A Combination of Central Pattern Generator-based and Reflex-based Neural Networks for Dynamic, Adaptive, Robust Bipedal Locomotion

DEFF Research Database (Denmark)

Di Canio, Giuliano; Larsen, Jørgen Christian; Wörgötter, Florentin

2016-01-01

Robotic systems inspired from humans have always been lightening up the curiosity of engineers and scientists. Of many challenges, human locomotion is a very difficult one where a number of different systems needs to interact in order to generate a correct and balanced pattern. To simulate...... the interaction of these systems, implementations with reflexbased or central pattern generator (CPG)-based controllers have been tested on bipedal robot systems. In this paper we will combine the two controller types, into a controller that works with both reflex and CPG signals. We use a reflex-based neural...... network to generate basic walking patterns of a dynamic bipedal walking robot (DACBOT) and then a CPG-based neural network to ensure robust walking behavior...

Muscle weakness and lack of reflex gain adaptation predominate during post-stroke posture control of the wrist

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van der Helm Frans CT

2009-07-01

Full Text Available Abstract Background Instead of hyper-reflexia as sole paradigm, post-stroke movement disorders are currently considered the result of a complex interplay between neuronal and muscular properties, modified by level of activity. We used a closed loop system identification technique to quantify individual contributors to wrist joint stiffness during an active posture task. Methods Continuous random torque perturbations applied to the wrist joint by a haptic manipulator had to be resisted maximally. Reflex provoking conditions were applied i.e. additional viscous loads and reduced perturbation signal bandwidth. Linear system identification and neuromuscular modeling were used to separate joint stiffness into the intrinsic resistance of the muscles including co-contraction and the reflex mediated contribution. Results Compared to an age and sex matched control group, patients showed an overall 50% drop in intrinsic elasticity while their reflexive contribution did not respond to provoking conditions. Patients showed an increased mechanical stability compared to control subjects. Conclusion Post stroke, we found active posture tasking to be dominated by: 1 muscle weakness and 2 lack of reflex adaptation. This adds to existing doubts on reflex blocking therapy as the sole paradigm to improve active task performance and draws attention to muscle strength and power recovery and the role of the inability to modulate reflexes in post stroke movement disorders.

Cross-Modal Calibration of Vestibular Afference for Human Balance.

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Martin E Héroux

Full Text Available To determine how the vestibular sense controls balance, we used instantaneous head angular velocity to drive a galvanic vestibular stimulus so that afference would signal that head movement was faster or slower than actual. In effect, this changed vestibular afferent gain. This increased sway 4-fold when subjects (N = 8 stood without vision. However, after a 240 s conditioning period with stable balance achieved through reliable visual or somatosensory cues, sway returned to normal. An equivalent galvanic stimulus unrelated to sway (not driven by head motion was equally destabilising but in this situation the conditioning period of stable balance did not reduce sway. Reflex muscle responses evoked by an independent, higher bandwidth vestibular stimulus were initially reduced in amplitude by the galvanic stimulus but returned to normal levels after the conditioning period, contrary to predictions that they would decrease after adaptation to increased sensory gain and increase after adaptation to decreased sensory gain. We conclude that an erroneous vestibular signal of head motion during standing has profound effects on balance control. If it is unrelated to current head motion, the CNS has no immediate mechanism of ignoring the vestibular signal to reduce its influence on destabilising balance. This result is inconsistent with sensory reweighting based on disturbances. The increase in sway with increased sensory gain is also inconsistent with a simple feedback model of vestibular reflex action. Thus, we propose that recalibration of a forward sensory model best explains the reinterpretation of an altered reafferent signal of head motion during stable balance.

Effects of Bed Rest on Conduction Velocity of the Triceps Surae Stretch Reflex and Postural Control

Science.gov (United States)

Reschke, M. F.; Wood, S. J.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Esteves, J. T.; Taylor, L. C.; DeDios, Y. E.; Harm, D. L.

2011-01-01

Despite rigorous exercise and nutritional management during space missions, astronauts returning from microgravity exhibit neuromuscular deficits and a significant loss in muscle mass in the postural muscles of the lower leg. Similar changes in the postural muscles occur in subjects participating in long-duration bed rest studies. These adaptive muscle changes manifest as a reduction in reflex conduction velocity during head-down bed rest. Because the stretch reflex encompasses both the peripheral (muscle spindle and nerve axon) and central (spinal synapse) components involved in adaptation to calf muscle unloading, it may be used to provide feedback on the general condition of neuromuscular function, and might be used to evaluate the effectiveness of countermeasures aimed at preserving muscle mass and function during periods of unloading. Stretch reflexes were measured on 18 control subjects who spent 60 to 90 days in continuous 6 deg head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 degrees at a peak velocity of about 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender. Computerized posturography was also conducted on these same subjects before and after bed rest as part of the standard measures. Peak-to-peak sway was measured during Sensory Organization Tests (SOTs) to evaluate changes in the ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Although no gender differences were found, a significant increase in reflex latency and a significant decrease in CV were observed during the bed

Isometric and Dynamic Control of Neck Muscles : Reflexive contributions and muscle synergies

NARCIS (Netherlands)

De Bruijn, E.

2014-01-01

It is well established that the central nervous system (CNS) stabilizes the head using reflexive feedback and cocontraction. The major reflexive pathways in the neck are through muscle spindles generating the cervicocollic reflex (CCR) and through the vestibular organ generating the vestibulocollic

Adaptation of multijoint coordination during standing balance in healthy young and healthy old individuals

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Pasma, J. H.; Schouten, A. C.; Aarts, R. G. K. M.; Meskers, C. G. M.; Maier, A. B.; van der Kooij, H.

2015-01-01

Standing balance requires multijoint coordination between the ankles and hips. We investigated how humans adapt their multijoint coordination to adjust to various conditions and whether the adaptation differed between healthy young participants and healthy elderly. Balance was disturbed by push/pull rods, applying two continuous and independent force disturbances at the level of the hip and between the shoulder blades. In addition, external force fields were applied, represented by an external stiffness at the hip, either stabilizing or destabilizing the participants' balance. Multivariate closed-loop system-identification techniques were used to describe the neuromuscular control mechanisms by quantifying the corrective joint torques as a response to body sway, represented by frequency response functions (FRFs). Model fits on the FRFs resulted in an estimation of time delays, intrinsic stiffness, reflexive stiffness, and reflexive damping of both the ankle and hip joint. The elderly generated similar corrective joint torques but had reduced body sway compared with the young participants, corresponding to the increased FRF magnitude with age. When a stabilizing or destabilizing external force field was applied at the hip, both young and elderly participants adapted their multijoint coordination by lowering or respectively increasing their neuromuscular control actions around the ankles, expressed in a change of FRF magnitude. However, the elderly adapted less compared with the young participants. Model fits on the FRFs showed that elderly had higher intrinsic and reflexive stiffness of the ankle, together with higher time delays of the hip. Furthermore, the elderly adapted their reflexive stiffness around the ankle joint less compared with young participants. These results imply that elderly were stiffer and were less able to adapt to external force fields. PMID:26719084

Modulation of the Fibularis Longus Hoffmann Reflex and Postural Instability Associated With Chronic Ankle Instability

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Kim, Kyung-Min; Hart, Joseph M.; Saliba, Susan A.; Hertel, Jay

2016-01-01

Context: Individuals with chronic ankle instability (CAI) present with decreased modulation of the Hoffmann reflex (H-reflex) from a simple to a more challenging task. The neural alteration is associated with impaired postural control, but the relationship has not been investigated in individuals with CAI. Objective: To determine differences in H-reflex modulation and postural control between individuals with or without CAI and to identify if they are correlated in individuals with CAI. Design: Descriptive laboratory study. Setting: Laboratory. Patients or Other Participants: A total of 15 volunteers with CAI (9 males, 6 females; age = 22.6 ± 5.8 years, height = 174.7 ± 8.1 cm, mass = 74.9 ± 12.8 kg) and 15 healthy sex-matched volunteers serving as controls (9 males, 6 females; age = 23.8 ± 5.8 years, height = 171.9 ± 9.9 cm, mass = 68.9 ± 15.5 kg) participated. Intervention(s): Maximum H-reflex (Hmax) and motor wave (Mmax) from the soleus and fibularis longus were recorded while participants lay prone and then stood in unipedal stance. We assessed postural tasks of unipedal stance with participants' eyes closed for 10 seconds using a forceplate. Main Outcome Measure(s): We normalized Hmax to Mmax to obtain Hmax : Mmax ratios for the 2 positions. For each muscle, H-reflex modulation was quantified using the percentage change scores in Hmax : Mmax ratios calculated from prone position to unipedal stance. Center-of-pressure data were used to compute 4 time-to-boundary variables. Separate independent-samples t tests were performed to determine group differences. Pearson product moment correlation coefficients were calculated between the modulation and balance measures in the CAI group. Results: The CAI group presented less H-reflex modulation in the soleus (t26 = −3.77, P = .001) and fibularis longus (t25 = −2.59, P = .02). The mean of the time-to-boundary minima in the anteroposterior direction was lower in the CAI group (t28 = −2.06, P = .048

Gaze stability, dynamic balance and participation deficits in people with multiple sclerosis at fall-risk.

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Garg, Hina; Dibble, Leland E; Schubert, Michael C; Sibthorp, Jim; Foreman, K Bo; Gappmaier, Eduard

2018-05-05

Despite the common complaints of dizziness and demyelination of afferent or efferent pathways to and from the vestibular nuclei which may adversely affect the angular Vestibulo-Ocular Reflex (aVOR) and vestibulo-spinal function in persons with Multiple Sclerosis (PwMS), few studies have examined gaze and dynamic balance function in PwMS. 1) Determine the differences in gaze stability, dynamic balance and participation measures between PwMS and controls, 2) Examine the relationships between gaze stability, dynamic balance and participation. Nineteen ambulatory PwMS at fall-risk and 14 age-matched controls were recruited. Outcomes included (a) gaze stability [angular Vestibulo-Ocular Reflex (aVOR) gain (ratio of eye to head velocity); number of Compensatory Saccades (CS) per head rotation; CS latency; gaze position error; Coefficient of Variation (CV) of aVOR gain], (b) dynamic balance [Functional Gait Assessment, FGA; four square step test], and (c) participation [dizziness handicap inventory; activities-specific balance confidence scale]. Separate independent t-tests and Pearson's correlations were calculated. PwMS were age = 53 ± 11.7yrs and had 4.2 ± 3.3 falls/yr. PwMS demonstrated significant (pbalance and participation measures compared to controls. CV of aVOR gain and CS latency were significantly correlated with FGA. Deficits and correlations across a spectrum of disability measures highlight the relevance of gaze and dynamic balance assessment in PwMS. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Effect of betel nut chewing on the otolithic reflex system.

Science.gov (United States)

Lin, Chuan-Yi; Young, Yi-Ho

2017-01-01

This study investigated the effect of betel nut chewing on the otolithic reflex system. Seventeen healthy volunteers without any experience of chewing betel nut (fresh chewers) and 17 habitual chewers underwent vital sign measurements, ocular vestibular-evoked myogenic potential (oVEMP), and cervical VEMP (cVEMP) tests prior to the study. Each subject then chewed two pieces of betel nut for 2min (dosing). The same paradigm was repeated immediately, 10min, and 20min after chewing. On a different day, 10 fresh chewers masticated chewing gum as control. Fresh chewers exhibited significantly decreased response rates of oVEMP (53%) and cVEMP (71%) after dosing compared with those from the predosing period. These abnormal VEMPs returned to normal 20min after dosing. In contrast, 100% response rates of oVEMP and cVEMP were observed before and after masticating chewing gum. In habitual chewers, the response rates of oVEMP and cVEMP were 32% and 29%, respectively, 20min after dosing. Chewing betel nuts induced a transient loss of the otolithic reflexes in fresh chewers but may cause permanent loss in habitual chewers. Chewing betel nuts can cause a loss of otholitic reflex function. This creates a risk for disturbed balance and malfunction, for instance, during driving. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Association between vestibulo-ocular reflex suppression, balance, gait, and fall risk in ageing and neurodegenerative disease: protocol of a one-year prospective follow-up study.

Science.gov (United States)

Srulijes, Karin; Mack, David J; Klenk, Jochen; Schwickert, Lars; Ihlen, Espen A F; Schwenk, Michael; Lindemann, Ulrich; Meyer, Miriam; Srijana, K C; Hobert, Markus A; Brockmann, Kathrin; Wurster, Isabel; Pomper, Jörn K; Synofzik, Matthis; Schneider, Erich; Ilg, Uwe; Berg, Daniela; Maetzler, Walter; Becker, Clemens

2015-10-09

Falls frequency increases with age and particularly in neurogeriatric cohorts. The interplay between eye movements and locomotion may contribute substantially to the occurrence of falls, but is hardly investigated. This paper provides an overview of current approaches to simultaneously measure eye and body movements, particularly for analyzing the association of vestibulo-ocular reflex (VOR) suppression, postural deficits and falls in neurogeriatric risk cohorts. Moreover, VOR suppression is measured during head-fixed target presentation and during gaze shifting while postural control is challenged. Using these approaches, we aim at identifying quantitative parameters of eye-head-coordination during postural balance and gait, as indicators of fall risk. Patients with Progressive Supranuclear Palsy (PSP) or Parkinson's disease (PD), age- and sex-matched healthy older adults, and a cohort of young healthy adults will be recruited. Baseline assessment will include a detailed clinical assessment, covering medical history, neurological examination, disease specific clinical rating scales, falls-related self-efficacy, activities of daily living, neuro-psychological screening, assessment of mobility function and a questionnaire for retrospective falls. Moreover, participants will simultaneously perform eye and head movements (fixating a head-fixed target vs. shifting gaze to light emitting diodes in order to quantify vestibulo-ocular reflex suppression ability) under different conditions (sitting, standing, or walking). An eye/head tracker synchronized with a 3-D motion analysis system will be used to quantify parameters related to eye-head-coordination, postural balance, and gait. Established outcome parameters related to VOR suppression ability (e.g., gain, saccadic reaction time, frequency of saccades) and motor related fall risk (e.g., step-time variability, postural sway) will be calculated. Falls will be assessed prospectively over 12 months via protocols and

Balance control in older adults

NARCIS (Netherlands)

Van Dieën, Jaap H.; Pijnappels, Mirjam

2017-01-01

To avoid falls during everyday movements, we need to maintain balance, i.e., control the position of our body's center of mass relative to our base of support. The balance control system comprises sensory subsystems, their afferent nerves, an extensive brain network, and the motor system.

Danish Working Environment Regulation. How reflexive - how political? -a Scandinavian case

DEFF Research Database (Denmark)

Koch, Christian

an understanding of the directions of the reforms made in this period. The paper operate with two analytical perspectives: The reflexive regulation perspective and the political process perspective. Danish working environment regulation is discussed through the general political initiatives taken, and through four...... specific regulation topics: The Occupational Health Services (OHS), regulation of the psychological working environment, the 'Monotonous Repeated Work'-plan and the workers' compensation. Taking the last twenty years' development as a whole the main developments in the regulation is a further shift...... in balance between material and reflexive regulation elements to the benefit of the latter. But although the reflexive elements seem to stabilize, they are vulnerable to a loss of legitimacy and changes in the political pattern.The impact on enterprise power patterns is summed up in a polarization thesis...

Human stick balancing: Tuning Lèvy flights to improve balance control

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Cabrera, Juan Luis; Milton, John G.

2004-09-01

State-dependent, or parametric, noise is an essential component of the neural control mechanism for stick balancing at the fingertip. High-speed motion analysis in three dimensions demonstrates that the controlling movements made by the fingertip during stick balancing can be described by a Lévy flight. The Lévy index, α, is approximately 0.9; a value close to optimal for a random search. With increased skill, the index α does not change. However, the tails of the Lévy distribution become broader. These observations suggest a Lévy flight that is truncated by the properties of the nervous and musculoskeletal system; the truncation decreasing as skill level increases. Measurements of the cross-correlation between the position of the tip of the stick and the fingertip demonstrate that the role of closed-loop feedback changes with increased skill. Moreover, estimation of the neural latencies for stick balancing show that for a given stick length, the latency increases with skill level. It is suggested that the neural control for stick balancing involves a mechanism in which brief intervals of consciously generated, corrective movements alternate with longer intervals of prediction-free control. With learning the truncation of the Lévy flight becomes better optimized for balance control and hence the time between successive conscious corrections increases. These observations provide the first evidence that changes in a Lévy flight may have functional significance for the nervous system. This work has implications for the control of balancing problems ranging from falling in the elderly to the design of two-legged robots and earthquake proof buildings.

Deprivation and Recovery of Sleep in Succession Enhances Reflexive Motor Behavior

OpenAIRE

Sprenger, Andreas; Weber, Frederik D.; Machner, Bjoern; Talamo, Silke; Scheffelmeier, Sabine; Bethke, Judith; Helmchen, Christoph; Gais, Steffen; Kimmig, Hubert; Born, Jan

2015-01-01

Sleep deprivation impairs inhibitory control over reflexive behavior, and this impairment is commonly assumed to dissipate after recovery sleep. Contrary to this belief, here we show that fast reflexive behaviors, when practiced during sleep deprivation, is consolidated across recovery sleep and, thereby, becomes preserved. As a model for the study of sleep effects on prefrontal cortex-mediated inhibitory control in humans, we examined reflexive saccadic eye movements (express saccades), as w...

Effect of Somatosensory Impairments on Balance Control

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Alireza Hassanpour

2012-10-01

Full Text Available Background and Aim: The somatosensory system is one of the most effective systems in balance control. It consists of peripheral and central components. Knowing the role of these components in balance control assists the developing of effective rehabilitation protocols. In some diseases peripheral components and in others central components are impaired. This paper reviews the effect of impairment of peripheral and central components of the somatosensory system on balance control.Methods: In this study publication about somatosensory impairments from 1983 through 2011 in PubMed, Scopus, ProQuest, Google Scholar, Iran Medex, Iran Doc and Magiran were reviewed. Medical subject headings terms and keywords related to balance, somatosensory, somatosensory loss, and sensory integration/processing were used to perform the searches.Conclusion: Somatosensory impairments either with peripheral or central origin, can cause problems in balance control. However, these problems are not considered in some patients. In these impairments, balance training is recommended to be used alongside other routine treatments in the patients' rehabilitation programs.

Being reflexive in qualitative grounded theory: discussion and application of a model of reflexivity.

Science.gov (United States)

Engward, Hilary; Davis, Geraldine

2015-07-01

A discussion of the meaning of reflexivity in research with the presentation of examples of how a model of reflexivity was used in a grounded theory research project. Reflexivity requires the researcher to make transparent the decisions they make in the research process and is therefore important in developing quality in nursing research. The importance of being reflexive is highlighted in the literature in relation to nursing research, however, practical guidance as to how to go about doing research reflexively is not always clearly articulated. This is a discussion paper. The concept of reflexivity in research is explored using the Alvesson and Skoldberg model of reflexivity and practical examples of how a researcher developed reflexivity in a grounded theory project are presented. Nurse researchers are encouraged to explore and apply the concept of reflexivity in their research practices to develop transparency in the research process and to increase robustness in their research. The Alvesson and Skoldberg model is of value in applying reflexivity in qualitative nursing research, particularly in grounded theory research. Being reflexive requires the researcher to be completely open about decisions that are made in the research process. The Alvesson and Skolberg model of reflexivity is a useful model that can enhance reflexivity in the research process. It can be a useful practical tool to develop reflexivity in grounded theory research. © 2015 John Wiley & Sons Ltd.

Fundamental Principles underlying Motor Reflexes

NARCIS (Netherlands)

K. Zhou (Kuikui)

2017-01-01

markdownabstractThe cerebellum has been suggested to be involved in motor control ever since the early 19th century. The motor control ranges from timing and strength of simple reflexes to multiple joint/limb coordination and complex motor sequence acquisition. The current thesis discusses the

Attentional modulation of reflex cough.

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Janssens, Thomas; Silva, Mitchell; Davenport, Paul W; Van Diest, Ilse; Dupont, Lieven J; Van den Bergh, Omer

2014-07-01

Reflex cough is a defensive response generated in the brainstem in response to chemical and mechanical stimulation of the airways. However, converging evidence shows that reflex cough is also influenced by central neural control processes. In this study, we investigate whether reflex cough can be modulated by attentional focus on either external stimuli or internal cough-related stimuli. Healthy volunteers (N = 24; seven men; age range, 18-25 years) completed four blocks of citric acid-induced cough challenges while, simultaneously, auditory stimuli were presented. Within each block, four concentrations were administered (30, 100, 300 and 1,000 mM, randomized). During two subsequent blocks, participants focused their attention externally (counting tones). During the other two blocks, participants focused their attention internally (counting coughs). The order of attentional focus was counterbalanced across participants. Ratings of the urge to cough were collected after each challenge. Cough frequency was determined by audio recording. Cough frequency was higher when participants focused their attention internally vs externally (P Reflex cough can be modulated by attentional focus. Internally focused attention may be a mechanism involved in excessive (idiopathic) cough, while an external focus may be introduced as part of treatments targeting excessive cough.

Cumulative vibratory indices and the H/M ratio of the soleus H-reflex: a quantitative study in control and spastic subjects

NARCIS (Netherlands)

Ongerboer de Visser, B. W.; Bour, L. J.; Koelman, J. H.; Speelman, J. D.

1989-01-01

Suppression of the soleus (Sol) H-reflex recruitment curve by Achilles tendon vibration and the ratio of maximum Sol H-reflex (Hmax) to maximum M-response (H/M ratio) have been studied by means of computer processing on the basis of peak-to-peak (P-P) and area values in 46 controls and in 16 spastic

Dorsal light reflex is absent in the postural control system of the upside-down swimming catfish, Synodontis nigriventris

Science.gov (United States)

Ohnishi, T.; Ohnishi, K.; Okamoto, N.; Yamamoto, T.; Hosoi, H.; Takahashi, A.; Kawai, H.

A kind of catfish, Synodontis nigriventris, has a unique habit of maintaining an upside-down posture under normal gravity conditions (1 G). We exposed S. nigriventris to a microgravity environment provided by the parabolic flights of an aircraft and observed the dorsal light reflex (DLR), which is well known to be an important visually guided postural reaction in fish. In general, fish directs its back to an illuminated direction, depending on DLR: DLR is observed more clearly under microgravity as compared with 1 G. Interestingly, S. nigriventris exhibited no DLR response even under microgravity. In contrast, clear DLR was observed under microgravity in two other species, which have an upside-up swimming habit, Synodontis multipunctatus, belonging to the same Synodontis family, and Corydoras paleatus, belonging to a different catfish family. Our parabolic flight experiments have confirmed for the first time that S. nigriventris has a novel balance sensation which does not induce DLR. This allows us to address a new and attractive strategy for the analysis of the postural control mechanism of vertebrate.

Voltage Balancing Control of Diode-Clamped Multilevel Inverter

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ŞCHIOP Adrian

2013-10-01

Full Text Available In this paper is developed a control scheme for mono-phase diode clamped inverter to achieve balancing voltages on inverter capacitors. First, it develops a control scheme without taking into account the need to balance voltage on two capacitors. It examines the effects on the output voltage inverter, and then it realizes two control schemes that will balance the voltages. The simulations of control schemes were performed in OrCAD Pspice.

ZAG-Otolith: Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control during Variable Radius Centrifugation Following Space Flight

Science.gov (United States)

Wood, S. J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

2009-01-01

Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved with vibrotactile feedback of orientation.

Etnography and Reflexivity

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Mario Cardano

2014-01-01

Full Text Available This essay deals with a relevant and controversial topic – objectivity in ethnographic research. More specifically, I would like to examine how reflexive procedures, more precisely “reflexive account”, can increase the robustness of results gained through an ethnographic research. The essay is organized in five parts. I will start by giving a preliminary definition of the two key concepts which are at the center of the analysis – objectivity and reflexivity. I will then give a brief description of the epistemological framework in which the proposed conceptions of objectivity and reflexivity are located. Thirdly, I move on to consider the epistemic status of ethnographic research, and will emphasize that ethnographies are not just “theory-laden”, as many writers have stated, but also “praxis” or “procedure laden”. In other words, I will stress that it is not only theories which are inevitably embedded in research, influencing how observations can be made; much the same can also be said of the concrete research practices which contribute to determine the experience of the ethnographer and its representation in a text. Fourthly, I will discuss why it is useful to employ reflexive practices, and then immediately afterwards will illustrate the ways in which reflexive descriptions can contribute to greater objectivity of ethnographic accounts. In conclusion, I will discuss a number of objections which have been raised against this use of reflexivity.

Altered Patterns of Reflex Excitability, Balance, and Locomotion Following Spinal Cord Injury (SCI and Locomotor Training.

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Prodip K Bose

2012-07-01

Full Text Available Spasticity is an important problem that complicates daily living in many individuals with SCI. While previous studies in human and animals revealed significant improvements in locomotor ability with treadmill locomotor training, it is not known to what extent locomotor training influences spasticity. In addition, it would be of considerable practical interest to know how the more ergonomically feasible cycle training compares with treadmill training as therapy to manage SCI-induced spasticity and to improve locomotor function. Our present studies were initiated to evaluate the influence of different types of locomotor training on measures of limb spasticity, gait, and reflex components that contribute to locomotion. For these studies, thirty animals received midthoracic SCI using the standard MASCIS protocol (10 g 2.5 cm weight drop. They were divided randomly into three equal groups: control (contused untrained, contused treadmill trained, and contused cycle trained. Velocity-dependent ankle torque was tested across a wide range of velocities (612 – 49 deg/sec to permit quantitation of tonic (low velocity and dynamic (high velocity contributions to lower limb spasticity. Treadmill and cycle training were started on post-injury day 8. By post-injury weeks 4 and 6, the untrained group revealed significant velocity-dependent ankle extensor spasticity, compared to pre-surgical control values. At these post-injury time points, spasticity was not observed in either of the two training groups. Instead, a significantly milder form of velocity dependent spasticity was detected at postcontusion week 8 through 12 in both treadmill and bicycle training groups at the four fastest ankle rotation velocities (350 - 612 deg/sec. Locomotor training using treadmill or bicycle also produced significant increase in the rate of recovery of limb placement measures (limb axis, base of support, and BBB and reflex rate depression, a quantitative assessment of

Adaptation to sensory-motor reflex perturbations is blind to the source of errors.

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Hudson, Todd E; Landy, Michael S

2012-01-06

In the study of visual-motor control, perhaps the most familiar findings involve adaptation to externally imposed movement errors. Theories of visual-motor adaptation based on optimal information processing suppose that the nervous system identifies the sources of errors to effect the most efficient adaptive response. We report two experiments using a novel perturbation based on stimulating a visually induced reflex in the reaching arm. Unlike adaptation to an external force, our method induces a perturbing reflex within the motor system itself, i.e., perturbing forces are self-generated. This novel method allows a test of the theory that error source information is used to generate an optimal adaptive response. If the self-generated source of the visually induced reflex perturbation is identified, the optimal response will be via reflex gain control. If the source is not identified, a compensatory force should be generated to counteract the reflex. Gain control is the optimal response to reflex perturbation, both because energy cost and movement errors are minimized. Energy is conserved because neither reflex-induced nor compensatory forces are generated. Precision is maximized because endpoint variance is proportional to force production. We find evidence against source-identified adaptation in both experiments, suggesting that sensory-motor information processing is not always optimal.

Affective Modulation of the Startle Eyeblink and Postauricular Reflexes in Autism Spectrum Disorder

Science.gov (United States)

Dichter, Gabriel S.; Benning, Stephen D.; Holtzclaw, Tia N.; Bodfish, James W.

2010-01-01

Eyeblink and postauricular reflexes to standardized affective images were examined in individuals without (n = 37) and with (n = 20) autism spectrum disorders (ASDs). Affective reflex modulation in control participants replicated previous findings. The ASD group, however, showed anomalous reflex modulation patterns, despite similar self-report…

Control Structures for Smart Grid Balancing

DEFF Research Database (Denmark)

Juelsgaard, Morten; Totu, Luminita Cristiana; Shafiei, Seyed Ehsan

2013-01-01

This work addresses the problem of maintaining the balance between consumption and production in the electricity grid when volatile resources, such as wind and sun, account for a large percentage of the power generation. We present control structures for Smart Grid balancing services on three...

Contributions to lateral balance control in ambulatory older adults.

Science.gov (United States)

Sparto, Patrick J; Newman, A B; Simonsick, E M; Caserotti, P; Strotmeyer, E S; Kritchevsky, S B; Yaffe, K; Rosano, C

2018-06-01

In older adults, impaired control of standing balance in the lateral direction is associated with the increased risk of falling. Assessing the factors that contribute to impaired standing balance control may identify areas to address to reduce falls risk. To investigate the contributions of physiological factors to standing lateral balance control. Two hundred twenty-two participants from the Pittsburgh site of the Health, Aging and Body Composition Study had lateral balance control assessed using a clinical sensory integration balance test (standing on level and foam surface with eyes open and closed) and a lateral center of pressure tracking test using visual feedback. The center of pressure was recorded from a force platform. Multiple linear regression models examined contributors of lateral control of balance performance, including concurrently measured tests of lower extremity sensation, knee extensor strength, executive function, and clinical balance tests. Models were adjusted for age, body mass index, and sex. Larger lateral sway during the sensory integration test performed on foam was associated with longer repeated chair stands time. During the lateral center of pressure tracking task, the error in tracking increased at higher frequencies; greater error was associated with worse executive function. The relationship between sway performance and physical and cognitive function differed between women and men. Contributors to control of lateral balance were task-dependent. Lateral standing performance on an unstable surface may be more dependent upon general lower extremity strength, whereas visual tracking performance may be more dependent upon cognitive factors. Lateral balance control in ambulatory older adults is associated with deficits in strength and executive function.

Reflex control of robotic gait using human walking data.

Directory of Open Access Journals (Sweden)

Catherine A Macleod

Full Text Available Control of human walking is not thoroughly understood, which has implications in developing suitable strategies for the retraining of a functional gait following neurological injuries such as spinal cord injury (SCI. Bipedal robots allow us to investigate simple elements of the complex nervous system to quantify their contribution to motor control. RunBot is a bipedal robot which operates through reflexes without using central pattern generators or trajectory planning algorithms. Ground contact information from the feet is used to activate motors in the legs, generating a gait cycle visually similar to that of humans. Rather than developing a more complicated biologically realistic neural system to control the robot's stepping, we have instead further simplified our model by measuring the correlation between heel contact and leg muscle activity (EMG in human subjects during walking and from this data created filter functions transferring the sensory data into motor actions. Adaptive filtering was used to identify the unknown transfer functions which translate the contact information into muscle activation signals. Our results show a causal relationship between ground contact information from the heel and EMG, which allows us to create a minimal, linear, analogue control system for controlling walking. The derived transfer functions were applied to RunBot II as a proof of concept. The gait cycle produced was stable and controlled, which is a positive indication that the transfer functions have potential for use in the control of assistive devices for the retraining of an efficient and effective gait with potential applications in SCI rehabilitation.

Task-dependent changes of corticospinal excitability during observation and motor imagery of balance tasks.

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Mouthon, A; Ruffieux, J; Wälchli, M; Keller, M; Taube, W

2015-09-10

Non-physical balance training has demonstrated to be efficient to improve postural control in young people. However, little is known about the potential to increase corticospinal excitability by mental simulation in lower leg muscles. Mental simulation of isolated, voluntary contractions of limb muscles increase corticospinal excitability but more automated tasks like walking seem to have no or only minor effects on motor-evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS). This may be related to the way of performing the mental simulation or the task itself. Therefore, the present study aimed to clarify how corticospinal excitability is modulated during AO+MI, MI and action observation (AO) of balance tasks. For this purpose, MEPs and H-reflexes were elicited during three different mental simulations (a) AO+MI, (b) MI and (c) passive AO. For each condition, two balance tasks were evaluated: (1) quiet upright stance (static) and (2) compensating a medio-lateral perturbation while standing on a free-swinging platform (dynamic). AO+MI resulted in the largest facilitation of MEPs followed by MI and passive AO. MEP facilitation was significantly larger in the dynamic perturbation than in the static standing task. Interestingly, passive observation resulted in hardly any facilitation independent of the task. H-reflex amplitudes were not modulated. The current results demonstrate that corticospinal excitability during mental simulation of balance tasks is influenced by both the type of mental simulation and the task difficulty. As H-reflexes and background EMG were not modulated, it may be argued that changes in excitability of the primary motor cortex were responsible for the MEP modulation. From a functional point of view, our findings suggest best training/rehabilitation effects when combining MI with AO during challenging postural tasks. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The effects of team reflexivity on psychological well-being in manufacturing teams.

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Chen, Jingqiu; Bamberger, Peter A; Song, Yifan; Vashdi, Dana R

2018-04-01

While the impact of team reflexivity (a.k.a. after-event-reviews, team debriefs) on team performance has been widely examined, we know little about its implications on other team outcomes such as member well-being. Drawing from prior team reflexivity research, we propose that reflexivity-related team processes reduce demands, and enhance control and support. Given the centrality of these factors to work-based strain, we posit that team reflexivity, by affecting these factors, may have beneficial implications on 3 core dimensions of employee burnout, namely exhaustion, cynicism, and inefficacy (reduced personal accomplishment). Using a sample of 469 unskilled manufacturing workers employed in 73 production teams in a Southern Chinese factory, we implemented a time lagged, quasi-field experiment, with half of the teams trained in and executing an end-of-shift team debriefing, and the other half assigned to a control condition and undergoing periodic postshift team-building exercises. Our findings largely supported our hypotheses, demonstrating that relative to team members assigned to the control condition, those assigned to the reflexivity condition experienced a significant improvement in all 3 burnout dimensions over time. These effects were mediated by control and support (but not demands) and amplified as a function of team longevity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Reflex responses of lip muscles in young and older women.

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Wohlert, A B

1996-06-01

The perioral reflex in response to innocuous mechanical stimulation of the lip vermilion was studied in 20 young and 20 older women. Responses to stimuli at the right and left sides of both the upper and lower lips were recorded. Results show significant specificity of response, especially for upper lip sites. Reflex response at the site of stimulation was greatest in amplitude and shortest in latency, followed by response at sites ipsilateral to the site of stimulation. Younger subjects showed greater localizing tendency than older subjects. Stimulation was significantly less likely to produce a reflex response in the older group. When reflex responses did occur, they were significantly lower in amplitude and longer in latency than the responses of the younger group. Nonetheless, reflex responses were common in both groups, with responses at the site of stimulation occurring 78% of the time in older women and 90% of the time in younger women. Every participant showed at least one reflex response to lip stimulation. Results suggest decreasing complexity of synaptic drive to the perioral system in old age but also show that reflexive response does not deteriorate completely, remaining an available element for motor control in normal older women.

Evolution of Motor Control: From Reflexes and Motor Programs to the Equilibrium-Point Hypothesis

OpenAIRE

Latash, Mark L.

2008-01-01

This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive (reflexes) features of voluntary movements. It suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the equilibrium-point hypothesis. Physical, physiological, and behavioral foundations of the EP-hypothesis are considered as well as relations between the EP-hypothesis and the recent developments of the notion of m...

The Gateway Reflex, a Novel Neuro-Immune Interaction for the Regulation of Regional Vessels

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Yuki Tanaka

2017-10-01

Full Text Available The gateway reflex is a new phenomenon that explains how immune cells bypass the blood–brain barrier to infiltrate the central nervous system (CNS and trigger neuroinflammation. To date, four examples of gateway reflexes have been discovered, each described by the stimulus that evokes the reflex. Gravity, electricity, pain, and stress have all been found to create gateways at specific regions of the CNS. The gateway reflex, the most recently discovered of the four, has also been shown to upset the homeostasis of organs in the periphery through its action on the CNS. These reflexes provide novel therapeutic targets for the control of local neuroinflammation and organ function. Each gateway reflex is activated by different neural activations and induces inflmammation at different regions in the CNS. Therefore, it is theoretically possible to manipulate each independently, providing a novel therapeutic strategy to control local neuroinflammation and peripheral organ homeostasis.

Reflexivity in qualitative research

DEFF Research Database (Denmark)

Evans, Adam Brian; Nistrup, Anne; Henderson, Hannah

2018-01-01

There has been something of a “reflexive shift” in sociological research. Sociological researchers are increasingly encouraged to be “present” within their work, and to recognize their own role in structuring the entire research process. One way to achieve this is through engagement in reflexive...... practice, that is, to reflect on our own values, beliefs, and biographies. It can be difficult to know exactly how a researcher should engage in these practices, however. Here, we discuss our reflexive practice in two case studies, both which utilized the same figurational theoretical framework...... Kingdom. Reflexive practice in both studies was affected by researcher biographies and by study design. In Study 1, both researchers were reasonably detached from the study context, the theoretical framework was in place from the very beginning, and reflexive practice was embedded in the study design...

Plantar reflex excitability is increased in the evening in restless legs syndrome patients.

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Dafkin, Chloe; Green, Andrew; Olivier, Benita; McKinon, Warrick; Kerr, Samantha

2017-11-01

To investigate if diurnal changes in spinal excitability (plantar reflex) occur in restless legs syndrome (RLS) participants compared to healthy matched controls. Thirteen RLS participants and 13 healthy control participants' plantar reflex responses were evaluated in the evening (PM) and the morning (AM). Plantar reflex responses were assessed electromyographically, using motion analysis (kinematically) and by subjective nociception (Visual Analogue Scale). RLS participants showed a circadian variation in plantar reflex responses whilst control participants did not. Evening ankle angle changes were larger and faster in RLS participants compared to morning responses. In addition RLS participants displayed significantly smaller change in ankle angle and significantly slower ankle movements in the evening and the morning as well as significantly lower lateral gastrocnemius maximum amplitude in the compared to control participants. The findings of the current study support the theory of RLS circadian fluctuations in spinal excitability. An unexpected finding was decreased plantar reflex responses in RLS participants compared to healthy control participants. However this finding supports the theory of mechanical hypoesthesia in RLS. The results of this study provide further insight into the pathophysiology of RLS, highlighting that not all sensory processing is affected in the same manner. Copyright © 2017 Elsevier B.V. All rights reserved.

Soleus muscle H-reflex monitoring in endoscopic surgery under general anesthesia percutaneous interlaminar approach.

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Wang, Huixue; Gao, Yingji; Ji, Lixin; Bai, Wanshan

2018-05-01

The clinical value of soleus muscle H-reflex monitoring in general anesthesia percutaneous interlaminar approach was investigated. A total of 80 cases with unilateral L5-S1 disc herniation between January 2015 and October 2016 were randomly divided into control group (without soleus muscle H-reflex monitoring, n=40) and observation group (with soleus muscle H-reflex monitoring, n=40). Results showed that the operation time of the observation group was shorter than that of the control group (Ph after operation, the amplitude of H-reflex in diseased side soleus muscle was significantly lower than that in healthy side (Ph postoperatively, the latency of H-reflex in diseased side soleus muscle was shorter than that of healthy side (PH-reflex latency in soleus muscle were significantly lower (PH-reflex monitoring can effectively reduce the damage to the nerve roots under percutaneous endoscopic intervertebral endoscopic surgery under general anesthesia, improve the accuracy of surgery, reduce the complications, shorten the operation time and reduce the surgical bleeding, which is more beneficial to patients smooth recovery.

Swedish Massage and Abnormal Reflexes of Children with Spastic Cerebral Palsy

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Vida Alizad

2007-09-01

Full Text Available Objectives: Massage therapy is one of the most widely used complementary and alternative medicine therapies for children. This study was conducted to determine the effect of wedish massage on abnormal reflexes in children with spastic cerebral palsy (CP. Methods: This study was a single blind clinical trial conducted on forty children with spastic CP who were recruited from clinics of the University of Social Welfare & Rehabilitation Sciences. They were randomly assigned to intervention and control groups. The routine occupational therapy (OT techniques were performed during a 3 month-period in both groups. The intervention group also received Swedish massage for 30 minutes before every OT session. Primary, spinal, brain stem, midbrain, cortical and automatic reflexes were evaluated at the beginning of the study and 3 months later. The data analysis was done by parametric and nonparametric tests. Results: Finally, thirteen subjects in the intervention group and 14 subjects in the control group were remained and studied. The average ages in the intervention and control groups were 49.5 and 42.1 months respectively. There were no statistically significant differences in abnormal reflexes in the intervention group in comparison to the control (P>0.05. Discussion: Adding Swedish massage to traditional OT techniques had no significant effects on abnormal reflexes in children with spastic cerebral palsy. Evidently more research is required in order to completely reject the effects of Swedish massage on abnormal reflexes of children with CP.

The Assessment of Postural Control, Reflex Integration, and Bilateral Motor Coordination of Young Handicapped Children. Final Report.

Science.gov (United States)

DeGangi, Georgia; Larsen, Lawrence A.

A measurement device, Assessment of Sensorimotor Integration in Preschool Children, was developed to assess postural control, reflex integration and bilateral motor integration in developmentally delayed children (3 to 5 years old). The test was administered to 113 normal children and results were compared with data collected on 23 developmentally…

Plasticity of the human otolith-ocular reflex

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Wall, C. 3rd; Smith, T. R.; Furman, J. M.

1992-01-01

The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

Sensorimotor control of balance: a Tai Chi solution for balance disorders in older subjects.

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Tsang, William W N; Hui-Chan, Christina W Y

2008-01-01

In addition to environmental factors, deteriorating sensorimotor control of balance will predispose older adults to falls. Understanding the aging effects on sensorimotor control of balance performance is important for designing fall prevention programs for older adults. How repeated practice of Tai Chi can improve limb joint proprioception, integration of neural signals in the central nervous system for balance control, and motor output at the level of knee muscles is discussed in this chapter. Our previous studies showed that elderly Tai Chi practitioners performed significantly better than elderly nonpractitioners in (1) knee joint proprioception, (2) reduced or conflicting sensory situations that demand more visual or vestibular contributions, (3) standing balance control after vestibular stimulation without visual input, (4) voluntary weight shifting in different directions within the base of support, (5) single-leg stance during perturbations of the support surface, and (6) knee extensor and flexor muscle strength. In a prospective study, we further showed that 4 weeks of daily Tai Chi practice but not general education produced significant improvement in balance performance. The requirements of Tai Chi for accurate joint positioning and weight transfer involving smooth coordination of neck, trunk, upper and lower limb movements, make it particularly useful for improving the sensorimotor control of balance in the elderly. Because Tai Chi can be practiced any time and anywhere, and is well accepted by older people in both the East and now the West, it is especially suited to be a key component of a low-costing community-based fall prevention program alongside with education about environmental factors.

Soleus H reflex extinction in controls and spastic patients: ordered occlusion or diffuse inhibition?

NARCIS (Netherlands)

Hilgevoord, A. A.; Bour, L. J.; Koelman, J. H.; Ongerboer de Visser, B. W.

1995-01-01

Extinction of the soleus H reflex at higher stimulus intensities is commonly attributed to retrograde conduction of action potentials in motor axons. This study was designed to gain further insight into the mechanisms underlying the extinction. The decrease of the H reflex was quantified in a group

Researching Reflexively With Patients and Families: Two Studies Using Video-Reflexive Ethnography to Collaborate With Patients and Families in Patient Safety Research.

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Collier, Aileen; Wyer, Mary

2016-06-01

Patient safety research has to date offered few opportunities for patients and families to be actively involved in the research process. This article describes our collaboration with patients and families in two separate studies, involving end-of-life care and infection control in acute care. We used the collaborative methodology of video-reflexive ethnography, which has been primarily used with clinicians, to involve patients and families as active participants and collaborators in our research. The purpose of this article is to share our experiences and findings that iterative researcher reflexivity in the field was critical to the progress and success of each study. We present and analyze the complexities of reflexivity-in-the-field through a framework of multilayered reflexivity. We share our lessons here for other researchers seeking to actively involve patients and families in patient safety research using collaborative visual methods. © The Author(s) 2015.

Role of ionotropic GABA, glutamate and glycine receptors in the tonic and reflex control of cardiac vagal outflow in the rat

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Goodchild Ann K

2010-10-01

Full Text Available Abstract Background Cardiac vagal preganglionic neurons (CVPN are responsible for the tonic, reflex and respiratory modulation of heart rate (HR. Although CVPN receive GABAergic and glutamatergic inputs, likely involved in respiratory and reflex modulation of HR respectively, little else is known regarding the functions controlled by ionotropic inputs. Activation of g-protein coupled receptors (GPCR alters these inputs, but the functional consequence is largely unknown. The present study aimed to delineate how ionotropic GABAergic, glycinergic and glutamatergic inputs contribute to the tonic and reflex control of HR and in particular determine which receptor subtypes were involved. Furthermore, we wished to establish how activation of the 5-HT1A GPCR affects tonic and reflex control of HR and what ionotropic interactions this might involve. Results Microinjection of the GABAA antagonist picrotoxin into CVPN decreased HR but did not affect baroreflex bradycardia. The glycine antagonist strychnine did not alter HR or baroreflex bradycardia. Combined microinjection of the NMDA antagonist, MK801, and AMPA antagonist, CNQX, into CVPN evoked a small bradycardia and abolished baroreflex bradycardia. MK801 attenuated whereas CNQX abolished baroreceptor bradycardia. Control intravenous injections of the 5-HT1A agonist 8-OH-DPAT evoked a small bradycardia and potentiated baroreflex bradycardia. These effects were still observed following microinjection of picrotoxin but not strychnine into CVPN. Conclusions We conclude that activation of GABAA receptors set the level of HR whereas AMPA to a greater extent than NMDA receptors elicit baroreflex changes in HR. Furthermore, activation of 5-HT1A receptors evokes bradycardia and enhances baroreflex changes in HR due to interactions with glycinergic neurons involving strychnine receptors. This study provides reference for future studies investigating how diseases alter neurochemical inputs to CVPN.

How Can Hypnodontics Manage Severe Gag Reflex for Root Canal Therapy? A Case Report

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Ramazani, Mohsen; zarenejad, Nafiseh; Parirokh, Masoud; Zahedpasha, Samir

2016-01-01

In endodontics, severe involuntary gagging can have a severe impact on treatment procedure. There are many ways to ease the gag reflex, one of which is hypnosis. A 34-year-old male was referred for root canal treatment of a molar tooth. He had not received any dental treatments for the past nine years due to fear of severe gag reflex. Three hypnotic sessions based upon eye fixation, progressive muscle relaxation and guided imagery techniques were spent for psychosomatic management. The gag reflex was controlled and reduced to a normal level, and the required dental treatments including root canal therapy and restoration were performed successfully. This report shows that hypnosis can control gag reflex for dental treatments. PMID:27141226

Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control During Variable Radius Centrifugation Following Space Flight

Science.gov (United States)

Wood, Scott J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

2009-01-01

Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, less than 20 cm radius), the effects of stimulus frequency (0.15 - 0.6 Hz) are examined on eye movements and motion perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. One result of this study will be to characterize the variability (gain, asymmetry) in both otolith-ocular responses and motion perception during variable radius centrifugation, and measure the time course of post-flight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved

[Reflex seizures, cinema and television].

Science.gov (United States)

Olivares-Romero, Jesús

2015-12-16

In movies and television series are few references to seizures or reflex epilepsy even though in real life are an important subgroup of total epileptic syndromes. It has performed a search on the topic, identified 25 films in which they appear reflex seizures. Most seizures observed are tonic-clonic and visual stimuli are the most numerous, corresponding all with flashing lights. The emotions are the main stimuli in higher level processes. In most cases it is not possible to know if a character suffers a reflex epilepsy or suffer reflex seizures in the context of another epileptic syndrome. The main conclusion is that, in the movies, the reflex seizures are merely a visual reinforcing and anecdotal element without significant influence on the plot.

Arakeri’s Reflex: an Alternative Pathway for Dento-Cardiac Reflex Mediated Syncope

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Veena Arali

2010-03-01

Full Text Available Introduction: Dentocardiac reflex, a variant of trigeminocardiac reflex elicited specifically during tooth extraction procedures in den-tal/maxillofacial surgery and is believed to cause syncope with an afferent link mediated by posterior superior alveolar nerve. Another variant of trigeminocardiac reflex which is also of interest to the oral and maxillofacial surgeon is oculocardiac reflex which can be triggered by direct or indirect manipulation of eye globe or muscles around it.The hypothesis: Excessive or injudicious pressure or manipulations around the maxillary first molars during extraction procedure are as-sociated with maximum incidence of bradycardia and hypotension than around incisor/ canine/ third molars. This is because; the pressure on eye globe and ophthalmic rectus muscle is maximum during extraction of first molar than incisor/canine and third molars. This observation led us to postulate an alternative pathway for dentocardiac reflex mediated syncope which may possibly justify the maxillary first molar region as a prone factor for the trigger. Evaluation of the hypothesis: Present hypothesis may not confer the specific factor responsible for switch in autonomic response in syncope origin during the tooth extraction procedure, but may provide a clue to where we should be looking.

