John P Abt, Scott M Lephart
CONTEXT: Postural stability is essential for injury prevention and performance. Differences between genders may affect training focus. OBJECTIVE: To examine static and dynamic postural stability (PS) in male and female Soldiers Design: Descriptive Laboratory Study. SETTING: Biomechanics laboratory. PARTICIPANTS: Twenty-five healthy female Soldiers (26.4 ± 5.3 years) and twenty-five healthy male Soldiers (26.4 ± 4.9) years matched on physical demand rating, and years of service from the Army's 101st Airborne Division (Air Assault)...
January 17, 2017: Journal of Sport Rehabilitation
https://www.readbyqxmd.com/read/28092413/disruption-of-right-posterior-parietal-cortex-by-ctbs-alters-the-control-of-body-balance-in-quiet-stance
#14
David Kaulmann, Joachim Hermsdörfer, Leif Johannsen
Control of body balance relies on the integration of multiple sensory modalities. Lightly touching an earth-fixed reference augments the control of body sway. We aimed to advance the understanding of cortical integration of an afferent signal from light fingertip contact (LT) for the stabilisation of standing body balance. Assuming that right-hemisphere Posterior Parietal Cortex (rPPC) is involved in the integration and processing of touch for postural control, we expected that disrupting rPPC would attenuate any effects of light touch...
January 16, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28069073/quantification-of-postural-stability-in-minimally-disabled-multiple-sclerosis-patients-by-means-of-dynamic-posturography-an-observational-study
#15
Lucia Grassi, Stefano Rossi, Valeria Studer, Gessica Vasco, Caterina Motta, Fabrizio Patanè, Enrico Castelli, Silvia Rossi, Paolo Cappa
BACKGROUND: Multiple Sclerosis (MS) is a widespread progressive neurologic disease with consequent impairments in daily activities. Disorders of balance are frequent and equilibrium tests are potentially useful to quantify disability and to verify treatment effectiveness. The fair sensitivity of the widely used not-perturbed tests to detect balance disturbances in MS patients have prompted the development of mechatronic systems capable to impose known equilibrium perturbations, in order to challenge the balance control and, consequently, to better assess the level of impairment...
January 10, 2017: Journal of Neuroengineering and Rehabilitation
https://www.readbyqxmd.com/read/28068962/correlation-between-lumbar-dysfunction-and-fat-infiltration-in-lumbar-multifidus-muscles-in-patients-with-low-back-pain
#16
Markus Hildebrandt, Gabriela Fankhauser, André Meichtry, Hannu Luomajoki
BACKGROUND: Lumbar multifidus muscles (LMM) are important for spinal motion and stability. Low back pain (LBP) is often associated with fat infiltration in LMM. An increasing fat infiltration of LMM may lead to lumbar dysfunction. The purpose of this study was to investigate whether there is a correlation between the severity of lumbar dysfunction and the severity of fat infiltration of LMM. METHODS: In a cross-sectional study, 42 patients with acute or chronic LBP were recruited...
January 10, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28061401/the-effect-of-weight-bearing-asymmetry-on-dynamic-postural-stability-in-people-with-chronic-stroke
#17
Digna de Kam, Jip F Kamphuis, Vivian Weerdesteyn, Alexander C H Geurts
After stroke, weight-bearing asymmetry (WBA) towards the non-paretic side is associated with postural instability. It remains unknown whether WBA is a cause or consequence of postural instability, as both phenomena depend on stroke severity. We investigated the effect of WBA on the ability to recover from balance perturbations in people with stroke. Fourteen people in the chronic phase of stroke underwent multidirectional translational perturbations at three levels of initial WBA (0, 10 and 20% of body weight unloading of the paretic leg)...
December 21, 2016: Gait & Posture
https://www.readbyqxmd.com/read/28054910/examining-effects-of-physical-exertion-on-the-dynamic-visual-acuity-test-in-collegiate-athletes
#18
Jessie N Patterson, Anna M Murphy, Julie A Honaker
BACKGROUND: Acute symptoms of dizziness and/or imbalance commonly experienced in athletes postconcussion are speculated to arise from dysfunction at multiple levels (i.e., inner ear or central vestibular system) to appropriately integrate afferent sensory information. Disruption along any pathway of the balance system can result in symptoms of dizziness, decreased postural control function (vestibulospinal reflex), and reduced vestibulo-ocular reflex function. This may also lead to decreased gaze stability with movements of the head and may account for symptoms of blurred vision or diplopia reported in almost half of athletes sustaining a concussion...
January 2017: Journal of the American Academy of Audiology
https://www.readbyqxmd.com/read/28036322/effects-of-femoral-rotational-taping-on-dynamic-postural-stability-in-female-patients-with-patellofemoral-pain
#19
Chen-Yi Song, Jiu-Jenq Lin, Alison H Chang
OBJECTIVE: To investigate the effects of femoral rotational taping on task performance, dynamic postural control, and pain during the Star Excursion Balance Test (SEBT) in patients with patellofemoral pain (PFP) compared to healthy controls. DESIGN: Case-control study, pretest-posttest. SETTING: Laboratory. PARTICIPANTS: Twenty-four female participants (16 with PFP, 8 controls). INTERVENTIONS: Participants in both the PFP and control groups performed SEBT with no taping, sham taping, and femoral rotational taping...
October 10, 2016: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
https://www.readbyqxmd.com/read/28030997/mandibular-position-influence-on-pilots-postural-balance-analyzed-under-dynamic-conditions
#20
Alberto Baldini, Alessandro Nota, Clementina Cioffi, Fabiana Ballanti, Simona Tecco
OBJECTIVE: The aim of this study is to evaluate the influence of the mandibular position on the postural stability in a sample of civilian and military pilots. METHODS: Twenty military pilots (males, mean age 35.15 ± 3.14 years) and 17 civilian pilots (males, mean 34.91 ± 2.15 years) were enrolled in this study and underwent a Sensory Organization Test (SOT) using the EquiTest® (NeuroCom International Inc., Clackamas, OR, USA) computerized dynamic posturography...
December 29, 2016: Cranio: the Journal of Craniomandibular Practice
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