Effect of balance training on postural balance control and risk of fall in children with diplegic cerebral palsy.

Science.gov (United States)

El-Shamy, Shamekh Mohamed; Abd El Kafy, Ehab Mohamed

2014-01-01

The purpose of this study was to evaluate the effects of balance training on postural control and fall risk in children with diplegic cerebral palsy. Thirty spastic diplegic cerebral palsied children (10-12 years) were included in this study. Children were randomly assigned into two equal-sized groups: control and study groups. Participants in both groups received a traditional physical therapy exercise program. The study group additionally received balance training on the Biodex balance system. Treatment was provided 30 min/d, 3 d/week for 3 successive months. To evaluate the limit of stability and fall risk, participated children received baseline and post-treatment assessments using the Biodex balance system. Overall directional control, total time to complete the test, overall stability index of the fall risk test and total score of the pediatric balance scale were measured. Children in both groups showed significant improvements in the mean values of all measured variables post-treatment (p control group (p postural balance control in children with diplegic cerebral palsy.

Muscle and reflex changes with varying joint angle in hemiparetic stroke

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Alibiglou Laila

2008-02-01

Full Text Available Abstract Background Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by musculo-tendinous structures. The present study addresses this deficit by characterizing the contribution of neural and muscular components to the abnormally high stiffness of the spastic joint. Methods Using system identification techniques, we characterized the neuromuscular abnormalities associated with spasticity of ankle muscles in chronic hemiparetic stroke survivors. In particular, we systematically tracked changes in muscle mechanical properties and in stretch reflex activity during changes in ankle joint angle. Modulation of mechanical properties was assessed by applying perturbations at different initial angles, over the entire range of motion (ROM. Experiments were performed on both paretic and non-paretic sides of stroke survivors, and in healthy controls. Results Both reflex and intrinsic muscle stiffnesses were significantly greater in the spastic/paretic ankle than on the non-paretic side, and these changes were strongly position dependent. The major reflex contributions were observed over the central portion of the angular range, while the intrinsic contributions were most pronounced with the ankle in the dorsiflexed position. Conclusion In spastic ankle muscles, the abnormalities in intrinsic and reflex components of joint torque varied systematically with changing position over the full angular range of motion, indicating that clinical perceptions of increased tone may have quite different origins depending upon the angle where the tests are initiated. Furthermore, reflex stiffness was considerably larger in the non-paretic limb of stroke patients than in healthy control subjects

[H reflex in patients with spastic quadriplegia].

Science.gov (United States)

Miyama, Sahoko; Arimoto, Kiyoshi; Kimiya, Satoshi

2009-01-01

Hoffmann reflex (H reflex) is an electrically elicited spinal monosynaptic reflex. H reflex was examined in 18 patients with spastic quadriplegia who had perinatal or postnatal problems. H reflex was elicitable in 11 patients for the abductor pollicis brevis (61.1%), 10 for the abductor digiti minimi (55.6%) and 16 for the abductor hallucis (88.9%). Because the abductor pollicis brevis and the abductor digiti minimi do not exhibit H reflex in normal subjects, it was suggested that the excitability of alpha motor neurons innervating these muscles was increased. H reflex was not detected for the extensor digitorum brevis in any patients, indicating the difference in the excitability among alpha motor neurons. In some patients, H reflex did not disappear under supramaximal stimuli. We conclude that the mechanism of evolution of H reflex in patients with spastic quadriplegia is different from that in normal subjects.

No Neuromuscular Side-Effects of Scopolamine in Sensorimotor Control and Force-Generating Capacity Among Parabolic Fliers

Science.gov (United States)

Ritzmann, Ramona; Freyler, Kathrin; Krause, Anne; Gollhofer, Albert

2016-10-01

Scopolamine is used to counteract motion sickness in parabolic flight (PF) experiments. Although the drug's anticholinergic properties effectively impede vomiting, recent studies document other sensory side-effects in the central nervous system that may considerably influence sensorimotor performance. This study aimed to quantify such effects in order to determine if they are of methodological and operational significance for sensorimotor control. Ten subjects of a PF campaign received a weight-sex-based dose of a subcutaneous scopolamine injection. Sensorimotor performance was recorded before medication, 20min, 2h and 4h after injection in four space-relevant paradigms: balance control in one-leg stance with eyes open (protocol 1) and closed as well as force-generating capacity in countermovement jumps and hops (protocol 2). Postural sway, forces and joint angles were recorded. Neuromuscular control was assessed by electromyography and peripheral nerve stimulation; H-reflexes and M-waves were used to monitor spinal excitability of the Ia afferent reflex circuitry and maximal motor output. (1) H-reflex amplitudes, latencies and functional reflexes remained unchanged after scopolamine injection. (2) M-waves, neuromuscular activation intensities and antagonistic muscle coordination did not change with scopolamine administration. (3) Balance performance and force-generating capacity were not impeded by scopolamine. We found no evidence for changes in sensorimotor control in response to scopolamine injection. Sensory processing of daily relevant reflexes, spinal excitability, maximal motor output and performance parameters were not sensitive to the medication. We conclude that scopolamine administration can be used to counteract motion sickness in PF without methodological and operational concerns or interference regarding sensorimotor skills associated with neuromuscular control.

Effects of Artificial Gravity and Bed Rest on Spatial Orientation and Balance Control

Science.gov (United States)

Paloski, William H.; Moore, S. T.; Feiveson, A. H.; Taylor, L. C.

2007-01-01

While the vestibular system should be well-adapted to bed rest (a condition it experiences approximately 8/24 hrs each day), questions remain regarding the degree to which repeated exposures to the unusual gravito-inertial force environment of a short-radius centrifuge might affect central processing of vestibular information used in spatial orientation and balance control. Should these functions be impaired by intermittent AG, its feasibility as a counter-measure would be diminished. We, therefore, examined the effects of AG on spatial orientation and balance control in 15 male volunteers before and after 21 days of 6 HDT bed rest (BR). Eight of the subjects were treated with daily 1hr AG exposures (2.5g at the feet; 1.0g at the heart) aboard a short radius (3m) centrifuge, while the other seven served as controls (C). Spatial orientation was assessed by measures of ocular counter-rolling (OCR; rotation of the eye about the line of sight, an otolith-mediated reflex) and subjective visual vertical (SVV; perception of the spatial upright). Both OCR and SVV measurements were made with the subject upright, lying on their left sides, and lying on their right sides. OCR was measured from binocular eye orientation recordings made while the subjects fixated for 10s on a point target directly in front of the face at a distance of 1 m. SVV was assessed by asking subjects (in the dark) to adjust to upright (using a handheld controller) the orientation of a luminous bar randomly perturbed (15) to either side of the vertical meridian. Balance control performance was assessed using a computerized dynamic posturography (CDP) protocol similar to that currently required for all returning crew members. During each session, the subjects completed a combination of trials of sensory organization test (SOT) 2 (eyes closed, fixed platform) and SOT 5 (eyes closed, sway-referenced platform) with and without static and dynamic pitch plane head movements (plus or minus 20 deg., dynamic

Balance control in elderly people with osteoporosis

Directory of Open Access Journals (Sweden)

Wei-Li Hsu

2014-06-01

Full Text Available Osteoporosis is a prevalent health concern among older adults and is associated with an increased risk of falls that incur fracture, injury, or mortality. Identifying the risk factors of falls within this population is essential for the development of effective regimes for fall prevention. Studies have shown that muscle quality and good posture alignments are critical for balance control in elderly individuals. People with osteoporosis often have muscle weakness and increased spine kyphosis leading to vertebral fractures and poor balance control, or even falls. Therefore, improving muscle quality, strengthening weak muscles, and correcting postural alignment are essential elements for the prevention of falls and fractures in older adults with osteoporosis. This review reports the necessary information regarding the critical factors of balance control in older adults with osteoporosis, as well as testing the clinical innovations of exercise training to improve the long-term prognosis of osteoporosis in this vulnerable population.

On Reflexive Data Models

Energy Technology Data Exchange (ETDEWEB)

Petrov, S.

2000-08-20

An information system is reflexive if it stores a description of its current structure in the body of stored information and is acting on the base of this information. A data model is reflexive, if its language is meta-closed and can be used to build such a system. The need for reflexive data models in new areas of information technology applications is argued. An attempt to express basic notions related to information systems is made in the case when the system supports and uses meta-closed representation of the data.

Hip proprioceptors preferentially modulate reflexes of the leg in human spinal cord injury

Science.gov (United States)

Onushko, Tanya; Hyngstrom, Allison

2013-01-01

Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conversely, whether knee and ankle stretch afferents affect hip-triggered reflexes. A custom-built servomotor apparatus was used to stretch the hip muscles in nine chronic SCI subjects by oscillating the legs about the hip joint bilaterally from 10° of extension to 40° flexion. To test whether stretch-related feedback from the knee or ankle would be affected by hip movement, patellar tendon percussions and Achilles tendon vibration were delivered when the hip was either extending or flexing. Surface electromyograms (EMGs) and joint torques were recorded from both legs. Patellar tendon percussions and Achilles tendon vibration both elicited reflex responses local to the knee or ankle, respectively, and did not influence reflex responses observed at the hip. Rather, the movement direction of the hip modulated the reflex responses local to the joint. The patellar tendon reflex amplitude was larger when the perturbation was delivered during hip extension compared with hip flexion. The response to Achilles vibration was modulated by hip movement, with an increased tonic component during hip flexion compared with extension. These results demonstrate that hip-mediated sensory signals modulate activity in distal muscles of the leg and appear to play a unique role in modulation of spastic muscle activity throughout the leg in SCI. PMID:23615544

Dissociative identity disorder and prepulse inhibition of the acoustic startle reflex

Science.gov (United States)

Dale, Karl Yngvar; Flaten, Magne Arve; Elden, Åke; Holte, Arne

2008-01-01

A group of persons with dissociative identity disorder (DID) was compared with a group of persons with other dissociative disorders, and a group of nondiagnosed controls with regard to prepulse inhibition (PPI) of the acoustic startle reflex. The findings suggest maladaptive attentional processes at a controlled level, but not at a preattentive automatic level, in persons with DID. The prepulse occupied more controlled attentional resources in the DID group compared with the other two groups. Preattentive automatic processing, on the other hand, was normal in the DID group. Moreover, startle reflexes did not habituate in the DID group. In conclusion, increased PPI and delayed habituation is consistent with increased vigilance in individuals with DID. The present findings of reduced habituation of startle reflexes and increased PPI in persons with DID suggest the operation of a voluntary process that directs attention away from unpleasant or threatening stimuli. Aberrant voluntary attentional processes may thus be a defining characteristic in DID. PMID:18830396

Sympathetic reflex control of skeletal muscle blood flow in patients with congestive heart failure: evidence for beta-adrenergic circulatory control

International Nuclear Information System (INIS)

Kassis, E.; Jacobsen, T.N.; Mogensen, F.; Amtorp, O.

1986-01-01

Mechanisms controlling forearm muscle vascular resistance (FMVR) during postural changes were investigated in seven patients with severe congestive heart failure (CHF) and in seven control subjects with unimpaired left ventricular function. Relative brachioradial muscle blood flow was determined by the local 133 Xe-washout technique. Unloading of baroreceptors with use of 45 degree upright tilt was comparably obtained in the patients with CHF and control subjects. Control subjects had substantially increased FMVR and heart rate to maintain arterial pressure whereas patients with CHF had decreased FMVR by 51 +/- 11% and had no increase in heart rate despite a fall in arterial pressure during upright tilt. The autoregulatory and local vasoconstrictor reflex responsiveness during postural changes in forearm vascular pressures were intact in both groups. In the patients with CHF, the left axillary nerve plexus was blocked by local anesthesia. No alterations in forearm vascular pressures were observed. This blockade preserved the local regulation of FMVR but reversed the vasodilator response to upright tilt as FMVR increased by 30 +/- 7% (p less than .02). Blockade of central neural impulses to this limb combined with brachial arterial infusions of phentolamine completely abolished the humoral vasoconstriction in the tilted position. Infusions of propranolol to the contralateral brachial artery that did not affect baseline values of heart rate, arterial pressure, or the local reflex regulation of FMVR reversed the abnormal vasodilator response to upright tilt as FMVR increased by 42 +/- 12% (p less than .02). Despite augmented baseline values, forearm venous but not arterial plasma levels of epinephrine increased in the tilted position, as did arteri rather than venous plasma concentrations of norepinephrine in these patients

Functionality of the contralateral biceps femoris reflex response during human walking

DEFF Research Database (Denmark)

Stevenson, Andrew James Thomas; Geertsen, Svend Sparre; Sinkjaer, Thomas

2014-01-01

of the body in order to maintain dynamic equilibrium during walking. Therefore, we hypothesized that if we suddenly slowed the treadmill participants were walking on, the cBF reflex would be inhibited because the necessity to break the forward progression of the body would be decreased. Conversely, if we...... the treadmill velocity was altered concurrently or 50 ms after knee perturbation onset. These results, together with the finding that the cBF reflex response is under some cortical control [1], strongly suggest a functional role for the cBF reflex during walking that is adaptable to the environmental situation....

Neurodevelopmental Reflex Testing in Neonatal Rat Pups.

Science.gov (United States)

Nguyen, Antoinette T; Armstrong, Edward A; Yager, Jerome Y

2017-04-24

Neurodevelopmental reflex testing is commonly used in clinical practice to assess the maturation of the nervous system. Neurodevelopmental reflexes are also referred to as primitive reflexes. They are sensitive and consistent with later outcomes. Abnormal reflexes are described as an absence, persistence, reappearance, or latency of reflexes, which are predictive indices of infants that are at high risk for neurodevelopmental disorders. Animal models of neurodevelopmental disabilities, such as cerebral palsy, often display aberrant developmental reflexes, as would be observed in human infants. The techniques described assess a variety of neurodevelopmental reflexes in neonatal rats. Neurodevelopmental reflex testing offers the investigator a testing method that is not otherwise available in such young animals. The methodology presented here aims to assist investigators in examining developmental milestones in neonatal rats as a method of detecting early-onset brain injury and/or determining the effectiveness of therapeutic interventions. The methodology presented here aims to provide a general guideline for investigators.

CMOS current controlled fully balanced current conveyor

International Nuclear Information System (INIS)

Wang Chunhua; Zhang Qiujing; Liu Haiguang

2009-01-01

This paper presents a current controlled fully balanced second-generation current conveyor circuit (CF-BCCII). The proposed circuit has the traits of fully balanced architecture, and its X-Y terminals are current controllable. Based on the CFBCCII, two biquadratic universal filters are also proposed as its applications. The CFBCCII circuits and the two filters were fabricated with chartered 0.35-μm CMOS technology; with ±1.65 V power supply voltage, the total power consumption of the CFBCCII circuit is 3.6 mW. Comparisons between measured and HSpice simulation results are also given.

Velocity and Motion Control of a Self-Balancing Vehicle Based on a Cascade Control Strategy

Directory of Open Access Journals (Sweden)

Miguel Velazquez

2016-06-01

Full Text Available This paper presents balancing, velocity and motion control of a self-balancing vehicle. A cascade controller is implemented for both balancing control and angular velocity control. This controller is tested in simulations using a proposed mathematical model of the system. Motion control is achieved based on the kinematics of the robot. Control hardware is designed and integrated to implement the proposed controllers. Pitch is kept under 1° from the equilibrium position with no external disturbances. The linear cascade control is able to handle slight changes in the system dynamics, such as in the centre of mass and the slope on an inclined surface.

A Half-Bridge Voltage Balancer with New Controller for Bipolar DC Distribution Systems

Directory of Open Access Journals (Sweden)

Byung-Moon Han

2016-03-01

Full Text Available This paper proposes a half-bridge voltage balancer with a new controller for bipolar DC distribution systems. The proposed control scheme consists of two cascaded Proportional Integral (PI controls rather than one PI control for balancing the pole voltage. In order to confirm the excellence of voltage balancing performance, a typical bipolar DC distribution system including a half-bridge voltage balancer with proposed controller was analyzed by computer simulations. Experiments with a scaled prototype were also carried out to confirm the simulation results. The half-bridge voltage balancer with proposed controller shows better performance than the half-bridge voltage balancer with one PI control for balancing the pole voltage.

Role of adenosine A2A receptor signaling in the nicotine-evoked attenuation of reflex cardiac sympathetic control

International Nuclear Information System (INIS)

El-Mas, Mahmoud M.; El-gowilly, Sahar M.; Fouda, Mohamed A.; Saad, Evan I.

2011-01-01

Baroreflex dysfunction contributes to increased cardiovascular risk in cigarette smokers. Given the importance of adenosinergic pathways in baroreflex control, the hypothesis was tested that defective central adenosinergic modulation of cardiac autonomic activity mediates the nicotine-baroreflex interaction. Baroreflex curves relating changes in heart rate (HR) to increases or decreases in blood pressure (BP) evoked by i.v. doses (1-16 μg/kg) of phenylephrine (PE) and sodium nitroprusside (SNP), respectively, were constructed in conscious rats; slopes of the curves were taken as measures of baroreflex sensitivity (BRS). Nicotine (25 and 100 μg/kg i.v.) dose-dependently reduced BRS SNP in contrast to no effect on BRS PE . BRS SNP was also attenuated after intracisternal (i.c.) administration of nicotine. Similar reductions in BRS SNP were observed in rats pretreated with atropine or propranolol. The combined treatment with nicotine and atropine produced additive inhibitory effects on BRS, an effect that was not demonstrated upon concurrent exposure to nicotine and propranolol. BRS SNP was reduced in preparations treated with i.c. 8-phenyltheophylline (8-PT, nonselective adenosine receptor antagonist), 8-(3-Chlorostyryl) caffeine (CSC, A 2A antagonist), or VUF5574 (A 3 antagonist). In contrast, BRS SNP was preserved after blockade of A 1 (DPCPX) or A 2B (alloxazine) receptors or inhibition of adenosine uptake by dipyridamole. CSC or 8-PT abrogated the BRS SNP depressant effect of nicotine whereas other adenosinergic antagonists were without effect. Together, nicotine preferentially impairs reflex tachycardia via disruption of adenosine A 2A receptor-mediated facilitation of reflex cardiac sympathoexcitation. Clinically, the attenuation by nicotine of compensatory sympathoexcitation may be detrimental in conditions such as hypothalamic defense response, posture changes, and ventricular rhythms. - Research highlights: → The role of central adenosinergic sites in

Reflex and Non-Reflex Torque Responses to Stretch of the Human Knee Extensors

National Research Council Canada - National Science Library

Mrachacz-Kersting, N

2001-01-01

.... The quadriceps muscles were stretched at various background torques, produced either voluntarily or electrically and thus the purely reflex-mediated torque could be calculated. The contribution of the reflex mediated stiffness initially low, increased with increasing background torques for the range of torques investigated.

Human H-reflexes are smaller in difficult beam walking than in normal treadmill walking.

Science.gov (United States)

Llewellyn, M; Yang, J F; Prochazka, A

1990-01-01

Hoffman (H) reflexes were elicited from the soleus (SOL) muscle while subjects walked on a treadmill and on a narrow beam (3.5 cm wide, raised 34 cm from the floor). The speed of walking on the treadmill was selected for each subject to match the background activation level of their SOL muscle during beam walking. The normal reciprocal activation pattern of the tibialis anterior and SOL muscles in treadmill walking was replaced by a pattern dominated by co-contraction on the beam. In addition, the step cycle duration was more variable and the time spent in the swing phase was reduced on the beam. The H-reflexes were highly modulated in both tasks, the amplitude being high in the stance phase and low in the swing phase. The H-reflex amplitude was on average 40% lower during beam walking than treadmill walking. The relationship between the H-reflex amplitude and the SOL EMG level was quantified by a regression line relating the two variables. The slope of this line was on average 41% lower in beam walking than treadmill walking. The lower H-reflex gain observed in this study and the high level of fusimotor drive observed in cats performing similar tasks suggest that the two mechanisms which control the excitability of this reflex pathway (i.e. fusimotor action and control of transmission at the muscle spindle to moto-neuron synapse) may be controlled independently.

Intramuscular Neurotrophin-3 normalizes low threshold spinal reflexes, reduces spasms and improves mobility after bilateral corticospinal tract injury in rats.

Science.gov (United States)

Kathe, Claudia; Hutson, Thomas Haynes; McMahon, Stephen Brendan; Moon, Lawrence David Falcon

2016-10-19

Brain and spinal injury reduce mobility and often impair sensorimotor processing in the spinal cord leading to spasticity. Here, we establish that complete transection of corticospinal pathways in the pyramids impairs locomotion and leads to increased spasms and excessive mono- and polysynaptic low threshold spinal reflexes in rats. Treatment of affected forelimb muscles with an adeno-associated viral vector (AAV) encoding human Neurotrophin-3 at a clinically-feasible time-point after injury reduced spasticity. Neurotrophin-3 normalized the short latency Hoffmann reflex to a treated hand muscle as well as low threshold polysynaptic spinal reflexes involving afferents from other treated muscles. Neurotrophin-3 also enhanced locomotor recovery. Furthermore, the balance of inhibitory and excitatory boutons in the spinal cord and the level of an ion co-transporter in motor neuron membranes required for normal reflexes were normalized. Our findings pave the way for Neurotrophin-3 as a therapy that treats the underlying causes of spasticity and not only its symptoms.

Evolution of Motor Control: From Reflexes and Motor Programs to the Equilibrium-Point Hypothesis.

Science.gov (United States)

Latash, Mark L

2008-01-01

This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive (reflexes) features of voluntary movements. It suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the equilibrium-point hypothesis. Physical, physiological, and behavioral foundations of the EP-hypothesis are considered as well as relations between the EP-hypothesis and the recent developments of the notion of motor synergies. The paper ends with a brief review of the criticisms of the EP-hypothesis and challenges that the hypothesis faces at this time.

Charitable giving and reflexive individuals: How personal reflexivity mediates between structure and agency.

Science.gov (United States)

Sanghera, Balihar

2017-03-01

This article examines how individuals are reflexive beings who interpret the world in relation to things that matter to them, and how charitable acts are evaluated and embedded in their lives with different degrees of meaning and importance. Rather than framing the discussion of charitable practices in terms of an altruism/egoism binary or imputing motivations and values to social structures, the article explains how reflexivity is an important and neglected dimension of social practices, and how it interacts with sympathy, sentiments and discourses to shape giving. The study also shows that there are different modes of reflexivity, which have varied effects on charity and volunteering.

Modification of Spastic Stretch Reflexes at the Elbow by Flexion Synergy Expression in Individuals With Chronic Hemiparetic Stroke.

Science.gov (United States)

McPherson, Jacob G; Stienen, Arno H; Drogos, Justin M; Dewald, Julius P

2018-03-01

To systematically characterize the effect of flexion synergy expression on the manifestation of elbow flexor stretch reflexes poststroke, and to relate these findings to elbow flexor stretch reflexes in individuals without neurologic injury. Controlled cohort study. Academic medical center. Participants (N=20) included individuals with chronic hemiparetic stroke (n=10) and a convenience sample of individuals without neurologic or musculoskeletal injury (n=10). Participants with stroke were interfaced with a robotic device that precisely manipulated flexion synergy expression (by regulating shoulder abduction loading) while delivering controlled elbow extension perturbations over a wide range of velocities. This device was also used to elicit elbow flexor stretch reflexes during volitional elbow flexor activation, both in the cohort of individuals with stroke and in a control cohort. In both cases, the amplitude of volitional elbow flexor preactivation was matched to that generated involuntarily during flexion synergy expression. The amplitude of short- and long-latency stretch reflexes in the biceps brachii, assessed by electromyography, and expressed as a function of background muscle activation and stretch velocity. Increased shoulder abduction loading potentiated elbow flexor stretch reflexes via flexion synergy expression in the paretic arm. Compared with stretch reflexes in individuals without neurologic injury, paretic reflexes were larger at rest but were approximately equal to control muscles at matched levels of preactivation. Because flexion synergy expression modifies stretch reflexes in involved muscles, interventions that reduce flexion synergy expression may confer the added benefit of reducing spasticity during functional use of the arm. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Multi-Objective Predictive Balancing Control of Battery Packs Based on Predictive Current

Directory of Open Access Journals (Sweden)

Wenbiao Li

2016-04-01

Full Text Available Various balancing topology and control methods have been proposed for the inconsistency problem of battery packs. However, these strategies only focus on a single objective, ignore the mutual interaction among various factors and are only based on the external performance of the battery pack inconsistency, such as voltage balancing and state of charge (SOC balancing. To solve these problems, multi-objective predictive balancing control (MOPBC based on predictive current is proposed in this paper, namely, in the driving process of an electric vehicle, using predictive control to predict the battery pack output current the next time. Based on this information, the impact of the battery pack temperature caused by the output current can be obtained. Then, the influence is added to the battery pack balancing control, which makes the present degradation, temperature, and SOC imbalance achieve balance automatically due to the change of the output current the next moment. According to MOPBC, the simulation model of the balancing circuit is built with four cells in Matlab/Simulink. The simulation results show that MOPBC is not only better than the other traditional balancing control strategies but also reduces the energy loss in the balancing process.

Frequency-Weighted Balancing Related Controller Reduction

OpenAIRE

Varga, Andras; Anderson, Brian D.O.

2002-01-01

The efficient solution of a class of controller approximation problems by using frequency-weighted balancing related model reduction approaches is considered. It is shown that for certain standard performance and stability enforcing frequency-weights, the computation of the frequency-weighted controllability and observability grammians can be done by solving reduced order Lyapunov equations regardless the controller itself is stable or unstable. The new approach can be used in conjunction wit...

Vestibular control of sympathetic activity. An otolith-sympathetic reflex in humans.

Science.gov (United States)

Kaufmann, H; Biaggioni, I; Voustianiouk, A; Diedrich, A; Costa, F; Clarke, R; Gizzi, M; Raphan, T; Cohen, B

2002-04-01

It has been proposed that a vestibular reflex originating in the otolith organs and other body graviceptors modulates sympathetic activity during changes in posture with regard to gravity. To test this hypothesis, we selectively stimulated otolith and body graviceptors sinusoidally along different head axes in the coronal plane with off-vertical axis rotation (OVAR) and recorded sympathetic efferent activity in the peroneal nerve (muscle sympathetic nerve activity, MSNA), blood pressure, heart rate, and respiratory rate. All parameters were entrained during OVAR at the frequency of rotation, with MSNA increasing in nose-up positions during forward linear acceleration and decreasing when nose-down. MSNA was correlated closely with blood pressure when subjects were within +/-90 degrees of nose-down positions with a delay of 1.4 s, the normal latency of baroreflex-driven changes in MSNA. Thus, in the nose-down position, MSNA was probably driven by baroreflex afferents. In contrast, when subjects were within +/-45 degrees of the nose-up position, i.e., when positive linear acceleration was maximal along the naso-ocipital axis, MSNA was closely related to gravitational acceleration at a latency of 0.4 s. This delay is too short for MSNA changes to be mediated by the baroreflex, but it is compatible with the delay of a response originating in the vestibular system. We postulate that a vestibulosympathetic reflex, probably originating mainly in the otolith organs, contributes to blood pressure maintenance during forward linear acceleration. Because of its short latency, this reflex may be one of the earliest mechanisms to sustain blood pressure upon standing.

[Laryngeal adduction reflex].

Science.gov (United States)

Ptok, M; Bonenberger, S; Miller, S; Kühn, D; Jungheim, M

2014-07-01

Laryngeal Adductor Reflex Background: A rapid closure of the vocal folds is necessary, whenever foreign materials or food particles penetrate into the larynx. Otherwise a passage of these particles into the trachea or the lower respiratory tract would be imminent. An aspiration could mechanically block the respiratory tract and cause severe dyspnoea or cause aspiration pneumonia. For this systematic review a selective literature research in PubMed and Scopus using the keywords "laryngeal adductor reflex" and "vocal fold closure" has been carried out. Apart from the oesophago-glottal and pharyngo-glottal closure reflexes, the laryngeal adductor reflex (LAR) has been investigated in particular. The LAR qualifies as a reflectory laryngeal adductor mechanism and involves early, presumably di- or oligosynaptic ipsilateral LAR1 as well as late polysynaptic ipsi- and contralateral LAR2 components. In clinical routine diagnostic settings of dysphagia, LAR is only assessed qualitatively and usually triggered by air pulses or tactile stimulation. Dysphagiologists often find that not only the laryngeal sensibility in general is impaired, but especially the protective laryngeal adduction mechanism, which results in a higher risk of aspiration. Thus, it appears mandatory to test the LAR not only qualitatively but also quantitatively. Unfortunately a valid and reliable method that can be employed in clinical practice has not yet been put forward. © Georg Thieme Verlag KG Stuttgart · New York.

Effect of Low-level LASER Therapy on P6 Acupoint to Control Gag Reflex in Children: A Clinical Trial

Directory of Open Access Journals (Sweden)

Himani Goel

2017-10-01

Conclusion: LLLT on PC6 point was found to be effective in lowering anxiety levels as observed by faces modified anxiety rating scale. Further, it was authenticated as the pulse rates were significantly reduced and oxygen saturation levels were significantly increased. Also, gag reflex was significantly controlled when LASER stimulation was done at PC6.

Feasibility and effects of newly developed balance control trainer for mobility and balance in chronic stroke patients: a randomized controlled trial.

Science.gov (United States)

Lee, So Hyun; Byun, Seung Deuk; Kim, Chul Hyun; Go, Jin Young; Nam, Hyeon Uk; Huh, Jin Seok; Jung, Tae Du

2012-08-01

To investigate the feasibility and effects of balance training with a newly developed Balance Control Trainer (BCT) that applied the concept of vertical movement for the improvements of mobility and balance in chronic stroke patients. Forty chronic stroke patients were randomly assigned to an experimental or a control group. The experimental group (n=20) underwent training with a BCT for 20 minutes a day, 5 days a week for 4 weeks, in addition to concurrent conventional physical therapy. The control group (n=20) underwent only conventional therapy for 4 weeks. All participants were assessed by: the Functional Ambulation Categories (FAC), 10-meter Walking Test (10mWT), Timed Up and Go test (TUG), Berg Balance Scale (BBS), Korean Modified Barthel Index (MBI), and Manual Muscle Test (MMT) before training, and at 2 and 4 weeks of training. There were statistically significant improvements in all parameters except knee extensor power at 2 weeks of treatment, and in all parameters except MBI which showed further statistically significant progress in the experimental group over the next two weeks (pgait in ambulatory chronic stroke patients. Furthermore, it may provide additional benefits when used in conjunction with conventional therapies.

Effect of chronic and acute cigarette smoking on the pharyngo-upper oesophageal sphincter contractile reflex and reflexive pharyngeal swallow

OpenAIRE

Dua, K; Bardan, E; Ren, J; Sui, Z; Shaker, R

1998-01-01

Background—Cigarette smoking is known to affect adversely the defence mechanisms against gastro-oesophageal reflux. The effect of smoking on the supraoesophageal reflexes that prevent aspiration of gastric contents has not been previously studied. 
Aims—To elucidate the effect of cigarette smoking on two of the supraoesophageal reflexes: the pharyngo-upper oesophageal sphincter (UOS) contractile reflex; and the reflexive pharyngeal swallow. 
Methods—Ten chronic smokers and 10 non-...

Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping

Directory of Open Access Journals (Sweden)

Christian Schumacher

2017-11-01

Full Text Available In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB, velocity (VFB and force feedback (FFB pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort. Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map. The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency. Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length or environmental parameters (ground compliance. Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a

Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping.

Science.gov (United States)

Schumacher, Christian; Seyfarth, André

2017-01-01

In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB), velocity (VFB) and force feedback (FFB) pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort). Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map . The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency). Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length) or environmental parameters (ground compliance). Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a specific

Quantifying balance control during stance : a multivariate system identification approach

NARCIS (Netherlands)

Engelhart, Denise

2015-01-01

Balance control involves the contribution of neural, muscular and sensory systems, which work together via complex feedback pathways in a closed loop. With age or disease, the underlying systems in balance control can deteriorate; e.g. muscle strength decreases, the sensory systems become less

ESO Reflex: a graphical workflow engine for data reduction

Science.gov (United States)

Hook, Richard; Ullgrén, Marko; Romaniello, Martino; Maisala, Sami; Oittinen, Tero; Solin, Otto; Savolainen, Ville; Järveläinen, Pekka; Tyynelä, Jani; Péron, Michèle; Ballester, Pascal; Gabasch, Armin; Izzo, Carlo

ESO Reflex is a prototype software tool that provides a novel approach to astronomical data reduction by integrating a modern graphical workflow system (Taverna) with existing legacy data reduction algorithms. Most of the raw data produced by instruments at the ESO Very Large Telescope (VLT) in Chile are reduced using recipes. These are compiled C applications following an ESO standard and utilising routines provided by the Common Pipeline Library (CPL). Currently these are run in batch mode as part of the data flow system to generate the input to the ESO/VLT quality control process and are also exported for use offline. ESO Reflex can invoke CPL-based recipes in a flexible way through a general purpose graphical interface. ESO Reflex is based on the Taverna system that was originally developed within the UK life-sciences community. Workflows have been created so far for three VLT/VLTI instruments, and the GUI allows the user to make changes to these or create workflows of their own. Python scripts or IDL procedures can be easily brought into workflows and a variety of visualisation and display options, including custom product inspection and validation steps, are available. Taverna is intended for use with web services and experiments using ESO Reflex to access Virtual Observatory web services have been successfully performed. ESO Reflex is the main product developed by Sampo, a project led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. The goal was to look into the needs of the ESO community in the area of data reduction environments and to create pilot software products that illustrate critical steps along the road to a new system. Sampo concluded early in 2008. This contribution will describe ESO Reflex and show several examples of its use both locally and using Virtual Observatory remote web services. ESO Reflex is expected to be released to the community in early 2009.

Short-term locomotor adaptation to a robotic ankle exoskeleton does not alter soleus Hoffmann reflex amplitude.

Science.gov (United States)

Kao, Pei-Chun; Lewis, Cara L; Ferris, Daniel P

2010-07-26

To improve design of robotic lower limb exoskeletons for gait rehabilitation, it is critical to identify neural mechanisms that govern locomotor adaptation to robotic assistance. Previously, we demonstrated soleus muscle recruitment decreased by approximately 35% when walking with a pneumatically-powered ankle exoskeleton providing plantar flexor torque under soleus proportional myoelectric control. Since a substantial portion of soleus activation during walking results from the stretch reflex, increased reflex inhibition is one potential mechanism for reducing soleus recruitment when walking with exoskeleton assistance. This is clinically relevant because many neurologically impaired populations have hyperactive stretch reflexes and training to reduce the reflexes could lead to substantial improvements in their motor ability. The purpose of this study was to quantify soleus Hoffmann (H-) reflex responses during powered versus unpowered walking. We tested soleus H-reflex responses in neurologically intact subjects (n=8) that had trained walking with the soleus controlled robotic ankle exoskeleton. Soleus H-reflex was tested at the mid and late stance while subjects walked with the exoskeleton on the treadmill at 1.25 m/s, first without power (first unpowered), then with power (powered), and finally without power again (second unpowered). We also collected joint kinematics and electromyography. When the robotic plantar flexor torque was provided, subjects walked with lower soleus electromyographic (EMG) activation (27-48%) and had concomitant reductions in H-reflex amplitude (12-24%) compared to the first unpowered condition. The H-reflex amplitude in proportion to the background soleus EMG during powered walking was not significantly different from the two unpowered conditions. These findings suggest that the nervous system does not inhibit the soleus H-reflex in response to short-term adaption to exoskeleton assistance. Future studies should determine if the

Physical load handling and listening comprehension effects on balance control.

Science.gov (United States)

Qu, Xingda

2010-12-01

The purpose of this study was to determine the physical load handling and listening comprehension effects on balance control. A total of 16 young and 16 elderly participants were recruited in this study. The physical load handling task required holding a 5-kg load in each hand with arms at sides. The listening comprehension task involved attentive listening to a short conversation. Three short questions were asked regarding the conversation right after the testing trial to test the participants' attentiveness during the experiment. Balance control was assessed by centre of pressure-based measures, which were calculated from the force platform data when the participants were quietly standing upright on a force platform. Results from this study showed that both physical load handling and listening comprehension adversely affected balance control. Physical load handling had a more deleterious effect on balance control under the listening comprehension condition vs. no-listening comprehension condition. Based on the findings from this study, interventions for the improvement of balance could be focused on avoiding exposures to physically demanding tasks and cognitively demanding tasks simultaneously. STATEMENT OF RELEVANCE: Findings from this study can aid in better understanding how humans maintain balance, especially when physical and cognitive loads are applied. Such information is useful for developing interventions to prevent fall incidents and injuries in occupational settings and daily activities.

Monosynaptic Stretch Reflex Fails to Explain the Initial Postural Response to Sudden Lateral Perturbations

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Andreas Mühlbeier

2017-06-01

Full Text Available Postural reflexes are essential for locomotion and postural stability, and may play an important role in the etiology of chronic back pain. It has recently been theoretically predicted, and with the help of unilateral perturbations of the trunk experimentally confirmed that the sensorimotor control must lower the reflex amplitude for increasing reflex delays to maintain spinal stability. The underlying neuromuscular mechanism for the compensation of postural perturbations, however, is not yet fully understood. In this study, we applied unilateral and bilateral sudden external perturbations to the trunk of healthy subjects and measured the muscular activity and the movement onset of the trunk. We found that the onset of the trunk muscle activity is prior to, or coincident with, the onset of the trunk movement. Additionally, the results of our experiments imply that the muscular response mechanism integrates distant sensory information from both sides of the body. These findings rule out a simple monosynaptic stretch reflex in favor of a more complex polysynaptic postural reflex mechanism to compensate postural perturbations. Moreover, the previously predicted negative correlation between reflex delay and reflex gain was also confirmed for bilateral perturbations.

"On Becoming a Critically Reflexive Practitioner" Redux: What Does It Mean to "Be" Reflexive?

Science.gov (United States)

Cunliffe, Ann L.

2016-01-01

In this commentary, Cunliffe states that is convinced that reflexivity offers a way of foregrounding our moral and ethical responsibility for people and for the world around us. To "BE" reflexive was defined as embracing "subjective understandings of reality as a basis for thinking more critically about the impact of our…

Artificial-reflex stimulation for FES-induced standing with minimum quadriceps force

NARCIS (Netherlands)

Mulder, A.J.; Mulder, A.J.; Boom, H.B.K.; Hermens, Hermanus J.; Zilvold, G.; Zilvold, G.

1990-01-01

A control strategy is proposed to decrease quadriceps activity during standing. Modified on/off (or artificial reflex) control is used: a non-numerical or finite-state control scheme based on feedback of knee angle and angular velocity. The control strategy is evaluated in paraplegic patients in an

Abnormal reflex activation of hamstring muscles in dogs with cranial cruciate ligament rupture.

Science.gov (United States)

Hayes, Graham M; Granger, Nicolas; Langley-Hobbs, Sorrel J; Jeffery, Nick D

2013-06-01

The mechanisms underlying cranial cruciate ligament rupture (CCLR) in dogs are poorly understood. In this study hamstring muscle reflexes in response to cranial tibial translation were analysed to determine whether these active stabilisers of the stifle joint are differently activated in dogs with CCLR compared to control dogs. In a prospective clinical study reflex muscle activity from the lateral and medial hamstring muscles (biceps femoris and semimembranosus) was recorded using surface electrodes in control dogs (n=21) and dogs with CCLR (n=22). These electromyographic recordings were analysed using an algorithm previously validated in humans. The hamstring reflex was reliably and reproducibly recorded in normal dogs. Both a short latency response (SLR, 17.6±2.1ms) and a medium latency response (MLR, 37.7±2.7ms) could be identified. In dogs with unilateral CCLR, the SLR and MLR were not significantly different between the affected and the unaffected limbs, but the MLR latency of both affected and unaffected limbs in CCLR dogs were significantly prolonged compared to controls. In conclusion, the hamstring reflex can be recorded in dogs and the MLR is prolonged in dogs with CCLR. Since both affected and unaffected limbs exhibit prolonged MLR, it is possible that abnormal hamstring reflex activation is a mechanism by which progressive CCL damage may occur. The methodology allows for further investigation of the relationship between neuromuscular imbalance and CCLR or limitations in functional recovery following surgical intervention. Copyright © 2012 Elsevier Ltd. All rights reserved.

AMPUTATION AND REFLEX SYMPATHETIC DYSTROPHY

NARCIS (Netherlands)

GEERTZEN, JHB; EISMA, WH

Reflex sympathetic dystrophy is a chronic pain syndrome characterized by chronic burning pain, restricted range of motion, oedema and vasolability. Patients are difficult to treat and the prognosis is very often poor. This report emphasizes that an amputation in case of a reflex sympathetic

Portraying Reflexivity in Health Services Research.

Science.gov (United States)

Rae, John; Green, Bill

2016-09-01

A model is proposed for supporting reflexivity in qualitative health research, informed by arguments from Bourdieu and Finlay. Bourdieu refers to mastering the subjective relation to the object at three levels-the overall social space, the field of specialists, and the scholastic universe. The model overlays Bourdieu's levels of objectivation with Finlay's three stages of research (pre-research, data collection, and data analysis). The intersections of these two ways of considering reflexivity, displayed as cells of a matrix, pose questions and offer prompts to productively challenge health researchers' reflexivity. Portraiture is used to show how these challenges and prompts can facilitate such reflexivity, as illustrated in a research project. © The Author(s) 2016.

The Effects of Multisensory Balance Training on Postural Control in Older Adults

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Farnoosh Shams

2011-10-01

Full Text Available Objectives: It has been found that older adults fall or sway significantly more than younger ones under sensory conflict conditions. Considering the prospects of future increases in the elderly population size of Iran and the lack of proper postural control and the high costs of its probable consequences, this study investigated the effects of multi balance training on postural control. Methods & Materials: In this semi-experimental study, 34 elderly women participated in two training and control groups with the mean ages of 72.4 and 72.9 respectively. Before and after training, to investigate the functional balance and postural control, the Berg Balance Scale and a force plate were used. The training group participated in multisensory balance training sessions of 1 hour classes held three days per week for five weeks. Data was analyzed using an independent sample and a paired t-test. Results: The analysis showed significant differences between the training group and the control after balance training in the measured parameters of postural control consisting of path length and mean velocity in the eyes open (P=0.001 and eyes closed (P=0.0001 conditions and the Berg Balance Scale (P=0.002. Conclusion: Results indicate that multisensory balance training can improve the parameters of postural control even in short term.

PID Controller Design for FES Applied to Ankle Muscles in Neuroprosthesis for Standing Balance.

Science.gov (United States)

Rouhani, Hossein; Same, Michael; Masani, Kei; Li, Ya Qi; Popovic, Milos R

2017-01-01

Closed-loop controlled functional electrical stimulation (FES) applied to the lower limb muscles can be used as a neuroprosthesis for standing balance in neurologically impaired individuals. The objective of this study was to propose a methodology for designing a proportional-integral-derivative (PID) controller for FES applied to the ankle muscles toward maintaining standing balance for several minutes and in the presence of perturbations. First, a model of the physiological control strategy for standing balance was developed. Second, the parameters of a PID controller that mimicked the physiological balance control strategy were determined to stabilize the human body when modeled as an inverted pendulum. Third, this PID controller was implemented using a custom-made Inverted Pendulum Standing Apparatus that eliminated the effect of visual and vestibular sensory information on voluntary balance control. Using this setup, the individual-specific FES controllers were tested in able-bodied individuals and compared with disrupted voluntary control conditions in four experimental paradigms: (i) quiet-standing; (ii) sudden change of targeted pendulum angle (step response); (iii) balance perturbations that simulate arm movements; and (iv) sudden change of targeted angle of a pendulum with individual-specific body-weight (step response). In paradigms (i) to (iii), a standard 39.5-kg pendulum was used, and 12 subjects were involved. In paradigm (iv) 9 subjects were involved. Across the different experimental paradigms and subjects, the FES-controlled and disrupted voluntarily-controlled pendulum angle showed root mean square errors of controlled balance were significantly smaller or tended to be smaller than those observed with voluntarily-controlled balance, implying improved steady-state and transient responses of FES-controlled balance. At the same time, the FES-controlled balance required similar torque levels (no significant difference) as voluntarily-controlled

Evaluation of Advanced Control for Li-ion Battery Balancing Systems using Convex Optimization

DEFF Research Database (Denmark)

Pinto, Claudio; Barreras, Jorge Varela; Schaltz, Erik

2016-01-01

Typically, the unique objective pursued in either active or passive balancing is equalization of single cell charge. However, a balancing circuit may offer more control features, like virtual equalization of single cell internal resistance or thermal balancing. Such control features for balancing...

The role of sympathetic reflex control of cerebral blood flow and microcirculation during normoxia and hypoxia

International Nuclear Information System (INIS)

Kissen, I.

1989-01-01

The purpose of this study was to investigate the hypothesis that there is sympathetic reflex regulation of the cerebral blood flow (CBF) and the utilization of microvessels during normoxia and hypoxia. Regional CBF was determined in conscious Long Evans rats with 4-iodo[N-methyl- 14 C]antipyrine. The percentage of the microvessels perfused as determined by comparing perfused microvessels (FITC-dextran), with the total microvasculature (alkaline phosphatase stain). To test this hypothesis, arcs of the proposed reflex were eliminated. The first experiment examined the effect of bilateral superior cervical ganglionectomy on CBF and microcirulation during normoxia and hypoxia. CBF increased during hypoxia from 67 ± 2 to 115 ± 3 ml/min/100 g in control, and from 77 ± 2 to 155 ± 6 ml/min/100 g in ganglionectomized animals. In control, hypoxic flow to caudal areas was higher than to rostral areas and that difference was prevented by ganglionectomy. Utilization of arterioles during hypoxia increased from 51 ± 2% to 63 ± 2% in control, and from 52 ± 1% to 77 ± 2% in ganglionectomized group. The percent perfused capillaries during normoxia was 49 ± 2% in control, and 52 ± 1% in ganglionectomized group, and during hypoxia it was 73 ± 2% in both groups. In the second study, cerebral vascular responses to hypoxia were determined after administration of alpha-adrenoceptor antagonists N-methyl chlorpromazine (does not cross the blood-brain barrier), and phenoxybenzamine (crosses the blood-brain barrier). Neither phenoxybenzamine nor N-methyl chlorpromazine affected CBF and microcirculation during normoxia. During hypoxia, they similarly reversed the rostral to caudal gradient of flow, increased utilization of arterioles in rostral brain areas, and did not affect capillaries

A Study on the Effects of Bee Venom Aqua-Acupuncture on Writhing Reflex

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Jeong Sun-Hee

2000-07-01

Full Text Available Introduction:In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex Materials and Methods:Pain animal model was used acetic acid method. The changes of writhing reflex of the mice which were derived pain by injecting acetic acid into the abdomen, after stimulating Bee Venom aqua-acupuncture on Chungwan(CV12 and non acupuncture point on the backside were measured. Results:1. It showed that the writhing reflex were appeared on the groups which injected acetic acid only, and saline-acetic acid group(sample I, but not on the group bee venom-saline group(sample II. 2. The change of writhing reflex by Chungwan(CV12 Bee Venom aqua-acupuncture showed significant decrease in the order of Chungwan(CV12 Bee Venom aqua-acupuncture group III(2.5×10-3g/kg, II(2.5×10-4g/kg, and I(2.5×10-5g/kg, compared with control group. There were significant decrease of number of writhing reflex in 5～10, 10～15 and 15～20 minutes intervals of Chung wan(CV12 Bee Venom aqua-acupuncture group I, and in 0～5, 5～10, 10～15 and 15～20 minutes intervals of II and III, compared with control group. 3. The change of writhing reflex by non acupuncture point Bee Venom aqua-acupuncture showed significant decrease in the 0～5 and 5～10 minutes intervals and the total number of writhing reflex in 2.5×10-4g/kg group, compared with control group 4. The effects of writhing reflex of Chungwan(CV12 Bee Venom aqua-acupuncture group showed significant decrease, compared with non acupuncture point Bee Venom aqua-acupuncture group. Conclusion:This study shows that the Bee Venom aqua-acupuncture on Chungwan(CV12 decreases the numbers of writhing reflex. As the

The energy cost for balance control during upright standing

NARCIS (Netherlands)

Houdijk, J.H.P.; Fickert, R.; van Velzen, J.; van Bennekom, C.A.M.

2009-01-01

The aim of this study was to investigate whether balance control during a static upright standing task with and without balance perturbations elicits a significant and meaningful metabolic energy demand and to test whether this energy demand correlates with conventional posturography measures for

Too Busy for Reflexivity?

DEFF Research Database (Denmark)

Ratner, Helene

What Danish school managers can teach STS researchers about epistemological ideals and pragmatic morals. Reflexivity has an ambivalent status in both anthropology and Science and Technology Studies. On the one hand, the critique of representation at the heart of the reflexivity debates of the 1980s...... highlighted non-symmetric relationships between observer and observed and accused the academic text of enacting a realist genre, concealing the relativism entailed in textual production (Clifford and Marcus 1986, Woolgar 1988, Ashmore 1989). On the other hand, the reflexivity program produced fears...... of a “corrosive relativism in which everything is but a more or less clever expression of opinion” (Geertz 1988:2, 3) and it has suffered the little flattering accusations of piling "layer upon layer of self-consciousness to no avail" (Latour 1988:170) with little “interest [for] … theoretically ambitious...

The passive of reflexive verbs in Icelandic

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Hlíf Árnadóttir

2011-10-01

Full Text Available The Reflexive Passive in Icelandic is reminiscent of the so-called New Passive (or New Impersonal in that the oblique case of a passivized object NP is preserved. As is shown by recent surveys, however, speakers who accept the Reflexive Passive do not necessarily accept the New Passive, whereas conversely, speakers who accept the New Passive do also accept the Reflexive Passive. Based on these results we suggest that there is a hierarchy in the acceptance of passive sentences in Icelandic, termed the Passive Acceptability Hierarchy. The validity of this hierarchy is confirmed by our diachronic corpus study of open access digital library texts from Icelandic journals and newspapers dating from the 19th and 20th centuries (tímarit.is. Finally, we sketch an analysis of the Reflexive Passive, proposing that the different acceptability rates of the Reflexive and New Passives lie in the argument status of the object. Simplex reflexive pronouns are semantically dependent on the verbs which select them, and should therefore be analyzed as syntactic arguments only, and not as semantic arguments of these verbs.

PID Controller Design for FES Applied to Ankle Muscles in Neuroprosthesis for Standing Balance

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Hossein Rouhani

2017-06-01

Full Text Available Closed-loop controlled functional electrical stimulation (FES applied to the lower limb muscles can be used as a neuroprosthesis for standing balance in neurologically impaired individuals. The objective of this study was to propose a methodology for designing a proportional-integral-derivative (PID controller for FES applied to the ankle muscles toward maintaining standing balance for several minutes and in the presence of perturbations. First, a model of the physiological control strategy for standing balance was developed. Second, the parameters of a PID controller that mimicked the physiological balance control strategy were determined to stabilize the human body when modeled as an inverted pendulum. Third, this PID controller was implemented using a custom-made Inverted Pendulum Standing Apparatus that eliminated the effect of visual and vestibular sensory information on voluntary balance control. Using this setup, the individual-specific FES controllers were tested in able-bodied individuals and compared with disrupted voluntary control conditions in four experimental paradigms: (i quiet-standing; (ii sudden change of targeted pendulum angle (step response; (iii balance perturbations that simulate arm movements; and (iv sudden change of targeted angle of a pendulum with individual-specific body-weight (step response. In paradigms (i to (iii, a standard 39.5-kg pendulum was used, and 12 subjects were involved. In paradigm (iv 9 subjects were involved. Across the different experimental paradigms and subjects, the FES-controlled and disrupted voluntarily-controlled pendulum angle showed root mean square errors of <1.2 and 2.3 deg, respectively. The root mean square error (all paradigms, rise time, settle time, and overshoot [paradigms (ii and (iv] in FES-controlled balance were significantly smaller or tended to be smaller than those observed with voluntarily-controlled balance, implying improved steady-state and transient responses of FES-controlled

A High-Gain Reflex-Based Bidirectional DC Charger with Efficient Energy Recycling for Low-Voltage Battery Charging-Discharging Power Control

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Ching-Ming Lai

2018-03-01

Full Text Available This study proposes a high-gain reflex-charging-based bidirectional DC charger (RC-BDC to enhance the battery charging efficiency of light electric vehicles (LEV in a DC-microgrid. The proposed charger topology consists of an unregulated level converter (ULC and a two-phase interleaved buck-boost charge-pump converter (IBCPC, which together provide low ripple and high voltage conversion ratio. As the high-gain RC-BDC charges, the LEV’s battery with reflex charging currents, high battery charging efficiency, and prolonged battery life cycles are achieved. This is possible due to the recovering of negative pulse energy of reflex charging currents to reduce charge dissipations within LEV’s batteries. Derivations of the operating principles of the high-gain RC-BDC, analyses of its topology, and the closed-loop control designs were presented. Simulations and experiments were implemented with battery voltage of 48 V and DC-bus voltage of 400 V for a 500 W prototype. The results verify the feasibility of the proposed concept and were compared with the typical constant-current/constant-voltage (CC/CV charger. The comparison shows that the proposed high gain RC-BDC improves battery charging speed and reduces the battery thermal deterioration effect by about 12.7% and 25%, respectively.

The Pivotal Role of the Parieto-Occipital Lobe in Card Game-Induced Reflex Epilepsy: A Voxel-Based Morphometry Study.

Science.gov (United States)

Park, Kang Min; Kim, Sung Eun; Lee, Byung In

2016-01-01

The pathogenesis of card game-induced reflex epilepsy has not been determined so far. The aim of this study was to evaluate structural abnormalities using voxel-based morphometry (VBM) analysis, which may give some clue about the pathogenesis in card game-induced reflex epilepsy. The 3 subjects were diagnosed with card game-induced reflex epilepsy. Evaluation involved a structured interview to obtain clinical information and brain MRI. In VBM analysis, Statistical Parametric Mapping 8 running on the MATLAB platform was employed to analyze the structural differences between patients with card game-induced reflex epilepsy and age- and sex-matched control subjects. The results of VBM analysis revealed that patients with card game-induced reflex epilepsy had significantly increased gray matter volume in the right occipital and parietal lobe. However, there were no structures with decreased gray matter volume in patients with card game-induced reflex epilepsy compared with control subjects. In addition, we found that the patients with card game-induced reflex epilepsy had onset of seizures in adulthood rather than in adolescence, and all of the patients were men. The parieto-occipital lobes might be partially involved in the neuronal network responsible for card game-induced reflex epilepsy. © 2016 S. Karger AG, Basel.

Characterization and Early Detection of Balance Deficits in Fragile X Premutation Carriers With and Without Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS).

Science.gov (United States)

O'Keefe, Joan A; Robertson-Dick, Erin; Dunn, Emily J; Li, Yan; Deng, Youping; Fiutko, Amber N; Berry-Kravis, Elizabeth; Hall, Deborah A

2015-12-01

Fragile X-associated tremor/ataxia syndrome (FXTAS) results from a "premutation" size 55-200 CGG repeat expansion in the fragile X mental retardation 1 (FMR1) gene. Core motor features include cerebellar gait ataxia and kinetic tremor, resulting in progressive mobility disability. There are no published studies characterizing balance deficits in FMR1 premutation carriers with and without FXTAS using a battery of quantitative measures to test the sensory integration underlying postural control, automatic postural reflexes, and dynamic postural stability limits. Computerized dynamic posturography (CDP) and two performance-based balance measures were administered in 44 premutation carriers, 21 with FXTAS and 23 without FXTAS, and 42 healthy controls to compare balance and functional mobility between these groups. Relationships between FMR1 molecular variables, age, and sex and CDP scores were explored. FXTAS subjects demonstrated significantly lower scores on the sensory organization test (with greatest reductions in the vestibular control of balance), longer response latencies to balance perturbations, and reduced stability limits compared to controls. Premutation carriers without FXTAS also demonstrated significantly delayed response latencies and disrupted sensory weighting for balance control. Advancing age, male sex, increased CGG repeat size, and reduced X activation of the normal allele in premutation carrier women predicted balance dysfunction. These postural control deficits in carriers with and without FXTAS implicate dysfunctional cerebellar neural networks and may provide valuable outcome markers for tailored rehabilitative interventions. Our findings suggest that CDP may provide sensitive measures for early detection of postural control impairments in at-risk carriers and better characterize balance dysfunction and progression in FXTAS.

The stretch reflex and the contributions of C David Marsden

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Kalyan B Bhattacharyya

2017-01-01

Full Text Available The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail , and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

Balance circuit classes to improve balance among rehabilitation inpatients: a protocol for a randomised controlled trial.

Science.gov (United States)

Treacy, Daniel; Schurr, Karl; Sherrington, Catherine

2013-07-20

Impaired balance and mobility are common among rehabilitation inpatients. Poor balance and mobility lead to an increased risk of falling. Specific balance exercise has been shown to improve balance and reduce falls within the community setting. However few studies have measured the effects of balance exercises on balance within the inpatient setting. A single centre, randomised controlled trial with concealed allocation, assessor blinding and intention-to-treat analysis. One hundred and sixty two patients admitted to the general rehabilitation ward at Bankstown-Lidcombe Hospital will be recruited. Eligible participants will have no medical contraindications to exercise and will be able to: fully weight bear; stand unaided independently for at least 30 seconds; and participate in group therapy sessions with minimal supervision. Participants will be randomly allocated to an intervention group or usual-care control group. Both groups will receive standard rehabilitation intervention that includes physiotherapy mobility training and exercise for at least two hours on each week day. The intervention group will also receive six 1-hour circuit classes of supervised balance exercises designed to maximise the ability to make postural adjustments in standing, stepping and walking. The primary outcome is balance. Balance will be assessed by measuring the total time the participant can stand unsupported in five different positions; feet apart, feet together, semi-tandem, tandem and single-leg-stance. Secondary outcomes include mobility, self reported physical functioning, falls and hospital readmissions. Performance on the outcome measures will be assessed before randomisation and at two-weeks and three-months after randomisation by physiotherapists unaware of intervention group allocation. This study will determine the impact of additional balance circuit classes on balance among rehabilitation inpatients. The results will provide essential information to guide evidence

An Integrated Gait and Balance Analysis System to Define Human Locomotor Control

Science.gov (United States)

2016-04-29

test hypotheses they developed about how people walk. An Integrated Gait and Balance Analysis System to define Human Locomotor Control W911NF-14-R-0009...An Integrated Gait and Balance Analysis System to Define Human Locomotor Control Walking is a complicated task that requires the motor coordination...Gait and Balance Analysis System to Define Human Locomotor Control Report Title Walking is a complicated task that requires the motor coordination across

Effect of Playful Balancing Training - A Pilot Randomized Controlled Trial

DEFF Research Database (Denmark)

Lund, Henrik Hautop; Jessen, Jari Due

2013-01-01

We used the modular playware in the form of modular interactive tiles for playful training of community-dwelling elderly with balancing problem. During short-term play on the modular interactive tiles, the elderly were playing physical, interactive games that were challenging their dynamic balance...... increase in balancing performance (DGI score: 21.3) after short-term playful training with the modular interactive tiles, whereas the control group remained with a score indicating balancing problems and risk of falling (DGI score: 16.6). The small pilot randomized controlled trial suggests...... that the playful interaction with the modular interactive tiles has a significant effect even after a very short time of play. The average total training time to obtain the statistical significant effect amounted to just 2h45m....

O conceito de reflexão de Hegel como crítica aos conceitos de essência e de reflexão tradicionais

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Christian Iber

2017-02-01

Full Text Available O presente artigo ilumina o específico do conceito de reflexão de Hegel em cinco momentos. Em um primeiro momento, delineia-se um esboço do conceito de reflexão na lógica da essência de Hegel. Em um segundo momento, o conceito de reflexão de Hegel é apresentado como estrutura lógica objetiva em contraste com a reflexão subjetiva da consciência e do entendimento, com a qual, ao mesmo tempo, o conceito de essência ontológica independente da reflexão é submetido a uma crítica. Do novo conceito de reflexão de Hegel resulta, em terceiro lugar, uma adaptação radical do círculo vicioso na teoria tradicional da reflexão da autoconsciência. Num quarto momento, lança-se um olhar sobre o conceito de reflexão anterior de Hegel como pensar do entendimento que separa, do qual o conceito de reflexão posterior se distingue. Por fim, apresenta-se, em quinto lugar, a lógica da reflexão de Hegel como crítica à fundação ontológica da reflexão em Schelling. O conceito de reflexão de Hegel se mostra, com isto, como crítica da metafísica ontológica tradicional e como fundação de uma metafísica da relacionalidade absoluta que supera a relatividade do pensar moderno do entendimento.

Dissociative identity disorder and prepulse inhibition of the acoustic startle reflex

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Karl Yngvar Dale

2008-06-01

Full Text Available Karl Yngvar Dale1, Magne Arve Flaten1, Åke Elden1, Arne Holte21Department of Psychology, University of Tromsø, Norway; 2The Norwegian Institute of Public Health, Department of Mental Health, Oslo, Norway and University of Oslo, NorwayAbstract: A group of persons with dissociative identity disorder (DID was compared with a group of persons with other dissociative disorders, and a group of nondiagnosed controls with regard to prepulse inhibition (PPI of the acoustic startle reflex. The findings suggest maladaptive attentional processes at a controlled level, but not at a preattentive automatic level, in persons with DID. The prepulse occupied more controlled attentional resources in the DID group compared with the other two groups. Preattentive automatic processing, on the other hand, was normal in the DID group. Moreover, startle reflexes did not habituate in the DID group. In conclusion, increased PPI and delayed habituation is consistent with increased vigilance in individuals with DID. The present findings of reduced habituation of startle reflexes and increased PPI in persons with DID suggest the operation of a voluntary process that directs attention away from unpleasant or threatening stimuli. Aberrant voluntary attentional processes may thus be a defining characteristic in DID.Keywords: dissociation, DID, PPI, startle, habituation

Relationship between vomiting reflex during esophagogastroduodenoscopy and dyspepsia symptoms.

Science.gov (United States)

Enomoto, Shotaro; Watanabe, Mika; Yoshida, Takeichi; Mukoubayashi, Chizu; Moribata, Kosaku; Muraki, Yosuke; Shingaki, Naoki; Deguchi, Hisanobu; Ueda, Kazuki; Inoue, Izumi; Maekita, Takao; Iguchi, Mikitaka; Tamai, Hideyuki; Kato, Jun; Fujishiro, Mitsuhiro; Oka, Masashi; Mohara, Osamu; Ichinose, Masao

2012-09-01

Although frequent vomiting reflexes during esophagogastroduodenoscopy (EGD) causes suffering in patients, very few studies have investigated the characteristics of subjects who frequently develop vomiting reflexes. This study examined the incidence of the vomiting reflex and related factors, especially upper gastrointestinal symptoms, among individuals undergoing transoral EGD. Subjects included 488 consecutive adults (mean age, 56.1 ± 8.9 years) who underwent transoral EGD for gastric cancer screening between February 2010 and March 2011. All procedures were performed by an endoscopist with 15 years of experience. Based on a questionnaire survey using the frequency scale for the symptoms of gastroesophageal reflux disease (FSSG), symptoms (dyspepsia and acid reflux symptoms) and the number of vomiting reflexes during EGD were recorded. Of the 488 subjects, 271 (56%) developed vomiting reflexes (mean, 4.2 times). This reflex-positive group was younger (54.3 ± 9.5 years) than the reflex-negative group (58.3 ± 7.7 years, P reflex-positive group with a high FSSG dyspepsia score (2.27 ± 2.57 vs 1.23 ± 1.84; P acid reflux symptom score (1.96 ± 2.22 vs 1.34 ± 2.14; P reflex-negative group. Multivariate analysis also showed a significant correlation between these four factors and the occurrence of vomiting reflexes. Using an FSSG dyspepsia score of 1 as the cut-off offered 68% sensitivity and 57% specificity for predicting the occurrence of vomiting reflexes. Based on FSSG questionnaire responses on upper gastrointestinal symptoms, dyspepsia symptoms, in particular, are related to presence of vomiting reflexes during EGD. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

Fitness, Balance Efficacy, and Postural Control in Community-Dwelling Older Adults

Directory of Open Access Journals (Sweden)

Anna Lee

2016-02-01

Full Text Available Age-related declines in postural control and physical fitness are strong risk factors for falls in older adults. Balance efficacy has been utilized to identify poor postural control, reduced physical function, and fall risk. However, it is not clear as to whether balance efficacy is truly a better predictor of functional fitness outcomes or postural control. Distinguishing these associations is an important step in the future derivation of physiotherapeutic programming to remediate acute and chronic decline. Therefore, the purpose of this cross-sectional study was to partition which measures are more associated with balance efficacy, fitness, or postural control. One hundred eleven community-dwelling older adults participated and were asked to complete the Balance Efficacy Scale (BES, a functional fitness measure (the Senior Fitness Test [SFT], and a measure of postural control (the Sensory Organization Test [SOT].We found that the SFT was more significantly associated with balance efficacy (R2 = .37 than the SOT (R2 = .08 in older adults. Overall, aerobic endurance, functional mobility in the SFT, and the vestibular score on the SOT were significantly associated with balance efficacy. We concluded that clinicians utilizing the BES as a preliminary screen should recommend physiotherapy follow-up activities that build endurance (walking, lower extremity functional mobility (sit-to-stand, and vestibular function (head movement while walking. Understanding the links between a preliminary screening tool and the physiological needs of the patient will allow for targeted activities to be prescribed.

The effect of general and spinal anesthesia on balance control in elderly patients.

Science.gov (United States)

Suárez, Alejo; Macadar, Omar

2008-01-01

Falls are a major problem in the elderly population, but few communications address the influence of anesthesia on balance control. This study reports how a general balanced anesthesia (GBA) and a spinal anesthesia (SA) affect balance control in the elderly. We divided into three groups, according to electronystagmography findings and type of anesthesia, 21 men older than 65 years (mean age, 72 years) who were scheduled for prostate adenectomy. One group, designated GBN, consisted of normal subjects who underwent surgery under GBA. In another group, designated GBP, were pathological subjects who had clinically compensated central vestibular disorders (CVDs) and underwent surgery under GBA. The third group, designated SP, contained CVD patients who underwent surgery under SA. We assessed balance control via static posturography preoperatively and 48 hours postoperatively. We observed no change in balance control parameters (center of pressure distribution area [COPa] or COP sway velocity [SV]) for those patients in the GBN group or for those in the SP group. We did observe a significant difference for the patients in the GBP group, with higher postoperative values of COPa and SV (Wilcoxon signed rank test). Our results showed that in subjects with clinically compensated underlying CVD prior to a GBA, balance control worsens after the procedure, whereas no change in balance control occurs after an SA. Balance control in subjects with normal vestibuloocular function did not change even after a GBA.

A near catastrophe from trigeminocardiac reflex

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Parmod K Bithal

2017-01-01

Full Text Available Trigeminocardiac reflex is a brainstem reflex that results from stimulation of any branch of the trigeminal nerve along its course. It produces a constellation of signs and symptoms decrease in blood pressure (BP and heart rate, dysrhythmias, apnoea and increased gastric motility. We present a case of 80-year-old female patient who developed alarming hypotension and bradycardia during craniotomy for meningioma excision resulting from this reflex. In the face of refractory hypotension despite administering ephedrine and phenylephrine, we had to resort to adrenaline to restore her normal BP.

Tai Chi and balance control.

Science.gov (United States)

Wong, Alice M K; Lan, Ching

2008-01-01

Balance function begins to decline from middle age on, and poor balance function increases the risk of fall and injury. Suitable exercise training may improve balance function and prevent accidental falls. The coordination of visual, proprioceptive, vestibular and musculoskeletal system is important to maintain balance. Balance function can be evaluated by functional balance testing and sensory organization testing. Tai Chi Chuan (TC) is a popular conditioning exercise in the Chinese community, and recent studies substantiate that TC is effective in balance function enhancement and falls prevention. In studies utilizing functional balance testing, TC may increase the duration of one-leg standing and the distance of functional reach. In studies utilizing sensory organization testing, TC improves static and dynamic balance, especially in more challenging sensory perturbed condition. Therefore, TC may be prescribed as an alternative exercise program for elderly subjects or balance-impaired patients. Participants can choose to perform a complete set of TC or selected movements according to their needs. In conclusion, TC may improve balance function and is appropriate for implementation in the community.

Multi-Objective Control of Balancing Systems for Li-Ion Battery Packs

DEFF Research Database (Denmark)

Barreras, Jorge Varela; Pinto, Claudio; de Castro, Ricardo

2014-01-01

While a great number of battery balancing circuit topologies have been proposed, the unique control objective typically pursued is equalization of single cell charge. However, a balancing circuit could offer potentially more control features, especially with topologies able to provide bidirection...... and evaluated for a battery pack made up of 48 large format Li-Ion cells in series in a e-mobility application. Simulation results demonstrate the technical feasibility of this newly defined concept.......While a great number of battery balancing circuit topologies have been proposed, the unique control objective typically pursued is equalization of single cell charge. However, a balancing circuit could offer potentially more control features, especially with topologies able to provide bidirectional...... in terminal cell voltage. Secondly, thermal management, to achieve a more uniform temperature distribution within a battery pack. Third, on-board diagnosis or fault detection tools, e.g. to perform characterization tests or to identify and even isolate problematic cells. In this paper, this issue is discussed...

Time-varying auditory gain control in response to double-pulse stimuli in harbour porpoises is not mediated by a stapedial reflex

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Asger Emil Munch Schrøder

2017-04-01

Full Text Available Echolocating animals reduce their output level and hearing sensitivity with decreasing echo delays, presumably to stabilize the perceived echo intensity during target approaches. In bats, this variation in hearing sensitivity is formed by a call-induced stapedial reflex that tapers off over time after the call. Here, we test the hypothesis that a similar mechanism exists in toothed whales by subjecting a trained harbour porpoise to a series of double sound pulses varying in delay and frequency, while measuring the magnitudes of the evoked auditory brainstem responses (ABRs. We find that the recovery of the ABR to the second pulse is frequency dependent, and that a stapedial reflex therefore cannot account for the reduced hearing sensitivity at short pulse delays. We propose that toothed whale auditory time-varying gain control during echolocation is not enabled by the middle ear as in bats, but rather by frequency-dependent mechanisms such as forward masking and perhaps higher-order control of efferent feedback to the outer hair cells.

The use of acupuncture in controlling the gag reflex in patients requiring an upper alginate impression: an audit.

Science.gov (United States)

Rosted, P; Bundgaard, M; Fiske, J; Pedersen, A M L

2006-12-09

A pronounced gag reflex (GR) can be a problem to both the acceptance and delivery of dental treatment. Despite a range of management strategies, some patients cannot accept even simple dental treatment. The aim of this study was to evaluate the use of acupuncture point CV-24 in controlling a profound gag reflex during dental treatment requiring an upper alginate impression. Members of the British Dental Acupuncture Society were invited to take part in an audit of the role of acupuncture point CV-24 in controlling the gag reflex. They were issued with patient inclusion criteria, a standardised procedure instruction sheet and a recording form. All patients fulfilling the inclusion criteria had an upper dental alginate impression taken (or an attempt made at it) before acupuncture, and a second upper alginate impression taken immediately after acupuncture of point CV-24. The GR assessment was undertaken prior to insertion of the acupuncture needle using the Gagging Severity Index (GSI); and after the acupuncture and impression taking using the Gagging Prevention Index (GPI). Both the GSI and GPI were recorded at three stages of the dental impression taking procedure, ie, when the empty impression tray was tried in the mouth, when the loaded tray was inserted into the mouth, and on completion of the impression taking. Twenty-one dentists submitted 64 case reports of which 37 fulfilled the inclusion criteria. Prior to acupuncture all 37 patients (20 females and 17 males with a mean age of 46.8 years) were unable to accept the impression taking. After acupuncture of point CV-24, an improvement of between 51-55% (mean 53%) for the three stages of impression taking was noticed. Thirty patients (81%) were able to accept the impression taking, whereas seven (19%) remained unable to tolerate the procedure. Assessed by the GSI and GPI, there was a significant decrease in GR scores at all three stages of the impression taking procedure (median 3 vs 1; 4 vs 2; 4 vs 2; p dental

The effects of moderate fatigue on dynamic balance control and attentional demands

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Teasdale Normand

2006-09-01

Full Text Available Abstract Background During daily activities, the active control of balance often is a task per se (for example, when standing in a moving bus. Other constraints like fatigue can add to the complexity of this balance task. In the present experiment, we examined how moderate fatigue induced by fast walking on a treadmill challenged dynamic balance control. We also examined if the attentional demands for performing the balance task varied with fatigue. Methods Subjects (n = 10 performed simultaneously a dynamic balance control task and a probe reaction time task (RT (serving as an indicator of attentional demands before and after three periods of moderate fatigue (fast walking on a treadmill. For the balance control task, the real-time displacement of the centre of pressure (CP was provided on a monitor placed in front of the subject, at eye level. Subjects were asked to keep their CP within a target (moving box moving upward and downward on the monitor. The tracking performance was measured (time spent outside the moving box and the CP behavior analyzed (mean CP speed and mean frequency of the CP velocity. Results Moderate fatigue led to an immediate decrement of the performance on the balance control task; increase of the percentage of time spent outside the box and increase of the mean CP speed. Across the three fatigue periods, subjects improved their tracking performance and reduced their mean CP speed. This was achieved by increasing their frequency of actions; mean frequency of the CP velocity were higher for the fatigue periods than for the no fatigue periods. Fatigue also induced an increase in the attentional demands suggesting that more cognitive resources had to be allocated to the balance task with than without fatigue. Conclusion Fatigue induced by fast walking had an initial negative impact on the control of balance. Nonetheless, subjects were able to compensate the effect of the moderate fatigue by increasing the frequency of

Effects of Balance Control Training on Functional Outcomes in Subacute Hemiparetic Stroke Patients.

Science.gov (United States)

Huh, Jin Seok; Lee, Yang-Soo; Kim, Chul-Hyun; Min, Yu-Sun; Kang, Min-Gu; Jung, Tae-Du

2015-12-01

To investigate the efficacy of balance control training using a newly developed balance control trainer (BalPro) on the balance and gait of patients with subacute hemiparetic stroke. Forty-three subacute stroke patients were assigned to either a balance control training (BCT) group or a control group. The BCT group (n=23) was trained with BalPro for 30 minutes a day, 5 days a week for 2 weeks, and received one daily session of conventional physical therapy. The control group (n=20) received two sessions of conventional physical therapy every day for 2 weeks. The primary outcome was assessment with the Berg Balance Scale (BBS). Secondary outcomes were Functional Ambulation Category (FAC), the 6-minute walking test (6mWT), Timed Up and Go (TUG), the Korean version of Modified Barthel Index (K-MBI), and the manual muscle test (MMT) of the knee extensor. All outcome measures were evaluated before and after 2 weeks of training in both groups. There were statistically significant improvements in all parameters except MMT and FAC after 2 weeks of treatment in both groups. After training, the BCT group showed greater improvements in the BBS and the 6mWT than did the control group. Balance control training using BalPro could be a useful treatment for improving balance and gait in subacute hemiparetic stroke patients.

An ecologically-controlled exoskeleton can improve balance recovery after slippage

Science.gov (United States)

Monaco, V.; Tropea, P.; Aprigliano, F.; Martelli, D.; Parri, A.; Cortese, M.; Molino-Lova, R.; Vitiello, N.; Micera, S.

2017-05-01

The evolution to bipedalism forced humans to develop suitable strategies for dynamically controlling their balance, ensuring stability, and preventing falling. The natural aging process and traumatic events such as lower-limb loss can alter the human ability to control stability significantly increasing the risk of fall and reducing the overall autonomy. Accordingly, there is an urgent need, from both end-users and society, for novel solutions that can counteract the lack of balance, thus preventing falls among older and fragile citizens. In this study, we show a novel ecological approach relying on a wearable robotic device (the Active Pelvis Orthosis, APO) aimed at facilitating balance recovery after unexpected slippages. Specifically, if the APO detects signs of balance loss, then it supplies counteracting torques at the hips to assist balance recovery. Experimental tests conducted on eight elderly persons and two transfemoral amputees revealed that stability against falls improved due to the “assisting when needed” behavior of the APO. Interestingly, our approach required a very limited personalization for each subject, and this makes it promising for real-life applications. Our findings demonstrate the potential of closed-loop controlled wearable robots to assist elderly and disabled subjects and to improve their quality of life.

Fitness, Balance Efficacy, and Postural Control in Community-Dwelling Older Adults

OpenAIRE

Anna Lee; John R. Biggan; Christopher Ray

2016-01-01

Age-related declines in postural control and physical fitness are strong risk factors for falls in older adults. Balance efficacy has been utilized to identify poor postural control, reduced physical function, and fall risk. However, it is not clear as to whether balance efficacy is truly a better predictor of functional fitness outcomes or postural control. Distinguishing these associations is an important step in the...

Network Condition Based Adaptive Control and its Application to Power Balancing in Electrical Grids

DEFF Research Database (Denmark)

Pedersen, Rasmus; Findrik, Mislav; Sloth, Christoffer

2017-01-01

To maintain a reliable and stable power grid there must be balance between consumption and production. To achieve power balance in a system with high penetration of distributed renewable resources and flexible assets, these individual system can be coordinated through a control unit to become part...... of the power balancing effort. Such control strategies require communication networks for exchange of control loop information. In this work, we show how a congested communication network can have a dramatic impact on the control performance of such a power balancing controller. To alleviate potential...

The Balance Control of Children with and without Hearing Impairment in Singapore--A Case Study

Science.gov (United States)

Jernice, Tan Sing Yee; Nonis, Karen P.; Yi, Chow Jia

2011-01-01

The purpose of this study is to compare the balance control of participants with and without HI and also to investigate the effect of a Balance Programme (BP) on their balance control (HI; n = 2, M age = 7 years old). The BP consisted of six practice sessions of 45 minutes each. The Balance Tasks used to assess balance control were static Balance…

Increased Prepulse Inhibition and Sensitization of the Startle Reflex in Autistic Children

DEFF Research Database (Denmark)

Madsen, Gitte Falcher; Bilenberg, Niels; Cantio, Cathriona

2014-01-01

The relation between autism spectrum disorders (ASD) and schizophrenia is a subject of intense debate and research due to evidence of common neurobiological pathways in the two disorders. The objective of this study was to explore whether deficits in prepulse inhibition (PPI) of the startle reflex......, as usually seen in schizophrenic patients, can be replicated in a group of children with ASD in comparison with a group of matched neuro-typically developed (NTD) controls. An additional aim was to explore possible psychophysiological subgroups within our ASD sample. In a case-control design, 35 ASD patients...... and 40 matched NTD controls were tested in a psychophysiological test battery. The PPI of the acoustic startle reflex was analyzed in 18 ASD subjects and 34 NTD controls. Habituation and sensitization were analyzed in 23 ASD subjects and 39 NTD controls. In trials with less intense prestimuli (76 d...

Robust balancing and position control of a single spherical wheeled mobile platform

OpenAIRE

Yavuz, Fırat; Yavuz, Firat; Ünel, Mustafa; Unel, Mustafa

2016-01-01

Self-balancing mobile platforms with single spherical wheel, generally called ballbots, are suitable example of underactuated systems. Balancing control of a ballbot platform, which aims to maintain the upright orientation by rejecting external disturbances, is important during station keeping or trajectory tracking. In this paper, acceleration based balancing and position control of a single spherical wheeled mobile platform that has three single-row omniwheel drive m...

Reversal of functional disorders by aspiration, expiration and cough reflexes and their voluntary counterparts

Directory of Open Access Journals (Sweden)

Zoltan eTomori

2012-12-01

Full Text Available Agonal gasping provoked by asphyxia can save ~15% of mammals even from untreated ventricular fibrillation, but it fails to revive infants with sudden infant death syndrome. Our systematic study of airway reflexes in cats and other animals indicated that in addition to cough, there are 2 distinct airway reflexes that may contribute to auto-resuscitation. Gasp- and sniff-like spasmodic inspirations can be elicited by nasopharyngeal stimulation, strongly activating the brainstem generator for inspiration, which is also involved in the control of gasping. This aspiration reflex (AspR is characterized by spasmodic inspiration without subsequent active expiration and can be elicited during agonal gasping, caused by brainstem trans-sections in cats. Stimulation of the larynx can activate the generator for expiration to evoke the expiration reflex, manifesting with prompt expiration without preceding inspiration. Stimulation of the oro-pharynx and lower airways provokes the cough reflex which results from activating of both generators. The powerful potential of the AspR resembling auto-resuscitation by gasping can influence the control mechanisms of vital functions, mediating reversal of various functional disorders.The AspR in cats interrupted hypoxic apnea, laryngo- and bronchospasm, apneusis and even transient asphyxic coma, and can normalize various hypo- and hyper-functional disorders. Introduction of a nasogastric catheter evoked similar spasmodic inspirations in premature infants and interrupted hiccough attacks in adults. Coughing on demand can prevent anaphylactic shock and resuscitate the pertinent subject. Sniff representing nasal inspiratory pressure and maximal inspiratory and expiratory pressures are voluntary counterparts of airway reflexes, and are useful for diagnosis and therapy of various cardio-respiratory and neuromuscular disorders.

Energy saving in greenhouses can be obtained by energy balance-controlled screens

Energy Technology Data Exchange (ETDEWEB)

Andersson, N. E. (Univ. of Aarhus, Faculty of Agricultural Sciences, Dept. of Horticulture, Aarslev (Denmark)), e-mail: niels.andersson@agrsci.dk

2011-03-15

The energy screens in two greenhouses, one clad with double acrylic and one with single glass, were controlled by an energy balance model. The parameters in the model were heat transmission coefficients, air temperature in the greenhouse and outdoors, irradiance and a single constant for the solar energy efficiency. The energy consumption, screen movements and daily light integral were compared with a glass greenhouse in which the energy screens were controlled by irradiance. In the greenhouse with light-controlled screens the set point for opening and closing of the screens was 5 Wm-2. The energy-saving screens controlled by the energy balance model opened later and closed earlier than in the greenhouse with light-controlled screens. When using the energy balance model the energy saving was 14% for the glass greenhouse and 41% for the double acrylic greenhouse compared with the glass greenhouse with light-controlled screens. The air temperature was on average similar in the three greenhouses, but when the screens were controlled by energy balance the daily light integral was approximately 10% lower and the number of hours the screens were closed was prolonged with 35% for the glass-covered greenhouse and 25% for the double acrylic-covered greenhouse compared with the greenhouse with light-controlled screens. Energy peaks in connection with operation of the screens were not reduced. During the experiment Begonia elatior, Dendranthema grandiflora (Chrysanthemum), Hedera helix, Helianthus annuus, Gerbera jamesonii and Kalanchoe blossfeldiana were grown in the greenhouses. There was a trend in prolongation of the production time when the plants were grown in the glass greenhouse with energy balance control of the screens. A lower number of flowers or inflorescences were observed for some of the plant species produced in the greenhouses with energy balance-controlled screens

The capsaicin cough reflex in patients with symptoms elicited by odorous chemicals

DEFF Research Database (Denmark)

Holst, H.; Arendt-Nielsen, Lars; Mosbech, H.

2010-01-01

between groups in age, body mass index or pulmonary function. The median C5 were 129 micromol/L (control group), 48 micromol/L (multiple chemical sensitivity patients), 32 micromol/L (eczema patients). The reporting of lower airway symptoms from odorous chemicals was significantly (p......Patients with multiple chemical sensitivity and eczema patients with airway symptoms elicited by odorous chemicals have enhanced cough reflex to capsaicin when applying the tidal breathing method. The aims of the present study were to test whether the capsaicin induced cough reflex was enhanced...... when applying the single breath inhalation method in similar groups of patients with symptoms related to odorous chemicals e.g. other persons wearing of perfume; and to investigate to what extent the reporting of lower airway symptoms influenced the cough reflex. Sixteen patients fulfilling Cullen...

Wh-filler-gap dependency formation guides reflexive antecedent search

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Michael eFrazier

2015-10-01

Full Text Available Prior studies on online sentence processing have shown that the parser can resolve non-local dependencies rapidly and accurately. This study investigates the interaction between the processing of two such non-local dependencies: wh-filler-gap dependencies (WhFGD and reflexive-antecedent dependencies. We show that reflexive-antecedent dependency resolution is sensitive to the presence of a WhFGD, and argue that the filler-gap dependency established by WhFGD resolution is selected online as the antecedent of a reflexive dependency. We investigate the processing of constructions like (1, where two NPs might be possible antecedents for the reflexive, namely which cowgirl and Mary. Even though Mary is linearly closer to the reflexive, the only grammatically licit antecedent for the reflexive is the more distant wh-NP, which cowgirl. 1. Which cowgirl did Mary expect to have injured herself due to negligence?Four eye-tracking text-reading experiments were conducted on examples like (1, differing in whether the embedded clause was non-finite (1 and 3 or finite (2 and 4, and in whether the tail of the wh-dependency intervened between the reflexive and its closest overt antecedent (1 and 2 or the wh-dependency was associated with a position earlier in the sentence (3 and 4.The results of Experiments 1 and 2 indicate the parser accesses the result of WhFGD formation during reflexive antecedent search. The resolution of a wh-dependency alters the representation that reflexive antecedent search operates over, allowing the grammatical but linearly distant antecedent to be accessed rapidly. In the absence of a long-distance WhFGD (Exp. 3 and 4, wh-NPs were not found to impact reading times of the reflexive, indicating that the parser's ability to select distant wh-NPs as reflexive antecedents crucially involves syntactic structure.

Reflexivity and social justice

DEFF Research Database (Denmark)

Maksimovic, Tijana; Jakobsen, Helle Nordentoft

2017-01-01

Career practitioners’ reflexive understanding of their professional role as change agents in career guidance and counselling practices has a major impact on how social justice can be achieved. This entitles an awareness of the way in which guidance and counselling practices are embedded in the co......Career practitioners’ reflexive understanding of their professional role as change agents in career guidance and counselling practices has a major impact on how social justice can be achieved. This entitles an awareness of the way in which guidance and counselling practices are embedded...

The mechano-gated channel inhibitor GsMTx4 reduces the exercise pressor reflex in decerebrate rats.

Science.gov (United States)

Copp, Steven W; Kim, Joyce S; Ruiz-Velasco, Victor; Kaufman, Marc P

2016-02-01

Mechanical and metabolic stimuli from contracting muscles evoke reflex increases in blood pressure, heart rate and sympathetic nerve activity. Little is known, however, about the nature of the mechano-gated channels on the thin fibre muscle afferents that contribute to evoke this reflex, termed the exercise pressor reflex. We determined the effect of GsMTx4, an inhibitor of mechano-gated Piezo channels, on the exercise pressor reflex evoked by intermittent contraction of the triceps surae muscles in decerebrated, unanaesthetized rats. GsMTx4 reduced the pressor, cardioaccelerator and renal sympathetic nerve responses to intermittent contraction but did not reduce the pressor responses to femoral arterial injection of compounds that stimulate the metabolically-sensitive thin fibre muscle afferents. Expression levels of Piezo2 channels were greater than Piezo1 channels in rat dorsal root ganglia. Our findings suggest that mechanically-sensitive Piezo proteins contribute to the generation of the mechanical component of the exercise pressor reflex in rats. Mechanical and metabolic stimuli within contracting skeletal muscles evoke reflex autonomic and cardiovascular adjustments. In cats and rats, gadolinium has been used to investigate the role played by the mechanical component of this reflex, termed the exercise pressor reflex. Gadolinium, however, has poor selectivity for mechano-gated channels and exerts multiple off-target effects. We tested the hypothesis that GsMTX4, a more selective mechano-gated channel inhibitor than gadolinium and a particularly potent inhibitor of mechano-gated Piezo channels, reduced the exercise pressor reflex in decerebrate rats. Injection of 10 μg of GsMTx4 into the arterial supply of the hindlimb reduced the peak pressor (control: 24 ± 5, GsMTx4: 12 ± 5 mmHg, P acid. Moreover, injection of 10 μg of GsMTx4 into the arterial supply of the hindlimb reduced the peak pressor (control: 24 ± 2, GsMTx4: 14 ± 3 mmHg, P reflex in

Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans.

Science.gov (United States)

Makihara, Yukiko; Segal, Richard L; Wolpaw, Jonathan R; Thompson, Aiko K

2014-09-15

In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion. Copyright © 2014 the American Physiological Society.

Robust balance shift control with posture optimization

NARCIS (Netherlands)

Kavafoglu, Z.; Kavafoglu, Ersan; Egges, J.

2015-01-01

In this paper we present a control framework which creates robust and natural balance shifting behaviours during standing. Given high-level features such as the position of the center of mass projection and the foot configurations, a kinematic posture satisfying these features is synthesized using

Enhanced startle reflexivity during presentation of visual nurture cues in young adults who experienced parental divorce in early childhood.

Science.gov (United States)

Hengesch, Xenia; Larra, Mauro F; Finke, Johannes B; Blumenthal, Terry D; Schächinger, Hartmut

2017-10-01

Adverse childhood experiences (ACE) may influence stress and affective processing in adulthood. Animal and human studies show enhanced startle reflexivity in adult participants with ACE. This study examined the impact of one of the most common ACE, parental divorce, on startle reflexivity in adulthood. Affective modulation of acoustically-elicited startle eye blink was assessed in a group of 23 young adults with self-reported history of parental divorce, compared to an age- and sex-matched control group (n=18). Foreground pictures were either aversive (e.g. mutilation and injury), standard appetitive (e.g. erotic, recreational sport), or nurture pictures (e.g. related to early life, parental care), intermixed with neutral pictures (e.g. household objects), and organized in three valence blocks delivered in a balanced, pseudo-randomized sequence. During picture viewing startle eye blinks were elicited by binaural white noise bursts (50ms, 105 dB) via headphones and recorded at the left orbicularis oculi muscle via EMG. A significant interaction of group×picture valence (p=0.01) was observed. Contrast with controls revealed blunted startle responsiveness of the ACE group during presentation of aversive pictures, but enhanced startle during presentation of nurture-related pictures. No group differences were found during presentation of standard appetitive pictures. ACE participants rated nurture pictures as more arousing (p=0.02) than did control participants. Results suggest that divorce in childhood led to altered affective context information processing in early adulthood. When exposed to unpleasant (vs. neutral) pictures participants with ACE showed less startle potentiation than controls. Nurture context, however, potentiated startle in ACE participants, suggesting visual cuing to activate protective behavioral responses. Copyright © 2017 Elsevier B.V. All rights reserved.

Postural orientation and equilibrium: what do we need to know about neural control of balance to prevent falls?

Science.gov (United States)

Horak, Fay B

2006-09-01

Postural control is no longer considered simply a summation of static reflexes but, rather, a complex skill based on the interaction of dynamic sensorimotor processes. The two main functional goals of postural behaviour are postural orientation and postural equilibrium. Postural orientation involves the active alignment of the trunk and head with respect to gravity, support surfaces, the visual surround and internal references. Sensory information from somatosensory, vestibular and visual systems is integrated, and the relative weights placed on each of these inputs are dependent on the goals of the movement task and the environmental context. Postural equilibrium involves the coordination of movement strategies to stabilise the centre of body mass during both self-initiated and externally triggered disturbances of stability. The specific response strategy selected depends not only on the characteristics of the external postural displacement but also on the individual's expectations, goals and prior experience. Anticipatory postural adjustments, prior to voluntary limb movement, serve to maintain postural stability by compensating for destabilising forces associated with moving a limb. The amount of cognitive processing required for postural control depends both on the complexity of the postural task and on the capability of the subject's postural control system. The control of posture involves many different underlying physiological systems that can be affected by pathology or sub-clinical constraints. Damage to any of the underlying systems will result in different, context-specific instabilities. The effective rehabilitation of balance to improve mobility and to prevent falls requires a better understanding of the multiple mechanisms underlying postural control.

Test-bed Assessment of Communication Technologies for a Power-Balancing Controller

DEFF Research Database (Denmark)

Findrik, Mislav; Pedersen, Rasmus; Hasenleithner, Eduard

2016-01-01

and control. In this paper, we present a Smart Grid test-bed that integrates various communication technologies and deploys a power balancing controller for LV grids. Control performance of the introduced power balancing controller is subsequently investigated and its robustness to communication network cross......Due to growing need for sustainable energy, increasing number of different renewable energy resources are being connected into distribution grids. In order to efficiently manage a decentralized power generation units, the smart grid will rely on communication networks for information exchange...

H-index is important for postural control for people with impaired foot sole sensation.

Directory of Open Access Journals (Sweden)

Shuqi Zhang

Full Text Available People with Peripheral Neuropathy (PN, especially those with impaired sensory inputs through the small-afferent fiber (type II afferent fibers reflex loop (SAF, might depend more on the large-afferent fiber (type I afferent fibers reflex loop (LAF for postural control.To examine whether the function of the LAF reflex loop, reflected by the H-reflex and ankle joint proprioception, influences postural control when the SAF reflex loop is impaired, as indicated by reduced foot sole cutaneous sensation.Thirteen participants (8 women, 5 men diagnosed with PN and 12 age-matched controls (7 women, 5 men completed the testing protocol. Measures of interest included the H-index, active (AAP and passive (PAP ankle proprioception, plantar pressure sensitivity (PPS, average sway velocity (VAVG and area (A95 during 30 seconds eyes-closed standing, 6-minute walk distance (6MWD and timed up-and-go duration (TUG.Statistically significant group-dependent regression was observed between VAVG and H-index. Compared to the control group, the PN group demonstrated reduced PPS (2.0 ± 1.9 vs. 4.2 ± 1.2, P < .05 and H-index (63.6 ± 10.9 vs. 76.4 ± 16.0, P < .05, greater VAVG (3.5 ± 2.1 vs. 1.6 ± 0.6 cm/s, P < .05 and A95 (10.0 ± 10.1 vs. 2.5 ± 1.5 cm2, P < .05, shorter 6MWD (442.2 ± 93.0 vs. 525.3 ± 68.2 m, P < .05, and longer TUG (9.4 ± 1.6 vs. 6.5 ± 1.3 s, P < .05. Within the PN group, but not the control group, the H-index was correlated with VAVG (r = -.56, P < .05. Moreover, within the PN group only, PAP scores were correlated with 6MWD (r = -.68, P < .05 and TUG (r = -.59, P < .05 performance. No other statistically significant group difference, correlation or group-dependent regression was observed.VAVG, 6MWD, and TUG correlated with LAF reflex loop function observed among those with impaired functioning of the SAF reflex loop. This observation suggests that the LAF reflex loop may be critical to the control of balance in those individuals suffering

Enhancement of the intrinsic defecation reflex by mosapride, a 5-HT4 agonist, in chronically lumbosacral denervated guinea pigs.

Science.gov (United States)

Kojima, Yu; Fujii, Hisao; Katsui, Renta; Nakajima, Yoshiyuki; Takaki, Miyako

2006-10-01

The defecation reflex is composed of rectal distension-evoked rectal (R-R) reflex contractions and synchronous internal anal sphincter (R-IAS) reflex relaxations in guinea pigs. These R-R and R-IAS reflexes are controlled via extrinsic sacral excitatory nerve pathway (pelvic nerves), lumbar inhibitory nerve pathways (colonic nerves) and by intrinsic cholinergic excitatory and nitrergic inhibitory nerve pathways. The effect of mosapride (a prokinetic benzamide) on the intrinsic reflexes, mediated via enteric 5-HT(4) receptors, was evaluated by measuring the mechanical activity of the rectum and IAS in anesthetized guinea pigs using an intrinsic R-R and R-IAS reflex model resulting from chronic (two to nine days) lumbosacral denervation (PITH). In this model, the myenteric plexus remains undamaged and the distribution of myenteric and intramuscular interstitial cells of Cajal is unchanged. Although R-R and R-IAS reflex patterns markedly changed, the reflex indices (reflex pressure or force curve-time integral) of both the R-R contractions and the synchronous R-IAS relaxations were unchanged. The frequency of the spontaneous R and IAS motility was also unchanged. Mosapride (0.1-1.0 mg/kg) dose-dependently increased both intrinsic R-R (maximum: 1.82) and R-IAS reflex indices (maximum: 2.76) from that of the control (1.0) 6-9 days following chronic PITH. The dose-response curve was similar to that in the intact guinea pig, and had shifted to the left from that in the guinea pig after acute PITH. A specific 5-HT(4) receptor antagonist, GR 113808 (1.0 mg/kg), decreased both reflex indices by approximately 50% and antagonized the effect of mosapride 1.0 mg/kg. This was quite different from the result in the intact guinea pig where GR 113808 (1.0 mg/kg) did not affect either of the reflex indices. The present results indicate that mosapride enhanced the intrinsic R-R and R-IAS reflexes and functionally compensated for the deprivation of extrinsic innervation. The actions of

Comparative Effects of Different Balance-Training-Progression Styles on Postural Control and Ankle Force Production: A Randomized Controlled Trial.

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Cuğ, Mutlu; Duncan, Ashley; Wikstrom, Erik

2016-02-01

Despite the effectiveness of balance training, the exact parameters needed to maximize the benefits of such programs remain unknown. One such factor is how individuals should progress to higher levels of task difficulty within a balance-training program. Yet no investigators have directly compared different balance-training-progression styles. To compare an error-based progression (ie, advance when proficient at a task) with a repetition-based progression (ie, advance after a set amount of repetitions) style during a balance-training program in healthy individuals. Randomized controlled trial. Research laboratory. A total of 28 (16 women, 12 men) physically healthy young adults (age = 21.57 ± 3.95 years, height = 171.60 ± 11.03 cm, weight = 72.96 ± 16.18 kg, body mass index = 24.53 ± 3.7). All participants completed 12 supervised balance-training sessions over 4 weeks. Each session consisted of a combination of dynamic unstable-surface tasks that incorporated a BOSU ball and lasted about 30 minutes. Static balance from an instrumented force plate, dynamic balance as measured via the Star Excursion Balance Test, and ankle force production in all 4 cardinal planes of motion as measured with a handheld dynamometer before and after the intervention. Selected static postural-control outcomes, dynamic postural control, and ankle force production in all planes of motion improved (P .05) for any of the outcome measures. A 4-week balance-training program consisting of dynamic unstable-surface exercises on a BOSU ball improved dynamic postural control and ankle force production in healthy young adults. These results suggest that an error-based balance-training program is comparable with but not superior to a repetition-based balance-training program in improving postural control and ankle force production in healthy young adults.

Clinical correlates of between-limb synchronization of standing balance control and falls during inpatient stroke rehabilitation.

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Mansfield, Avril; Mochizuki, George; Inness, Elizabeth L; McIlroy, William E

2012-01-01

Stroke-related sensorimotor impairment potentially contributes to impaired balance. Balance measures that reveal underlying limb-specific control problems, such as a measure of the synchronization of both lower limbs to maintain standing balance, may be uniquely informative about poststroke balance control. This study aimed to determine the relationships between clinical measures of sensorimotor control, functional balance, and fall risk and between-limb synchronization of balance control. The authors conducted a retrospective chart review of 100 individuals with stroke admitted to inpatient rehabilitation. Force plate-based measures were obtained while standing on 2 force plates, including postural sway (root mean square of anteroposterior and mediolateral center of pressure [COP]), stance load asymmetry (percentage of body weight borne on the less-loaded limb), and between-limb synchronization (cross-correlation of the COP recordings under each foot). Clinical measures obtained were motor impairment (Chedoke-McMaster Stroke Assessment), plantar cutaneous sensation, functional balance (Berg Balance Scale), and falls experienced in rehabilitation. Synchronization was significantly related to motor impairment and prospective falls, even when controlling for other force plate-based measures of standing balance control (ie, postural sway and stance load symmetry). Between-limb COP synchronization for standing balance appears to be a uniquely important index of balance control, independent of postural sway and load symmetry during stance.

Components of Standing Postural Control Evaluated in Pediatric Balance Measures: A Scoping Review.

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Sibley, Kathryn M; Beauchamp, Marla K; Van Ooteghem, Karen; Paterson, Marie; Wittmeier, Kristy D

2017-10-01

To identify measures of standing balance validated in pediatric populations, and to determine the components of postural control captured in each tool. Electronic searches of MEDLINE, Embase, and CINAHL databases using key word combinations of postural balance/equilibrium, psychometrics/reproducibility of results/predictive value of tests, and child/pediatrics; gray literature; and hand searches. Inclusion criteria were measures with a stated objective to assess balance, with pediatric (≤18y) populations, with at least 1 psychometric evaluation, with at least 1 standing task, with a standardized protocol and evaluation criteria, and published in English. Two reviewers independently identified studies for inclusion. There were 21 measures included. Two reviewers extracted descriptive characteristics, and 2 investigators independently coded components of balance in each measure using a systems perspective for postural control, an established framework for balance in pediatric populations. Components of balance evaluated in measures were underlying motor systems (100% of measures), anticipatory postural control (72%), static stability (62%), sensory integration (52%), dynamic stability (48%), functional stability limits (24%), cognitive influences (24%), verticality (9%), and reactive postural control (0%). Assessing children's balance with valid and comprehensive measures is important for ensuring development of safe mobility and independence with functional tasks. Balance measures validated in pediatric populations to date do not comprehensively assess standing postural control and omit some key components for safe mobility and independence. Existing balance measures, that have been validated in adult populations and address some of the existing gaps in pediatric measures, warrant consideration for validation in children. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

O conceito de reflexão de Hegel como crítica aos conceitos de essência e de reflexão tradicionais

OpenAIRE

Christian Iber

2017-01-01

O presente artigo ilumina o específico do conceito de reflexão de Hegel em cinco momentos. Em um primeiro momento, delineia-se um esboço do conceito de reflexão na lógica da essência de Hegel. Em um segundo momento, o conceito de reflexão de Hegel é apresentado como estrutura lógica objetiva em contraste com a reflexão subjetiva da consciência e do entendimento, com a qual, ao mesmo tempo, o conceito de essência ontológica independente da reflexão é submetido a uma crítica. Do novo conceito d...

The capsaicin cough reflex in patients with symptoms elicited by odorous chemicals

DEFF Research Database (Denmark)

Holst, H; Arendt-Nielsen, L; Mosbech, H

2010-01-01

Patients with multiple chemical sensitivity and eczema patients with airway symptoms elicited by odorous chemicals have enhanced cough reflex to capsaicin when applying the tidal breathing method. The aims of the present study were to test whether the capsaicin induced cough reflex was enhanced...... when applying the single breath inhalation method in similar groups of patients with symptoms related to odorous chemicals e.g. other persons wearing of perfume; and to investigate to what extent the reporting of lower airway symptoms influenced the cough reflex. Sixteen patients fulfilling Cullen......'s criteria for multiple chemical sensitivity and 15 eczema patients with airway symptoms elicited by odorous chemicals were compared with 29 age-matched, healthy controls. We measured C5--the capsaicin concentration causing five coughs or more--using the single breath inhalation test. No difference was found...

[Effects of morphine on pupillary light reflex in monkeys].

Science.gov (United States)

Meng, Zhi-Qiang; Zhang, Yu-Hua; Chen, Nan-Hui; Miao, Ying-Da; Hu, Xin-Tian; Ma, Yuan-Ye

2010-06-01

The pupil size of both human and other animals can be affected by light. Many kinds of psychiatrical and psychological disorders, such as drug abuse, associate with abnormal properties of pupillary light reflex. Thus, the properties of pupillary light reflex could serve as an indicator for drug abuse detection. However, the effect of drug abuse on pupillary light reflex is till unclear. To assess the effects of addictive drugs on pupillary light reflex quantificationally, in the present study, we examined the effects of morphine on pupil diameter and pupillary light reflex in rhesus monkeys. By measuring the pupil diameter at different timing points before and after the administration of morphine, we found that morphine administration reduced the diameter of pupil and decreased the constriction rate. Our present results provide an experimental support for applying the properties of pupillary light reflex as a reference in addicts' detection.

The effects of attention capacity on dynamic balance control following concussion

Directory of Open Access Journals (Sweden)

Chou Li-Shan

2011-02-01

Full Text Available Abstract The purpose of this study was to examine how individuals modulate attention in a gait/cognition dual task during a 4-week period following a concussion. Ten individuals suffering from a grade 2 concussion and 10 matched controls performed a single task of level walking, a seated auditory Stroop task and a simultaneous auditory Stroop and walking task. Reaction time and accuracy were measured from the Stroop task. Dynamic balance control during gait was measured by the interaction (displacement and velocity between the center of mass (CoM and center of pressure (CoP in the coronal and sagittal planes. Concussed individuals shifted from conservative control of balance (shorter separation between CoM and CoP immediately after injury to normal balance control over 28 days post-injury. Immediately after injury, correlations analyses using each subject on each testing day as a data point showed that there was a spectrum of deficient performance among concussed individuals on the first testing day. Within a testing session, deficiencies in reaction time of processing involved in the Stroop task were commonly seen with reduce dynamic balance control. However, the prioritization was not always towards the same task between trials. There were no correlations in the control group. Information provided in this study would enhance our understanding of the interaction between attention and gait following concussion.

Vestibular control of standing balance is enhanced with increased cognitive load.

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McGeehan, Michael A; Woollacott, Marjorie H; Dalton, Brian H

2017-04-01

When cognitive load is elevated during a motor task, cortical inhibition and reaction time are increased; yet, standing balance control is often unchanged. This disconnect is likely explained by compensatory mechanisms within the balance system such as increased sensitivity of the vestibulomotor pathway. This study aimed to determine the effects of increased cognitive load on the vestibular control of standing balance. Participants stood blindfolded on a force plate with their head facing left and arms relaxed at their sides for two trials while exposed to continuous electrical vestibular stimulation (EVS). Participants either stood quietly or executed a cognitive task (double-digit arithmetic). Surface electromyography (EMG) and anterior-posterior ground-body forces (APF) were measured in order to evaluate vestibular-evoked balance responses in the frequency (coherence and gain) and time (cumulant density) domains. Total distance traveled for anterior-posterior center of pressure (COP) was assessed as a metric of balance variability. Despite similar distances traveled for COP, EVS-medial gastrocnemius (MG) EMG and EVS-APF coherence and EVS-TA EMG and EVS-MG EMG gain were elevated for multiple frequencies when standing with increased cognitive load. For the time domain, medium-latency peak amplitudes increased by 13-54% for EVS-APF and EVS-EMG relationships with the cognitive task compared to without. Peak short-latency amplitudes were unchanged. These results indicate that reliance on vestibular control of balance is enhanced when cognitive load is elevated. This augmented neural strategy may act to supplement divided cortical processing resources within the balance system and compensate for the acute neuromuscular modifications associated with increased cognitive demand.

Deprivation and Recovery of Sleep in Succession Enhances Reflexive Motor Behavior.

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Sprenger, Andreas; Weber, Frederik D; Machner, Bjoern; Talamo, Silke; Scheffelmeier, Sabine; Bethke, Judith; Helmchen, Christoph; Gais, Steffen; Kimmig, Hubert; Born, Jan

2015-11-01

Sleep deprivation impairs inhibitory control over reflexive behavior, and this impairment is commonly assumed to dissipate after recovery sleep. Contrary to this belief, here we show that fast reflexive behaviors, when practiced during sleep deprivation, is consolidated across recovery sleep and, thereby, becomes preserved. As a model for the study of sleep effects on prefrontal cortex-mediated inhibitory control in humans, we examined reflexive saccadic eye movements (express saccades), as well as speeded 2-choice finger motor responses. Different groups of subjects were trained on a standard prosaccade gap paradigm before periods of nocturnal sleep and sleep deprivation. Saccade performance was retested in the next morning and again 24 h later. The rate of express saccades was not affected by sleep after training, but slightly increased after sleep deprivation. Surprisingly, this increase augmented even further after recovery sleep and was still present 4 weeks later. Additional experiments revealed that the short testing after sleep deprivation was sufficient to increase express saccades across recovery sleep. An increase in speeded responses across recovery sleep was likewise found for finger motor responses. Our findings indicate that recovery sleep can consolidate motor disinhibition for behaviors practiced during prior sleep deprivation, thereby persistently enhancing response automatization. © The Author 2015. Published by Oxford University Press.

The Role of Ankle Proprioception for Balance Control in relation to Sports Performance and Injury.

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Han, Jia; Anson, Judith; Waddington, Gordon; Adams, Roger; Liu, Yu

2015-01-01

Balance control improvement is one of the most important goals in sports and exercise. Better balance is strongly positively associated with enhanced athletic performance and negatively associated with lower limb sports injuries. Proprioception plays an essential role in balance control, and ankle proprioception is arguably the most important. This paper reviews ankle proprioception and explores synergies with balance control, specifically in a sporting context. Central processing of ankle proprioceptive information, along with other sensory information, enables integration for balance control. When assessing ankle proprioception, the most generalizable findings arise from methods that are ecologically valid, allow proprioceptive signals to be integrated with general vision in the central nervous system, and reflect the signal-in-noise nature of central processing. Ankle proprioceptive intervention concepts driven by such a central processing theory are further proposed and discussed for the improvement of balance control in sport.

The Use of Restoring Resources of the Survival Roles and Reflex Patterns in MNRI® (Reflex Integration Interactive Training of Personality Growth and Interpersonal Relations

Directory of Open Access Journals (Sweden)

Masgutova S.K.

2017-12-01

Full Text Available Personality growth as a socio-psychological problem is a multi-complex phenomenon that targets Self-identity, Self-actualization, and other areas. During the last decade scientists started studying other factors limiting the personality growth, such as stress and post-trauma. However, the Survival Roles, the socio-individual patterns based on neurophysiological and psychological defense mechanisms blocking the personality Self-actualization, social interaction and professional business qualities, are rarely discussed. Thus this study based on Survival Roles may extend the personality growth oriented concepts and therapy modality tools. This study showed a correlation between Survival Role patterns, stress resilience, and survival reflexes (integrative units of the nervous system functions. Comparative data on 464 business professionals from high management jobs (Study Group — n=340, and Control Group — n=124 participated in this research which found 70.9 % (n=329 of the total group was in stress. This stress activated socio-individual Survival Roles and protective reflex patterns which responded with reactivity, over-protection, non-constructive interactions with others and limited business strategies. The MNRI® reflex integrative training used in this study demonstrated improvement of functions of the protective reflex patterns effected positively the survival mechanisms including increased stress resilience, and decreased negative effect of Survival Roles. MNRI® proposes a new paradigm in the realm of personality growth and socio-interpersonal activity, and supports the neurophysiological aspects to optimize the overall quality of life of business professionals from a variety of high management business areas.

Adaptive control of dynamic balance in human gait on a split-belt treadmill.

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Buurke, Tom J W; Lamoth, Claudine J C; Vervoort, Danique; van der Woude, Lucas H V; den Otter, Rob

2018-05-17

Human bipedal gait is inherently unstable and staying upright requires adaptive control of dynamic balance. Little is known about adaptive control of dynamic balance in reaction to long-term, continuous perturbations. We examined how dynamic balance control adapts to a continuous perturbation in gait, by letting people walk faster with one leg than the other on a treadmill with two belts (i.e. split-belt walking). In addition, we assessed whether changes in mediolateral dynamic balance control coincide with changes in energy use during split-belt adaptation. In nine minutes of split-belt gait, mediolateral margins of stability and mediolateral foot roll-off changed during adaptation to the imposed gait asymmetry, especially on the fast side, and returned to baseline during washout. Interestingly, no changes in mediolateral foot placement (i.e. step width) were found during split-belt adaptation. Furthermore, the initial margin of stability and subsequent mediolateral foot roll-off were strongly coupled to maintain mediolateral dynamic balance throughout the gait cycle. Consistent with previous results net metabolic power was reduced during split-belt adaptation, but changes in mediolateral dynamic balance control were not correlated with the reduction of net metabolic power during split-belt adaptation. Overall, this study has shown that a complementary mechanism of relative foot positioning and mediolateral foot roll-off adapts to continuously imposed gait asymmetry to maintain dynamic balance in human bipedal gait. © 2018. Published by The Company of Biologists Ltd.

Improved postural control after dynamic balance training in older overweight women.

Science.gov (United States)

Bellafiore, Marianna; Battaglia, Giuseppe; Bianco, Antonino; Paoli, Antonio; Farina, Felicia; Palma, Antonio

2011-01-01

Many studies have reported a greater frequency of falls among older women than men in conditions which stress balance. Previously, we found an improvement in static balance in older women with an increased support surface area and equal load redistribution on both feet, in response to a dynamic balance training protocol. The aim of the present study was to examine whether the same training program and body composition would have effects on the postural control of older overweight women. Ten healthy women (68.67 ± 5.50 yrs; 28.17 ± 3.35 BMI) participated in a five-week physical activity program. This included dynamic balance exercises, such as heel-to-toe walking in different directions, putting their hands on their hips, eyes open (EO) or closed (EC), with a tablet on their heads, going up and down one step, and walking on a mat. Postural stability was assessed before and after training with an optoelectronic platform and a uni-pedal balance performance test. Body composition of the trunk, upper limbs and lower limbs was measured by bio-impedance analysis. The mean speed (MS), medial-lateral MS (MS-x), anterior-posterior MS (MS-y), sway path (SP) and ellipse surface area (ESA) of the pressure center was reduced after training in older women. However, only MS, MS-x, MS-y and SP significantly decreased in bipodalic conditions with EO and MS-y also with EC (punipedal static balance. Our dynamic balance training protocol appears to be feasible, safe and repeatable for older overweight women and to have positive effects in improving their lateral and anterior-posterior postural control, mainly acting on the visual and skeletal muscle components of the balance control system.

Using ESO Reflex with Web Services

Science.gov (United States)

Järveläinen, P.; Savolainen, V.; Oittinen, T.; Maisala, S.; Ullgrén, M. Hook, R.

2008-08-01

ESO Reflex is a prototype graphical workflow system, based on Taverna, and primarily intended to be a flexible way of running ESO data reduction recipes along with other legacy applications and user-written tools. ESO Reflex can also readily use the Taverna Web Services features that are based on the Apache Axis SOAP implementation. Taverna is a general purpose Web Service client, and requires no programming to use such services. However, Taverna also has some restrictions: for example, no numerical types such integers. In addition the preferred binding style is document/literal wrapped, but most astronomical services publish the Axis default WSDL using RPC/encoded style. Despite these minor limitations we have created simple but very promising test VO workflow using the Sesame name resolver service at CDS Strasbourg, the Hubble SIAP server at the Multi-Mission Archive at Space Telescope (MAST) and the WESIX image cataloging and catalogue cross-referencing service at the University of Pittsburgh. ESO Reflex can also pass files and URIs via the PLASTIC protocol to visualisation tools and has its own viewer for VOTables. We picked these three Web Services to try to set up a realistic and useful ESO Reflex workflow. They also demonstrate ESO Reflex abilities to use many kind of Web Services because each of them requires a different interface. We describe each of these services in turn and comment on how it was used

Altered characteristics of balance control in obese older adults.

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Melzer, Itshak; Oddsson, Lars I E

2016-01-01

Obesity is one of the most significant epidemiological trends of the last decades. Recently it was found that obese individuals show postural instability. Balance control mechanisms in obese older adults were less studied. Therefore we aimed to investigate the effect of obesity on balance control mechanisms in older adults. Parameters from Stabilogram-Diffusion Analysis (SDA) and measures from summary statistics of foot centre-of-pressure (COP) displacements along the anterior-posterior (AP) and mediolateral (ML) directions in eyes open and eyes closed conditions were used to characterize postural control in 22 obese (30-postural control process in obese older adults. A greater sway displacement before closed-loop feedback mechanisms are called into play was seen in the ML direction that may lead to a higher risk of instability and fall events. Copyright © 2015 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

Prevalence of family history in patients with reflex syncope

DEFF Research Database (Denmark)

Holmegard, Haya N; Benn, Marianne; Kaijer, Michelle Nymann

2013-01-01

Reflex syncope is defined by a rapid transient loss of consciousness caused by global cerebral hypoperfusion resulting from vasodilatation and/or bradycardia attributable to inappropriate cardiovascular reflexes. A hereditary component has been suggested, but prevalence of family history may differ...... among subtypes of reflex syncope, as these have different autonomic responses and pathogeneses may be diverse. The present study aimed to assess the prevalence of a positive family history of syncope and cardiovascular characteristics in patients with cardioinhibitory and vasodepressor reflex syncope....... Patients (n=74) were classified into subtypes of reflex syncope - cardioinhibition/asystole (Vasovagal Syncope International Study subtypes II-B [VASIS II-B], n=38) or vasodepressor (VASIS III, n=36) - using the head-up tilt test. Family history was obtained by questionnaires supplemented by interview...

Cortical processes associated with continuous balance control as revealed by EEG spectral power.

Science.gov (United States)

Hülsdünker, T; Mierau, A; Neeb, C; Kleinöder, H; Strüder, H K

2015-04-10

Balance is a crucial component in numerous every day activities such as locomotion. Previous research has reported distinct changes in cortical theta activity during transient balance instability. However, there remains little understanding of the neural mechanisms underlying continuous balance control. This study aimed to investigate cortical theta activity during varying difficulties of continuous balance tasks, as well as examining the relationship between theta activity and balance performance. 37 subjects completed nine balance tasks with different levels of surface stability and base of support. Throughout the balancing task, electroencephalogram (EEG) was recorded from 32 scalp locations. ICA-based artifact rejection was applied and spectral power was analyzed in the theta frequency band. Theta power increased in the frontal, central, and parietal regions of the cortex when balance tasks became more challenging. In addition, fronto-central and centro-parietal theta power correlated with balance performance. This study demonstrates the involvement of the cerebral cortex in maintaining upright posture during continuous balance tasks. Specifically, the results emphasize the important role of frontal and parietal theta oscillations in balance control. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Influence of job demands and job control on work-life balance among Taiwanese nurses.

Science.gov (United States)

Ng, Lee-Peng; Chen, I-Chi; Ng, Hui-Fuang; Lin, Bo-Yen; Kuar, Lok-Sin

2017-09-01

This study investigated the extent to which the job demands and job control of nurses were related to their work-life balance. The inability to achieve work-life balance is one of the major reasons for the declining retention rate among nurses. Job demands and job control are two major work domain factors that can have a significant influence on the work-life balance of nurses. The study measured the job demands, job control and work-life balance of 2040 nurses in eight private hospitals in Taiwan in 2013. Job demands and job control significantly predicted all the dimensions of work-life balance. Job demands increased the level of work-life imbalance among nurses. While job control showed positive effects on work/personal life enhancement, it was found to increase both work interference with personal life and personal life interference with work. Reducing the level of job demands (particularly for psychological demands) between family and career development and maintaining a proper level of job control are essential to the work-life balance of nurses. Flexible work practices and team-based management could be considered by nursing management to lessen job demand pressure and to facilitate job engagement and participation among nurses, thus promoting a better balance between work and personal life. © 2017 John Wiley & Sons Ltd.

Visual Biofeedback Balance Training Using Wii Fit after Stroke: A Randomized Controlled Trial

Science.gov (United States)

Barcala, Luciana; Grecco, Luanda André Collange; Colella, Fernanda; Lucareli, Paulo Roberto Garcia; Salgado, Afonso Shiguemi Inoue; Oliveira, Claudia Santos

2013-01-01

[Purpose] The aim of the present study was to investigate the effect of balance training with visual biofeedback on balance, body symmetry, and function among individuals with hemiplegia following a stroke. [Subjects and Methods] The present study was performed using a randomized controlled clinical trial with a blinded evaluator. The subjects were twenty adults with hemiplegia following a stroke. The experimental group performed balance training with visual biofeedback using Wii Fit® together with conventional physical therapy. The control group underwent conventional physical therapy alone. The intervention lasted five weeks, with two sessions per week. Body symmetry (baropodometry), static balance (stabilometry), functional balance (Berg Balance Scale), functional mobility (Timed Up and Go test), and independence in activities of daily living (Functional Independence Measure) were assessed before and after the intervention. [Results] No statistically significant differences were found between the experimental and control groups. In the intragroup analysis, both groups demonstrated a significant improvement in all variables studied. [Conclusion] The physical therapy program combined with balance training involving visual biofeedback (Wii Fit®) led to an improvement in body symmetry, balance, and function among stroke victims. However, the improvement was similar to that achieved with conventional physical therapy alone. PMID:24259909

(Re)constructing Reflexivity: A Relational Constructionist Approach

NARCIS (Netherlands)

Hosking, D.M.; Pluut, B.

2010-01-01

This article distinguishes three discourses of reflexivity in relation to human inquiry. One of these arises from a post-modern, relational constructionist perspective which radically re-conceptualizes reflexivity: (a) as a local and co-constructed process oriented towards the question (b) how are

Ultimate concerns in late modernity: Archer, Bourdieu and reflexivity.

Science.gov (United States)

Farrugia, David; Woodman, Dan

2015-12-01

Through a critique of Margaret Archer's theory of reflexivity, this paper explores the theoretical contribution of a Bourdieusian sociology of the subject for understanding social change. Archer's theory of reflexivity holds that conscious 'internal conversations' are the motor of society, central both to human subjectivity and to the 'reflexive imperative' of late modernity. This is established through critiques of Bourdieu, who is held to erase creativity and meaningful personal investments from subjectivity, and late modernity is depicted as a time when a 'situational logic of opportunity' renders embodied dispositions and the reproduction of symbolic advantages obsolete. Maintaining Archer's focus on 'ultimate concerns' in a context of social change, this paper argues that her theory of reflexivity is established through a narrow misreading and rejection of Bourdieu's work, which ultimately creates problems for her own approach. Archer's rejection of any pre-reflexive dimensions to subjectivity and social action leaves her unable to sociologically explain the genesis of 'ultimate concerns', and creates an empirically dubious narrative of the consequences of social change. Through a focus on Archer's concept of 'fractured reflexivity', the paper explores the theoretical necessity of habitus and illusio for understanding the social changes that Archer is grappling with. In late modernity, reflexivity is valorized just as the conditions for its successful operation are increasingly foreclosed, creating 'fractured reflexivity' emblematic of the complex contemporary interaction between habitus, illusio, and accelerating social change. © London School of Economics and Political Science 2015.

Reflexive Aero Structures for Enhanced Survivability, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) proposes to develop an advanced reflexive structure system to increase the survivability of aerostructures. This reflexive...

The Role of Ankle Proprioception for Balance Control in relation to Sports Performance and Injury

Science.gov (United States)

Han, Jia; Waddington, Gordon; Adams, Roger; Liu, Yu

2015-01-01

Balance control improvement is one of the most important goals in sports and exercise. Better balance is strongly positively associated with enhanced athletic performance and negatively associated with lower limb sports injuries. Proprioception plays an essential role in balance control, and ankle proprioception is arguably the most important. This paper reviews ankle proprioception and explores synergies with balance control, specifically in a sporting context. Central processing of ankle proprioceptive information, along with other sensory information, enables integration for balance control. When assessing ankle proprioception, the most generalizable findings arise from methods that are ecologically valid, allow proprioceptive signals to be integrated with general vision in the central nervous system, and reflect the signal-in-noise nature of central processing. Ankle proprioceptive intervention concepts driven by such a central processing theory are further proposed and discussed for the improvement of balance control in sport. PMID:26583139

Anticausatives are weak scalar expressions, not reflexive expressions

Directory of Open Access Journals (Sweden)

Florian Schäfer

2016-07-01

Full Text Available We discuss conceptual and empirical arguments from Germanic, Romance and Slavic languages against an analysis treating anticausative verbs as derived from their lexical causative counterparts under reflexivization. Instead, we defend the standard account to the semantics of the causative alternation according to which anticausatives in general, and anticausatives marked with reflexive morphology in particular, denote simple one-place inchoative events that are logically entailed by their lexical causative counterparts. Under such an account, anticausative verbs are weak scalar expressions that stand in a semantico-pragmatic opposition to their strong lexical causative counterparts. Due to this scalar relation, the use of an anticausative can trigger the implicature that the use of its lexical causative counterpart is too strong. As usual with implicatures, they can be ‘metalinguistically’ denied, cancelled, or reinforced and we argue that these mechanisms explain all central empirical facts brought up in the literature in favor of a treatment of anticausatives as semantically reflexive predicates. Our results reinforce the view that the reflexive morphemes used in many (Indo-European languages to mark anticausatives do not necessarily trigger reflexive semantics. However, we also show that a string involving a reflexively marked (anti-causative verb can be forced into a semantically reflexive construal under particular conceptual or grammatical circumstances.

Comparative Effects of Different Balance-Training–Progression Styles on Postural Control and Ankle Force Production: A Randomized Controlled Trial

Science.gov (United States)

Cuğ, Mutlu; Duncan, Ashley; Wikstrom, Erik

2016-01-01

Context:  Despite the effectiveness of balance training, the exact parameters needed to maximize the benefits of such programs remain unknown. One such factor is how individuals should progress to higher levels of task difficulty within a balance-training program. Yet no investigators have directly compared different balance-training–progression styles. Objective:  To compare an error-based progression (ie, advance when proficient at a task) with a repetition-based progression (ie, advance after a set amount of repetitions) style during a balance-training program in healthy individuals. Design:  Randomized controlled trial. Setting:  Research laboratory. Patients or Other Participants:  A total of 28 (16 women, 12 men) physically healthy young adults (age = 21.57 ± 3.95 years, height = 171.60 ± 11.03 cm, weight = 72.96 ± 16.18 kg, body mass index = 24.53 ± 3.7). Intervention(s):  All participants completed 12 supervised balance-training sessions over 4 weeks. Each session consisted of a combination of dynamic unstable-surface tasks that incorporated a BOSU ball and lasted about 30 minutes. Main Outcome Measure(s):  Static balance from an instrumented force plate, dynamic balance as measured via the Star Excursion Balance Test, and ankle force production in all 4 cardinal planes of motion as measured with a handheld dynamometer before and after the intervention. Results:  Selected static postural-control outcomes, dynamic postural control, and ankle force production in all planes of motion improved (P .05) for any of the outcome measures. Conclusions:  A 4-week balance-training program consisting of dynamic unstable-surface exercises on a BOSU ball improved dynamic postural control and ankle force production in healthy young adults. These results suggest that an error-based balance-training program is comparable with but not superior to a repetition-based balance-training program in improving postural control and ankle force production in

Reflexive Planning as Design and Work

DEFF Research Database (Denmark)

Lissandrello, Enza; Grin, John

2011-01-01

in planning emerges as a new tool for generating critical knowledge and dialogue that can synthesise the perspectives of multiple actors in a common understanding, existing structural constraints and a collective imagination of alternative future possibilities. Such research highlights the potential......In recent years, planning theorists have advanced various interpretations of the notion of reflexivity, inspired by American pragmatism, complexity theory, hermeneutics, discursive and collaborative planning. Scholars agree that “reflexivity” has a strong temporal dimension: it not only aims...... to solve present planning problems, but to imagine and understand alternative trajectories for future action. This article explores the practical utility of reflexivity for planners, through a case study that focuses on a project to promote sustainable development in the Port of Amsterdam. Reflexivity...

Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment.

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Yang Wang

Full Text Available Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown.To 1 review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2 review the evidence relating hearing impairment and parasympathetic activity and 3 seek evidence of possible connections between hearing impairment and the pupil light reflex.Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment.Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment.As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing

Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment.

Science.gov (United States)

Wang, Yang; Zekveld, Adriana A; Naylor, Graham; Ohlenforst, Barbara; Jansma, Elise P; Lorens, Artur; Lunner, Thomas; Kramer, Sophia E

2016-01-01

Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown. To 1) review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2) review the evidence relating hearing impairment and parasympathetic activity and 3) seek evidence of possible connections between hearing impairment and the pupil light reflex. Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment. Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment. As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing impairment

Acoustic startle reflex and pre-pulse inhibition in tinnitus patients

Institute of Scientific and Technical Information of China (English)

Kelly Shadwick; Wei Sun

2014-01-01

Gap induced pre-pulse inhibition (Gap-PPI) of acoustic startle reflex has been used as a measurement of tinnitus in animal models. However, whether this test is sensitive to detect tinnitus in humans is still unclear. Based on the testing procedure used in animal studies, a human subject testing method was formulated and conducted to investigate if a similar result could be found in tinnitus patients. Audiologic and tinnitus assessments and acoustic startle reflex measurements were performed on seven tinnitus subjects and nine age matched subjects without tinnitus. There was no significant difference found between the control and tinnitus group on the Gap-PPI across the frequencies evaluated. The amplitude of the startle response in the tinnitus group with normal hearing thresholds was significantly higher than the control group and those with tinnitus and hearing loss. This preliminary result suggests that hyperexcitability in the central auditory system may be involved in tinnitus. There was no correlation between hearing thresholds and the increased amplitude of startle response.

Toward Balance Recovery With Leg Prostheses Using Neuromuscular Model Control

Science.gov (United States)

Geyer, Hartmut

2016-01-01

Objective Lower limb amputees are at high risk of falling as current prosthetic legs provide only limited functionality for recovering balance after unexpected disturbances. For instance, the most established control method used on powered leg prostheses tracks local joint impedance functions without taking the global function of the leg in balance recovery into account. Here we explore an alternative control policy for powered transfemoral prostheses that considers the global leg function and is based on a neuromuscular model of human locomotion. Methods We adapt this model to describe and simulate an amputee walking with a powered prosthesis using the proposed control, and evaluate the gait robustness when confronted with rough ground and swing leg disturbances. We then implement and partially evaluate the resulting controller on a leg prosthesis prototype worn by a non-amputee user. Results In simulation, the proposed prosthesis control leads to gaits that are more robust than those obtained by the impedance control method. The initial hardware experiments with the prosthesis prototype show that the proposed control reproduces normal walking patterns qualitatively and effectively responds to disturbances in early and late swing. However, the response to mid-swing disturbances neither replicates human responses nor averts falls. Conclusions The neuromuscular model control is a promising alternative to existing prosthesis controls, although further research will need to improve on the initial implementation and determine how well these results transfer to amputee gait. Significance This work provides a potential avenue for future development of control policies that help improve amputee balance recovery. PMID:26315935

Balance control during gait initiation: State-of-the-art and research perspectives.

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Yiou, Eric; Caderby, Teddy; Delafontaine, Arnaud; Fourcade, Paul; Honeine, Jean-Louis

2017-11-18

It is well known that balance control is affected by aging, neurological and orthopedic conditions. Poor balance control during gait and postural maintenance are associated with disability, falls and increased mortality. Gait initiation - the transient period between the quiet standing posture and steady state walking - is a functional task that is classically used in the literature to investigate how the central nervous system (CNS) controls balance during a whole-body movement involving change in the base of support dimensions and center of mass progression. Understanding how the CNS in able-bodied subjects exerts this control during such a challenging task is a pre-requisite to identifying motor disorders in populations with specific impairments of the postural system. It may also provide clinicians with objective measures to assess the efficiency of rehabilitation programs and better target interventions according to individual impairments. The present review thus proposes a state-of-the-art analysis on: (1) the balance control mechanisms in play during gait initiation in able bodied subjects and in the case of some frail populations; and (2) the biomechanical parameters used in the literature to quantify dynamic stability during gait initiation. Balance control mechanisms reviewed in this article included anticipatory postural adjustments, stance leg stiffness, foot placement, lateral ankle strategy, swing foot strike pattern and vertical center of mass braking. Based on this review, the following viewpoints were put forward: (1) dynamic stability during gait initiation may share a principle of homeostatic regulation similar to most physiological variables, where separate mechanisms need to be coordinated to ensure stabilization of vital variables, and consequently; and (2) rehabilitation interventions which focus on separate or isolated components of posture, balance, or gait may limit the effectiveness of current clinical practices.

On the Control of Self-Balancing Unicycles

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Felix Freiberger

2015-11-01

Full Text Available This paper discusses the problem of designing a self-balancing unicycle where pedals are used for both power generation and speed control. After developing the principal physical aspects (in the longitudinal dimension, we describe an abstract model in the form of a collection of hybrid automata, together with design requirements to be met by an ideal controller. We discuss simplifications and assumptions that make this model amenable to verification and validation tools such as SpaceEx. To enable experimentation with different prototypical controllers and user behaviours in concrete scenarios, we also develop a simple simulation framework using digital time.

Efficacy of ankle control balance training on postural balance and gait ability in community-dwelling older adults: a single-blinded, randomized clinical trial.

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Lee, Kyeongjin; Lee, Yong Woo

2017-09-01

[Purpose] This study was conducted to investigate the effects of ankle control balance training (ACBT) on postural balance and gait ability in community-dwelling older adults. [Subjects and Methods] Fifty-four subjects were randomly divided into two groups, with 27 subjects in the ACBT group and 27 subjects in the control group. Subjects in the ACBT group received ACBT for 60 minutes, twice per week for 4 weeks, and all subjects had undergone fall prevention education for 60 minutes, once per week for 4 weeks. The main outcome measures, including the Berg balance scale; the functional reach test and one leg stance test for postural balance; and the timed up-and-go test and 10-meter walking test for gait ability, were assessed at baseline and after 4 weeks of training. [Results] The postural balance and gait ability in the ACBT group improved significantly compared to those in the control group, except BBS. [Conclusion] The results of this study showed improved postural balance and gait abilities after ACBT and that ACBT is a feasible method for improving postural balance and gait ability in community-dwelling older adults.

Median sep and blink reflex in thyroid diseases.

Science.gov (United States)

Oflazoğlu, B; Somay, G; Us, O; Surardamar, A; Tanridağ, T

2006-11-01

Pathological disturbances of thyroid hormones is associated with central and peripheral nervous system disturbances. The aim of this study is to evaluate median nerve stimulated somatosensory evoked potential (SEP) and blink reflex of thyroid patients (hypo and hyperthyroidism). Median SEP was performed in 40 patients (21 with hyperthyroidism and 19 with hypothyroidism). We evaluated the latencies of N9, N11, N13, P9, P11, P14, N20 and P25 waves and the N9-N20, N9-N13, N13-N20 and P14-N20 interpeak latencies. We compared the results of patients with the control group (26 persons). We found that the N20 latency was longer in patients with hyperthyroidism than in the control group and the difference was statistically significant. There was not any statistically significant difference regarding the N9, N11, N13, P9, P11, P14, N20 and P25 latencies and the N9-N20, N9-N13, N13-N20 and P14-N20 interpeak latencies between hypothyroid patients and controls. We performed the blink reflex study in 28 of 40 patients (14 patients with hyperthyroidism and 14 patients with hypothyroidism). Comparing the R1, R2, CR2 (contralateral R2) latencies and durations of the patients and controls, we found that R2 and CR2 duration was shorter in patients with hyperthyroidism. This difference was statistically significant.

Gain modulation of the middle latency cutaneous reflex in patients with chronic joint instability after ankle sprain.

Science.gov (United States)

Futatsubashi, Genki; Sasada, Shusaku; Tazoe, Toshiki; Komiyama, Tomoyoshi

2013-07-01

To investigate the neural alteration of reflex pathways arising from cutaneous afferents in patients with chronic ankle instability. Cutaneous reflexes were elicited by applying non-noxious electrical stimulation to the sural nerve of subjects with chronic ankle instability (n=17) and control subjects (n=17) while sitting. Electromyographic (EMG) signals were recorded from each ankle and thigh muscle. The middle latency response (MLR; latency: 70-120 ms) component was analyzed. In the peroneus longus (PL) and vastus lateralis (VL) muscles, linear regression analyses between the magnitude of the inhibitory MLR and background EMG activity showed that, compared to the uninjured side and the control subjects, the gain of the suppressive MLR was increased in the injured side. This was also confirmed by the pooled data for both groups. The degree of MLR alteration was significantly correlated to that of chronic ankle instability in the PL. The excitability of middle latency cutaneous reflexes in the PL and VL is modulated in subjects with chronic ankle instability. Cutaneous reflexes may be potential tools to investigate the pathological state of the neural system that controls the lower limbs in subjects with chronic ankle instability. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Acute Whole-Body Vibration does not Facilitate Peak Torque and Stretch Reflex in Healthy Adults

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Ella W. Yeung

2013-03-01

Full Text Available The acute effect of whole-body vibration (WBV training may enhance muscular performance via neural potentiation of the stretch reflex. The purpose of this study was to investigate if acute WBV exposure affects the stretch induced knee jerk reflex [onset latency and electromechanical delay (EMD] and the isokinetic knee extensor peak torque performance. Twenty-two subjects were randomly assigned to the intervention or control group. The intervention group received WBV in a semi-squat position at 30° knee flexion with an amplitude of 0.69 mm, frequency of 45 Hz, and peak acceleration of 27.6 m/s2 for 3 minutes. The control group underwent the same semii-squatting position statically without exposure of WBV. Two-way mixed repeated measures analysis of variance revealed no significant group effects differences on reflex latency of rectus femoris (RF and vastus lateralis (VL; p = 0.934 and 0.935, respectively EMD of RF and VL (p = 0.474 and 0.551, respectively and peak torque production (p = 0.483 measured before and after the WBV. The results of this study indicate that a single session of WBV exposure has no potentiation effect on the stretch induced reflex and peak torque performance in healthy young adults.

Post-activation depression of soleus stretch reflexes in healthy and spastic humans

DEFF Research Database (Denmark)

Grey, Michael James; Klinge, Klaus; Crone, Clarissa

2007-01-01

Reduced depression of transmitter release from Ia afferents following previous activation (post-activation depression) has been suggested to be involved in the pathophysiology of spasticity. However, the effect of this mechanism on the myotatic reflex and its possible contribution to increased...... reflex excitability in spastic participants has not been tested. To investigate these effects, we examined post-activation depression in Soleus H-reflex responses and in mechanically evoked Soleus stretch reflex responses. Stretch reflex responses were evoked with consecutive dorsiflexion perturbations...... of the soleus stretch reflex and H-reflex decreased as the interval between the stimulus/perturbation was decreased. Similarly, the stretch-evoked torque decreased. In the spastic participants, the post-activation depression of both reflexes and the stretch-evoked torque was significantly smaller than...

A Tool for Balance Control Training Using Muscle Synergies and Multimodal Interfaces

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D. Galeano

2014-01-01

Full Text Available Balance control plays a key role in neuromotor rehabilitation after stroke or spinal cord injuries. Computerized dynamic posturography (CDP is a classic technological tool to assess the status of balance control and to identify potential disorders. Despite the more accurate diagnosis generated by these tools, the current strategies to promote rehabilitation are still limited and do not take full advantage of the technologies available. This paper presents a novel balance training platform which combines a CDP device made from low-cost interfaces, such as the Nintendo Wii Balance Board and the Microsoft Kinect. In addition, it integrates a custom electrical stimulator that uses the concept of muscle synergies to promote natural interaction. The aim of the platform is to support the exploration of innovative multimodal therapies. Results include the technical validation of the platform using mediolateral and anteroposterior sways as basic balance training therapies.

The Effects of Pilates Training on Balance Control and Self-Reported Health Status in Community-Dwelling Older Adults: A Randomized Controlled Trial.

Science.gov (United States)

Gabizon, Hadas; Press, Yan; Volkov, Ilia; Melzer, Itshak

2016-07-01

To evaluate the effect of a group-based Pilates training program on balance control and health status in healthy older adults. A single-blind, randomized, controlled trial. General community. A total of 88 community-dwelling older adults (age 71.15 ± 4.30 years), without evidence of functional balance impairment, were recruited and allocated at random to a Pilates intervention group (n = 44) or a control group (n = 44). The Pilates intervention group received 36 training sessions over three months (3 sessions a week), while the control group did not receive any intervention. Standing upright postural stability, performance-based measures of balance, and self-reported health status was assessed in both groups at baseline and at the end of the intervention period. Compared with the control group, the Pilates intervention did not improve postural stability, baseline functional measures of balance, or health status. The results suggest that because Pilates training is not task specific, it does not improve balance control or balance function in independent older adults.

21 CFR 890.1450 - Powered reflex hammer.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered reflex hammer. 890.1450 Section 890.1450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... hammer. (a) Identification. A powered reflex hammer is a motorized device intended for medical purposes...

Effects of postural changes of the upper limb on reflex transmission in the lower limb. Cervicolumbar reflex interactions in man.

Science.gov (United States)

Delwaide, P J; Figiel, C; Richelle, C

1977-06-01

The influence of passive changes in upper limb position on the excitability of three myotatic arc reflexes (soleus, quadriceps, and biceps femoris) of the lower limb has been explored on 42 volunteers. The results indicate that the excitability of the three myotatic arcs can be influenced at a distance by postural modifications of the upper limb. When the ipsilateral upper limb is forwards or the contralateral backwards, a facilitation of both soleus and quadriceps tendon reflexes is observed while the biceps femoris reflexes are reduced. This pattern of facilitation and inhibition is reversed when the ipsilateral upper limb is backwards or the contralateral forwards. The facilitations as well as inhibitions of proximal myotatic arc reflexes are quantitatively more marked than that of the soleus reflex. Facilitation and inhibition are not linearly related to the angle of the arm with the trunk. Effects begin at a considerable angle, become maximal at 45 degrees, and progressively disappear for greater values. It is suggested that the distinct pattern of facilitation and inhibition which is exerted in reciprocal fashion on extensor and flexor motor nuclei might depend on the long propriospinal neurones connecting cervical and lumbar enlargements.

Proprioceptive changes impair balance control in individuals with chronic obstructive pulmonary disease.

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Lotte Janssens

Full Text Available Balance deficits are identified as important risk factors for falling in individuals with chronic obstructive pulmonary disease (COPD. However, the specific use of proprioception, which is of primary importance during balance control, has not been studied in individuals with COPD. The objective was to determine the specific proprioceptive control strategy during postural balance in individuals with COPD and healthy controls, and to assess whether this was related to inspiratory muscle weakness.Center of pressure displacement was determined in 20 individuals with COPD and 20 age/gender-matched controls during upright stance on an unstable support surface without vision. Ankle and back muscle vibration were applied to evaluate the relative contribution of different proprioceptive signals used in postural control.Individuals with COPD showed an increased anterior-posterior body sway during upright stance (p = 0.037. Compared to controls, individuals with COPD showed an increased posterior body sway during ankle muscle vibration (p = 0.047, decreased anterior body sway during back muscle vibration (p = 0.025, and increased posterior body sway during simultaneous ankle-muscle vibration (p = 0.002. Individuals with COPD with the weakest inspiratory muscles showed the greatest reliance on ankle muscle input when compared to the stronger individuals with COPD (p = 0.037.Individuals with COPD, especially those with inspiratory muscle weakness, increased their reliance on ankle muscle proprioceptive signals and decreased their reliance on back muscle proprioceptive signals during balance control, resulting in a decreased postural stability compared to healthy controls. These proprioceptive changes may be due to an impaired postural contribution of the inspiratory muscles to trunk stability. Further research is required to determine whether interventions such as proprioceptive training and inspiratory muscle training improve postural balance and reduce the

Outside home. Notes on reflexivity

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Mara Clemente

2017-01-01

The paper proffers the idea in which a “reflexive process” on subjectivity can involve and/or hopefully involve the entire experience of the researcher, going beyond the borders of a single research. In the process, unexpected elements of subjectivity can come into play; in other cases the meaning attributed to them can change in time or can have a role different from what had been expected. Some elements, objects of epistemological analyses, as imposed by a reflexive approach, can become objects of attention also on the phenomenological level.

Intact reflexive but deficient voluntary social orienting in autism spectrum disorder

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Megan Anne Kirchgessner

2015-12-01

Full Text Available Impairment in social interactions is a primary characteristic of people diagnosed with autism spectrum disorder (ASD. Although these individuals tend to orient less to naturalistic social cues than do typically developing (TD individuals, laboratory experiments testing social orienting in ASD have been inconclusive, possibly because of a failure to fully isolate reflexive (stimulus-driven and voluntary (goal-directed social orienting processes. The purpose of the present study was to separately examine potential reflexive and/or voluntary social orienting differences in individuals with ASD relative to TD controls. Subjects (ages 7-14 with high-functioning ASD and a matched control group completed three gaze cueing tasks on an iPad in which individuals briefly saw a face with averted gaze followed by a target after a variable delay. Two tasks were 100% predictive with either all congruent (target appears in gaze direction or all incongruent (target appears opposite from gaze direction trials, respectively. Another task was non-predictive with these same trials (half congruent and half incongruent intermixed randomly. Response times (RTs to the target were used to calculate reflexive (incongruent condition RT – congruent condition RT and voluntary (non-predictive condition RT – predictive condition RT gaze cueing effects. Subjects also completed two additional non-social orienting tasks (ProPoint and AntiPoint. Subjects with ASD demonstrate intact reflexive but deficient voluntary gaze following. Similar results were found in a separate test of non-social orienting. This suggests problems with using social cues, but only in a goal-directed fashion, in our sample of high-functioning individuals with ASD. Such findings may not only explain inconclusive previous findings but more importantly be critical for understanding social dysfunctions in ASD and for developing future interventions.

The Multiple Faces of Reflexive Research Designs

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Karl H. Müller

2015-10-01

Full Text Available Reflexive research can be grouped into five clusters with circular relations between two elements x ↔ x, namely circular relations between observers, between scientific building blocks like concepts, theories or models, between systemic levels, between rules and rule systems or as circular relations or x ↔ y between these four components. By far the most important cluster is the second cluster which becomes reflexive through a re-entry operation RE into a scientific element x and which establishes its circular formation as x(x. Many of the research problems in these five clusters in reflexivity research are still unexplored and pose grand challenges for future research.

Effect of a balance-training programme on postural balance, aerobic capacity and frequency of falls in women with osteoporosis: A randomized controlled trial

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Ibolya Miko

2018-05-01

Full Text Available Objective: To investigate the effect of a 12-month complex balance-training programme on static and dynamic postural balance, aerobic capacity and frequency of falls in women with established osteoporosis. Design: Randomized controlled trial in which the intervention group was assigned a 12-month exercise programme (3 times a week for 30 min and the control group had no intervention. Subjects: A total of 100 osteoporotic women with at least one previous fracture. Methods: Performance-based Timed Up and Go (TUG, Berg Balance Scale (BBS and stabilometric platform tests were used to evaluate balance. Aerobic capacity was measured by bicycle ergometry. Frequency of falls was assessed using a falls diary. Results: After 1 year, there was a statistically significant difference between the improvement achieved in the intervention and control groups on the performance-based TUG, BBS and stabilometric platform tests (p < 0.05. Mean metabolic equivalent (MET value decreased in the intervention group, from 4.91 to 3.82 (a significant difference from the change achieved in the control group; p = 0.05. Relative risk of falls was 0.534 at 1 year (p = 0.17. Conclusion: The 12-month balance-training programme significantly improved postural balance and increased aerobic capacity in women with established osteoporosis.

A Prototype Analysis of Spanish Indeterminate Reflexive Constructions.

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Turley, Jeffrey S.

1998-01-01

Discussion of the Spanish indeterminate reflexive construction, the impersonal reflexive, finds that prototype theory allows this subjectless Spanish construction to be included within the category of generally subject-bearing indeterminates in Romance languages. (MSE)

Resistance versus Balance Training to Improve Postural Control in Parkinson's Disease: A Randomized Rater Blinded Controlled Study.

Science.gov (United States)

Schlenstedt, Christian; Paschen, Steffen; Kruse, Annika; Raethjen, Jan; Weisser, Burkhard; Deuschl, Günther

2015-01-01

Reduced muscle strength is an independent risk factor for falls and related to postural instability in individuals with Parkinson's disease. The ability of resistance training to improve postural control still remains unclear. To compare resistance training with balance training to improve postural control in people with Parkinson's disease. 40 patients with idiopathic Parkinson's disease (Hoehn&Yahr: 2.5-3.0) were randomly assigned into resistance or balance training (2x/week for 7 weeks). Assessments were performed at baseline, 8- and 12-weeks follow-up: primary outcome: Fullerton Advanced Balance (FAB) scale; secondary outcomes: center of mass analysis during surface perturbations, Timed-up-and-go-test, Unified Parkinson's Disease Rating Scale, Clinical Global Impression, gait analysis, maximal isometric leg strength, PDQ-39, Beck Depression Inventory. Clinical tests were videotaped and analysed by a second rater, blind to group allocation and assessment time. 32 participants (resistance training: n = 17, balance training: n = 15; 8 drop-outs) were analyzed at 8-weeks follow-up. No significant difference was found in the FAB scale when comparing the effects of the two training types (p = 0.14; effect size (Cohen's d) = -0.59). Participants from the resistance training group, but not from the balance training group significantly improved on the FAB scale (resistance training: +2.4 points, Cohen's d = -0.46; balance training: +0.3 points, Cohen's d = -0.08). Within the resistance training group, improvements of the FAB scale were significantly correlated with improvements of rate of force development and stride time variability. No significant differences were found in the secondary outcome measures when comparing the training effects of both training types. The difference between resistance and balance training to improve postural control in people with Parkinson's disease was small and not significant with this sample size. There was weak evidence that freely

Resistance versus Balance Training to Improve Postural Control in Parkinson's Disease: A Randomized Rater Blinded Controlled Study.

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Christian Schlenstedt

Full Text Available Reduced muscle strength is an independent risk factor for falls and related to postural instability in individuals with Parkinson's disease. The ability of resistance training to improve postural control still remains unclear.To compare resistance training with balance training to improve postural control in people with Parkinson's disease.40 patients with idiopathic Parkinson's disease (Hoehn&Yahr: 2.5-3.0 were randomly assigned into resistance or balance training (2x/week for 7 weeks. Assessments were performed at baseline, 8- and 12-weeks follow-up: primary outcome: Fullerton Advanced Balance (FAB scale; secondary outcomes: center of mass analysis during surface perturbations, Timed-up-and-go-test, Unified Parkinson's Disease Rating Scale, Clinical Global Impression, gait analysis, maximal isometric leg strength, PDQ-39, Beck Depression Inventory. Clinical tests were videotaped and analysed by a second rater, blind to group allocation and assessment time.32 participants (resistance training: n = 17, balance training: n = 15; 8 drop-outs were analyzed at 8-weeks follow-up. No significant difference was found in the FAB scale when comparing the effects of the two training types (p = 0.14; effect size (Cohen's d = -0.59. Participants from the resistance training group, but not from the balance training group significantly improved on the FAB scale (resistance training: +2.4 points, Cohen's d = -0.46; balance training: +0.3 points, Cohen's d = -0.08. Within the resistance training group, improvements of the FAB scale were significantly correlated with improvements of rate of force development and stride time variability. No significant differences were found in the secondary outcome measures when comparing the training effects of both training types.The difference between resistance and balance training to improve postural control in people with Parkinson's disease was small and not significant with this sample size. There was weak evidence that

Changes in soleus H-reflex during walking in middle-aged, healthy subjects

DEFF Research Database (Denmark)

Raffalt, Peter C; Alkjær, Tine; Simonsen, Erik B

2015-01-01

INTRODUCTION: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4±6.9 years) and 15 young (mean age 23.7±3.9 years) subjects were compared. METHODS: The H-reflex amplitude, muscle activity (EMG) of the soleus...... and tibialis anterior muscles, and EMG/H-reflex gain were measured during 4-km/h treadmill walking. RESULTS: The normalized H-reflex amplitude was lower in the swing phase for the middle-aged group, and there was no difference in muscle activity. EMG/H-reflex gain did not differ between groups. CONCLUSIONS: H......-reflex amplitude during walking was affected by aging, and changes during the swing phase could be seen in the middle-aged subjects. Subdividing the 2 age groups into groups of facilitated or suppressed swing-phase H-reflex revealed that the H-reflex amplitude modulation pattern in the group with facilitated swing...

The Effects of Slackline Balance Training on Postural Control in Older Adults.

Science.gov (United States)

Thomas, Monika; Kalicinski, Michael

2016-07-01

The present study investigated whether slackline training enhances postural control in older adults. Twenty-four participants were randomized into an intervention and a control group. The intervention group received 6 weeks of slackline training, two times per week. Pre-post measurement included the time of different standing positions on a balance platform with and without an external disturbance and the acceleration of the balance platform. Results showed significantly improved standing times during one-leg stance without external disturbance and a significantly reduced acceleration of the balance platform for the intervention group after the training period during tandem stance with and without an external disturbance. We conclude that slackline training in older adults has a positive impact on postural control and thus on the reduction of fall risk.

Training induced adaptations in characteristics of postural reflexes in elderly men.

Science.gov (United States)

Granacher, U; Gollhofer, A; Strass, D

2006-12-01

The aging neuromuscular system is affected by structural and functional changes which lead to a general slowing down of neuromuscular performance and an increased risk of falling. The impact of heavy resistance (HR) training in the elderly on maximum voluntary contraction (MVC) and rate of force development (RFD) has been investigated in the past. However, the influence of sensorimotor (SENSO) training and HR training on the ability to compensate for gait perturbations has not yet been investigated in the elderly. Therefore, the purpose of the study was to examine the impact of HR and SENSO training in elderly men on unexpected treadmill perturbations. Functional reflex activity was recorded by means of surface EMG in 40 male subjects (>60 years) before and after 13 weeks of HR and SENSO training and in another 20 male subjects (>60 years), which served as a CONTROL-group. SENSO training resulted in a decrease in onset latency, an enhanced reflex activity in the prime mover as well as a decrease in maximal angular velocity of the ankle joint complex during the perturbation impulses. No significant changes were observed in the HR- and in the CONTROL-group. The results clearly indicate that SENSO training has an impact on spinal motor control mechanisms in the elderly. Training induced improvements in perception and procession of afferent information could be a possible reason for the increase in reflex contraction. Due to these adaptive processes, SENSO training could be a well-suited method for fall preventive programs in elderly people.

Acoustic Reflex Screening of Conductive Hearing Loss for Third Window Disorders.

Science.gov (United States)

Hong, Robert S; Metz, Christopher M; Bojrab, Dennis I; Babu, Seilesh C; Zappia, John; Sargent, Eric W; Chan, Eleanor Y; Naumann, Ilka C; LaRouere, Michael J

2016-02-01

This study examines the effectiveness of acoustic reflexes in screening for third window disorders (eg, superior semicircular canal dehiscence) prior to middle ear exploration for conductive hearing loss. Case series with chart review. Outpatient tertiary otology center. A review was performed of 212 ears with acoustic reflexes, performed as part of the evaluation of conductive hearing loss in patients without evidence of chronic otitis media. The etiology of hearing loss was determined from intraoperative findings and computed tomography imaging. The relationship between acoustic reflexes and conductive hearing loss etiology was assessed. Eighty-eight percent of ears (166 of 189) demonstrating absence of all acoustic reflexes had an ossicular etiology of conductive hearing loss. Fifty-two percent of ears (12 of 23) with at least 1 detectable acoustic reflex had a nonossicular etiology. The positive and negative predictive values for an ossicular etiology were 89% and 57% when acoustic reflexes were used alone for screening, 89% and 39% when third window symptoms were used alone, and 94% and 71% when reflexes and symptoms were used together, respectively. Acoustic reflex testing is an effective means of screening for third window disorders in patients with a conductive hearing loss. Questioning for third window symptoms should complement screening. The detection of even 1 acoustic reflex or third window symptom (regardless of reflex status) should prompt further workup prior to middle ear exploration. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Reflex epilepsy: triggers and management strategies

Directory of Open Access Journals (Sweden)

Okudan ZV

2018-01-01

Full Text Available Zeynep Vildan Okudan,1 Çiğdem Özkara2 1Department of Neurology, Bakirkoy Dr Sadi Konuk Education and Research Hospital, 2Department of Neurology and Clinical Neurophysiology, Cerrahpasa Faculty of Medicine, University of Istanbul, Istanbul, Turkey Abstract: Reflex epilepsies (REs are identified as epileptic seizures that are consistently induced by identifiable and objective-specific triggers, which may be an afferent stimulus or by the patient’s own activity. RE may have different subtypes depending on the stimulus characteristic. There are significant clinical and electrophysiologic differences between different RE types. Visual stimuli-sensitive or photosensitive epilepsies constitute a large proportion of the RE and are mainly related to genetic causes. Reflex epilepsies may present with focal or generalized seizures due to specific triggers, and sometimes seizures may occur spontaneously. The stimuli can be external (light flashes, hot water, internal (emotion, thinking, or both and should be distinguished from triggering precipitants, which most epileptic patients could report such as emotional stress, sleep deprivation, alcohol, and menstrual cycle. Different genetic and acquired factors may play a role in etiology of RE. This review will provide a current overview of the triggering factors and management of reflex seizures. Keywords: seizure, reflex epilepsy, photosensitivity, hot water, reading, thinking

Upper limb contributions to frontal plane balance control in rollator-assisted walking.

Science.gov (United States)

Tung, James Y; Gage, William H; Poupart, Pascal; McIlroy, William E

2014-01-01

While assisting with balance is a primary reason for rollator use, few studies have examined how the upper limbs are used for balance. This study examines upper limb contributions to balance control during rollator-assisted walking. We hypothesized that there would be an increased upper limb contribution, measured by mean vertical loading (Fz) and variation in frontal plane center-of-pressure (COPhigh), when walking balance is challenged/impaired. Experiment 1 compared straight-line and beam-walking in young adults (n = 11). As hypothesized, Fz and COPhighincreased in beam-walking compared to baseline (mean Fz: 13.7 vs. 9.1% body weight (BW), p < 0.001, RMS COPhigh: 1.35 vs. 1.07 cm, p < 0.001). Experiment 2 compared older adults who regularly use rollators (RU, n = 10) to older adult controls (CTL, n = 10). The predicted higher upper limb contribution in the RU group was not supported. However, when individuals were grouped by balance impairment, those with the lowest Berg Balance scores (< 45) demonstrated greater speed-adjusted COPhigh than those with higher scores (p = 0.013). Furthermore, greater COPhigh and Fz were correlated to greater reduction in step width, supporting the role of upper limb contributions to frontal plane balance. This work will guide studies assessing reliance on rollators by providing a basis for measurement of upper limb balance contributions.

Cerebellar interaction with the acoustic reflex.

Science.gov (United States)

Jastreboff, P J

1981-01-01

The involvement of the cerebellar vermis in the acoustic reflex was analyzed in 12 cats, decerebrated or in pentobarbital anesthesia. Anatomical data suggested the existence of a connection of lobules VIII with the ventral cochlear nucleus. Single cell recording and evoked potential techniques demonstrated the existence of the acoustic projection to lobulus VIII. Electrical stimulation of this area changed the tension of the middle ear muscle and caused evoked potential responses in the caudal part of the ventral cochlear nucleus. Electrical stimulation of the motor nucleus of the facial nerve evoked a slow wave in the recording taken from the surrounding of the cochlear round window. A hypothesis is proposed which postulates the involvement of the acoustic reflex in space localization of acoustic stimuli and the action of cerebellar vermis in order to assure the stability and plasticity of the acoustic reflex arc.

Reflex syncope: Diagnosis and treatment

Directory of Open Access Journals (Sweden)

Richard Sutton

2017-12-01

Full Text Available For the diagnosis of reflex syncope, diligent history-building with the patient and a witness is required. In the Emergency Department (ED, the assessment of syncope is a challenge which may be addressed by an ED Observation Unit or by a referral to a Syncope Unit. Hospital admission is necessary for those with life-threatening cardiac conditions although risk stratification remains an unsolved problem. Other patients may be investigated with less urgency by carotid sinus massage (>40 years, tilt testing, and electrocardiogram loop recorder insertion resulting in a clear cause for syncope. Management includes, in general terms, patient education, avoidance of circumstances in which syncope is likely, increase in fluid and salt consumption, and physical counter-pressure maneuvers. In older patients, those that will benefit from cardiac pacing are now well defined. In all patients, the benefit of drug therapy is often disappointing and there remains no ideal drug. A role for catheter ablation may emerge for the highly symptomatic reflex syncope patient. Keywords: Cardiac pacing, Catheter ablation, Diagnosis, Drugs, Management, Reflex syncope

Cortical Contribution to Linear, Non-linear and Frequency Components of Motor Variability Control during Standing.

Science.gov (United States)

König Ignasiak, Niklas; Habermacher, Lars; Taylor, William R; Singh, Navrag B

2017-01-01

Motor variability is an inherent feature of all human movements and reflects the quality of functional task performance. Depending on the requirements of the motor task, the human sensory-motor system is thought to be able to flexibly govern the appropriate level of variability. However, it remains unclear which neurophysiological structures are responsible for the control of motor variability. In this study, we tested the contribution of cortical cognitive resources on the control of motor variability (in this case postural sway) using a dual-task paradigm and furthermore observed potential changes in control strategy by evaluating Ia-afferent integration (H-reflex). Twenty healthy subjects were instructed to stand relaxed on a force plate with eyes open and closed, as well as while trying to minimize sway magnitude and performing a "subtracting-sevens" cognitive task. In total 25 linear and non-linear parameters were used to evaluate postural sway, which were combined using a Principal Components procedure. Neurophysiological response of Ia-afferent reflex loop was quantified using the Hoffman reflex. In order to assess the contribution of the H-reflex on the sway outcome in the different standing conditions multiple mixed-model ANCOVAs were performed. The results suggest that subjects were unable to further minimize their sway, despite actively focusing to do so. The dual-task had a destabilizing effect on PS, which could partly (by 4%) be counter-balanced by increasing reliance on Ia-afferent information. The effect of the dual-task was larger than the protective mechanism of increasing Ia-afferent information. We, therefore, conclude that cortical structures, as compared to peripheral reflex loops, play a dominant role in the control of motor variability.

The relevance of clinical balance assessment tools to differentiate balance deficits

OpenAIRE

Mancini, Martina; Horak, Fay B

2010-01-01

Control of balance is complex and involves maintaining postures, facilitating movement, and recovering equilibrium. Balance control consists of controlling the body center of mass over its limits of stability. Clinical balance assessment can help assess fall risk and/or determine the underlying reasons for balance disorders. Most functional balance assessment scales assess fall risk and the need for balance rehabilitation but do not differentiate types of balance deficits. A system approach t...

Trigeminal cardiac reflex and cerebral blood flow regulation

Directory of Open Access Journals (Sweden)

Dominga Lapi

2016-10-01

Full Text Available The stimulation of some facial regions is known to trigger the trigemino-cardiac reflex: the main stimulus is represented by the contact of the face with water. This phenomenon called diving reflex induces a set of reactions in the cardiovascular and respiratory systems occurring in all mammals, especially marine (whales, seals. During the immersion of the face in the water, the main responses are aimed at reducing the oxygen consumption of the organism. Accordingly reduction in heart rate, peripheral vasoconstriction, blood pooling in certain organs, especially the heart and brain, and an increase in blood pressure have been reported. Moreover, the speed and intensity of the reflex is inversely proportional to the temperature of the water: more cold the water, more reactions as described are strong. In the case of deep diving an additional effect, such as blood deviation, has been reported: the blood is requested within the lungs, to compensate for the increase in the external pressure, preventing them from collapsing.The trigeminal-cardiac reflex is not just confined to the diving reflex; recently it has been shown that a brief proprioceptive stimulation (10 min by jaw extension in rats produces interesting effects both at systemic and cerebral level, reducing the arterial blood pressure and vasodilating the pial arterioles. The arteriolar dilation is associated with rhythmic diameter changes characterized by an increase in the endothelial activity. Fascinating the stimulation of trigeminal nerve is able to activated the nitric oxide release by vascular endothelial. Therefore the aim of this review was to highlight the effects due to trigeminal cardiac reflex induced by a simple mandibular extension, because produced opposite effects compared to those elicited by the diving reflex as it induces hypotension and modulation of cerebral arteriolar tone.

Measures of static postural control moderate the association of strength and power with functional dynamic balance.

Science.gov (United States)

Forte, Roberta; Boreham, Colin A G; De Vito, Giuseppe; Ditroilo, Massimiliano; Pesce, Caterina

2014-12-01

Age-related reductions in strength and power are considered to negatively impact balance control, but the existence of a direct association is still an issue of debate. This is possibly due to the fact that balance assessment is complex, reflects different underlying physiologic mechanisms and involves quantitative measurements of postural sway or timing of performance during balance tasks. The present study evaluated the moderator effect of static postural control on the association of power and strength with dynamic balance tasks. Fifty-seven healthy 65-75 year old individuals performed tests of dynamic functional balance (walking speed under different conditions) and of strength, power and static postural control. Dynamic balance performance (walking speed) was associated with lower limb strength and power, as well as postural control under conditions requiring postural adjustments (narrow surface walking r(2) = 0.31, p balance tasks. Practical implications for assessment and training are discussed.

The acoustic reflex threshold in aging ears.

Science.gov (United States)

Silverman, C A; Silman, S; Miller, M H

1983-01-01

This study investigates the controversy regarding the influence of age on the acoustic reflex threshold for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators between Jerger et al. [Mono. Contemp. Audiol. 1 (1978)] and Jerger [J. Acoust. Soc. Am. 66 (1979)] on the one hand and Silman [J. Acoust. Soc. Am. 66 (1979)] and others on the other. The acoustic reflex thresholds for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators were evaluated under two measurement conditions. Seventy-two normal-hearing ears were drawn from 72 subjects ranging in age from 20-69 years. The results revealed that age was correlated with the acoustic reflex threshold for BBN activator but not for any of the tonal activators; the correlation was stronger under the 1-dB than under the 5-dB measurement condition. Also, the mean acoustic reflex thresholds for broadband noise activator were essentially similar to those reported by Jerger et al. (1978) but differed from those obtained in this study under the 1-dB measurement condition.

Soleus and lateral gastrocnemius H-reflexes during standing with unstable footwear.

Science.gov (United States)

Friesenbichler, Bernd; Lepers, Romuald; Maffiuletti, Nicola A

2015-05-01

Unstable footwear has been shown to increase lower extremity muscle activity, but the reflex response to perturbations induced by this intervention is unknown. Twenty healthy subjects stood in stable and unstable footwear conditions (presented randomly) while H-reflex amplitude and background muscle activity were measured in the soleus and lateral gastrocnemius (LG) muscles. Wearing unstable footwear resulted in larger H-reflexes (normalized to the maximal M-wave) for the LG (+12%; P = 0.025), but not for the soleus (+4%; P > 0.05). Background activity of both muscles was significantly higher in the unstable condition. The H-reflex facilitation observed with unstable footwear was unexpected, as challenging postural conditions usually result in reflex depression. Increased muscle activity, decreased presynaptic inhibition, and/or more forward postural position may have (over-)compensated the expected reflex depression. Differences between LG and soleus H-reflex modulation may be due to diverging motor unit recruitment thresholds. © 2015 Wiley Periodicals, Inc.

A simple measurement hammer for quantitative reflex studies

NARCIS (Netherlands)

Stam, J.; van Leeuwen, J. R.

1984-01-01

A reflex hammer for measurement of the mechanical stimulus strength was designed. Combined with standard EMG equipment this instrument permits the study of both stimulus-response relations and latencies of myotatic reflexes. Some results in normal subjects are discussed

Determinants of sport-specific postural control strategy and balance performance of amateur rugby players.

Science.gov (United States)

Chow, Gary C C; Fong, Shirley S M; Chung, Joanne W Y; Chung, Louisa M Y; Ma, Ada W W; Macfarlane, Duncan J

2016-11-01

Postural control strategy and balance performance of rugby players are important yet under-examined issues. This study aimed to examine the differences in balance strategy and balance performance between amateur rugby players and non-players, and to explore training- and injury-related factors that may affect rugby players' balance outcomes. Cross-sectional and exploratory study. Forty-five amateur rugby players and 41 healthy active individuals participated in the study. Balance performance and balance strategies were assessed using the sensory organization test (SOT) of the Smart Equitest computerized dynamic posturography machine. Rugby training history and injury history were solicited from the participants. The SOT strategy scores were 1.99-54.90% lower in the rugby group than in the control group (prugby group than in the control group (prugby training (in years) was independently associated with the SOT condition 6 strategy score, explaining 15.7% of its variance (p=0.006). There was no association between SOT condition 6 strategy/equilibrium scores and injury history among the rugby players (p>0.05). Amateur rugby players demonstrated inferior balance strategy and balance performance compared to their non-training counterparts. Their suboptimal balance strategy was associated with insufficient training experience but not with history of injury. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Postural control and functional balance in individuals with diabetic peripheral neuropathy

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Ana Claudia de Souza Fortaleza

2013-04-01

Full Text Available Diabetic Peripheral Neuropathy (DPN brings on reduced somatosensation, which can lead to changes in postural control. The objective of this study was to evaluate postural control in a standing position and in different conditions, as well as functional balance in individuals with DPN, make the correlation between the results obtained from the postural control assessment with the values from the functional balance test and compare the results obtained in the neuropathy group with those of the control group, checking for possible differences between the evaluation conditions of both groups. The study included 13 women with DPN (NG and 17 non-diabetic women (CG. Postural control assessment was performed by kinemetry in the following conditions: eyes opened (EO, eyes closed (EC, and semi-tandem (ST. The data was processed in MATLAB and the following variables were generated: mean amplitude of oscillation (MAO in the anterior-posterior (AP and medial-lateral (ML direction; and average speed of oscillation (ASO in AP and ML direction. Functional balance was assessed by the Timed Up and Go Test. There was significant difference between the groups (p≤0.005 in MAO-AP EO and EC, MAO-ML EC and ST, and ASO-ML ST. There were differences between the conditions EO and ST (p≤0.005 and EC and ST (p≤0.005 for the variables MAO-ML and ASO-ML with greater damage to the NG, which also had a lower functional balance (p=0.001. ML instability was positively correlated with functional imbalance. The results show a change in the postural control system in the DPN, which could lead these individuals to a higher risk for falls and functional impairment.

Reflexive fatherhood in everyday life

DEFF Research Database (Denmark)

Westerling, Allan

2015-01-01

This article looks at fathering practices in Denmark, using the findings from a research project on everyday family life in Denmark. It takes a social psychological perspective and employs discursive psychology and theories about reflexive modernisation. It shows how fathers orient towards intimacy...... in their relationships with their children. Moreover, it discusses how fathers’ relatedness reflects individualisation and detraditionalisation. It is argued that reflexive modernisation entails subjective orientations that enable novel pathways to intimacy in contemporary father–child relationships. Through...... this analysis and discussion, the article offers a way to understand the complexities of fathering in everyday life from the perspective of fathers....

Selection of material balance areas and item control areas

International Nuclear Information System (INIS)

1975-04-01

Section 70.58, ''Fundamental Nuclear Material Controls,'' of 10 CFR Part 70, ''Special Nuclear Material,'' requires certain licensees authorized to possess more than one effective kilogram of special nuclear material to establish Material Balance Areas (MBAs) or Item Control Areas (ICAs) for the physical and administrative control of nuclear materials. This section requires that: (1) each MBA be an identifiable physical area such that the quantity of nuclear material being moved into or out of the MBA is represented by a measured value; (2) the number of MBAs be sufficient to localize nuclear material losses or thefts and identify the mechanisms; (3) the custody of all nuclear material within an MBA or ICA be the responsibility of a single designated individual; and (4) ICAs be established according to the same criteria as MBAs except that control into and out of such areas would be by item identity and count for previously determined special nuclear material quantities, the validity of which must be ensured by tamper-safing unless the items are sealed sources. This guide describes bases acceptable to the NRC staff for the selection of material balance areas and item control areas. (U.S.)

Buriti oil (Mauritia flexuosa L.) negatively impacts somatic growth and reflex maturation and increases retinol deposition in young rats.

Science.gov (United States)

Medeiros, Maria C; Aquino, Jailane S; Soares, Juliana; Figueiroa, Edigleide B; Mesquita, Hanni M; Pessoa, Debora C; Stamford, Tania M

2015-11-01

Buriti oil contains nutrients such as essential fatty acids and vitamins, which are directly involved with neonates' development. However, the refining process of this oil can change its nutrient profile. This study investigated the effects of maternal consumption of Buriti oil (crude or refined), on reflex and somatic development and retinol levels in neonatal rats. Thirty-six Wistar male neonate rats born from mothers who consumed diet with 7% lipids during gestation and lactation were used. Rats were randomized into three groups: rats receiving diet added of soybean oil (control-CG), crude Buriti oil (CB) and refined Buriti oil (RB). Offspring weight, tail length, reflex ontogeny and somatic maturation were assessed during lactation. At the end of the experiment, serum and liver retinol concentrations were measured. Animals from CB and RB groups showed delayed onset of palm grasp, righting reflex and cliff avoidance reflexes compared to the control group (CG). However, animals from RB group showed anticipation of auditory startle compared to those from BC group. Regarding somatic maturation indicators, animals from RB group showed delayed eye opening and eruption of superior and inferior incisors in relation to control and anticipation in the auditory conduit opening in relation to CB group. Rats from CB and RB groups showed higher serum and liver vitamin A contents. Buriti oil delays physical parameters and reflex maturation and increases serum and liver retinol deposition among neonatal rats. Copyright © 2015. Published by Elsevier Ltd.

Reflexive intergroup bias in third-party punishment.

Science.gov (United States)

Yudkin, Daniel A; Rothmund, Tobias; Twardawski, Mathias; Thalla, Natasha; Van Bavel, Jay J

2016-11-01

Humans show a rare tendency to punish norm-violators who have not harmed them directly-a behavior known as third-party punishment. Research has found that third-party punishment is subject to intergroup bias, whereby people punish members of the out-group more severely than the in-group. Although the prevalence of this behavior is well-documented, the psychological processes underlying it remain largely unexplored. Some work suggests that it stems from people's inherent predisposition to form alliances with in-group members and aggress against out-group members. This implies that people will show reflexive intergroup bias in third-party punishment, favoring in-group over out-group members especially when their capacity for deliberation is impaired. Here we test this hypothesis directly, examining whether intergroup bias in third-party punishment emerges from reflexive, as opposed to deliberative, components of moral cognition. In 3 experiments, utilizing a simulated economic game, we varied participants' group relationship to a transgressor, measured or manipulated the extent to which they relied on reflexive or deliberative judgment, and observed people's punishment decisions. Across group-membership manipulations (American football teams, nationalities, and baseball teams) and 2 assessments of reflexive judgment (response time and cognitive load), reflexive judgment heightened intergroup bias, suggesting that such bias in punishment is inherent to human moral cognition. We discuss the implications of these studies for theories of punishment, cooperation, social behavior, and legal practice. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Thermal Storage Power Balancing with Model Predictive Control

DEFF Research Database (Denmark)

Halvgaard, Rasmus; Poulsen, Niels Kjølstad; Madsen, Henrik

2013-01-01

The method described in this paper balances power production and consumption with a large number of thermal loads. Linear controllers are used for the loads to track a temperature set point, while Model Predictive Control (MPC) and model estimation of the load behavior are used for coordination....... The total power consumption of all loads is controlled indirectly through a real-time price. The MPC incorporates forecasts of the power production and disturbances that influence the loads, e.g. time-varying weather forecasts, in order to react ahead of time. A simulation scenario demonstrates...

The Effects of Uniquely-Processed Titanium on Balance and Walking Performance in Healthy Older Adults

Directory of Open Access Journals (Sweden)

Melissa J. Black

2018-06-01

Full Text Available The increased risk of falls associated with advancing age has increased demand for methods to improve balance and mobility. The primary purpose of the study was to determine whether wearing Aqua Titan-treated stockings could improve balance and walking performance in an older population; secondary was to elucidate the mechanisms. In a randomized, double-blind crossover, 16 healthy older adults (age, 67.9 ± 4.2 years; BMI, 24.8 ± 3.1 kg/m2 performed two 4-day trials composed of baseline measures and fatiguing exercise on Day 1, with recovery measures at 14, 38 and 62 h post-exercise, wearing Aqua Titan and control stockings. Balance, walking performance, triceps surae stretch reflex, ankle range of motion and gastrocnemius muscle microvascular perfusion, blood flow and oxygen consumption were measured at baseline and during recovery. Aqua Titan had no effect on the microvascular parameters, but increased total ankle range of motion at 38 h (2.4°; 95% CI ± 1.8° and 62 h (2.7°; ±1.7°, contributed to by increases in dorsiflexion and plantar flexion. There was decreasing persistence in the medial-lateral center of pressure movement at 38 h (q = 0, −0.0635 ± 0.0455, compared to control stockings. Aqua Titan garments hold potential for improving balance and mobility in older adults in the days following a bout of fatiguing exercise. The proposed mechanisms associated with enhanced sensory feedback require further exploration.

Snout and Visual Rooting Reflexes in Infantile Autism. Brief Report.

Science.gov (United States)

Minderaa, Ruud B.; And Others

1985-01-01

The authors conducted extensive neurological evaluations of 42 autistic individuals and were surprised to discover a consistently positive snout reflex in most of them. Difficulties with assessing the reflex are noted. The authors then reassessed the Ss for a series of primitive reflexes which are interpreted as signs of diffuse cortical brain…

The influence of reflexive educational environment on students ...

African Journals Online (AJOL)

The influence of reflexive educational environment on students' reflection development in ... based on them) from which, as they integrate, a reflexive personality style is developed. ... (narrative, dialogical, cognitive and axiological) are the factors influencing the outcome of social adaptation. ... AJOL African Journals Online.

[The influence of metabolic disturbances present in diabetes mellitus type I on vestibulo-spinal reflexes in children and young adults].

Science.gov (United States)

Gawron, Wojciech; Pośpiech, Lucyna; Orendorz-Fraczkowska, Krystyna; Noczyńska, Anna

2002-01-01

Diabetic neuropathy encompasses various disturbances concerning somatic and autonomic nervous system and has significant impact on prognosis and course of diabetes mellitus. The aim of the work is an evaluation of vestibulo-spinal reflexes in children and young adults suffering from diabetes mellitus type 1. Material--95 children and young adults aged from 6 to 28 years with diabetes mellitus type 1 diagnosed. The control group consisted of 44 otoneurologically healthy subjects aged from 6 to 28 years. After detailed medical history collection and physical ENT examination stato-posturography was performed in each case. Posturographer PE 62 Model 04 was applied in the studies. Static posturography as well as dynamic one (one leg standing test) was performed in each case. 6 patients belonging to diabetic group complained about vertigo or dizziness. There were worse stabilograms parameters in diabetic group in comparison to control one, statistically significant in younger children. There were better stabilogram parameters in diabetic patients with longer history of the disease. The parameters analysed were significantly worse in the subgroup with not compensated diabetes. The parameters were slightly better in relation to the presence of hypoglycaemic incidents. No apparent differences in stabilograms parameters were present in relation to the presence of diabetic complications. Diabetes mellitus type 1 with slight or without complications does not have significant influence on vestibulo-spinal reflexes and posture stability of the patients. Balance organ disturbances in diabetes mellitus type 1 in children and young adults despite their presence have subclinical course. Perhaps one should consider monitoring of those disturbances in the course of the disease.

Understanding balance differences in individuals with multiple sclerosis with mild disability: An investigation of differences in sensory feedback on postural and dynamic balance control

Science.gov (United States)

Denomme, Luke T.

Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS) and causes a broad range of neurological symptoms. One of the most common symptoms experienced by individuals with MS is poor balance control during standing and walking. The main mechanism underlying impaired balance control in MS appears to result from slowed somatosensory conduction and impaired central integration. The current thesis assessed postural and dynamic control of balance of 'individuals with MS with mild disability' (IwMS). IwMS were compared to 'healthy age-matched individuals' (HAMI) and community-dwelling 'older adults' (OA). The purpose of this thesis was to quantify differences in postural and dynamic control of balance in IwMS to the two populations who display balance control differences across the lifespan and represent two extreme ends of the balance control continuum due to natural aging. IwMS (n = 12, x¯age: 44 +/- 9.4 years), HAMI (n = 12, x¯age: 45 +/- 9.9 years) and community-dwelling OA (n = 12, x¯ age: 68.1 +/- 4.5 years) postural and dynamic balance control were evaluated during a Romberg task as well as a dynamic steering task. The Romberg task required participants to stand with their feet together and hands by their sides for 45 seconds with either their eyes open or closed. The dynamic steering task required participants to walk and change direction along the M-L plane towards a visual goal. Results from these two tasks reveal that IwMS display differences in postural control when compared to HAMI when vision was removed as well as differences in dynamic stability margin during steering situations. During the postural control task IwMS displayed faster A-P and M-L COP velocities when vision was removed and their COP position was closer to their self-selected maximum stability limits compared to HAMI. Assessment of dynamic stability during the steering task revealed that IwMS displayed reduced walking speed and cadence during the

Balancing Training Techniques for Flight Controller Certification

Science.gov (United States)

Gosling, Christina

2011-01-01

Training of ground control teams has been a difficult task in space operations. There are several intangible skills that must be learned to become the steely eyed men and women of mission control who respond to spacecraft failures that can lead to loss of vehicle or crew if handled improperly. And as difficult as training is, it can also be costly. Every day, month or year an operator is in training, is a day that not only they are being trained without direct benefit to the organization, but potentially an instructor or mentor is also being paid for hours spent assisting them. Therefore, optimization of the training flow is highly desired. Recently the Expedition Division (DI) at Johnson Space Flight Center has recreated their training flows for the purpose of both moving to an operator/specialist/instructor hierarchy and to address past inefficiencies in the training flow. This paper will discuss the types of training DI is utilizing in their new flows, and the balance that has been struck between the ideal learning environments and realistic constraints. Specifically, the past training flow for the ISS Attitude Determination and Control Officer will be presented, including drawbacks that were encountered. Then the new training flow will be discussed and how a new approach utilizes more training methods and teaching techniques. We will look at how DI has integrated classes, workshops, checkouts, module reviews, scenarios, OJT, paper sims, Mini Sims, and finally Integrated Sims to balance the cost and timing of training a new flight controller.

Do measures of reactive balance control predict falls in people with stroke returning to the community?

Science.gov (United States)

Mansfield, A; Wong, J S; McIlroy, W E; Biasin, L; Brunton, K; Bayley, M; Inness, E L

2015-12-01

To determine if reactive balance control measures predict falls after discharge from stroke rehabilitation. Prospective cohort study. Rehabilitation hospital and community. Independently ambulatory individuals with stroke who were discharged home after inpatient rehabilitation (n=95). Balance and gait measures were obtained from a clinical assessment at discharge from inpatient stroke rehabilitation. Measures of reactive balance control were obtained: (1) during quiet standing; (2) when walking; and (3) in response to large postural perturbations. Participants reported falls and activity levels up to 6 months post-discharge. Logistic and Poisson regressions were used to identify measures of reactive balance control that were related to falls post-discharge. Decreased paretic limb contribution to standing balance control [rate ratio 0.8, 95% confidence interval (CI) 0.7 to 1.0; P=0.011], reduced between-limb synchronisation of quiet standing balance control (rate ratio 0.9, 95% CI 0.8 to 0.9; Pfall rates when controlling for age, stroke severity, functional balance and daily walking activity. Impaired reactive balance control in standing and walking predicted increased risk of falls post-discharge from stroke rehabilitation. Specifically, measures that revealed the capacity of both limbs to respond to instability were related to increased risk of falls. These results suggest that post-stroke rehabilitation strategies for falls prevention should train responses to instability, and focus on remediating dyscontrol in the more-affected limb. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

A balance of activity in brain control and reward systems predicts self-regulatory outcomes.

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Lopez, Richard B; Chen, Pin-Hao A; Huckins, Jeremy F; Hofmann, Wilhelm; Kelley, William M; Heatherton, Todd F

2017-05-01

Previous neuroimaging work has shown that increased reward-related activity following exposure to food cues is predictive of self-control failure. The balance model suggests that self-regulation failures result from an imbalance in reward and executive control mechanisms. However, an open question is whether the relative balance of activity in brain systems associated with executive control (vs reward) supports self-regulatory outcomes when people encounter tempting cues in daily life. Sixty-nine chronic dieters, a population known for frequent lapses in self-control, completed a food cue-reactivity task during an fMRI scanning session, followed by a weeklong sampling of daily eating behaviors via ecological momentary assessment. We related participants' food cue activity in brain systems associated with executive control and reward to real-world eating patterns. Specifically, a balance score representing the amount of activity in brain regions associated with self-regulatory control, relative to automatic reward-related activity, predicted dieters' control over their eating behavior during the following week. This balance measure may reflect individual self-control capacity and be useful for examining self-regulation success in other domains and populations. © The Author (2017). Published by Oxford University Press.

Load Dependency of Postural Control--Kinematic and Neuromuscular Changes in Response to over and under Load Conditions.

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Ritzmann, Ramona; Freyler, Kathrin; Weltin, Elmar; Krause, Anne; Gollhofer, Albert

2015-01-01

Load variation is associated with changes in joint torque and compensatory reflex activation and thus, has a considerable impact on balance control. Previous studies dealing with over (OL) and under loading (UL) used water buoyancy or additional weight with the side effects of increased friction and inertia, resulting in substantially modified test paradigms. The purpose of this study was to identify gravity-induced load dependency of postural control in comparable experimental conditions and to determine the underlying neuromuscular mechanisms. Balance performance was recorded under normal loading (NL, 1 g), UL (0.16 g 0.38 g) and OL (1.8 g) in monopedal stance. Center of pressure (COP) displacement and frequency distribution (low 0.15-0.5 Hz (LF), medium 0.5-2 Hz (MF), high 2-6 Hz (HF)) as well as ankle, knee and hip joint kinematics were assessed. Soleus spinal excitability was determined by H/M-recruitment curves (H/M-ratios). Compared to NL, OL caused an increase in ankle joint excursion, COP HF domain and H/M-ratio. Concomitantly, hip joint excursion and COP LF decreased. Compared to NL, UL caused modulations in the opposite direction: UL decreased ankle joint excursions, COP HF and H/M-ratio. Collaterally, hip joint excursion and COP LF increased. COP was augmented both in UL and in OL compared to NL. Subjects achieved postural stability in OL and UL with greater difficulty compared to NL. Reduced postural control was accompanied by modified balance strategies and compensatory reflex activation. With increasing load, a shift from hip to ankle strategy was observed. Accompanying, COP frequency distribution shifted from LF to HF and spinal excitability was enhanced. It is suggested that in OL, augmented ankle joint torques are compensated by quick reflex-induced postural reactions in distal muscles. Contrarily, UL is associated with diminished joint torques and thus, postural equilibrium may be controlled by the proximal segments to adjust the center of

Load Dependency of Postural Control - Kinematic and Neuromuscular Changes in Response to over and under Load Conditions

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Ritzmann, Ramona; Freyler, Kathrin; Weltin, Elmar; Krause, Anne; Gollhofer, Albert

2015-01-01

Introduction Load variation is associated with changes in joint torque and compensatory reflex activation and thus, has a considerable impact on balance control. Previous studies dealing with over (OL) and under loading (UL) used water buoyancy or additional weight with the side effects of increased friction and inertia, resulting in substantially modified test paradigms. The purpose of this study was to identify gravity-induced load dependency of postural control in comparable experimental conditions and to determine the underlying neuromuscular mechanisms. Methods Balance performance was recorded under normal loading (NL, 1g), UL (0.16g; 0.38g) and OL (1.8g) in monopedal stance. Center of pressure (COP) displacement and frequency distribution (low 0.15-0.5Hz (LF), medium 0.5-2Hz (MF), high 2-6Hz (HF)) as well as ankle, knee and hip joint kinematics were assessed. Soleus spinal excitability was determined by H/M-recruitment curves (H/M-ratios). Results Compared to NL, OL caused an increase in ankle joint excursion, COP HF domain and H/M-ratio. Concomitantly, hip joint excursion and COP LF decreased. Compared to NL, UL caused modulations in the opposite direction: UL decreased ankle joint excursions, COP HF and H/M-ratio. Collaterally, hip joint excursion and COP LF increased. COP was augmented both in UL and in OL compared to NL. Conclusion Subjects achieved postural stability in OL and UL with greater difficulty compared to NL. Reduced postural control was accompanied by modified balance strategies and compensatory reflex activation. With increasing load, a shift from hip to ankle strategy was observed. Accompanying, COP frequency distribution shifted from LF to HF and spinal excitability was enhanced. It is suggested that in OL, augmented ankle joint torques are compensated by quick reflex-induced postural reactions in distal muscles. Contrarily, UL is associated with diminished joint torques and thus, postural equilibrium may be controlled by the proximal

Load Dependency of Postural Control--Kinematic and Neuromuscular Changes in Response to over and under Load Conditions.

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Ramona Ritzmann

Full Text Available Load variation is associated with changes in joint torque and compensatory reflex activation and thus, has a considerable impact on balance control. Previous studies dealing with over (OL and under loading (UL used water buoyancy or additional weight with the side effects of increased friction and inertia, resulting in substantially modified test paradigms. The purpose of this study was to identify gravity-induced load dependency of postural control in comparable experimental conditions and to determine the underlying neuromuscular mechanisms.Balance performance was recorded under normal loading (NL, 1 g, UL (0.16 g 0.38 g and OL (1.8 g in monopedal stance. Center of pressure (COP displacement and frequency distribution (low 0.15-0.5 Hz (LF, medium 0.5-2 Hz (MF, high 2-6 Hz (HF as well as ankle, knee and hip joint kinematics were assessed. Soleus spinal excitability was determined by H/M-recruitment curves (H/M-ratios.Compared to NL, OL caused an increase in ankle joint excursion, COP HF domain and H/M-ratio. Concomitantly, hip joint excursion and COP LF decreased. Compared to NL, UL caused modulations in the opposite direction: UL decreased ankle joint excursions, COP HF and H/M-ratio. Collaterally, hip joint excursion and COP LF increased. COP was augmented both in UL and in OL compared to NL.Subjects achieved postural stability in OL and UL with greater difficulty compared to NL. Reduced postural control was accompanied by modified balance strategies and compensatory reflex activation. With increasing load, a shift from hip to ankle strategy was observed. Accompanying, COP frequency distribution shifted from LF to HF and spinal excitability was enhanced. It is suggested that in OL, augmented ankle joint torques are compensated by quick reflex-induced postural reactions in distal muscles. Contrarily, UL is associated with diminished joint torques and thus, postural equilibrium may be controlled by the proximal segments to adjust the center of

Effectiveness of treadmill training on balance control in elderly people: a randomized controlled clinical trial.

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Pirouzi, Soraya; Motealleh, Ali Reza; Fallahzadeh, Fatemeh; Fallahzadeh, Mohammad Amin

2014-11-01

Physical exercise would improve postural stability, which is an essential factor in preventing accidental fall among the elderly population. The aim of this study is to examine the effectiveness of treadmill walking on balance improvement among the elderly people. A total of 30 community dwelling older adults with a Berg Balance Scale score of 36-48 and the ability to walk without aid were considered and divided into control (n=15) and experimental (n=15) groups. Individuals in the experimental group participated in 30 minutes of forward and backward treadmill training based on three times a week interval for a period of four weeks. Individuals in the control group were instructed to continue with their daily routine activity. Before and after training, gait speed was measured by six-minute walk test and balance ability was evaluated by Fullerton Advanced Balance Scale (FABS) and Berg Balance Scale (BBS) tests. Postural sway items such as the Center of Pressure (COP), average displacement and velocity were evaluated by using a force platform system. Data were collected in quiet standing, tandem position and standing on foam pads before and after intervention. After intervention, balance variables in the experimental group indicated a significant improvement in quiet standing on firm and foam surfaces, but no considerable improvement was shown in tandem position. A between-group comparison showed a significant reduction in COP velocity in the sagittal plane (P=0.030) during quiet standing and in the frontal plane (P=0.001) during standing on foam, whereas no significant reduction in COP parameters during tandem position was found. It is recommended that twelve sessions of forward and backward treadmill walk are effective in balance improvement in elderly people. IRCT201209199440N2.

Effectiveness of Treadmill Training on Balance Control in Elderly People: A Randomized Controlled Clinical Trial

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Soraya Pirouzi

2014-11-01

Full Text Available Physical exercise would improve postural stability, which is an essential factor in preventing accidental fall among the elderly population. The aim of this study is to examine the effectiveness of treadmill walking on balance improvement among the elderly people. A total of 30 community dwelling older adults with a Berg Balance Scale score of 36-48 and the ability to walk without aid were considered and divided into control (n=15 and experimental (n=15 groups. Individuals in the experimental group participated in 30 minutes of forward and backward treadmill training based on three times a week interval for a period of four weeks. Individuals in the control group were instructed to continue with their daily routine activity. Before and after training, gait speed was measured by six-minute walk test and balance ability was evaluated by Fullerton Advanced Balance Scale (FABS and Berg Balance Scale (BBS tests. Postural sway items such as the Center of Pressure (COP, average displacement and velocity were evaluated by using a force platform system. Data were collected in quiet standing, tandem position and standing on foam pads before and after intervention. After intervention, balance variables in the experimental group indicated a significant improvement in quiet standing on firm and foam surfaces, but no considerable improvement was shown in tandem position. A between-group comparison showed a significant reduction in COP velocity in the sagittal plane (P=0.030 during quiet standing and in the frontal plane (P=0.001 during standing on foam, whereas no significant reduction in COP parameters during tandem position was found. It is recommended that twelve sessions of forward and backward treadmill walk are effective in balance improvement in elderly people. Trial Registration Number: IRCT201209199440N2

Blind Evaluation of Body Reflexes and Motor Skills in Learning Disability.

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Freides, David; And Others

1980-01-01

Twelve 6 to 10 year old boys with learning disability were blindly compared with paired controls on measures of postural and equilibrium reflexes as well as skills. Learning disabled children as a group showed significant deficits on all measures; a few, however, were totally without deficit. (Author/SBH)

Improvements in balance control in individuals with PCS detected following vestibular training: A case study.

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Prangley, Alyssa; Aggerholm, Mathew; Cinelli, Michael

2017-10-01

Concussed individuals have been found to experience balance deficits in the anterior-posterior (AP) direction as indicated by greater Center of Pressure (COP) displacement and velocity. One possible reason for this change in balance control could be due to damage to the lateral vestibulospinal tract which sends signals to control posterior muscles, specifically ankle extensors leading to compensatory torques about the ankle. The purpose of the study was to quantify balance assessments in individuals experiencing persistent post-concussion symptoms (PCS) to determine balance control changes following a vestibular training intervention. Participants (N=6,>26days symptomatic), were tested during their first appointment with a registered physiotherapist (PT) and during each follow up appointment. Participants were prescribed balance, visual, and neck strengthening exercises by the PT that were to be completed daily between bi-weekly appointments. Balance assessments were quantified using a Nintendo Wii board to record ground reaction forces. Participants completed 4 balance assessments: 1) Romberg stance eyes open (REO); 2) Romberg stance eyes closed (REC); 3) single leg stance eyes open (SEO); and 4) single leg stance eyes closed (SEC). The balance assessments were conducted on both a firm and compliant surfaces. Significant improvements in balance control were noted in ML/AP displacement and velocity of COP for both SEC and Foam REC conditions, with additional improvements in AP velocity of COP for Foam REC and in ML displacement of COP during Foam SEC. Overall, findings indicate that objectively quantifying balance changes for individuals experiencing persistent PCS allows for a more sensitive measure of balance and detects changes unrecognizable to the naked eye. Copyright © 2017 Elsevier B.V. All rights reserved.

[Human physiology: images and practices of the reflex].

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Wübben, Yvonne

2010-01-01

The essay examines the function of visualizations and practices in the formation of the reflex concept from Thomas Willis to Marshall Hall. It focuses on the specific form of reflex knowledge that images and practices can contain. In addition, the essay argues that it is through visual representations and experimental practices that technical knowledge is transferred to the field of human reflex physiology. When using technical metaphors in human physiology authors often seem to feel obliged to draw distinctions between humans, machines and animals. On closer scrutiny, these distinctions sometimes fail to establish firm borders between the human and the technical.

Reversal of reflex pulmonary vasoconstriction induced by main pulmonary arterial distension.

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Juratsch, C E; Grover, R F; Rose, C E; Reeves, J T; Walby, W F; Laks, M M

1985-04-01

Distension of the main pulmonary artery (MPA) induces pulmonary hypertension, most probably by neurogenic reflex pulmonary vasoconstriction, although constriction of the pulmonary vessels has not actually been demonstrated. In previous studies in dogs with increased pulmonary vascular resistance produced by airway hypoxia, exogenous arachidonic acid has led to the production of pulmonary vasodilator prostaglandins. Hence, in the present study, we investigated the effect of arachidonic acid in seven intact anesthetized dogs after pulmonary vascular resistance was increased by MPA distention. After steady-state pulmonary hypertension was established, arachidonic acid (1.0 mg/min) was infused into the right ventricle for 16 min; 15-20 min later a 16-mg bolus of arachidonic acid was injected. MPA distension was maintained throughout the study. Although the infusion of arachidonic acid significantly lowered the elevated pulmonary vascular resistance induced by MPA distension, the pulmonary vascular resistance returned to control levels only after the bolus injection of arachidonic acid. Notably, the bolus injection caused a biphasic response which first increased the pulmonary vascular resistance transiently before lowering it to control levels. In dogs with resting levels of pulmonary vascular resistance, administration of arachidonic acid in the same manner did not alter the pulmonary vascular resistance. It is concluded that MPA distension does indeed cause reflex pulmonary vasoconstriction which can be reversed by vasodilator metabolites of arachidonic acid. Even though this reflex may help maintain high pulmonary vascular resistance in the fetus, its function in the adult is obscure.

Nociceptive flexion reflexes during analgesic neurostimulation in man.

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García-Larrea, L; Sindou, M; Mauguière, F

1989-11-01

Nociceptive flexion reflexes of the lower limbs (RIII responses) have been studied in 21 patients undergoing either epidural (DCS, n = 16) or transcutaneous (TENS, n = 5) analgesic neurostimulation (AN) for chronic intractable pain. Flexion reflex RIII was depressed or suppressed by AN in 11 patients (52.4%), while no modification was observed in 9 cases and a paradoxical increase during AN was evidenced in 1 case. In all but 2 patients, RIII changes were rapidly reversible after AN interruption. RIII depression was significantly associated with subjective pain relief, as assessed by conventional self-rating; moreover, in 2 patients it was possible to ameliorate the pain-suppressing effects of AN by selecting those stimulation parameters (intensity and frequency) that maximally depressed nociceptive reflex RIII. We recorded 2 cases of RIII attenuation after contralateral neurostimulation. AN appeared to affect nociceptive reflexes rather selectively, with no or very little effect on other cutaneous, non-nociceptive responses. Recording of RIII reflexes is relatively simple to implement as a routine paraclinical procedure. It facilitates the objective assessment of AN efficacy and may help to choose the most appropriate parameters of neurostimulation. In addition, RIII behavior in patients could be relevant to the understanding of some of the mechanisms involved in AN-induced pain relief.

Postural control and functional balance in individuals with diabetic peripheral neuropathy

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Ana Claudia de Souza Fortaleza

2013-03-01

Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2013v15n3p305 Diabetic Peripheral Neuropathy (DPN brings on reduced somatosensation, which can lead to changes in postural control. The objective of this study was to evaluate postural control in a standing position and in different conditions, as well as functional balance in individuals with DPN, make the correlation between the results obtained from the postural control assessment with the values from the functional balance test and compare the results obtained in the neuropathy group with those of the control group, checking for possible differences between the evaluation conditions of both groups. The study included 13 women with DPN (NG and 17 non-diabetic women (CG. Postural control assessment was performed by kinemetry in the following conditions: eyes opened (EO, eyes closed (EC, and semi-tandem (ST. The data was processed in MATLAB and the following variables were generated: mean amplitude of oscillation (MAO in the anterior-posterior (AP and medial-lateral (ML direction; and average speed of oscillation (ASO in AP and ML direction. Functional balance was assessed by the Timed Up and Go Test. There was significant difference between the groups (p≤0.005 in MAO-AP EO and EC, MAO-ML EC and ST, and ASO-ML ST. There were differences between the conditions EO and ST (p≤0.005 and EC and ST (p≤0.005 for the variables MAO-ML and ASO-ML with greater damage to the NG, which also had a lower functional balance (p=0.001. ML instability was positively correlated with functional imbalance. The results show a change in the postural control system in the DPN, which could lead these individuals to a higher risk for falls and functional impairment.

Maternal intake of cashew nuts accelerates reflex maturation and facilitates memory in the offspring.

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de Melo, Marília Ferreira Frazão Tavares; Pereira, Diego Elias; Sousa, Morgana Moura; Medeiros, Dilian Maise Ferreira; Lemos, Leanderson Tulio Marques; Madruga, Marta Suely; Santos, Nayane Medeiros; de Oliveira, Maria Elieidy Gomes; de Menezes, Camila Carolina; Soares, Juliana Késsia Barbosa

2017-10-01

Essential fatty acids, being indispensable during the stages of pregnancy, lactation and infancy influence the transmission of nerve impulses and brain function, and cashew nuts are a good source of these fatty acids. The objective of this study was to evaluate the effects of cashew nut consumption on reflex development, memory and profile of fatty acids of rat offspring treated during pregnancy and lactation. The animals were divided into three groups: Control (CONT), treated with 7% lipid derived from soybean oil; Normolipidic (NL) treated with 7% lipids derived from cashew nuts; and Hyperlipidic (HL) treated with 20% lipids derived from cashew nuts. Reflex ontogeny, Open-field habituation test and the Object Recognition Test (ORT) were assessed. The profile of fatty acids in the brain was carried out when the animals were zero, 21 and 60days old. Accelerated reflex maturation was observed in animals treated with cashew nuts (pacids and less Docosahexaenoic acid (DHA) in animals of the HL. The data showed that maternal consumption of cashew nuts can accelerate reflex maturation and facilitate memory in offspring when offered in adequate quantities. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

Local vibration inhibits H-reflex but does not compromise manual dexterity and does not increase tremor.

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Budini, Francesco; Laudani, Luca; Bernardini, Sergio; Macaluso, Andrea

2017-10-01

The present work aimed at investigating the effects of local vibration on upper limb postural and kinetic tremor, on manual dexterity and on spinal reflex excitability. Previous studies have demonstrated a decrease in spinal reflex excitability and in force fluctuations in the lower limb but an increase in force fluctuation in the upper limbs. As hand steadiness is of vital importance in many daily-based tasks, and local vibration may also be applied in movement disorders, we decided to further explore this phenomenon. Ten healthy volunteers (26±3years) were tested for H reflex, postural and kinetic tremor and manual dexterity through a Purdue test. EMG was recorded from flexor carpi radialis (FCR) and extensor digitorum communis (EDC). Measurements were repeated at baseline, after a control period during which no vibration was delivered and after vibration. Intervention consisted in holding for two minutes a vibrating handle (frequency 75Hz, displacement∼7mm), control consisted in holding for two minutes the same handle powered off. Reflex excitability decreased after vibration whilst postural tremor and manual dexterity were not affected. Peak kinetic tremor frequency increased from baseline to control measurements (P=0.002). Co-activation EDC/FCR increased from control to vibration (P=0.021). These results show that two minutes local vibration lead to a decrease in spinal excitability, did not compromise manual dexterity and did not increase tremor; however, in contrast with expectations, tremor did not decrease. It is suggested that vibration activated several mechanisms with opposite effects, which resulted in a neutral outcome on postural and kinetic tremor. Copyright © 2017 Elsevier B.V. All rights reserved.

The Role of Clinical and Instrumented Outcome Measures in Balance Control of Individuals with Multiple Sclerosis

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Neeta Kanekar

2013-01-01

Full Text Available Purpose. The aim of the study was to investigate differences in balance control between individuals with multiple sclerosis (MS and healthy control subjects using clinical scales and instrumented measures of balance and determine relationships between balance measures, fatigue, and disability levels in individuals with MS with and without a history of falls. Method. Twelve individuals with MS and twelve healthy controls were evaluated using the Berg Balance and Activities-specific Balance Confidence Scales, Modified Clinical Test of Sensory Interaction on Balance, and Limits of Stability Tests as well as Fatigue Severity Scale and Barthel Index. Results. Mildly affected individuals with MS had significant balance performance deficits and poor balance confidence levels (P<0.05. MS group had higher sway velocities and diminished stability limits (P<0.05, significant sensory impairments, high fatigue and disability levels (P<0.05. Sway velocity was a significant predictor of balance performance and the ability to move towards stability limits for the MS group. For the MS-fallers group, those with lower disability levels had faster movement velocities and better balance performance. Conclusion. Implementation of both clinical and instrumented tests of balance is important for the planning and evaluation of treatment outcomes in balance rehabilitation of people with MS.

Falls prevention and balance rehabilitation in multiple sclerosis: a bi-centre randomised controlled trial.

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Cattaneo, Davide; Rasova, Kamila; Gervasoni, Elisa; Dobrovodská, Gabriela; Montesano, Angelo; Jonsdottir, Johanna

2018-03-01

People with Multiple Sclerosis (PwMS) have a high incidence of accidental falls that have a potentially detrimental effect on their daily life participation. The effect of balance specific rehabilitation on clinical balance measures and frequency of falls in PwMS was studied. A bi-centre randomised rater-blinded controlled trial. Participants in both groups received 20 treatment sessions. Participants in the intervention group received treatment aimed at improving balance and mobility. Participants in the control group received treatments to reduce limitations at activity and body function level. Primary measures were frequency of fallers (>1 fall in two months) and responders (>3 points improvement) at the Berg Balance Scale (BBS). Data was analysed according to an intention to treat approach. One hundred and nineteen participants were randomised. Following treatment frequency of fallers was 22% in the intervention group and 23% in the control group, odds ratio (OR) and (confidence limits): 1.05 (0.41 to 2.77). Responders on the BBS were 28% in the intervention group and 33% in the control group, OR = 0.75 (0.30 to 1.91). At follow up ORs for fallers and responders at BBS were 0.98 (0.48 to 2.01) and 0.79 (0.26 to 2.42), respectively. Twenty sessions 2-3 times/week of balance specific rehabilitation did not reduce fall frequency nor improve balance suggesting the need for more frequent and challenging interventions. Implications for Rehabilitation Programs for balance rehabilitation can improve balance but their effects in fall prevention are unclear. Twenty treatments sessions 2/3 times per week did not reduced frequency of falls in MS. The comparison with similar studies suggests that higher intensity of practice of highly challenging balance activities appears to be critical to maximizing effectiveness.

Reflex peripheral vasoconstriction is diminished in older men.

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Kenney, W L; Armstrong, C G

1996-02-01

The purpose of this study was to compare reflex control of limb blood flow in healthy young (Y; 26 +/- 2 yr) and older (O;61 +/- 2 yr) men during whole body cooling under resting conditions. To better isolate the effect of chronological age, the two age groups (n = 6 per group) were closely matched for maximal oxygen uptake, body surface area, skinfold thickness, and fat-free weight. Subjects sat in an environmentally controlled chamber clad in standardized (0.6-clo) light cotton clothing at a dry-bulb temperature (Tdb) of 28 degrees C. After 30 min, Tdb was decreased by 2 degrees C every 5 min until Tdb = 10 degrees C, where it was held constant for the remainder of the 120-min session. Esophageal and mean skin temperatures were monitored continuously. Forearm blood flow (FBF) was measured every 5 min by venous occlusion plethysmography by using a mercury-in-Silastic strain gauge while arm temperature between the wrist and elbow was clamped at 37.2 +/- 0.1 degrees C by localized warm air heating. In this way, limb vasoconstriction was driven solely by thermoregulatory reflexes and not by direct effects of localized cooling. Mean skin temperature decreased at a similar rate and to a similar extent (by approximately 6 degrees C over a 2-h period) in both age groups, whereas esophageal temperature was relatively unaffected. In response to the local heating, the Y group maintained a significantly higher FBF than did the O group during the initial 30 min but decreased FBF during the cooling phase at a greater rate and to a greater extent than did the O group, leading to a significantly lower FBF during the final 30 min (at Tdb = 10 degrees C). Because there was no age difference in the mean arterial pressure response, similar effects of age were seen on forearm vascular conductance (FBF/mean arterial pressure). It was concluded that older men have a diminished reflex limb vasoconstrictor response to skin cooling. Furthermore, this difference in control of peripheral

Long-term depression-like plasticity of the blink reflex for the treatment of blepharospasm.

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Kranz, Gottfried; Shamim, Ejaz A; Lin, Peter T; Kranz, George S; Hallett, Mark

2013-04-01

Our previous work showed a beneficial therapeutic effect on blepharospasm using slow repetitive transcranial magnetic stimulation, which produces a long-term depression (LTD)-like effect. High-frequency supraorbital electrical stimulation, asynchronous with the R2 component of the blink reflex, can also induce LTD-like effects on the blink reflex circuit in healthy subjects. Patients with blepharospasm have reduced inhibition of their blink recovery curves; therefore, a LTD-like intervention might normalize the blink reflex recovery (BRR) and have a favorable therapeutic effect. This is a randomized, sham-controlled, observer-blinded prospective study. In 14 blepharospasm patients, we evaluated the effects of high-frequency supraorbital stimulation on three separate treatment days. We applied 28 trains of nine stimuli, 400 Hz, either before or after the R2 or used sham stimulation. The primary outcome was the blink rate, number of spasms rated by a blinded physician and patient rating before, immediately after and 1 hour after stimulation while resting, reading, and talking; secondary outcome was the BRR. Stimulation "before" and "after" the R2 both showed a similar improvement as sham stimulation in physician rating, but patients felt significantly better with the before condition. Improvement in recovery of the blink reflex was noted only in the before condition. Clinical symptoms differed in the three baseline conditions (resting, reading, and talking). Stimulation before R2 increased inhibition in trigeminal blink reflex circuits in blepharospasm toward normal values and produced subjective, but not objective, improvement. Inhibition of the blink reflex pathway by itself appeared to be insufficient for a useful therapeutic effect. Copyright © 2013 Movement Disorder Society.

Ontogeny of mouse vestibulo-ocular reflex following genetic or environmental alteration of gravity sensing.

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Mathieu Beraneck

Full Text Available The vestibular organs consist of complementary sensors: the semicircular canals detect rotations while the otoliths detect linear accelerations, including the constant pull of gravity. Several fundamental questions remain on how the vestibular system would develop and/or adapt to prolonged changes in gravity such as during long-term space journey. How do vestibular reflexes develop if the appropriate assembly of otoliths and semi-circular canals is perturbed? The aim of present work was to evaluate the role of gravity sensing during ontogeny of the vestibular system. In otoconia-deficient mice (ied, gravity cannot be sensed and therefore maculo-ocular reflexes (MOR were absent. While canals-related reflexes were present, the ied deficit also led to the abnormal spatial tuning of the horizontal angular canal-related VOR. To identify putative otolith-related critical periods, normal C57Bl/6J mice were subjected to 2G hypergravity by chronic centrifugation during different periods of development or adulthood (Adult-HG and compared to non-centrifuged (control C57Bl/6J mice. Mice exposed to hypergravity during development had completely normal vestibulo-ocular reflexes 6 months after end of centrifugation. Adult-HG mice all displayed major abnormalities in maculo-ocular reflexe one month after return to normal gravity. During the next 5 months, adaptation to normal gravity occurred in half of the individuals. In summary, genetic suppression of gravity sensing indicated that otolith-related signals might be necessary to ensure proper functioning of canal-related vestibular reflexes. On the other hand, exposure to hypergravity during development was not sufficient to modify durably motor behaviour. Hence, 2G centrifugation during development revealed no otolith-specific critical period.

Simultaneous characterizations of reflex and nonreflex dynamic and static changes in spastic hemiparesis

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Chung, Sun G.; Ren, Yupeng; Liu, Lin; Roth, Elliot J.; Rymer, W. Zev

2013-01-01

This study characterizes tonic and phasic stretch reflex and stiffness and viscosity changes associated with spastic hemiparesis. Perturbations were applied to the ankle of 27 hemiparetic and 36 healthy subjects under relaxed or active contracting conditions. A nonlinear delay differential equation model characterized phasic and tonic stretch reflex gains, elastic stiffness, and viscous damping. Tendon reflex was characterized with reflex gain and threshold. Reflexively, tonic reflex gain was increased in spastic ankles at rest (P hemiparesis may help to evaluate and treat them more effectively. PMID:23636726

Sensory organisation and reactive balance control of amateur rugby players: A cross-sectional study.

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Chow, Gary C C; Chung, Joanne W Y; Ma, Ada W W; Macfarlane, Duncan J; Fong, Shirley S M

2017-05-01

This study compared the sensory organisation and reactive balance control of amateur rugby players and a control group. Forty-one amateur rugby players (22 males: 19 females; mean height ± SD = 168.8 ± 8.8 cm; mean weight ± SD = 63.9 ± 12.5 kg) and 31 control participants (22 males: 9 females; mean height ± SD = 171.5 ± 10.3 cm; mean weight ± SD = 63.8 ± 10.3 kg) completed the study. Their sensory organisation and standing balance performance were evaluated using a sensory organisation test (SOT), and their reactive balance performance was quantified using a motor control test (MCT). The SOT equilibrium scores (ES) and sensory ratios and the MCT motor response latencies were the major outcome measures. The results revealed that compared to the controls, amateur rugby players had lower SOT ESs under different sensory environments (P rugby group (P = .005, [Formula: see text] = 0.107 and 0.108, respectively). No significant difference was found in the somatosensory ratio (P = .853, [Formula: see text] rugby players demonstrated inferior standing balance performance compared to their non-trained counterparts. They relied less heavily on vestibular and visual inputs to maintain standing balance under different sensory environments. In addition, they reacted more slowly to postural disturbance, reflecting their suboptimal reactive balance ability in standing.

Balancing on a narrow ridge : biomechanics and control

NARCIS (Netherlands)

Otten, E.

1999-01-01

The balance of standing humans is usually explained by the inverted pendulum model. The subject invokes a horizontal ground-reaction force in this model and controls it by changing the location of the centre of pressure under the foot or feet. In experiments I showed that humans are able to stand on

Validation of a robotic balance system for investigations in the control of human standing balance.

Science.gov (United States)

Luu, Billy L; Huryn, Thomas P; Van der Loos, H F Machiel; Croft, Elizabeth A; Blouin, Jean-Sébastien

2011-08-01

Previous studies have shown that human body sway during standing approximates the mechanics of an inverted pendulum pivoted at the ankle joints. In this study, a robotic balance system incorporating a Stewart platform base was developed to provide a new technique to investigate the neural mechanisms involved in standing balance. The robotic system, programmed with the mechanics of an inverted pendulum, controlled the motion of the body in response to a change in applied ankle torque. The ability of the robotic system to replicate the load properties of standing was validated by comparing the load stiffness generated when subjects balanced their own body to the robot's mechanical load programmed with a low (concentrated-mass model) or high (distributed-mass model) inertia. The results show that static load stiffness was not significantly (p > 0.05) different for standing and the robotic system. Dynamic load stiffness for the robotic system increased with the frequency of sway, as predicted by the mechanics of an inverted pendulum, with the higher inertia being accurately matched to the load properties of the human body. This robotic balance system accurately replicated the physical model of standing and represents a useful tool to simulate the dynamics of a standing person. © 2011 IEEE

Correlation of augmented startle reflex with brainstem electrophysiological responses in Tay-Sachs disease.

Science.gov (United States)

Nakamura, Sadao; Saito, Yoshiaki; Ishiyama, Akihiko; Sugai, Kenji; Iso, Takashi; Inagaki, Masumi; Sasaki, Masayuki

2015-01-01

To clarify the evolution of an augmented startle reflex in Tay-Sachs disease and compare the temporal relationship between this reflex and brainstem evoked potentials. Clinical and electrophysiological data from 3 patients with Tay-Sachs disease were retrospectively collected. The augmented startle reflex appeared between the age of 3 and 17 months and disappeared between the age of 4 and 6 years. Analysis of brainstem auditory evoked potentials revealed that poor segregation of peak I, but not peak III, coincided with the disappearance of the augmented startle reflex. A blink reflex with markedly high amplitude was observed in a patient with an augmented startle reflex. The correlation between the augmented startle reflex and the preservation of peak I but not peak III supports the theory that the superior olivary nucleus is dispensable for this reflex. The blink reflex with high amplitudes may represent augmented excitability of reticular formation at the pontine tegmentum in Tay-Sachs disease, where the pattern generators for the augmented startle and blink reflexes may functionally overlap. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Balance and Gait Training With Augmented Feedback Improves Balance Confidence in People With Parkinson's Disease: A Randomized Controlled Trial.

Science.gov (United States)

Shen, Xia; Mak, Margaret K Y

2014-07-01

Background Fear of falling has been identified as an important and independent fall-risk predictor in patients with Parkinson's disease (PD). However, there are inconsistent findings on the effects of balance and gait training on balance confidence. Objective To explore whether balance and gait training with augmented feedback can enhance balance confidence in PD patients immediately after treatment and at 3- and 12-month follow-ups. Methods A total of 51 PD patients were randomly assigned to a balance and gait training (BAL) group or to an active control (CON) group. The BAL group received balance and gait training with augmented feedback, whereas CON participants received lower-limb strength training for 12 weeks. Outcome measures included Activities-Specific Balance Confidence (ABC) Scale, limits-of-stability test, single-leg-stance test, and spatiotemporal gait characteristics. All tests were administered before intervention (Pre), immediately after training (Post), and at 3 months (Post3m) and 12 months (Post12m) after treatment completion. Results The ABC score improved marginally at Post and significantly at Post3m and Post12m only in the BAL group (P point excursion at Post, but only the BAL group maintained the improvement at Post3m. The BAL group maintained significantly longer time-to-loss-of-balance during the single-leg stance test than the CON group at Post3m and Post12m (P balance confidence and balance and gait performance in patients with PD. © The Author(s) 2014.

Pain sensation and nociceptive reflex excitability in surgical patients and human volunteers

DEFF Research Database (Denmark)

Dahl, J B; Erichsen, C J; Fuglsang-Frederiksen, A

1992-01-01

Pain threshold, nociceptive flexion reflex (NFR) threshold and responses to suprathreshold stimulation were investigated in 15 female patients (mean age 32 yr (range 22-48 yr)) before and 68 (range 48-96) h after gynaecological laparotomy. Control measurements were performed in 17 healthy human v...

Analysis of balance control methods based on inverted pendulum for legged robots

OpenAIRE

Denisov, A.; Iakovlev, R.; Mamaev, I.; Pavliuk, N.

2017-01-01

Methods of balance control for a legged robot, the model of which is presented as a two-section inverted pendulum, are considered. The following balance methods for humanoid robots are analysed: the parallel algorithm of the network operator method; the method of natural synergies; the method of fuzzy control, the spherical inverted pendulum mode, a dual length linear inverted pendulum method. The best of these methods will be used in the development of the Russian anthropomorphic robot Antares.

The contribution of a central pattern generator in a reflex-based neuromuscular model

Science.gov (United States)

Dzeladini, Florin; van den Kieboom, Jesse; Ijspeert, Auke

2014-01-01

Although the concept of central pattern generators (CPGs) controlling locomotion in vertebrates is widely accepted, the presence of specialized CPGs in human locomotion is still a matter of debate. An interesting numerical model developed in the 90s’ demonstrated the important role CPGs could play in human locomotion, both in terms of stability against perturbations, and in terms of speed control. Recently, a reflex-based neuro-musculo-skeletal model has been proposed, showing a level of stability to perturbations similar to the previous model, without any CPG components. Although exhibiting striking similarities with human gaits, the lack of CPG makes the control of speed/step length in the model difficult. In this paper, we hypothesize that a CPG component will offer a meaningful way of controlling the locomotion speed. After introducing the CPG component in the reflex model, and taking advantage of the resulting properties, a simple model for gait modulation is presented. The results highlight the advantages of a CPG as feedforward component in terms of gait modulation. PMID:25018712

The Contribution of a Central Pattern Generator in a Reflex-Based Neuromuscular Model

Directory of Open Access Journals (Sweden)

Florin eDzeladini

2014-06-01

Full Text Available Although the concept of central pattern generators (CPGs controlling locomotion in vertebrates is widely accepted, the presence of specialized CPGs in human locomotion is still a matter of debate. An interesting numerical model developed in the 90s' demonstrated the important role CPGs could play in human locomotion, both in terms of stability against perturbations, and in terms of speed control. Recently, a reflex-based neuro-musculo-skeletal model has been proposed, showing a level of stability to perturbations similar to the previous model, without any CPG components. Although exhibiting striking similarities with human gaits, the lack of CPG makes the control of speed/step length in the model difficult. In this paper, we hypothesize that a CPG component will offer a meaningful way of controlling the locomotion speed. After introducing the CPG component in the reflex model, and taking advantage of the resulting properties, a simple model for gait modulation is presented.The results highlight the advantages that a feedforward component can have in terms of gait modulation.

Enhanced DC-Link Capacitor Voltage Balancing Control of DC–AC Multilevel Multileg Converters

DEFF Research Database (Denmark)

Busquets-Monge, Sergio; Maheshwari, Ram Krishan; Nicolas-Apruzzese, Joan

2015-01-01

This paper presents a capacitor voltage balancing control applicable to any multilevel dc–ac converter formed by a single set of series-connected capacitors implementing the dc link and semiconductor devices, such as the diode-clamped topology. The control is defined for any number of dc-link vol......This paper presents a capacitor voltage balancing control applicable to any multilevel dc–ac converter formed by a single set of series-connected capacitors implementing the dc link and semiconductor devices, such as the diode-clamped topology. The control is defined for any number of dc...

Student Mobility and Transnational Social Ties as Factors of Reflexivity

Directory of Open Access Journals (Sweden)

Tea Golob

2018-03-01

Full Text Available The article seeks to develop and apply new quantitative measurement instruments capable of significantly improving understanding of the relationship between the transnational mobility and transnational social ties of students, along with their reflexive capacities. With a focus on students building their personal networks, educational and professional activities that extend beyond the nation’s borders and organising their day-to-day routines in transnational social spaces, we analyse the role of mobility in their reflexive capacities. Applying a tool that is line with Archer’s theory and indicators to measure reflexivity, and transnational social ties as proposed by Molina et al., we analyse data collected via an on-line survey questionnaire administered to Slovenian students. In addition, students from the Middle East (Lebanon and the USA (Hawai’i are added for comparative purposes. The results of path analysis show the Slovenian students’ mobility as such implies higher scores for meta reflexivity, combined with lower scores for communicative and fractured reflexivity. Further, social transactions reaching beyond one’s physical localities in terms of transnational social ties implies they have higher levels of reflexivity in general.

Acute effects of high-frequency microfocal vibratory stimulation on the H reflex of the soleus muscle. A double-blind study in healthy subjects.

Science.gov (United States)

Alfonsi, Enrico; Paone, Paolo; Tassorelli, Cristina; De Icco, Roberto; Moglia, Arrigo; Alvisi, Elena; Marchetta, Lucky; Fresia, Mauro; Montini, Alessandra; Calabrese, Marzia; Versiglia, Vittorio; Sandrini, Giorgio

2015-01-01

This study in healthy subjects examined the effects of a system delivering focal microvibrations at high frequency (Equistasi®) on tonic vibration stimulus (TVS)-induced inhibition of the soleus muscle H reflex. Highfrequency microvibrations significantly increased the inhibitory effect of TVS on the H reflex for up to three minutes. Moreover, Equistasi® also significantly reduced alpha-motoneuron excitability, as indicated by the changes in the ratio between the maximumamplitude H reflex (Hmax reflex) and the maximumamplitude muscle response (Mmax response); this effect was due to reduction of the amplitude of the H reflex because the amplitude of muscle response remained unchanged. The present findings indicate that Equistasi® has a modulatory effect on proprioceptive reflex circuits. Therefore, Equistasi® might interfere with some mechanisms involved in both physiological and pathophysiological control of movement and of posture.

Effects of physical training on age-related balance and postural control.

Science.gov (United States)

Lelard, T; Ahmaidi, S

2015-11-01

In this paper, we review the effects of physical activity on balance performance in the elderly. The increase in the incidence of falls with age reflects the disorders of balance-related to aging. We are particularly interested in age-related changes in the balance control system as reflected in different static and dynamic balance tests. We report the results of studies demonstrating the beneficial effects of physical activity on postural balance. By comparing groups of practitioners of different physical activities, it appears that these effects on postural control depend on the type of activity and the time of practice. Thus, we have focused in the present review on "proprioceptive" and "strength" activities. Training programs offering a combination of several activities have demonstrated beneficial effects on the incidence of falls, and we present and compare the effects of these two types of training activities. It emerges that there are differential effects of programs of activities: while all activities improve participants' confidence in their ability, the "proprioceptive" activities rather improve performance in static tasks, while "strength" activities tend to improve performance in dynamic tasks. These effects depend on the targeted population and will have a greater impact on the frailest subjects. The use of new technologies in the form of "exergames" may also be proposed in home-based exercises. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Digital control of wind tunnel magnetic suspension and balance systems

Science.gov (United States)

Britcher, Colin P.; Goodyer, Michael J.; Eskins, Jonathan; Parker, David; Halford, Robert J.

1987-01-01

Digital controllers are being developed for wind tunnel magnetic suspension and balance systems, which in turn permit wind tunnel testing of aircraft models free from support interference. Hardware and software features of two existing digital control systems are reviewed. Some aspects of model position sensing and system calibration are also discussed.

Predictors of chronic ankle instability: Analysis of peroneal reaction time, dynamic balance and isokinetic strength.

Science.gov (United States)

Sierra-Guzmán, Rafael; Jiménez, Fernando; Abián-Vicén, Javier

2018-05-01

Previous studies have reported the factors contributing to chronic ankle instability, which could lead to more effective treatments. However, factors such as the reflex response and ankle muscle strength have not been taken into account in previous investigations. Fifty recreational athletes with chronic ankle instability and 55 healthy controls were recruited. Peroneal reaction time in response to sudden inversion, isokinetic evertor muscle strength and dynamic balance with the Star Excursion Balance Test and the Biodex Stability System were measured. The relationship between the Cumberland Ankle Instability Tool score and performance on each test was assessed and a backward multiple linear regression analysis was conducted. Participants with chronic ankle instability showed prolonged peroneal reaction time, poor performance in the Biodex Stability System and decreased reach distance in the Star Excursion Balance Test. No significant differences were found in eversion and inversion peak torque. Moderate correlations were found between the Cumberland Ankle Instability Tool score and the peroneal reaction time and performance on the Star Excursion Balance Test. Peroneus brevis reaction time and the posteromedial and lateral directions of the Star Excursion Balance Test accounted for 36% of the variance in the Cumberland Ankle Instability Tool. Dynamic balance deficits and delayed peroneal reaction time are present in participants with chronic ankle instability. Peroneus brevis reaction time and the posteromedial and lateral directions of the Star Excursion Balance Test were the main contributing factors to the Cumberland Ankle Instability Tool score. No clear strength impairments were reported in unstable ankles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Balance control in elderly people with osteoporosis

OpenAIRE

Hsu, Wei-Li; Chen, Chao-Yin; Tsauo, Jau-Yih; Yang, Rong-Sen

2014-01-01

Osteoporosis is a prevalent health concern among older adults and is associated with an increased risk of falls that incur fracture, injury, or mortality. Identifying the risk factors of falls within this population is essential for the development of effective regimes for fall prevention. Studies have shown that muscle quality and good posture alignments are critical for balance control in elderly individuals. People with osteoporosis often have muscle weakness and increased spine kyphosis l...

Reflexivity: The Creation of Liminal Spaces--Researchers, Participants, and Research Encounters.

Science.gov (United States)

Enosh, Guy; Ben-Ari, Adital

2016-03-01

Reflexivity is defined as the constant movement between being in the phenomenon and stepping outside of it. In this article, we specify three foci of reflexivity--the researcher, the participant, and the encounter--for exploring the interview process as a dialogic liminal space of mutual reflection between researcher and participant. Whereas researchers' reflexivity has been discussed extensively in the professional discourse, participants' reflexivity has not received adequate scholarly attention, nor has the promise inherent in reflective processes occurring within the encounter. © The Author(s) 2015.

Probabilities on Streams and Reflexive Games

Directory of Open Access Journals (Sweden)

Andrew Schumann

2014-01-01

Full Text Available Probability measures on streams (e.g. on hypernumbers and p-adic numbers have been defined. It was shown that these probabilities can be used for simulations of reflexive games. In particular, it can be proved that Aumann's agreement theorem does not hold for these probabilities. Instead of this theorem, there is a statement that is called the reflexion disagreement theorem. Based on this theorem, probabilistic and knowledge conditions can be defined for reflexive games at various reflexion levels up to the infinite level. (original abstract

Learning reflexively from a health promotion professional development program in Canada.

Science.gov (United States)

Tremblay, Marie-Claude; Richard, Lucie; Brousselle, Astrid; Beaudet, Nicole

2014-09-01

In recent decades, reflexivity has received much attention in the professional education and training literature, especially in the public health and health promotion fields. Despite general agreement on the importance of reflexivity, there appears to be no consensus on how to assess reflexivity or to conceptualize the different forms developed among professionals and participants of training programs. This paper presents an analysis of the reflexivity outcomes of the Health Promotion Laboratory, an innovative professional development program aimed at supporting practice changes among health professionals by fostering competency development and reflexivity. More specifically, this paper explores the difference between two levels of reflexivity (formative and critical) and highlights some implications of each for practice. Data were collected through qualitative interviews with participants from two intervention sites. Results showed that involvement in the Health Promotion Laboratory prompted many participants to modify their vision of their practice and professional role, indicating an impact on reflexivity. In many cases, new understandings seem to have played a formative function in enabling participants to improve their practice and their role as health promoters. The reflective process also served a critical function culminating in a social and moral understanding of the impacts on society of the professionals' practices and roles. This type of outcome is greatly desired in health promotion, given the social justice and equity concerns of this field of practice. By redefining the theoretical concept of reflexivity on two levels and discussing their impacts on practice, this study supports the usefulness of both levels of reflexivity. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Analysis of balance control methods based on inverted pendulum for legged robots

Directory of Open Access Journals (Sweden)

Denisov Alexander

2017-01-01

Full Text Available Methods of balance control for a legged robot, the model of which is presented as a two-section inverted pendulum, are considered. The following balance methods for humanoid robots are analysed: the parallel algorithm of the network operator method; the method of natural synergies; the method of fuzzy control, the spherical inverted pendulum mode, a dual length linear inverted pendulum method. The best of these methods will be used in the development of the Russian anthropomorphic robot Antares.

Study of Achilles Tendon Reflex in Normal Korean and Various Thyroid Diseases

International Nuclear Information System (INIS)

Kang, Jin Yung; Kim, Kwang Won; Yae, Sung Bo; Lee, Hong Kyu; Koh, Chang Soon

1975-01-01

In an attempt to establish the diagnostic value of Achilles tendon reflex and to determine the normal value of Achilles tendon reflex time in normal Korean, the author measured the Achilles tendon reflex time by photomotograph. This study was carried out in 272 cases with various thyroid diseases and 340 normal Korean. 1) The Achilles tendon reflex time in normal Korean was like this, between 11 years old and 20 years old; male (62 cases); 250±27 msec, female (36 cases); 266±27 msec, between 21 years old and 30 years old; male (38 cases); 271±27 msec, female (21 cases); 284±27 msec, between 31 years old and 40 years old; male (26 cases); 275±25 msec, female (29 cases); 291±27 msec, between 41 years old and 50 years old; male (20 cases); 286±35 msec, female (24 cases); 307±42 msec, between 51 years old and 60 years old, male (20 cases); 296±33 msec, female (20 cases); 318±46 msec, over 61 years; male (24 cases) 301±33 msec, female (20 cases); 325±35 msec. The Achilles tendon reflex time was delayed with increasing age and delayed in the female. 2) The Achilles tendon reflex time was markedly shortened to 221±20 msec in untreated hyperthyroidism. 3) The Achilles tendon reflex time was markedly delayed to 435±59 msec in hypothyroidism. 4) The Achilles tendon reflex time was not changed significantly in other thyroid diseases with norms thyroid function. 5) The Achilles tendon reflex time showed good correlationship with ETR, T 3 RU, 131 I thyroid uptake and serum TSH. 6) Reproducibility of Achilles tendon reflex time was good, and no significant difference between left and right was noted. 7) Diagnostic accuracy of Achilles tendon reflex time was 71% in hyperthyroidism and 90% in hypothyroidism. 8) The Achilles tendon reflex time showed useful test to evaluate the clinical course of the hyperthyroidism.

People with chronic low back pain have poorer balance than controls in challenging tasks.

Science.gov (United States)

da Silva, Rubens A; Vieira, Edgar R; Fernandes, Karen B P; Andraus, Rodrigo A; Oliveira, Marcio R; Sturion, Leandro A; Calderon, Mariane G

2018-06-01

To compare the balance of individuals with and without chronic low back pain during five tasks. The participants were 20 volunteers, 10 with and 10 without nonspecific chronic low back pain, mean age 34 years, 50% females. The participants completed the following balance tasks on a force platform in random order: (1) two-legged stance with eyes open, (2) two-legged stance with eyes closed, (3) semi-tandem with eyes open, (4) semi-tandem with eyes closed and (5) one-legged stance with eyes open. The participants completed three 60-s trials of tasks 1-4, and three 30-s trials of task 5 with 30-s rests between trials. The center of pressure area, velocity and frequency in the antero-posterior and medio-lateral directions were computed during each task, and compared between groups and tasks. Participants with chronic low back pain presented significantly larger center of pressure area and higher velocity than the healthy controls (p chronic low back pain group than two-legged stance tasks 1 and 2 (effect size >1.37 vs. effect size chronic low back pain presented poorer postural control using center of pressure measurements than the healthy controls, mainly during more challenging balance tasks such as semi-tandem and one-legged stance conditions. Implications for Rehabilitation People with chronic low back had poorer balance than those without it. Balance tasks need to be sensitive to capture impairments. Balance assessments during semi-tandem and one-legged stance were the most sensitive tasks to determine postural control deficit in people with chronic low back. Balance assessment should be included during rehabilitation programs for individuals with chronic low back pain for better clinical decision making related to balance re-training as necessary.

Autonomic Dysfunction in Muscular Dystrophy: A Theoretical Framework for Muscle Reflex Involvement

Directory of Open Access Journals (Sweden)

Scott Alan Smith

2014-02-01

Full Text Available Muscular dystrophies are a heterogeneous group of genetically inherited disorders whose most prominent clinical feature is progressive degeneration of skeletal muscle. In several forms of the disease, the function of cardiac muscle is likewise affected. The primary defect in this group of diseases is caused by mutations in myocyte proteins important to cellular structure and/or performance. That being stated, a growing body of evidence suggests that the development of autonomic dysfunction may secondarily contribute to the generation of skeletal and cardio-myopathy in muscular dystrophy. Indeed, abnormalities in the regulation of both sympathetic and parasympathetic nerve activity have been reported in a number of muscular dystrophy variants. However, the mechanisms mediating this autonomic dysfunction remain relatively unknown. An autonomic reflex originating in skeletal muscle, the exercise pressor reflex, is known to contribute significantly to the control of sympathetic and parasympathetic activity when stimulated. Given the skeletal myopathy that develops with muscular dystrophy, it is logical to suggest that the function of this reflex might also be abnormal with the pathogenesis of disease. As such, it may contribute to or exacerbate the autonomic dysfunction that manifests. This possibility along with a basic description of exercise pressor reflex function in health and disease are reviewed. A better understanding of the mechanisms that possibly underlie autonomic dysfunction in muscular dystrophy may not only facilitate further research but could also lead to the identification of new therapeutic targets for the treatment of muscular dystrophy.

The gait and balance of patients with diabetes can be improved: a randomised controlled trial

OpenAIRE

Allet, L.; Armand, S.; de Bie, R. A.; Golay, A.; Monnin, D.; Aminian, K.; Staal, J. B.; de Bruin, E. D.

2009-01-01

Aims/hypothesis Gait characteristics and balance are altered in diabetic patients. Little is known about possible treatment strategies. This study evaluates the effect of a specific training programme on gait and balance of diabetic patients. Methods This was a randomised controlled trial (n?=?71) with an intervention (n?=?35) and control group (n?=?36). The intervention consisted of physiotherapeutic group training including gait and balance exercises with function-orientated strengthening (...

Online Dynamic Balance Technology for High Speed Spindle Based on Gain Parameter Adaption and Scheduling Control

Directory of Open Access Journals (Sweden)

Shihai Zhang

2018-06-01

Full Text Available Unbalance vibration is one of the main vibration forms of a high speed machine tool spindle. The overlarge unbalance vibration will have some adverse effects on the working life of the spindle system and the surface quality of the work-piece. In order to reduce the unbalance of a high speed spindle system, a pneumatic online dynamic balance device and its control system are presented in the paper. To improve the balance accuracy and adaptation of the balance system, the gain parameter adaption and scheduling control method are proposed first, and then the different balance effects of the influence coefficient method and the gain scheduling control method are compared through many dynamic balance experiments of the high speed spindle. The experimental results indicate that the gain parameters can be changed timely according to the transformation of the speed and kinetic parameters of the spindle system. The balance accuracy can be improved for a high speed spindle with time-varying characteristics, based on the adaptive gain scheduling control method.

Avian reflex and electroencephalogram responses in different states of consciousness.

Science.gov (United States)

Sandercock, Dale A; Auckburally, Adam; Flaherty, Derek; Sandilands, Victoria; McKeegan, Dorothy E F

2014-06-22

Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n=10)). We evaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflex was consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. Copyright © 2014 Elsevier Inc. All rights reserved.

Intrapartum synthetic oxytocin reduce the expression of primitive reflexes associated with breastfeeding.

Science.gov (United States)

Marín Gabriel, Miguel A; Olza Fernández, Ibone; Malalana Martínez, Ana M; González Armengod, Carmen; Costarelli, Valeria; Millán Santos, Isabel; Fernández-Cañadas Morillo, Aurora; Pérez Riveiro, Pilar; López Sánchez, Francisco; García Murillo, Lourdes

2015-05-01

Several synthetic peptide manipulations during the time surrounding birth can alter the specific neurohormonal status in the newborn brain. This study is aimed at assessing whether intrapartum oxytocin administration has any effect on primitive neonatal reflexes and determining whether such an effect is dose-dependent. A cohort prospective study was conducted at a tertiary hospital. Mother-infant dyads who received intrapartum oxytocin (n=53) were compared with mother-infant dyads who did not receive intrapartum oxytocin (n=45). Primitive neonatal reflexes (endogenous, antigravity, motor, and rhythmic reflexes) were quantified by analyzing videotaped breastfeeding sessions in a biological nurturing position. Two observers blind to the group assignment and the oxytocin dose analyzed the videotapes and assesed the newborn's state of consciousness according to the Brazelton scale. The release of all rhythmic reflexes (p=0.01), the antigravity reflex (p=0.04), and total primitive neonatal reflexes (p=0.02) in the group exposed to oxytocin was lower than in the group not exposed to oxytocin. No correlations were observed between the dose of oxytocin administered and the percentage of primitive neonatal reflexes released (r=0.03; p=0.82). Intrapartum oxytocin administration might inhibit the expression of several primitive neonatal reflexes associated with breastfeeding. This correlation does not seem to be dose-dependent.

Influence of perturbation velocity on balance control in Parkinson's disease.

Directory of Open Access Journals (Sweden)

Lars B Oude Nijhuis

Full Text Available Underlying somatosensory processing deficits of joint rotation velocities may cause patients with Parkinson's disease (PD to be more unstable for fast rather than slow balance perturbations. Such deficits could lead to reduced proprioceptive amplitude feedback triggered by perturbations, and thereby to smaller or delayed stabilizing postural responses. For this reason, we investigated whether support surface perturbation velocity affects balance reactions in PD patients. We examined postural responses of seven PD patients (OFF medication and eight age-matched controls following backward rotations of a support-surface platform. Rotations occurred at three different speeds: fast (60 deg/s, medium (30 deg/s or slow (3.8 deg/s, presented in random order. Each subject completed the protocol under eyes open and closed conditions. Full body kinematics, ankle torques and the number of near-falls were recorded. Patients were significantly more unstable than controls following fast perturbations (26% larger displacements of the body's centre of mass; P<0.01, but not following slow perturbations. Also, more near-falls occurred in patients for fast rotations. Balance correcting ankle torques were weaker for patients than controls on the most affected side, but were stronger than controls for the least affected side. These differences were present both with eyes open and eyes closed (P<0.01. Fast support surface rotations caused greater instability and discriminated Parkinson patients better from controls than slow rotations. Although ankle torques on the most affected side were weaker, patients partially compensated for this by generating larger than normal stabilizing torques about the ankle joint on the least affected side. Without this compensation, instability may have been greater.

Unexpected perturbations training improves balance control and voluntary stepping times in older adults - a double blind randomized control trial.

Science.gov (United States)

Kurz, Ilan; Gimmon, Yoav; Shapiro, Amir; Debi, Ronen; Snir, Yoram; Melzer, Itshak

2016-03-04

Falls are common among elderly, most of them occur while slipping or tripping during walking. We aimed to explore whether a training program that incorporates unexpected loss of balance during walking able to improve risk factors for falls. In a double-blind randomized controlled trial 53 community dwelling older adults (age 80.1±5.6 years), were recruited and randomly allocated to an intervention group (n = 27) or a control group (n = 26). The intervention group received 24 training sessions over 3 months that included unexpected perturbation of balance exercises during treadmill walking. The control group performed treadmill walking with no perturbations. The primary outcome measures were the voluntary step execution times, traditional postural sway parameters and Stabilogram-Diffusion Analysis. The secondary outcome measures were the fall efficacy Scale (FES), self-reported late life function (LLFDI), and Performance-Oriented Mobility Assessment (POMA). Compared to control, participation in intervention program that includes unexpected loss of balance during walking led to faster Voluntary Step Execution Times under single (p = 0.002; effect size [ES] =0.75) and dual task (p = 0.003; [ES] = 0.89) conditions; intervention group subjects showed improvement in Short-term Effective diffusion coefficients in the mediolateral direction of the Stabilogram-Diffusion Analysis under eyes closed conditions (p = 0.012, [ES] = 0.92). Compared to control there were no significant changes in FES, LLFDI, and POMA. An intervention program that includes unexpected loss of balance during walking can improve voluntary stepping times and balance control, both previously reported as risk factors for falls. This however, did not transferred to a change self-reported function and FES. ClinicalTrials.gov NCT01439451 .

Does Nintendo Wii Balance Board improve standing balance? A randomized controlled trial in children with cerebral palsy.

Science.gov (United States)

Gatica-Rojas, Valeska; Méndez-Rebolledo, Guillermo; Guzman-Muñoz, Eduardo; Soto-Poblete, Alex; Cartes-Velásquez, Ricardo; Elgueta-Cancino, Edith; Cofré Lizama, L Eduardo

2017-08-01

Evidence on the effect of systemic exercise programs to improve the standing balance with the Nintendo Wii system is very limited and its post-treatment effectiveness is unknown in cerebral palsy (CP) patients. Primary aim was to compare the effect of Nintendo Wii balance board (Wii-therapy) and standard physiotherapy (SPT), on the performance of standing balance in children and adolescents with CP. Secondary aim was to determine the post-treatment effectiveness of Wii-therapy and SPT. Two-arm, matched-pairs, parallel-groups, randomized, controlled clinical trial. Outpatient Rehabilitation Centre in the city of Talca. Patients with CP type spastic hemiplegia (SHE) and spastic diplegia (SDI), aged 7 to 14 years, and level I or II of GMFCS or GMFCS-ER. Were excluded patients with FSIQWii-therapy (SDI=7; SHE=9) or SPT intervention (SDI=7; SHE=9). In each group, patients received three sessions per week over a period of 6 weeks. Standing balance was assessed at baseline and every 2 weeks. Additionally, two follow-up assessments (4 additional weeks) were performed to determine post-treatment effectiveness. Standing balance was quantified on force platform obtaining the outcomes area of center-of-pressure (CoP) sway (CoPSway), standard deviation in the medial-lateral (SDML) and the anterior-posterior (SDAP) directions, and velocity in both directions (VML and VAP). Compared to SPT, Wii-therapy significantly reduced the CoPSway (P=0.02) and SDAP in the eyes-open condition (P=0.01). However, the effects wane after 2-4 weeks. Post-hoc analysis revealed that only SHE children benefited from Wii-therapy. Wii-therapy was better than SPT in improving standing balance in patients with CP, but improves the balance only in SHE patients. Also, Wii-therapy effectiveness waned 2-4 weeks after the end the intervention. A systematic exercise program like Wii-therapy using the Nintendo Wii Balance Board device can be considered to improves the standing balance in patients with CP

Reflexion and control mathematical models

CERN Document Server

Novikov, Dmitry A

2014-01-01

This book is dedicated to modern approaches to mathematical modeling of reflexive processes in control. The authors consider reflexive games that describe the gametheoretical interaction of agents making decisions based on a hierarchy of beliefs regarding (1) essential parameters (informational reflexion), (2) decision principles used by opponents (strategic reflexion), (3) beliefs about beliefs, and so on. Informational and reflexive equilibria in reflexive games generalize a series of well-known equilibrium concepts in noncooperative games and models of collective behavior. These models allow posing and solving the problems of informational and reflexive control in organizational, economic, social and other systems, in military applications, etc. (the interested reader will find in the book over 30 examples of possible applications in these fields) and describing uniformly many psychological/sociological phenomena connected with reflexion, viz., implicit control, informational control via the mass media, re...

Development of Static Balance Measurement and Correction Compound Platform for Single Blade of Controllable Pitch Propeller

Science.gov (United States)

Chao, Zhang; Shijie, Su; Yilin, Yang; Guofu, Wang; Chao, Wang

2017-11-01

Aiming at the static balance of the controllable pitch propeller (CPP), a high efficiency static balance method based on the double-layer structure of the measuring table and gantry robot is adopted to realize the integration of torque measurement and corrected polish for controllable pitch propeller blade. The control system was developed by Microsoft Visual Studio 2015, and a composite platform prototype was developed. Through this prototype, conduct an experiment on the complete process of torque measurement and corrected polish based on a 300kg class controllable pitch propeller blade. The results show that the composite platform can correct the static balance of blade with a correct, efficient and labor-saving operation, and can replace the traditional method on static balance of the blade.

The Politics of Reflexive Governance: Challenges for Designing Adaptive Management and Transition Management

Directory of Open Access Journals (Sweden)

Jan-Peter Voß

2011-06-01

Full Text Available New concepts of governance take account of ambivalence, uncertainty, and distributed power in societal change. They aim for reflexivity regarding the limits of prognostic knowledge and actual control of complex processes of change. Adaptive management and transition management are two examples that evolved from the analysis of social-ecological and sociotechnical systems, respectively. Both feature strategies of collective experimentation and learning. In this paper, we ask how these two designs of reflexive governance consider politics. Based on a framework of different dimensions and levels of politics, we show that they are mainly concerned with problem solving by a focal process, but conflict and asymmetric power relations, as well as the embedding of processes within broader political contexts, are neglected. We suggest two routes for integrating politics into the design of reflexive governance: (1 recognize the politics of learning for sustainable development and develop safeguards against domination and capture by powerful actors, and (2 systematically consider the embedding of governance designs in political contexts and their ongoing dynamics for political fit.

Child-Computer Interaction at the Beginner Stage of Music Learning: Effects of Reflexive Interaction on Children's Musical Improvisation.

Science.gov (United States)

Addessi, Anna Rita; Anelli, Filomena; Benghi, Diber; Friberg, Anders

2017-01-01

In this article children's musical improvisation is investigated through the "reflexive interaction" paradigm. We used a particular system, the MIROR-Impro, implemented in the framework of the MIROR project (EC-FP7), which is able to reply to the child playing a keyboard by a "reflexive" output, mirroring (with repetitions and variations) her/his inputs. The study was conducted in a public primary school, with 47 children, aged 6-7. The experimental design used the convergence procedure, based on three sample groups allowing us to verify if the reflexive interaction using the MIROR-Impro is necessary and/or sufficient to improve the children's abilities to improvise. The following conditions were used as independent variables: to play only the keyboard, the keyboard with the MIROR-Impro but with not-reflexive reply, the keyboard with the MIROR-Impro with reflexive reply. As dependent variables we estimated the children's ability to improvise in solos, and in duets. Each child carried out a training program consisting of 5 weekly individual 12 min sessions. The control group played the complete package of independent variables; Experimental Group 1 played the keyboard and the keyboard with the MIROR-Impro with not-reflexive reply; Experimental Group 2 played only the keyboard with the reflexive system. One week after, the children were asked to improvise a musical piece on the keyboard alone (Solo task), and in pairs with a friend (Duet task). Three independent judges assessed the Solo and the Duet tasks by means of a grid based on the TAI-Test for Ability to Improvise rating scale. The EG2, which trained only with the reflexive system, reached the highest average results and the difference with EG1, which did not used the reflexive system, is statistically significant when the children improvise in a duet. The results indicate that in the sample of participants the reflexive interaction alone could be sufficient to increase the improvisational skills, and necessary

Reflex epileptic mechanisms in humans: Lessons about natural ictogenesis.

Science.gov (United States)

Wolf, Peter

2017-06-01

The definition of reflex epileptic seizures is that specific seizure types can be triggered by certain sensory or cognitive stimuli. Simple triggers are sensory (most often visual, more rarely tactile or proprioceptive; simple audiogenic triggers in humans are practically nonexistent) and act within seconds, whereas complex triggers like praxis, reading and talking, and music are mostly cognitive and work within minutes. The constant relation between a qualitatively, often even quantitatively, well-defined stimulus and a specific epileptic response provides unique possibilities to investigate seizure generation in natural human epilepsies. For several reflex epileptic mechanisms (REMs), this has been done. Reflex epileptic mechanisms have been reported less often in focal lesional epilepsies than in idiopathic "generalized" epilepsies (IGEs) which are primarily genetically determined. The key syndrome of IGE is juvenile myoclonic epilepsy (JME), where more than half of the patients present reflex epileptic traits (photosensitivity, eye closure sensitivity, praxis induction, and language-induced orofacial reflex myocloni). Findings with multimodal investigations of cerebral function concur to indicate that ictogenic mechanisms in IGEs largely (ab)use preexisting functional anatomic networks (CNS subsystems) normally serving highly complex physiological functions (e.g., deliberate complex actions and linguistic communication) which supports the concept of system epilepsy. Whereas REMs in IGEs, thus, are primarily function-related, in focal epilepsies, they are primarily localization-related. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic". Copyright © 2015 Elsevier Inc. All rights reserved.

FEFsem neuronal response during combined volitional and reflexive pursuit.

Science.gov (United States)

Bakst, Leah; Fleuriet, Jérome; Mustari, Michael J

2017-05-01

Although much is known about volitional and reflexive smooth eye movements individually, much less is known about how they are coordinated. It is hypothesized that separate cortico-ponto-cerebellar loops subserve these different types of smooth eye movements. Specifically, the MT-MST-DLPN pathway is thought to be critical for ocular following eye movements, whereas the FEF-NRTP pathway is understood to be vital for volitional smooth pursuit. However, the role that these loops play in combined volitional and reflexive behavior is unknown. We used a large, textured background moving in conjunction with a small target spot to investigate the eye movements evoked by a combined volitional and reflexive pursuit task. We also assessed the activity of neurons in the smooth eye movement subregion of the frontal eye field (FEFsem). We hypothesized that the pursuit system would show less contribution from the volitional pathway in this task, owing to the increased involvement of the reflexive pathway. In accordance with this hypothesis, a majority of FEFsem neurons (63%) were less active during pursuit maintenance in a combined volitional and reflexive pursuit task than during purely volitional pursuit. Interestingly and surprisingly, the neuronal response to the addition of the large-field motion was highly correlated with the neuronal response to a target blink. This suggests that FEFsem neuronal responses to these different perturbations-whether the addition or subtraction of retinal input-may be related. We conjecture that these findings are due to changing weights of both the volitional and reflexive pathways, as well as retinal and extraretinal signals.

ESO Reflex: A Graphical Workflow Engine for Data Reduction

Science.gov (United States)

Hook, R.; Romaniello, M.; Péron, M.; Ballester, P.; Gabasch, A.; Izzo, C.; Ullgrén, M.; Maisala, S.; Oittinen, T.; Solin, O.; Savolainen, V.; Järveläinen, P.; Tyynelä, J.

2008-08-01

Sampo {http://www.eso.org/sampo} (Hook et al. 2005) is a project led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. The goal is to assess the needs of the ESO community in the area of data reduction environments and to create pilot software products that illustrate critical steps along the road to a new system. Those prototypes will not only be used to validate concepts and understand requirements but will also be tools of immediate value for the community. Most of the raw data produced by ESO instruments can be reduced using CPL {http://www.eso.org/cpl} recipes: compiled C programs following an ESO standard and utilizing routines provided by the Common Pipeline Library. Currently reduction recipes are run in batch mode as part of the data flow system to generate the input to the ESO VLT/VLTI quality control process and are also made public for external users. Sampo has developed a prototype application called ESO Reflex {http://www.eso.org/sampo/reflex/} that integrates a graphical user interface and existing data reduction algorithms. ESO Reflex can invoke CPL-based recipes in a flexible way through a dedicated interface. ESO Reflex is based on the graphical workflow engine Taverna {http://taverna.sourceforge.net} that was originally developed by the UK eScience community, mostly for work in the life sciences. Workflows have been created so far for three VLT/VLTI instrument modes ( VIMOS/IFU {http://www.eso.org/instruments/vimos/}, FORS spectroscopy {http://www.eso.org/instruments/fors/} and AMBER {http://www.eso.org/instruments/amber/}), and the easy-to-use GUI allows the user to make changes to these or create workflows of their own. Python scripts and IDL procedures can be easily brought into workflows and a variety of visualisation and display options, including custom product inspection and validation steps, are available.

A balance of activity in brain control and reward systems predicts self-regulatory outcomes

OpenAIRE

Lopez, Richard B.; Chen, Pin-Hao A.; Huckins, Jeremy F.; Hofmann, Wilhelm; Kelley, William M.; Heatherton, Todd F.

2017-01-01

Abstract Previous neuroimaging work has shown that increased reward-related activity following exposure to food cues is predictive of self-control failure. The balance model suggests that self-regulation failures result from an imbalance in reward and executive control mechanisms. However, an open question is whether the relative balance of activity in brain systems associated with executive control (vs reward) supports self-regulatory outcomes when people encounter tempting cues in daily lif...

Orthodontic treatment-induced temporal alteration of jaw-opening reflex excitability.

Science.gov (United States)

Sasaki, Au; Hasegawa, Naoya; Adachi, Kazunori; Sakagami, Hiroshi; Suda, Naoto

2017-10-01

The impairment of orofacial motor function during orthodontic treatment needs to be addressed, because most orthodontic patients experience pain and motor excitability would be affected by pain. In the present study, the temporal alteration of the jaw-opening reflex excitability was investigated to determine if orthodontic treatment affects orofacial motor function. The excitability of jaw-opening reflex evoked by electrical stimulation on the gingiva and recorded bilaterally in the anterior digastric muscles was evaluated at 1 (D1), 3 (D3), and 7 days (D7) after orthodontic force application to the teeth of right side; morphological features (e.g., osteoclast genesis and tooth movement) were also evaluated. To clarify the underlying mechanism of orthodontic treatment-induced alteration of orofacial motor excitability, analgesics were administrated for 1 day. At D1 and D3, orthodontic treatment significantly decreased the threshold for inducing the jaw-opening reflex but significantly increased the threshold at D7. Other parameters of the jaw-opening reflex were also evaluated (e.g., latency, duration and area under the curve of anterior digastric muscles activity), and only the latency of the D1 group was significantly different from that of the other groups. Temporal alteration of the jaw-opening reflex excitability was significantly correlated with changes in morphological features. Aspirin (300 mg·kg -1 ·day -1 ) significantly increased the threshold for inducing the jaw-opening reflex, whereas a lower dose (75-150 mg·kg -1 ·day -1 ) of aspirin or acetaminophen (300 mg·kg -1 ·day -1 ) failed to alter the jaw-opening reflex excitability. These results suggest that an increase of the jaw-opening reflex excitability can be induced acutely by orthodontic treatment, possibly through the cyclooxygenase activation. NEW & NOTEWORTHY It is well known that motor function is affected by pain, but the effect of orthodontic treatment-related pain on the trigeminal

Effectiveness of Neuro-Developmental Treatment (Bobath Concept) on postural control and balance in Cerebral Palsied children.

Science.gov (United States)

Tekin, Fatih; Kavlak, Erdogan; Cavlak, Ugur; Altug, Filiz

2018-01-01

The aim of this study was to show the effects of an 8-week Neurodevelopmental Treatment based posture and balance training on postural control and balance in diparetic and hemiparetic Cerebral Palsied children (CPC). Fifteen CPC (aged 5-15 yrs) were recruited from Denizli Yağmur Çocukları Rehabilitation Centre. Gross Motor Function Classification System, Gross Motor Function Measure, 1-Min Walking Test, Modified Timed Up and Go Test, Paediatric Balance Scale, Functional Independence Measure for Children and Seated Postural Control Measure were used for assessment before and after treatment. An 8-week NDT based posture and balance training was applied to the CPC in one session (60-min) 2 days in a week. After the treatment program, all participants showed statistically significant improvements in terms of gross motor function (p< 0.05). They also showed statistically significant improvements about balance abilities and independence in terms of daily living activities (p< 0.05). Seated Postural Control Measure scores increased after the treatment program (p< 0.05). The results of this study indicate that an 8-week Neurodevelopmental Treatment based posture and balance training is an effective approach in order to improve functional motor level and functional independency by improving postural control and balance in diparetic and hemiparetic CPC.

The Narrow Ridge Balance Test : A measure for one-leg lateral balance control

NARCIS (Netherlands)

Curtze, Carolin; Postema, Klaas; Akkermans, Hilda W.; Otten, Bert; Hof, At L.

2010-01-01

The assessment of balance capacity for people with widely different balance abilities is an important issue in clinical practice We propose the narrow ridge balance test as a sensitive tool to assess one-leg balance capacity In this test participants are asked to perform single-leg stance on ridges

The development of the pupillary light reflex and menace response in neonatal lambs and kids.

Science.gov (United States)

Raoofi, Afshin; Mirfakhraie, Pejman; Yourdkhani, Sorush

2011-03-01

The aim of this study was to investigate the development of the pupillary light reflex and menace response in neonatal lambs and goat kids. Thirty lambs and 33 kids were assessed daily from birth until the pupillary light reflex and menace response had become established. All animals had a controlled pupillary light reflex within 20 h of birth. Lambs and kids had developed menace responses by 8 ± 3 and 14 ± 2 days, respectively. The Mann-Whitney test revealed a significant difference (P kids developed a menace response. Male kids developed this response significantly (P = 0.006) later than females. There was no sex difference in the menace response in the lambs. Overall, the findings indicated that lambs develop a menace response earlier than kids, and female kids develop this response more rapidly than their male counterparts. Copyright © 2010 Elsevier Ltd. All rights reserved.

The mechano-gated channel inhibitor GsMTx4 reduces the exercise pressor reflex in rats with ligated femoral arteries.

Science.gov (United States)

Copp, Steven W; Kim, Joyce S; Ruiz-Velasco, Victor; Kaufman, Marc P

2016-05-01

Mechanical and metabolic stimuli arising from contracting muscles evoke the exercise pressor reflex. This reflex is greater in a rat model of simulated peripheral arterial disease in which a femoral artery is chronically ligated than it is in rats with freely perfused femoral arteries. The role played by the mechanically sensitive component of the exaggerated exercise pressor reflex in ligated rats is unknown. We tested the hypothesis that the mechano-gated channel inhibitor GsMTx4, a relatively selective inhibitor of mechano-gated Piezo channels, reduces the exercise pressor reflex in decerebrate rats with ligated femoral arteries. Injection of 10 μg of GsMTx4 into the arterial supply of the hindlimb reduced the pressor response to Achilles tendon stretch (a purely mechanical stimulus) but had no effect on the pressor responses to intra-arterial injection of α,β-methylene ATP or lactic acid (purely metabolic stimuli). Moreover, injection of 10 μg of GsMTx4 into the arterial supply of the hindlimb reduced both the integrated pressor area (control 535 ± 21, GsMTx4 218 ± 24 mmHg·s; P reflex contributes to the exaggerated exercise pressor reflex during intermittent hindlimb muscle contractions in rats with ligated femoral arteries. Copyright © 2016 the American Physiological Society.

Comparison of Stretch Reflex Torques in Ankle Dorsiflexors and Plantarflexors

National Research Council Canada - National Science Library

Tung, J

2001-01-01

...) ankle muscles, Pulse, step, and a combination of random perturbation and step inputs were used to identify the reflex and intrinsic contributions to the measured torque, TA reflex torques were very...

Reflex muscle contraction in anterior shoulder instability.

Science.gov (United States)

Wallace, D A; Beard, D J; Gill, R H; Eng, B; Carr, A J

1997-01-01

Reduced proprioception may contribute to recurrent anterior shoulder instability. Twelve patients with unilateral shoulder instability were investigated for evidence of deficient proprioception with an activated pneumatic cylinder and surface electromyography electrodes; the contralateral normal shoulder was used as a control. The latency between onset of movement and the detection of muscle contraction was used as an index of proprioception. No significant difference in muscle contraction latency was detected between the stable and unstable shoulders, suggesting that there was no significant defect in muscular reflex activity. This study does not support the use proprioception-enhancing physiotherapy in the treatment of posttraumatic anterior shoulder instability.

Age effects on mediolateral balance control.

Directory of Open Access Journals (Sweden)

L Eduardo Cofré Lizama

Full Text Available BACKGROUND: Age-related balance impairments, particularly in mediolateral direction (ML may cause falls. Sufficiently sensitive and reliable ML balance tests are, however, lacking. This study is aimed to determine (1 the effect of age on and (2 the reliability of ML balance performance using Center of Mass (CoM tracking. METHODS: Balance performance of 19 young (26±3 years and 19 older (72±5 years adults on ML-CoM tracking tasks was compared. Subjects tracked predictable and unpredictable target displacements at increasing frequencies with their CoM by shifting their weight sideward. Phase-shift (response delay and gain (amplitude difference between the CoM and target in the frequency domain were used to quantify performance. Thirteen older and all young adults were reassessed to determine reliability of balance performance measures. In addition, all older adults performed a series of clinical balance tests and conventional posturography was done in a sub-sample. RESULTS: Phase-shift and gain dropped below pre-determined thresholds (-90 degrees and 0.5 at lower frequencies in the older adults and were even lower below these frequencies than in young adults. Performance measures showed good to excellent reliability in both groups. All clinical scores were close to the maximum and no age effect was found using posturography. ML balance performance measures exhibited small but systematic between-session differences indicative of learning. CONCLUSIONS: The ability to accurately perform ML-CoM tracking deteriorates with age. ML-CoM tracking tasks form a reliable tool to assess ML balance in young and older adults and are more sensitive to age-related impairment than posturography and clinical tests.

Internet-based home training is capable to improve balance in multiple sclerosis: a randomized controlled trial.

Science.gov (United States)

Frevel, D; Mäurer, M

2015-02-01

Balance disorders are common in multiple sclerosis. Aim of the study is to investigate the effectiveness of an Internet-based home training program (e-Training) to improve balance in patients with multiple sclerosis. A randomized, controlled study. Academic teaching hospital in cooperation with the therapeutic riding center Gut Üttingshof, Bad Mergentheim. Eighteen multiple sclerosis patients (mean EDSS 3,5) took part in the trial. Outcome of patients using e-Training (N.=9) was compared to the outcome of patients receiving hippotherapy (N.=9), which can be considered as an advanced concept for the improvement of balance and postural control in multiple sclerosis. After simple random allocation patients received hippotherapy or Internet-based home training (balance, postural control and strength training) twice a week for 12 weeks. Assessments were done before and after the intervention and included static and dynamic balance (primary outcome). Isometric muscle strength of the knee and trunk extension/flexion (dynamometer), walking capacity, fatigue and quality of life served as secondary outcome parameters. Both intervention groups showed comparable and highly significant improvement in static and dynamic balance capacity, no difference was seen between the both intervention groups. However looking at fatigue and quality of life only the group receiving hippotherapy improved significantly. Since e-Training shows even comparable effects to hippotherapy to improve balance, we believe that the established Internet-based home training program, specialized on balance and postural control training, is feasible for a balance and strength training in persons with multiple sclerosis. We demonstrated that Internet-based home training is possible in patients with multiple sclerosis.

Legged locomotion : Balance, control and tools - from equation to action

OpenAIRE

Ridderström, Christian

2003-01-01

This thesis is about control and balance stability of leggedlocomotion. It also presents a combination of tools that makesit easier to design controllers for large and complicated robotsystems. The thesis is divided into four parts. The first part studies and analyzes how walking machines arecontrolled, examining the literature of over twenty machinesbriefly, and six machines in detail. The goal is to understandhow the controllers work on a level below task and pathplanning, but above actuato...

Training for improved neuro-muscular control of balance in middle aged females.

Science.gov (United States)

Anderson, Gregory S; Deluigi, Fabio; Belli, Guido; Tentoni, Claudio; Gaetz, Michael B

2016-01-01

This study examined improvements in static balance and muscle electromyographic (EMG) activity following a four week progressive training program in 16 middle aged females (mean age = 46.9 ± 8.7 yrs; height 161.1 ± 6.0 cm; weight 65.4 ± 11.2 kg). Participants trained 3 times per week for 4 weeks, for 50 min per session, progressing base of support, stability, vision, resistance and torque in each of six basic exercises. Pre and post training measures of balance included feet together standing, a tandem stance and a one-leg stand (unsupported leg in the saggital plane) performed with the eyes closed, and a Stork Stand (unsupported leg in the frontal plane) with both eyes open and closed. In each position postural deviations were tallied for each individual while muscle recruitment was determined using root mean squared (RMS) EMG activity for the soleus, biceps femoris, erector spinae, rectus abdominis and internal oblique muscles of the dominant foot side. Balance scores were significantly improved post training in both the Balance Error Score System (p training in all muscles in each condition except the soleus in the tandem position, although not all significantly. Reduced biceps femoris activity suggest that improved core stability allowed participants to move from a hip to an ankle postural control strategy through improved coordination of muscles involved in balance and reduced body sway. The core muscles were able to control body position with less activity post training suggesting improved muscle coordination and efficiency. These results suggest that short term progressive floor to BOSU™ balance training can improve standing balance in middle aged women. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of a two-dimensional skin friction balance nulling circuit using multivariable control theory

Science.gov (United States)

Tripp, John S.; Patek, Stephen D.

1988-01-01

Measurement of planar skin friction forces in aerodynamic testing currently requires installation of two perpendicularly mounted, single-axis balances; consequently, force components must be sensed at two distinct locations. A two-axis instrument developed at the Langley Research Center to overcome this disadvantage allows measurement of a two-dimensional force at one location. This paper describes a feedback-controlled nulling circuit developed for the NASA two-axis balance which, without external compensation, is inherently unstable because of its low friction mechanical design. Linear multivariable control theory is applied to an experimentally validated mathematical model of the balance to synthesize a state-variable feedback control law. Pole placement techniques and computer simulation studies are employed to select eigenvalues which provide ideal transient response with decoupled sensing dynamics.

Reflex epilepsy: a review

Directory of Open Access Journals (Sweden)

Karim Nikkhah

2017-01-01

Full Text Available Interesting phenomena of reflex epileptic syndromes are characterized by epileptic seizures each one induced by specific stimulus with a variety of types. Simple triggers, which lead to seizures within seconds, are of sensory type (most commonly visual, most rarely tactile or proprioceptive stimuli. Complex triggers, which are mostly of cognitive type such as praxis, reading, talking, and music, usually induce the epileptic event within minutes. It should differ from what most epileptic patients report as provocative precipitants for seizures (such as emotional stress, fatigue, fever, sleep deprivation, alcohol, and menstrual cycle. The identification of a specific trigger is not only important for patients or their parents to avoid seizures, but also it might help neurologists to choose the most effective antiepileptic drug for each case. In addition, research in this area may possibly reveal some underlying pathophysiology of epileptic phenomena in the brain.In this review, we briefly introduce reported reflex epileptic seizures, their clinical features and management.

Reflexive Dressing: Rethinking Retro

Directory of Open Access Journals (Sweden)

Stella North

2016-03-01

Full Text Available This article undertakes a philosophical exploration of the act we know, or think we know, as ‘dressing’. Inhabiting, in thought, the moment in which we dress, I examine some of its constituent mechanisms, attending to the impulses by which dressing is generated out of subjective experience.  When those impulses are temporally marked, as they are in the case of retro dress, this generation is a two-pronged process, in which the holding of the body in time, and the holding of time in the body, recalibrate one another. The process of ‘dressing,’ in this understanding, has a reflexivity which is double; it entails the turning of the body, with dress as medium, towards itself, and the turning of present experience towards some felt notion of the past. Reflexively dressing, we are always becoming ourselves, and becoming other than ourselves, at once; a movement of circuitous internalisation and externalisation by which the ambiguation inherent in material experience is realised.

Summer comfort for deep renovated dwellings: Control of a delicate balance

NARCIS (Netherlands)

Bakker, L.G.; Borsboom, W.A.; Sijs, J.; Fransman, J.E.

2013-01-01

A model based indoor climate control concept is developed which improves the indoor comfort while saving energy. The controller developed within the EU-FP7 HERB project will automatically quantify key parameters describing the thermal balance of the building using a limited number of sensors and an

Reflexive anaphor resolution in spoken language comprehension: Structural constraints and beyond

Directory of Open Access Journals (Sweden)

Kaili eClackson

2014-08-01

Full Text Available We report results from an eye-tracking during listening study examining English-speaking adults’ online processing of reflexive pronouns, and specifically whether the search for an antecedent is restricted to syntactically appropriate positions. Participants listened to a short story where the recipient of an object was introduced with a reflexive, and were asked to identify the object recipient as quickly as possible. This allowed for the recording of participants’ offline interpretation of the reflexive, response times, and eye movements on hearing the reflexive. Whilst our offline results show that the ultimate interpretation for reflexives was constrained by binding principles, the response time and eye-movement data revealed that during processing participants were temporarily distracted by a structurally inappropriate competitor antecedent when this was prominent in the discourse. These results indicate that in addition to binding principles, online referential decisions are also affected by discourse-level information.

Reflexive anaphor resolution in spoken language comprehension: structural constraints and beyond

Science.gov (United States)

Clackson, Kaili; Heyer, Vera

2014-01-01

We report results from an eye-tracking during listening study examining English-speaking adults’ online processing of reflexive pronouns, and specifically whether the search for an antecedent is restricted to syntactically appropriate positions. Participants listened to a short story where the recipient of an object was introduced with a reflexive, and were asked to identify the object recipient as quickly as possible. This allowed for the recording of participants’ offline interpretation of the reflexive, response times, and eye movements on hearing the reflexive. Whilst our offline results show that the ultimate interpretation for reflexives was constrained by binding principles, the response time, and eye-movement data revealed that during processing participants were temporarily distracted by a structurally inappropriate competitor antecedent when this was prominent in the discourse. These results indicate that in addition to binding principles, online referential decisions are also affected by discourse-level information. PMID:25191290

A Fault Detection Filtering for Networked Control Systems Based on Balanced Reduced-Order

Directory of Open Access Journals (Sweden)

Da-Meng Dai

2015-01-01

Full Text Available Due to the probability of the packet dropout in the networked control systems, a balanced reduced-order fault detection filter is proposed. In this paper, we first analyze the packet dropout effects in the networked control systems. Then, in order to obtain a robust fault detector for the packet dropout, we use the balanced structure to construct a reduced-order model for residual dynamics. Simulation results are provided to testify the proposed method.

Management of Reflex Anoxic Seizures

Directory of Open Access Journals (Sweden)

J Gordon Millichap

2013-10-01

Full Text Available Investigators at the Roald Dahl EEG Unit, Alder Hey Children’s NHS Foundation, Liverpool, UK, review the definition, pathophysiology, clinical presentation, and management of reflex anoxic seizures (RAS in children.

Linear time delay methods and stability analyses of the human spine. Effects of neuromuscular reflex response.

Science.gov (United States)

Franklin, Timothy C; Granata, Kevin P; Madigan, Michael L; Hendricks, Scott L

2008-08-01

Linear stability methods were applied to a biomechanical model of the human musculoskeletal spine to investigate effects of reflex gain and reflex delay on stability. Equations of motion represented a dynamic 18 degrees-of-freedom rigid-body model with time-delayed reflexes. Optimal muscle activation levels were identified by minimizing metabolic power with the constraints of equilibrium and stability with zero reflex time delay. Muscle activation levels and associated muscle forces were used to find the delay margin, i.e., the maximum reflex delay for which the system was stable. Results demonstrated that stiffness due to antagonistic co-contraction necessary for stability declined with increased proportional reflex gain. Reflex delay limited the maximum acceptable proportional reflex gain, i.e., long reflex delay required smaller maximum reflex gain to avoid instability. As differential reflex gain increased, there was a small increase in acceptable reflex delay. However, differential reflex gain with values near intrinsic damping caused the delay margin to approach zero. Forward-dynamic simulations of the fully nonlinear time-delayed system verified the linear results. The linear methods accurately found the delay margin below which the nonlinear system was asymptotically stable. These methods may aid future investigations in the role of reflexes in musculoskeletal stability.

Adaptive control of two-wheeled mobile balance robot capable to adapt different surfaces using a novel artificial neural network–based real-time switching dynamic controller

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Ali Unluturk

2017-03-01

Full Text Available In this article, a novel real-time artificial neural network–based adaptable switching dynamic controller is developed and practically implemented. It will be used for real-time control of two-wheeled balance robot which can balance itself upright position on different surfaces. In order to examine the efficiency of the proposed controller, a two-wheeled mobile balance robot is designed and a test platform for experimental setup is made for balance problem on different surfaces. In a developed adaptive controller algorithm which is capable to adapt different surfaces, mean absolute target angle deviation error, mean absolute target displacement deviation error and mean absolute controller output data are employed for surface estimation by using artificial neural network. In a designed two-wheeled mobile balance robot system, robot tilt angle is estimated via Kalman filter from accelerometer and gyroscope sensor signals. Furthermore, a visual robot control interface is developed in C++ software development environment so that robot controller parameters can be changed as desired. In addition, robot balance angle, linear displacement and controller output can be observed online on personal computer. According to the real-time experimental results, the proposed novel type controller gives more effective results than the classic ones.

Postural control in elderly persons with osteoporosis: Efficacy of an intervention program to improve balance and muscle strength: a randomized controlled trial.

Science.gov (United States)

Burke, Thomaz Nogueira; França, Fábio Jorge Renovato; Ferreira de Meneses, Sarah Rúbia; Cardoso, Viviam Inhasz; Marques, Amélia Pasqual

2010-07-01

To assess the efficacy of an exercise program aiming to improve balance and muscular strength, for postural control and muscular strength of women with osteoporosis. Sample consisted of 33 women with osteoporosis, randomized into one of two groups: intervention group, in which exercises for balance and improvement of muscular strength of the inferior members were performed for 8 wks (n = 17, age 72.8 +/- 3.6 yrs); control group, which was women not practicing exercises (n = 16, age 74.4 +/- 3.7 yrs). At baseline and after 8 wks of treatment, postural control was assessed using a force plate (Balance Master, Neurocom), and muscular strength during ankle dorsiflexion, knee extension, and flexion was assessed by dynamometry. Adherence to the program was 82%. When compared with the control group, individuals in the intervention group significantly improved the center of pressure velocity (P = 0.02) in the modified clinical test of sensory interaction for balance test, center of pressure velocity (P control (P postural control and lower-limb strength in elderly women with osteoporosis.

A new hypothesis of cause of syncope: trigeminocardiac reflex during extraction of teeth.

Science.gov (United States)

Arakeri, Gururaj; Arali, Veena

2010-02-01

Transient Loss Of Consciousness (TLOC) or vasovagal syncope is well known phenomenon in dental/maxillofacial surgery. Despite considerable study of vasovagal syncope, its pathophysiology remains to be fully elucidated. After having encountered a case of trigeminocardiac reflex after extraction of maxillary first molar we observed and studied 400 extractions under local anesthesia to know the relation between trigeminocardiac reflex and syncope. We make hypothesis that trigeminocardiac reflex which is usually seen under general anesthesia when all sympathetic reflexes are blunted can also occur under local anesthesia during extractions of maxillary molars (dento-cardiac reflex) and mediate syncope.

High-power ion beam generation with an inverse reflex tetrode

International Nuclear Information System (INIS)

Pasour, J.A.; Mahaffey, R.A.; Golden, J.; Kapetanakos, C.A.

1980-01-01

A new reflexing-electron ion source is described. The device produces a unidirectional ion beam with relatively high efficiency even when the applied magnetic field exceeds the self-field. This new source operates at a low, constant impedance during much of the applied voltage pulse and is better matched to available high-power, low-impedance generators than previous reflexing-electron devices. Proton pulses with peak current approx.500 kA have been produced with the inverse reflex tetrode coupled to the Gamble II generator

The Role of Transformational Leadership in Enhancing Team Reflexivity

NARCIS (Netherlands)

M.C. Schippers (Michaéla); D.N. den Hartog (Deanne); P.L. Koopman (Paul); D.L. van Knippenberg (Daan)

2007-01-01

textabstractTeam reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to

The role of transformational leadership in enhancing team reflexivity

NARCIS (Netherlands)

Schippers, M.C.; den Hartog, D.N.; Koopman, P.L.; van Knippenberg, D.

2008-01-01

Team reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to develop

The effect of mindfulness meditation on cough reflex sensitivity.

Science.gov (United States)

Young, E C; Brammer, C; Owen, E; Brown, N; Lowe, J; Johnson, C; Calam, R; Jones, S; Woodcock, A; Smith, J A

2009-11-01

Chronic cough is common, and medical treatment can be ineffective. Mindfulness is a psychological intervention that aims to teach moment-to-moment non-judgemental awareness of thoughts, feelings and sensations. 30 healthy subjects and 30 patients with chronic cough were studied in two sequential trials. For both studies, cough reflex sensitivity to citric acid (C5) was measured on two occasions, with urge to cough rated following each inhalation; between challenges subjects were randomised to (1) no intervention, (2) mindfulness or (3) no intervention but modified cough challenge (subjects suppress coughing). For the healthy volunteers, measures were 1 h apart and mindfulness was practised for 15 min. For the patients with chronic cough measures were 1 week apart and mindfulness was practised daily for 30 min. In healthy volunteers, median change (interquartile range (IQR)) in cough reflex sensitivity (logC5) for no intervention, mindfulness and suppression was +1.0 (0.0 to +1.3), +2.0 (+1.0 to +3.0) and +3.0 (+2.8 to +3.0) doubling concentrations (p = 0.003); there were significant reductions for both mindfulness (p = 0.043) and suppression (p = 0.002) over no intervention. In patients with cough, median change (IQR) in logC5 for no intervention, mindfulness training and voluntary suppression was 0.0 (-1.0 to +1.0), +1.0 (-0.3 to +1.0) and +1.0 (+1.0 to +2.0) doubling concentrations (p = 0.046); there was a significant reduction for suppression (p = 0.02) but not mindfulness (p = 0.35). Urge to cough did not change after mindfulness compared with control in either healthy subjects (p = 0.33) or those with chronic cough (p = 0.47). Compared with control, mindfulness decreased cough reflex sensitivity in healthy volunteers, but did not alter cough threshold in patients with chronic cough. Both groups were able to suppress cough responses to citric acid inhalation.

An artificial neural network estimation of gait balance control in the elderly using clinical evaluations.

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Vipul Lugade

Full Text Available The use of motion analysis to assess balance is essential for determining the underlying mechanisms of falls during dynamic activities. Clinicians evaluate patients using clinical examinations of static balance control, gait performance, cognition, and neuromuscular ability. Mapping these data to measures of dynamic balance control, and the subsequent categorization and identification of community dwelling elderly fallers at risk of falls in a quick and inexpensive manner is needed. The purpose of this study was to demonstrate that given clinical measures, an artificial neural network (ANN could determine dynamic balance control, as defined by the interaction of the center of mass (CoM with the base of support (BoS, during gait. Fifty-six elderly adults were included in this study. Using a feed-forward neural network with back propagation, combinations of five functional domains, the number of hidden layers and error goals were evaluated to determine the best parameters to assess dynamic balance control. Functional domain input parameters included subject characteristics, clinical examinations, cognitive performance, muscle strength, and clinical balance performance. The use of these functional domains demonstrated the ability to quickly converge to a solution, with the network learning the mapping within 5 epochs, when using up to 30 hidden nodes and an error goal of 0.001. The ability to correctly identify the interaction of the CoM with BoS demonstrated correlation values up to 0.89 (P<.001. On average, using all clinical measures, the ANN was able to estimate the dynamic CoM to BoS distance to within 1 cm and BoS area to within 75 cm2. Our results demonstrated that an ANN could be trained to map clinical variables to biomechanical measures of gait balance control. A neural network could provide physicians and patients with a cost effective means to identify dynamic balance issues and possible risk of falls from routinely collected clinical

Proximally evoked soleus H-reflex to S1 nerve root stimulation in sensory neuronopathies (ganglionopathies).

Science.gov (United States)

Zhu, Dong-Qing; Zhu, Yu; Qiao, Kai; Zheng, Chao-Jun; Bradley, Scott; Weber, Robert; Chen, Xiang-Jun

2013-11-01

Sensory neuronopathy (SNN) mimics distal sensory axonopathy. The conventional H-reflex elicited by tibial nerve stimulation (tibial H-reflex) is usually abnormal in both conditions. We evaluated the proximally evoked soleus H-reflex in response to S1 nerve root stimulation (S1 foramen H-reflex) in SNN. Eleven patients with SNN and 6 with distal sensory axonopathy were studied. Tibial and S1 foramen H-reflexes were performed bilaterally in each patient. Tibial and S1 foramen H-reflexes were absent bilaterally in all patients with SNN. In the patients with distal sensory axonopathy, tibial H-reflexes were absent in 4 and demonstrated prolonged latencies in 2, but S1 foramen H-reflexes were normal. Characteristic absence of the H-reflex after both proximal and distal stimulation reflects primary loss of dorsal root ganglion (DRG) neurons and the distinct non-length-dependent impairment of sensory nerve fibers in SNN. Copyright © 2013 Wiley Periodicals, Inc.

Trigeminocardiac reflex during endoscopic juvenile nasopharyngeal angiofibroma surgery: an appraisal.

Science.gov (United States)

Sharma, Shilpee Bhatia; Janakiram, Trichy Narayanan; Baxi, Hina; Chinnasamy, Balamurugan

2017-07-01

Juvenile nasopharyngeal angiofibroma is a locally aggressive benign tumour which has propensity to erode the skull base. The tumour spreads along the pathways of least resistance and is in close proximity to the extracranial part of trigeminal nerve. Advancements in expanded approaches for endoscopic excision of tumours in infratemporal fossa and pterygopalatine fossa increase the vulnerability for the trigeminocardiac reflex. The manipulation of nerve and its branches during tumour dissection can lead to sensory stimulation and thus inciting the reflex. The aim of our study is to report the occurrence of trigeminocardiac reflex in endoscopic excision of juvenile nasopharyngeal angiofibroma. To describe the occurence of trigeminocardiac reflex during endoscopic endonasal excision of juvenile nasopharyngeal angiofibroma. We studied the occurrence of TCR in 15 patients (out of 242 primary cases and 52 revision cases) operated for endoscopic endonasal excision of JNA. The drop in mean arterial blood pressure and heart rate were observed and measured. To the best of our knowledge of English literature, this is the first case series reporting TCR as complication in endoscopic excision of JNA. occurence of this reflex has been mentioned in various occular, maxillofacial surgeries but its occurence during endoscopic excision of JNA has never been reported before. Manifestation of trigeminocardiac reflex during surgery can alter the course of the surgery and is a potential threat to life. It is essential for the anesthetist and surgeons to be familiar with the presentations, preventive measures and management protocols.

Functional-Strengthening: A Pilot Study on Balance Control Improvement in Community-Dwelling Older Adults

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Micah D. Josephson

2017-09-01

Full Text Available Adults over the age of 65 have a 1 in 3 chance of falling; in 2012, more than $30 billion was spent on medical costs due to these falls. The division of resistance training and neuromotor training balance improvement interventions has shown to yield low to moderate results. Athletes combine both resistance training and skill development (function training to improve skilled performance. Older adults may not be performing high-level sports activities, but still require strength, power, and functional fitness levels to perform relatively high-level skills. The purpose of this study was to determine the effects of combining resistance and functional training into functional-strength training on dynamic balance control in moderately active older adults. Eighteen healthy older adults were divided into three groups; functional resistance, standard resistance, and control. All groups met for their intervention twice a week for six weeks. Dynamic balance was assessed using the Fullerton Advanced Balance Scale (0-40. Results of individual paired T-tests showed a significant improvement in balance control in the functional resistance group (t(5 =-3.492, p=.017 and a very large effect size (d=1.33 whereas neither the standard resistance nor control group had a significant reduction in the risk of falls. Manipulating multidimensional, neuromotor function during resistance training exercises is an effective method of applying the overload principle in order to reduce falls risk in moderately active seniors.

Pilot study comparing changes in postural control after training using a video game balance board program and 2 standard activity-based balance intervention programs.

Science.gov (United States)

Pluchino, Alessandra; Lee, Sae Yong; Asfour, Shihab; Roos, Bernard A; Signorile, Joseph F

2012-07-01

To compare the impacts of Tai Chi, a standard balance exercise program, and a video game balance board program on postural control and perceived falls risk. Randomized controlled trial. Research laboratory. Independent seniors (N=40; 72.5±8.40) began the training, 27 completed. Tai Chi, a standard balance exercise program, and a video game balance board program. The following were used as measures: Timed Up & Go, One-Leg Stance, functional reach, Tinetti Performance Oriented Mobility Assessment, force plate center of pressure (COP) and time to boundary, dynamic posturography (DP), Falls Risk for Older People-Community Setting, and Falls Efficacy Scale. No significant differences were seen between groups for any outcome measures at baseline, nor were significant time or group × time differences for any field test or questionnaire. No group × time differences were seen for any COP measures; however, significant time differences were seen for total COP, 3 of 4 anterior/posterior displacement and both velocity, and 1 displacement and 1 velocity medial/lateral measure across time for the entire sample. For DP, significant improvements in the overall score (dynamic movement analysis score), and in 2 of the 3 linear and angular measures were seen for the sample. The video game balance board program, which can be performed at home, was as effective as Tai Chi and the standard balance exercise program in improving postural control and balance dictated by the force plate postural sway and DP measures. This finding may have implications for exercise adherence because the at-home nature of the intervention eliminates many obstacles to exercise training. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Balancing the dual responsibilities of business unit controllers: field and survey evidence

NARCIS (Netherlands)

Maas, V.S.; Matejka, M.

2009-01-01

We examine how business unit (BU) controllers balance their dual roles of providing information for both local decision-making (local responsibility) and corporate control (functional responsibility). The existing literature suggests that organizations can improve the quality of financial reporting

Once-per-step control of ankle-foot prosthesis push-off work reduces effort associated with balance during walking.

Science.gov (United States)

Kim, Myunghee; Collins, Steven H

2015-05-01

Individuals with below-knee amputation have more difficulty balancing during walking, yet few studies have explored balance enhancement through active prosthesis control. We previously used a dynamical model to show that prosthetic ankle push-off work affects both sagittal and frontal plane dynamics, and that appropriate step-by-step control of push-off work can improve stability. We hypothesized that this approach could be applied to a robotic prosthesis to partially fulfill the active balance requirements of human walking, thereby reducing balance-related activity and associated effort for the person using the device. We conducted experiments on human participants (N = 10) with simulated amputation. Prosthetic ankle push-off work was varied on each step in ways expected to either stabilize, destabilize or have no effect on balance. Average ankle push-off work, known to affect effort, was kept constant across conditions. Stabilizing controllers commanded more push-off work on steps when the mediolateral velocity of the center of mass was lower than usual at the moment of contralateral heel strike. Destabilizing controllers enforced the opposite relationship, while a neutral controller maintained constant push-off work regardless of body state. A random disturbance to landing foot angle and a cognitive distraction task were applied, further challenging participants' balance. We measured metabolic rate, foot placement kinematics, center of pressure kinematics, distraction task performance, and user preference in each condition. We expected the stabilizing controller to reduce active control of balance and balance-related effort for the user, improving user preference. The best stabilizing controller lowered metabolic rate by 5.5% (p = 0.003) and 8.5% (p = 0.02), and step width variability by 10.0% (p = 0.009) and 10.7% (p = 0.03) compared to conditions with no control and destabilizing control, respectively. Participants tended to prefer stabilizing controllers

The gait and balance of patients with diabetes can be improved: a randomised controlled trial.

Science.gov (United States)

Allet, L; Armand, S; de Bie, R A; Golay, A; Monnin, D; Aminian, K; Staal, J B; de Bruin, E D

2010-03-01

Gait characteristics and balance are altered in diabetic patients. Little is known about possible treatment strategies. This study evaluates the effect of a specific training programme on gait and balance of diabetic patients. This was a randomised controlled trial (n=71) with an intervention (n=35) and control group (n=36). The intervention consisted of physiotherapeutic group training including gait and balance exercises with function-orientated strengthening (twice weekly over 12 weeks). Controls received no treatment. Individuals were allocated to the groups in a central office. Gait, balance, fear of falls, muscle strength and joint mobility were measured at baseline, after intervention and at 6-month follow-up. The trial is closed to recruitment and follow-up. After training, the intervention group increased habitual walking speed by 0.149 m/s (pbalance (time to walk over a beam, balance index recorded on Biodex balance system), their performance-oriented mobility, their degree of concern about falling, their hip and ankle plantar flexor strength, and their hip flexion mobility compared with the control group. After 6 months, all these variables remained significant except for the Biodex sway index and ankle plantar flexor strength. Two patients developed pain in their Achilles tendon: the progression for two related exercises was slowed down. Specific training can improve gait speed, balance, muscle strength and joint mobility in diabetic patients. Further studies are needed to explore the influence of these improvements on the number of reported falls, patients' physical activity levels and quality of life. ClinicalTrials.gov NCT00637546 This work was supported by the Swiss National Foundation (SNF): PBSKP-123446/1/

Regularity in an environment produces an internal torque pattern for biped balance control.

Science.gov (United States)

Ito, Satoshi; Kawasaki, Haruhisa

2005-04-01

In this paper, we present a control method for achieving biped static balance under unknown periodic external forces whose periods are only known. In order to maintain static balance adaptively in an uncertain environment, it is essential to have information on the ground reaction forces. However, when the biped is exposed to a steady environment that provides an external force periodically, uncertain factors on the regularity with respect to a steady environment are gradually clarified using learning process, and finally a torque pattern for balancing motion is acquired. Consequently, static balance is maintained without feedback from ground reaction forces and achieved in a feedforward manner.

A novel dual task balance test with cognitive cues for the postural control

DEFF Research Database (Denmark)

Læssøe, Uffe; Grarup, Bo

Background and aim. There may be significant attention requirements for the postural control, depending on the postural task, the age and the balance abilities of the individual. The use of a dual task approach is therefore believed to be relevant in the assessment of balance. In this context...... in impaired performance in one or both tasks. The results indicate that the proposed test procedure in a standardized way reveal that the elderly require increased conscious attention to maintain postural control during reaching and stepping tasks....

Impact of Spasticity on Balance Control during Quiet Standing in Persons after Stroke

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Reza Rahimzadeh Khiabani

2017-01-01

Full Text Available Background. Balance impairments, falls, and spasticity are common after stroke, but the effect of spasticity on balance control after stroke is not well understood. Methods. In this cross-sectional study, twenty-seven participants with stroke were divided into two groups, based on ankle plantar flexor spasticity level. Fifteen individuals with high spasticity (Modified Ashworth Scale (MAS score of ≥2 and 12 individuals with low spasticity (MAS score <2 completed quiet standing trials with eyes open and closed conditions. Balance control measures included centre of pressure (COP root mean square (RMS, COP velocity, and COP mean power frequency (MPF in anterior-posterior and mediolateral (ML directions. Trunk sway was estimated using a wearable inertial measurement unit to measure trunk angle, trunk velocity, and trunk velocity frequency amplitude in pitch and roll directions. Results. The high spasticity group demonstrated greater ML COP velocity, trunk roll velocity, trunk roll velocity frequency amplitude at 3.7 Hz, and trunk roll velocity frequency amplitude at 4.9 Hz, particularly in the eyes closed condition (spasticity by vision interaction. ML COP MPF was greater in the high spasticity group. Conclusion. Individuals with high spasticity after stroke demonstrated greater impairment of balance control in the frontal plane, which was exacerbated when vision was removed.

[Balance trainability using the Nintendo Wii balance board in sportive people].

Science.gov (United States)

Paukowits, S; Stöggl, T

2014-03-01

A multivariable training has a positive impact on balance skills and risk of injury. To date the effect of this training using the Nintendo Wii balance board in sportive people has not yet been investigated. The aim of this study was to investigate whether training with the Nintendo Wii balance board can improve balance skills. 20 people were randomized into a control and an intervention group each with 10 people who performed a unilateral stance test with eyes open and closed as well as the star excursion balance test before and after the intervention. The control group completed their usual sports and the intervention group an adjunct training with the Nintendo Wii balance board for 4 weeks. Adjunct Training using the Nintendo Wii Balance Board did not improve sportive people's balance skills significantly. The intervention group, however, attained better results in the star excursion balance test, whereas the control group did not show any changes. The unilateral stance tests did not provide significant differences before and after training within both groups. The use of the Nintendo Wii balance board should be further investigated by employing individual difficulty levels. © Georg Thieme Verlag KG Stuttgart · New York.

From Incidental, Mechanically-Induced Arrhythmias to Reflex-Defined Arrhythmogenicity: On The Track of The Ternary Reflex System Resemblance to The "Infancy" of New Era or Rediscovery.

Science.gov (United States)

Stirbys, Petras

2016-01-01

The underlying pathophysiology of supraventricular and ventricular arrhythmias remains a matter of intense investigation. Though evolving, the contemporary explanations do not encompass all aspects of arrhythmogenicity. An improved understanding of arrhythmia substrate is needed to augment therapeutic capabilities. Our observation and literature sources demonstrate relatively high incidence of transitory arrhythmias which are non-intentionally generated by the endocardial lead/catheter manipulation. These findings are interesting and potentially may crystallize the reflex-dependent proarrhythmic cardiac activity. Herein we suggest the "reflexogenic arrhythmogenicity" concept extending an overall spectrum of known hypotheses. Cardiovascular reflex action can be categorized into three-tiered levels - intra-cellular, inter-cellular and inter-organic. The first two levels of the triplicate system reside within the cardiac anatomical landmarks (in fact intramurally, intra-organically), however the third one implicates central (cerebral) activity which boomerangs back via centripetal and centrifugal connections. These levels likely compose synoptic ternary reflex set system which may be validated in future studies. To hypothesize, coordinated mutual reciprocity of reflex activity results in stabilization of heart rhythm in robust heart. Any stressful cardiac event may lead to the shift of the rhythm toward unfavorable clinical entity probably via the loss of the influence of dominant reflex. Overall, an interaction and likely intrinsic inter-tiered competition along with possible interplay between physiological and pathological reflexes may be treated as contributing factors for the inception and maintaining of arrhythmias and cardiac performance as well. These assumptions await further documentation. If such a tenet were recognized, the changes in the clinical approach to arrhythmia management might be anticipated, preferably by selective reflex suppression or

Efficacy of ankle control balance training on postural balance and gait ability in community-dwelling older adults: a single-blinded, randomized clinical trial

OpenAIRE

Lee, Kyeongjin; Lee, Yong Woo

2017-01-01

[Purpose] This study was conducted to investigate the effects of ankle control balance training (ACBT) on postural balance and gait ability in community-dwelling older adults. [Subjects and Methods] Fifty-four subjects were randomly divided into two groups, with 27 subjects in the ACBT group and 27 subjects in the control group. Subjects in the ACBT group received ACBT for 60 minutes, twice per week for 4 weeks, and all subjects had undergone fall prevention education for 60 minutes, once per...

Abnormal sensory integration affects balance control in hemiparetic patients within the first year after stroke

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Clarissa B. Oliveira

2011-01-01

Full Text Available OBJECTIVE: Impairments in balance can be a consequence of changes in the motor, sensory, and integrative aspects of motor control. Abnormal sensory reweighting, i.e., the ability to select the most appropriate sensory information to achieve postural stability, may contribute to balance impairment. The Sensory Organization Test is a component of Computerized Dynamic Posturography that evaluates the impact of visual, vestibular, and somatosensory inputs, as well as sensory reweighting, under conditions of sensory conflict. The aim of this study is to compare balance control in hemiparetic patients during the first year post-stroke and in age-matched neurologically normal subjects using the Berg Balance Scale and Computerized Dynamic Posturography. METHODS: We compared the Berg Balance Scale and Sensory Organization Test scores in 21 patients with hemiparesis after first-ever ischemic stroke and in 21 age-matched, neurologically normal subjects. An equilibrium score was defined for each Sensory Organization Test condition. RESULTS: Berg Balance Scale scores were significantly lower in the patients than in the neurologically normal subjects. Equilibrium scores were significantly lower in the patients than in the neurologically normal subjects for those Sensory Organization Test conditions that did not provide appropriate somatosensory information and under conditions of sensory conflict. A history of falls was more frequent in patients with lower equilibrium scores. CONCLUSION: During the first year after a stroke, defective sensory reweighting significantly impacts balance control in hemiparetic patients. These results are important for the planning of effective rehabilitation interventions.

Emotion, reflexivity and social change in the era of extreme fossil fuels.

Science.gov (United States)

Davidson, Debra J

2018-05-09

Reflexivity is an important sociological lens through which to examine the means by which people engage in actions that contribute to social reproduction or social elaboration. Reflexivity theorists have largely overlooked the central place of emotions in reflexive processing, however, thus missing opportunities to enhance our understanding of reflexivity by capitalizing on recent scholarship on emotions emanating from other fields of inquiry. This paper explores the role of emotion in reflexivity, with a qualitative analysis of social responses to hydraulic fracturing in Alberta, Canada, utilizing narrative analysis of long-form interviews with rural landowners who have experienced direct impacts from hydraulic fracturing, and have attempted to voice their concerns in the public sphere. Based on interviews with a selection of two interview participants, the paper highlights the means by which emotions shape reflexivity in consequential ways, beginning with personal and highly individualized emotional responses to contingent situations, which then factor into the social interactions engaged in the pursuit of personal projects. The shared emotional context that emerges then plays a substantial role in shaping outcomes and their implications for social stasis or change. This study exemplifies the extent to which reflexive processing in response to breaches in the social order can be emotionally tumultuous affairs, constituting a significant personal toll that many may be unwilling to pay. © London School of Economics and Political Science 2018.

No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

Science.gov (United States)

Gibson, W; Campbell, A; Allison, G

2013-09-01

Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. Copyright © 2013 Elsevier B.V. All rights reserved.

Objective impairments of gait and balance in adults living with HIV-1 infection: a systematic review and meta-analysis of observational studies.

Science.gov (United States)

Berner, Karina; Morris, Linzette; Baumeister, Jochen; Louw, Quinette

2017-08-01

Gait and balance deficits are reported in adults with HIV infection and are associated with reduced quality of life. Current research suggests an increased fall-incidence in this population, with fall rates among middle-aged adults with HIV approximating that in seronegative elderly populations. Gait and postural balance rely on a complex interaction of the motor system, sensory control, and cognitive function. However, due to disease progression and complications related to ongoing inflammation, these systems may be compromised in people with HIV. Consequently, locomotor impairments may result that can contribute to higher-than-expected fall rates. The aim of this review was to synthesize the evidence regarding objective gait and balance impairments in adults with HIV, and to emphasize those which could contribute to increased fall risk. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search of published observational studies was conducted in March 2016. Methodological quality was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Narrative synthesis of gait and balance outcomes was performed, and meta-analyses where possible. Seventeen studies were included, with fair to low methodological quality. All studies used clinical tests for gait-assessment. Gait outcomes assessed were speed, initiation-time and cadence. No studies assessed kinetics or kinematics. Balance was assessed using both instrumented and clinical tests. Outcomes were mainly related to center of pressure, postural reflex latencies, and timed clinical tests. There is some agreement that adults with HIV walk slower and have increased center of pressure excursions and -long loop postural reflex latencies, particularly under challenging conditions. Gait and balance impairments exist in people with HIV, resembling fall-associated parameters in the elderly. Impairments are

THE CONCEPT OF REFLEXIVE MANAGEMENT OF CONSUMER DEMAND

Directory of Open Access Journals (Sweden)

Maryna Mavrina

2017-11-01

Full Text Available Development of theoretical approaches of demand management is conducted from the moment of awareness of the importance of this concept. Many models of individual consumers were developed. However, to predict the reaction of consumers to the commercial policy of the enterprise, exact methods do not exist yet because the available ones are mostly empirical in nature. Models of behaviour often do not provide the expected result because they use an erroneous approach to the analysis of the mechanism of demand formation. The subject of the research is the theoretical and methodological basis, methods of assessment, and reflexive management of consumer demand of commercial enterprises. The purpose of the paper is developing a concept of reflexive management of consumer demand. To achieve the research goal, the following tasks are set and solved: to substantiate the theoretical and methodological foundations of reflexive consumer management, to analyse existing approaches to the modelling of consumer behaviour; to improve the model of consumer behaviour; to develop a concept of reflexive management of consumer behaviour. Methodology. In the paper, we use such methods and approaches to research as: reflexive approach (phenomenological method, behavioural economic theory, marketing approach, abstract-logical analysis, analysis of theoretical approaches to the modelling of consumer behaviour. Results. Modern approaches to modelling of consumer behaviour are mostly empirical in nature and have shortcomings of general models. In them, there is no description of specific situations of the purchase of goods. They cannot be quantified. Therefore, they cannot be practical models. But they have a weighty advantage in a comprehensive look at motivated purchases, what makes it possible to evaluate the relevance of individual variables and to understand the fundamental processes of consumer behaviour. It makes possible to identify the variables necessary for the

The ubiquitous reflex and its critics in post-revolutionary Russia.

Science.gov (United States)

Sirotkina, Irina

2009-03-01

In the last century, the reflex was more than a scientific concept: it was a cultural idiom that could be used to various aims--political, scholarly, and artistic. In Russia in the 1920s, the reflex became a ubiquitous notion and a current word, part of the revolutionary discourse and, finally, a password to modernity. Two major factors contributed to it: physiological theories of the reflex, widespread in Russia at the early twentieth-century, and the materialist philosophy backed after the Revolution by the Communist party. Everybody who wished to be modern and materialist, in conformity with the official communist views, had to refer to reflexes. Yet, even in this period, the concept was not unproblematic and was criticized by some scientists, philosophers, artists and even Party members. In the paper, I describe both the array of uses of the term and the criticism it received in political, scientific and artistic discourses. It is not uncommon that, taking their origins in culture and common language, scientific concepts later return there in the form of metaphors. Similarly, the reflex was made into a rigorous scientific concept in the nineteenth century but, in the next century, it circulated as a cultural idiom penetrating various areas of political, artistic and academic life.

A dual-task home-based rehabilitation programme for improving balance control in patients with acquired brain injury: a single-blind, randomized controlled pilot study.

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Peirone, Eliana; Goria, Paolo Filiberto; Anselmino, Arianna

2014-04-01

To evaluate the safety, feasibility and effectiveness of a dual-task home-based rehabilitation programme on balance impairments among adult patients with acquired brain injury. Single-blind, randomized controlled pilot study. Single rehabilitation centre. Sixteen participants between 12 and 18 months post-acquired brain injury with balance impairments and a score task home-based programme six days a week for seven weeks. The primary outcome measure was the Balance Evaluation System Test; secondary measures were the Activities-specific Balance Confidence Scale and Goal Attainment Scaling. At the end of the pilot study, the intervention group showed significantly greater improvement in Balance Evaluation System Test scores (17.87, SD 6.05) vs. the control group (5.5, SD 3.53; P = 0.008, r = 0.63). There was no significant difference in improvement in Activities-specific Balance Confidence Scale scores between the intervention group (25.25, SD 25.51) and the control group (7.00, SD 14.73; P = 0.11, r = 0.63). There was no significant improvement in Goal Attainment Scaling scores in the intervention (19.37, SD 9.03) vs. the control group (16.28, SD 6.58; P = 0.093, r = 0.63). This pilot study shows the safety, feasibility and short-term benefit of a dual-task home-based rehabilitation programme to improve balance control in patients with acquired brain injury. A sample size of 26 participants is required for a definitive study.

Evaluation of cranial tibial and extensor carpi radialis reflexes before and after anesthetic block in cats.

Science.gov (United States)

Tudury, Eduardo Alberto; de Figueiredo, Marcella Luiz; Fernandes, Thaiza Helena Tavares; Araújo, Bruno Martins; Bonelli, Marília de Albuquerque; Diogo, Camila Cardoso; Silva, Amanda Camilo; Santos, Cássia Regina Oliveira; Rocha, Nadyne Lorrayne Farias Cardoso

2017-02-01

Objectives This study aimed to test the extensor carpi radialis and cranial tibial reflexes in cats before and after anesthetic block of the brachial and lumbosacral plexus, respectively, to determine whether they depend on a myotatic reflex arc. Methods Fifty-five cats with a normal neurologic examination that were referred for elective gonadectomy were divided into group 1 (29 cats) for testing the extensor carpi radialis reflex, and group 2 (26 cats) for testing the cranial tibial reflex. In group 1, the extensor carpi radialis reflex was tested after anesthetic induction and 15 mins after brachial plexus block with lidocaine. In group 2, the cranial tibial, withdrawal and patellar reflexes were elicited in 52 hindlimbs and retested 15 mins after epidural anesthesia. Results In group 1, before the anesthetic block, 55.17% of the cats had a decreased and 44.83% had a normal extensor carpi radialis reflex. After the block, 68.96% showed a decreased and 27.59% a normal reflex. No cat had an increased or absent reflex before anesthetic block. In group 2, prior to the anesthetic block, 15.38% of the cats had a decreased cranial tibial reflex and 84.62% had a normal response, whereas after the block it was decreased in 26.92% and normal in 73.08% of the cats. None of the cats had an increased or absent reflex. Regarding the presence of both reflexes before and after anesthetic block, there was no significant difference at 1% ( P = 0.013). Conclusions and relevance The extensor carpi radialis and cranial tibial reflexes in cats are not strictly myotatic reflexes, as they are independent of the reflex arc, and may be idiomuscular responses. Therefore, they are not reliable for neurologic examination in this species.

The influence of diabetic peripheral neuropathy on local postural muscle and central sensory feedback balance control.

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Toosizadeh, Nima; Mohler, Jane; Armstrong, David G; Talal, Talal K; Najafi, Bijan

2015-01-01

Poor balance control and increased fall risk have been reported in people with diabetic peripheral neuropathy (DPN). Traditional body sway measures are unable to describe underlying postural control mechanism. In the current study, we used stabilogram diffusion analysis to examine the mechanism under which balance is altered in DPN patients under local-control (postural muscle control) and central-control (postural control using sensory cueing). DPN patients and healthy age-matched adults over 55 years performed two 15-second Romberg balance trials. Center of gravity sway was measured using a motion tracker system based on wearable inertial sensors, and used to derive body sway and local/central control balance parameters. Eighteen DPN patients (age = 65.4±7.6 years; BMI = 29.3±5.3 kg/m2) and 18 age-matched healthy controls (age = 69.8±2.9; BMI = 27.0±4.1 kg/m2) with no major mobility disorder were recruited. The rate of sway within local-control was significantly higher in the DPN group by 49% (healthy local-controlslope = 1.23±1.06×10-2 cm2/sec, Pcontrol balance behavior in DPN patients. Unlike local-control, the rate of sway within central-control was 60% smaller in the DPN group (healthy central-controlslope-Log = 0.39±0.23, Pcontrol rate of sway with neuropathy severity (rPearson = 0.65-085, Pcontrols. However, as soon as they perceived the magnitude of sway using sensory feedback, they chose a high rigid postural control strategy, probably due to high concerns for fall, which may increase the energy cost during extended period of standing; the adaptation mechanism using sensory feedback depends on the level of neuropathy and the history of diabetes.

Cervico-ocular Reflex Is Increased in People With Nonspecific Neck Pain.

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de Vries, Jurryt; Ischebeck, Britta K; Voogt, Lennard P; Janssen, Malou; Frens, Maarten A; Kleinrensink, Gert-Jan; van der Geest, Jos N

2016-08-01

Neck pain is a widespread complaint. People experiencing neck pain often present an altered timing in contraction of cervical muscles. This altered afferent information elicits the cervico-ocular reflex (COR), which stabilizes the eye in response to trunk-to-head movements. The vestibulo-ocular reflex (VOR) elicited by the vestibulum is thought to be unaffected by afferent information from the cervical spine. The aim of the study was to measure the COR and VOR in people with nonspecific neck pain. This study utilized a cross-sectional design in accordance with the STROBE statement. An infrared eye-tracking device was used to record the COR and the VOR while the participant was sitting on a rotating chair in darkness. Eye velocity was calculated by taking the derivative of the horizontal eye position. Parametric statistics were performed. The mean COR gain in the control group (n=30) was 0.26 (SD=0.15) compared with 0.38 (SD=0.16) in the nonspecific neck pain group (n=37). Analyses of covariance were performed to analyze differences in COR and VOR gains, with age and sex as covariates. Analyses of covariance showed a significantly increased COR in participants with neck pain. The VOR between the control group, with a mean VOR of 0.67 (SD=0.17), and the nonspecific neck pain group, with a mean VOR of 0.66 (SD=0.22), was not significantly different. Measuring eye movements while the participant is sitting on a rotating chair in complete darkness is technically complicated. This study suggests that people with nonspecific neck pain have an increased COR. The COR is an objective, nonvoluntary eye reflex and an unaltered VOR. This study shows that an increased COR is not restricted to patients with traumatic neck pain. © 2016 American Physical Therapy Association.

Child–Computer Interaction at the Beginner Stage of Music Learning: Effects of Reflexive Interaction on Children’s Musical Improvisation

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Addessi, Anna Rita; Anelli, Filomena; Benghi, Diber; Friberg, Anders

2017-01-01

In this article children’s musical improvisation is investigated through the “reflexive interaction” paradigm. We used a particular system, the MIROR-Impro, implemented in the framework of the MIROR project (EC-FP7), which is able to reply to the child playing a keyboard by a “reflexive” output, mirroring (with repetitions and variations) her/his inputs. The study was conducted in a public primary school, with 47 children, aged 6–7. The experimental design used the convergence procedure, based on three sample groups allowing us to verify if the reflexive interaction using the MIROR-Impro is necessary and/or sufficient to improve the children’s abilities to improvise. The following conditions were used as independent variables: to play only the keyboard, the keyboard with the MIROR-Impro but with not-reflexive reply, the keyboard with the MIROR-Impro with reflexive reply. As dependent variables we estimated the children’s ability to improvise in solos, and in duets. Each child carried out a training program consisting of 5 weekly individual 12 min sessions. The control group played the complete package of independent variables; Experimental Group 1 played the keyboard and the keyboard with the MIROR-Impro with not-reflexive reply; Experimental Group 2 played only the keyboard with the reflexive system. One week after, the children were asked to improvise a musical piece on the keyboard alone (Solo task), and in pairs with a friend (Duet task). Three independent judges assessed the Solo and the Duet tasks by means of a grid based on the TAI-Test for Ability to Improvise rating scale. The EG2, which trained only with the reflexive system, reached the highest average results and the difference with EG1, which did not used the reflexive system, is statistically significant when the children improvise in a duet. The results indicate that in the sample of participants the reflexive interaction alone could be sufficient to increase the improvisational

Two-Dimension Sorting and Selection Algorithm featuring Thermal Balancing Control for Modular Multilevel Converters

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Máthé, Lászlo; Teodorescu, Remus

2016-01-01

With the aim to solve the unbalanced thermal behavior in the modular multilevel converter, introduced by mismatch in the submodule parameters, a thermal balancing control strategy is proposed here. The proposed solution ensures a balanced junction temperature for the power devices, while the bala...

Interindividual differences in H reflex modulation during normal walking

DEFF Research Database (Denmark)

Simonsen, Erik B; Dyhre-Poulsen, Poul; Alkjaer, T

2002-01-01

was greater for the S group. The hip joint moment was similar for the groups. The EMG activity in the vastus lateralis and anterior tibial muscles was greater prior to heel strike for the S group. These data indicate that human walking exhibits at least two different motor patterns as evaluated by gating...... of afferent input to the spinal cord, by EMG activity and by walking mechanics. Increasing H reflex excitability during the swing phase appears to protect the subject against unexpected perturbations around heel strike by a facilitated stretch reflex in the triceps surae muscle. Alternatively, in subjects...... with a suppressed H reflex in the swing phase the knee joint extensors seem to form the primary protection around heel strike....

Shoulder reflexes

DEFF Research Database (Denmark)

Diederichsen, L.; Krogsgaard, M.; Voigt, Michael

2002-01-01

long latency (300 ms) excitatory reflex has been found when nerves in the capsule were stimulated electrically during shoulder surgery. In addition, when the anterior-inferior capsule was excited in conscious humans with modest amplitude electrical stimuli during muscle activity, a strong inhibition...... activity around the shoulder. This has implications for rehabilitation and shoulder surgery.......Dynamic shoulder stability is dependent on muscular coordination and sensory inputs. In the shoulder, mechanoreceptors are found in the coracoacromial ligament, the rotator cuff tendons, the musculotendinous junctions of the rotator cuff and in the capsule. The number of receptors in the capsule...

An Intelligent Computerized Stretch Reflex Measurement System For Clinical And Investigative Neurology

Science.gov (United States)

Flanagan, P. M.; Chutkow, J. G.; Riggs, M. T.; Cristiano, V. D.

1987-05-01

We describe the design of a reliable, user-friendly preprototype system for quantifying the tendon stretch reflexes in humans and large mammals. A hand-held, instrumented reflex gun, the impactor of which contains a single force sensor, interfaces with a computer. The resulting test system can deliver sequences of reproducible stimuli at graded intensities and adjustable durations to a muscle's tendon ("tendon taps"), measure the impacting force of each tap, and record the subsequent reflex muscle contraction from the same tendon -- all automatically. The parameters of the reflex muscle contraction include latency; mechanical threshold; and peak time, peak magnitude, and settling time. The results of clinical tests presented in this paper illustrate the system's potential usefulness in detecting neurologic dysfunction affecting the tendon stretch reflexes, in documenting the course of neurologic illnesses and their response to therapy, and in clinical and laboratory neurologic research.

Current physical activity improves balance control during sensory conflicting conditions in older adults.

Science.gov (United States)

Buatois, S; Gauchard, G C; Aubry, C; Benetos, A; Perrin, P

2007-01-01

Aging process is characterized by difficulties in ensuring balance control, especially in conditions of reduced or conflicting sensory information, leading to an increased risk of falling. Conversely, the practise of physical activities (PA) has been recognized as a good approach to improve the quality of balance control. This study aimed to investigate the influence of current and/or past PA on balance-related neurosensorial organization in older adults on the maintenance of the upright stance, especially during sensory conflicting situations. Postural control was evaluated by means of the Sensory Organization Test on 130 healthy noninstitutionalized volunteers aged over 65, split into four groups according to the presence or absence of PA before or after retirement. Subjects who practised PA for a long time (Gr1) and subjects who started PA after retirement (Gr2) displayed the best postural performances and better managed sensory conflicting situations compared to subjects who had stopped PA for many years (Gr3) and subjects who had never practised PA (Gr4). Multiple regression analyses revealed that current PA was the major determinant for postural parameters during sensorial conflict compared to age, gender, body mass index and past PA. Regular PA, even when started late in life, allows appropriate reorganization of the different components of postural control during sensory conflicting situations. Indeed, active subjects were more able to compensate for suppressed or perturbed sensory information by an increased usage of another referential and so to correct their posture by adopting a more appropriate balance strategy. Thus, PA counteracts the age-related decline of postural control and could consequently reduce the risk of falling.

Orthodoxy and reflexivity in international comparative analysis

DEFF Research Database (Denmark)

Lind, Jens; Valkenburg, Ben

2002-01-01

This contribution aims at four points.First we want to argue why we think a reflexive social science is more adequate than the orthodox consensus. In current practice much of the criticism on the orthodox consensus is shared on a theoretical level, without considering the implications and acting...... upon the consequences on the level of empirical research. We want to avoid that, so our second and third subject will be the practical implications of reflexivity for empirical research as well as for social policy. Our discussion on these subjects is based on the practical experiences in the INPART...

Effects of short term water immersion on peripheral reflex excitability in hemiplegic and healthy individuals: A preliminary study.

Science.gov (United States)

Cronin, N J; Valtonen, A M; Waller, B; Pöyhönen, T; Avela, J

2016-03-01

Reflex excitability is increased in hemiplegic patients compared to healthy controls. One challenge of stroke rehabilitation is to decrease the effects of hyperreflexia, which may be possible with water immersion. Methods/Aims: The present study examined the effects of acute water immersion on electrically-evoked Hmax:Mmax ratios (a measure of reflex excitability) in 7 hyperreflexive hemiplegic patients and 7 age-matched healthy people. Hmax:Mmax ratios were measured from soleus on dry land (L1), immediately after (W1) and 5 minutes after immersion (W5), and again after five minutes on land (L5). Water immersion led to an acute increase in Hmax:Mmax ratio in both groups. However, after returning to dry land, there was a non-significant decrease in the Hmax:Mmax ratio of 8% in the hemiplegic group and 10% in healthy controls compared to pre-immersion values. A short period of water immersion can decrease peripheral reflex excitability after returning to dry land in both healthy controls and post-stroke patients, although longer immersion periods may be required for sustainable effects. Water immersion may offer promise as a low-risk, non-invasive and non-pharmaceutical method of decreasing hyperreflexivity, and could thus support aquatic rehabilitation following stroke.

Controlling factors of the oxygen balance in the Arabian Sea's OMZ

Digital Repository Service at National Institute of Oceanography (India)

Resplandy, L.; Levy, M.; Bopp, L.; Echevin, V.; Pous, S.; Sarma, V.V.S.S.; Kumar, M.D.

, 5095–5109, 2012 www.biogeosciences.net/9/5095/2012/ doi:10.5194/bg-9-5095-2012 © Author(s) 2012. CC Attribution 3.0 License. Biogeosciences Controlling factors of the oxygen balance in the Arabian Sea’s OMZ L. Resplandy1, M. Le´vy2, L. Bopp1, V. Echevin.... Resplandy et al.: Oxygen balance in the Arabian Sea OMZ OMZs are carefully examined for their possible interactions with the climate system and impacts on ecosystems. They could modulate atmospheric concentrations of major green- house gases such as CO2...

The reflexive case study method

DEFF Research Database (Denmark)

Rittenhofer, Iris

2015-01-01

This paper extends the international business research on small to medium-sized enterprises (SME) at the nexus of globalization. Based on a conceptual synthesis across disciplines and theoretical perspectives, it offers management research a reflexive method for case study research of postnational...

Complexity and dynamics of switched human balance control during quiet standing.

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Nema, Salam; Kowalczyk, Piotr; Loram, Ian

2015-10-01

In this paper, we use a combination of numerical simulations, time series analysis, and complexity measures to investigate the dynamics of switched systems with noise, which are often used as models of human balance control during quiet standing. We link the results with complexity measures found in experimental data of human sway motion during quiet standing. The control model ensuring balance, which we use, is based on an act-and-wait control concept, that is, a human controller is switched on when a certain sway angle is reached. Otherwise, there is no active control present. Given a time series data, we determine how does it look a typical pattern of control strategy in our model system. We detect the switched nonlinearity in the system using a frequency analysis method in the absence of noise. We also analyse the effect of time delay on the existence of limit cycles in the system in the absence of noise. We perform the entropy and detrended fluctuation analyses in view of linking the switchings (and the dead zone) with the occurrences of complexity in the model system in the presence of noise. Finally, we perform the entropy and detrended fluctuation analyses on experimental data and link the results with numerical findings in our model example.

Brain Ceramide Metabolism in the Control of Energy Balance

Directory of Open Access Journals (Sweden)

Céline Cruciani-Guglielmacci

2017-10-01

Full Text Available The regulation of energy balance by the central nervous system (CNS is a key actor of energy homeostasis in mammals, and deregulations of the fine mechanisms of nutrient sensing in the brain could lead to several metabolic diseases such as obesity and type 2 diabetes (T2D. Indeed, while neuronal activity primarily relies on glucose (lactate, pyruvate, the brain expresses at high level enzymes responsible for the transport, utilization and storage of lipids. It has been demonstrated that discrete neuronal networks in the hypothalamus have the ability to detect variation of circulating long chain fatty acids (FA to regulate food intake and peripheral glucose metabolism. During a chronic lipid excess situation, this physiological lipid sensing is impaired contributing to type 2 diabetes in predisposed subjects. Recently, different studies suggested that ceramides levels could be involved in the regulation of energy balance in both hypothalamic and extra-hypothalamic areas. Moreover, under lipotoxic conditions, these ceramides could play a role in the dysregulation of glucose homeostasis. In this review we aimed at describing the potential role of ceramides metabolism in the brain in the physiological and pathophysiological control of energy balance.

Reconceptualizing reflexivity and dissonance in professional and personal domains.

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Brooks, Ann

2008-09-01

Debates around 'reflexivity' and the construction of the gendered self within late modernity have occupied the attention of both 'reflexive modernization' theorists (Beck, Giddens and Lash 1994; Beck and Beck-Gernsheim 1996; Giddens 1991, 1992) as well as gender and feminist theorists. While theorists such as Beck and Giddens have been preoccupied with establishing the connection between reflexivity and the construction of the 'non-gendered' self, gender and feminist theorists have sought to amplify the debate by exploring the intersecting nexus of contemporary theorizing, more fully within this context. This paper explores the theoretical underpinnings of these debates and their application to specific professional and personal domains. I consider three case studies to assess these issues as outlined in my own work, Brooks 2006, and in the work of Wajcman and Martin 2002, and McDowell 1997, which draw on empirical research and explore changes to gender identity within professional and personal domains. I conclude that there is little evidence in the research presented here of any systematic reconfiguring of gender identities leading to a detraditionalization of gender as suggested by the 'reflexive modernization' theorists.

Modulation of the masseteric reflex by gastric vagal afferents.

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Pettorossi, V E

1983-04-01

Several investigations have shown that the vagal nerve can affect the reflex responses of the masticatory muscles acting at level either of trigeminal motoneurons or of the mesencephalic trigeminal nucleus (MTN). The present experiments have been devoted to establish the origin of the vagal afferent fibres involved in modulating the masseteric reflex. In particular, the gastric vagal afferents were taken into consideration and selective stimulations of such fibres were performed in rabbit. Conditioning electrical stimulation of truncus vagalis ventralis (TVV) reduced the excitability of the MTN cells as shown by a decrease of the antidromic response recorded from the semilunar ganglion and elicited by MTN single-shock electrical stimulation. Sympathetic and cardiovascular influences were not involved in these responses. Mechanical stimulation of gastric receptors, by means of gastric distension, clearly diminished the amplitude of twitch tension of masseteric reflex and inhibited the discharge frequency of proprioceptive MTN units. The effect was phasic and depended upon the velocity of distension. Thus the sensory volleys originating from rapid adapting receptors reach the brain stem through vagal afferents and by means of a polysynaptic connection inhibits the masseteric reflex at level of MTN cells.

An evaluation of a nurse-led rehabilitation programme (the ProBalance Programme) to improve balance and reduce fall risk of community-dwelling older people: A randomised controlled trial.

Science.gov (United States)

Gouveia, Bruna Raquel; Gonçalves Jardim, Helena; Martins, Maria Manuela; Gouveia, Élvio Rúbio; de Freitas, Duarte Luís; Maia, José António; Rose, Debra J

2016-04-01

This study aims to assess the effect of a nurse-led rehabilitation programme (the ProBalance Programme) on balance and fall risk of community-dwelling older people from Madeira Island, Portugal. Single-blind, randomised controlled trial. University laboratory. Community-dwelling older people, aged 65-85, with balance impairments. Participants were randomly allocated to an intervention group (IG; n=27) or a wait-list control group (CG; n=25). A rehabilitation nursing programme included gait, balance, functional training, strengthening, flexibility, and 3D training. One trained rehabilitation nurse administered the group-based intervention over a period of 12 weeks (90min sessions, 2 days per week). A wait-list control group was instructed to maintain their usual activities during the same time period. Balance was assessed using the Fullerton Advanced Balance (FAB) scale. The time points for assessment were at zero (pre-test), 12 (post-test), and 24 weeks (follow up). Changes in the mean (SD) FAB scale scores immediately following the 12-week intervention were 5.15 (2.81) for the IG and -1.45 (2.80) for the CG. At follow-up, the mean (SD) change scores were -1.88 (1.84) and 0.75 (2.99) for the IG and CG, respectively. The results of a mixed between-within subjects analysis of variance, controlling for physical activity levels at baseline, revealed a significant interaction between group and time (F (2, 42)=27.89, pbalance and reducing fall risk in a group of older people with balance impairment, immediately after the intervention. A decline in balance was observed for the IG after a period of no intervention. ACTRN12612000301864. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reflex impairment, physiological stress, and discard mortality of European plaice Pleuronectes platessa in an otter trawl fishery

DEFF Research Database (Denmark)

Methling, Caroline; Skov, Peter Vilhelm; Madsen, Niels

2017-01-01

whether reflex impairment can predict short-term mortality in commercially trawled European plaice upon landing and after air exposure of up to 90 min. Sub-lethal stress was assessed by a suite of physiological variables. Over a 10-day period, mortality was monitored for a total of 199 plaice following...... trawl and air exposure of varying duration, and for 50 control fish scored for reflex impairment on board the vessel. Mortality was only observed in fish exposed to air for >60 min, and averaged 11.1% (95% CI = 7.1–16.3%). Reflex impairment was found to be a significant (P ... of mortality in a generalized linear model, excluding other initially included variables by using a stepwise method. Plasma cortisol, haematocrit, and plasma osmolality all indicated a profound and increasing level of stress with air exposure, accompanied by a near depletion of muscle phosphocreatine...

Emotional Dissonance and Burnout: The Moderating Role of Team Reflexivity and Re-Evaluation.

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Andela, Marie; Truchot, Didier

2017-08-01

The aim of the present study was to better understand the relationship between emotional dissonance and burnout by exploring the buffering effects of re-evaluation and team reflexivity. The study was conducted with a sample of 445 nurses and healthcare assistants from a general hospital. Team reflexivity was evaluated with the validation of the French version of the team reflexivity scale (Facchin, Tschan, Gurtner, Cohen, & Dupuis, 2006). Burnout was measured with the MBI General Survey (Schaufeli, Leiter, Maslach, & Jackson, 1996). Emotional dissonance and re-evaluation were measured with the scale developed by Andela, Truchot, & Borteyrou (2015). With reference to Rimé's theoretical model (2009), we suggested that both dimensions of team reflexivity (task and social reflexivity) respond to both psychological necessities induced by dissonance (cognitive clarification and socio-affective necessities). Firstly, results indicated that emotional dissonance was related to burnout. Secondly, regression analysis confirmed the buffering role of re-evaluation and social reflexivity on the emotional exhaustion of emotional dissonance. Overall, results contribute to the literature by highlighting the moderating effect of re-evaluation and team reflexivity in analysing the relationship between emotional dissonance and burnout. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Delayed latency of peroneal reflex to sudden inversion with ankle taping or bracing.

Science.gov (United States)

Shima, N; Maeda, A; Hirohashi, K

2005-01-01

The purpose of the present study was to examine the effects of ankle taping and bracing based on the peroneal reflex in the hypermobile and normal ankle joints with and without history of ankle injury. Thirty-six ankle joints of 18 collegiate American football athletes with and without previous history of injury were studied. The angle of talar tilt (TT) was measured by stress radiograph for classifying normal (TT5 degrees ) ankles. They were tested with taping, bracing, and without any supports as a control. The latency of peroneus longus muscle was measured by a sudden inversion of 25 degrees using surface EMG signals. The results of the present study show no significant three-way Group (hypermobile or normal ankles) by History (previously injured or uninjured ankles) by Condition (control, taping, or bracing) interaction, while Condition main effect was significant (p0.05). In conclusion, ankle taping and bracing delayed the peroneal reflex latency not only for hypermobile ankles and/or injured ankle joints but also for intact ankle joints.

Inhibition of reflex vagal bradycardia by a central action of 5-hydroxytryptophan.

OpenAIRE

Tadepalli, A. S.

1980-01-01

1 Vagally mediated reflex bradycardia was elicited in spinal cats with intravenous pressor doses of noradrenaline. Administration of 5-hydroxytryptophan (1.5 and 3 mg total dose) into the fourth cerebral ventricle reduced the reflex bradycardia. 2 Inhibition of central amino acid decarboxylase with R044602 prevented the effects of 5-hydroxytryptophan. After intravenous administration of 5-hydroxytryptophan, vagal reflex bradycardia was not affected. 3 Results suggest that 5-hydroxytryptophan ...

Primitive reflexes and cognitive function Reflexos primitivos e função cognitiva

Directory of Open Access Journals (Sweden)

Alfredo Damasceno

2005-09-01

Full Text Available BACKGROUND: Data on the prevalence of primitive reflexes (PR in adulthood, their pathological significance and relationship to age and cognition are controversial. OBJECTIVE: To study the relationship between PR and cognition in 30 patients with probable Alzheimer's disease (AD and 154 control subjects. METHOD: Diagnosis of probable AD was based on DSM-IV, NINCDS-ADRDA, and CAMDEX criteria. Primitive reflexes were quantified from zero (absent to 1 (mild or 2 (markedly present. The Cognitive Abilities Screening Instrument - Short Form (CASI-S was used to evaluate registration, temporal orientation, verbal fluency and recall. A drawing test was added. RESULTS: Most frequent PR among demented and controls were suck (77% and 62%, respectively and snout (60% and 27%, followed by glabellar (30% and 19%, paratonia (37% and 5%, and palmomental (23% and 5%. None of controls had more than three PR. Frequency of PR tended to increase with age and cognitive deterioration. Grasp and Babinski responses were found only in dementia patients. Primitive reflexes were not correlated with each other, except snout with suck, and snout with glabellar reflex. CONCLUSION: The finding of grasp and Babinski sign, or the presence of more than three primitive signs, particularly the combination of paratonia, snout, suck, and palmomental reflexes strongly suggests brain dysfunction, especially when these signs are marked and accompanied by deficits in orientation, recall, verbal fluency, and constructional praxis.CONTEXTO: A prevalência e significado patológico dos reflexos primitivos (RP no adulto, bem como sua relação com a idade e a cognição, são questões controversas. OBJETIVO: Estudar a relação entre RP e cognição em 30 pacientes com doença de Alzheimer (DA e 154 sujeitos controles normais. MÉTODO: O diagnóstico de DA baseou-se nos critérios DSM-IV, NINCDS-ADRDA e CAMDEX. Os RP foram quantificados de 0 (ausente a 1 (leve ou 2 (acentuado. CASI

Acid-sensing ion channels contribute to the metaboreceptor component of the exercise pressor reflex

OpenAIRE

McCord, Jennifer L.; Tsuchimochi, Hirotsugu; Kaufman, Marc P.

2009-01-01

The exercise pressor reflex is evoked by both mechanical and metabolic stimuli arising in contracting skeletal muscle. Recently, the blockade of acid-sensing ion channels (ASICs) with amiloride and A-316567 attenuated the reflex. Moreover, amiloride had no effect on the mechanoreceptor component of the reflex, prompting us to determine whether ASICs contributed to the metaboreceptor component of the exercise pressor reflex. The metaboreceptor component can be assessed by measuring mean arteri...

New MMC capacitor voltage balancing using sorting-less strategy in nearest level control

DEFF Research Database (Denmark)

Ricco, Mattia; Máthé, Lászlo; Teodorescu, Remus

2016-01-01

This paper proposes a new strategy for balancing the Capacitor Voltages (CVs) for Modular Multilevel Converters (MMCs). The balancing is one of the main challenges in MMC applications and it is usually solved by adopting a global arm control approach. For performing such an approach, a sorted list...... of the SubModules (SMs) according to their capacitor voltages is required. A common way to accomplish this task is to implement a sorting algorithm in the same controller used for the modulation technique. However, the execution time and the computational efforts of these kinds of algorithms increase very...

Adaptive Backstepping Self-balancing Control of a Two-wheel Electric Scooter

Directory of Open Access Journals (Sweden)

Nguyen Ngoc Son

2014-10-01

Full Text Available This paper introduces an adaptive backstepping control law for a two-wheel electric scooter (eScooter with a nonlinear uncertain model. Adaptive backstepping control is integrated with feedback control that satisfies Lyapunov stability. By using the recursive structure to find the controlled function and estimate uncertain parameters, an adaptive backstepping method allows us to build a feedback control law that efficiently controls a self-balancing controller of the eScooter. Additionally, a controller area network (CAN bus with high reliability is applied for communicating between the modules of the eScooter. Simulation and experimental results demonstrate the robustness and good performance of the proposed adaptive backstepping control.

Effects of brainstem lesions on the masseter inhibitory reflex. Functional mechanisms of reflex pathways

NARCIS (Netherlands)

Ongerboer de Visser, B. W.; Cruccu, G.; Manfredi, M.; Koelman, J. H.

1990-01-01

The masseter inhibitory reflex (MIR) was investigated in 16 patients with localized brainstem lesions involving the trigeminal system. The MIR consists of two phases of EMG silence (S1 and S2) evoked by stimulation of the mental nerve during maximal clenching of the teeth. The extent of the lesions

Spasm of the near reflex: a spectrum of anomalies.

Science.gov (United States)

Goldstein, J H; Schneekloth, B B

1996-01-01

Spasm of the near reflex has been characterized as the variable appearance of pseudomyopia, convergent strabismus and miosis. These characteristics may appear together or separately. In addition, abnormalities of accommodation may appear not only as pseudomyopia, but may also be manifest in cases with significant hypermetropia in which the patient is unable to relax accommodation even when plus lenses are used. The intent of this review is to identify the various clinical presentations of anomalies of the entire near reflex as well as the component parts. The relationship to functional and organic disorders are discussed as well as the related neuroanatomy. We suggest that one may more readily understand the clinical manifestations as a spectrum of anomalies of the near reflex rather than a multitude of disconnected entities.

Effects of balance Vestibular Rehabilitation Therapy in elderly with Benign Paroxysmal Positional Vertigo: a randomized controlled trial.

Science.gov (United States)

Ribeiro, Karyna Myrelly Oliveira Bezerra de Figueiredo; Freitas, Raysa Vanessa de Medeiros; Ferreira, Lidiane Maria de Brito Macedo; Deshpande, Nandini; Guerra, Ricardo Oliveira

2017-06-01

To evaluate short-term effects of balance Vestibular Rehabilitation Therapy (VRT) on balance, dizziness symptoms and quality of life of the elderly with chronic Benign Paroxysmal Positional Vertigo (BPPV). In this randomized, single-blind and controlled trial, older adults with chronic BPPV were randomized into two groups, the experimental group (n = 7, age: 69 (65-78) years) and the control group (n = 7, age: 73 (65-76) years). Patients in the experimental group underwent balance VRT (50 min per session, two times a week) and Canalith Repositioning Maneuver (CRM) as required, for 13 weeks. The control group was treated using only CRM as required. Standing and dynamic balance, dizziness symptoms and quality of life were measured at the baseline, and at one, five, nine and thirteen weeks. There were no between-group differences in dizziness, quality of life and standing balance over the 13 weeks. Significant differences were observed in dynamic balance measures between groups (p CRM. Implications for Rehabilitation The findings that balance VRT in addition to CRM improves dynamic balance in elderly people with BPPV should be useful in guiding rehabilitation professionals' clinical decision making to design interventions for seniors suffering from BPPV; Improvements in tests of dynamic balance suggest that the risk of adverse consequences of BPPV in the elderly such as falls and fractures can be potentially reduced through implementation of CRM in conjunction with balance VRT; Lack of additional improvement in Visual Analogue Scale of dizziness and Dizziness Handicap Index suggests that addition of balance VRT does not influence dizziness symptomatology, per se, and CRM alone is effective to ameliorate vertiginous symptoms and potentially improve quality of life.

Static and dynamic balance ability, lumbo-pelvic movement control and injury incidence in cricket pace bowlers.

Science.gov (United States)

Olivier, B; Stewart, A V; Olorunju, S A S; McKinon, W

2015-01-01

This study aimed to establish the difference in lumbo-pelvic movement control, static and dynamic balance at the start and at the end of a cricket season in pace bowlers who sustained an injury during the season and those who did not. This is a longitudinal, observational study. Thirty-two, healthy, injury free, male premier league fast, fast-medium and medium pace bowlers between the ages of 18 and 26 years (mean age 21.8 years, standard deviation 1.8 years) participated in the study. The main outcome measures were injury incidence, lumbo-pelvic movement control, static and dynamic balance ability. Fifty-three percent of the bowlers (n=17) sustained injuries during the reviewed cricket season. Lumbo-pelvic movement control tests could not discriminate between bowlers who sustained an injury during the cricket season and bowlers who did not. However, performance in the single leg balance test (p=0.03; confidence interval 4.74-29.24) and the star excursion balance test (p=0.02; confidence interval 1.28-11.93) as measured at the start of the season was better in bowlers who did not sustain an injury during the season. The improvement in the lumbo-pelvic movement control and balance tests suggests that the intensity and type of physical conditioning that happens throughout the season may have been responsible for this improvement. Poor performance in the single leg balance test and the star excursion balance test at the start of the cricket season may be an indication that a bowler is at heightened risk of injury. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Hybrid Control of a Two-Wheeled Automatic-Balancing Robot with Backlash Feature

DEFF Research Database (Denmark)

Løhndorf, Petar Durdevic; Yang, Zhenyu

2013-01-01

This paper investigates the application of hybrid control for an automatic balancing robot system subject to backlash effect. The developed controller is a type of sliding mode controller, refereed to as a switching controller, with respect to different situations i.e., whether the backlash is pr...... and comparisons with other solutions show the proposed solution can lead to a very satisfactory anti-backlash performance, with an easy and cost-effective implementation....

Resource Leveling Based on Backward Controlling Activity in Line of Balance

Directory of Open Access Journals (Sweden)

Lihui Zhang

2017-01-01

Full Text Available The line of balance method that provides continuous and uninterrupted use of resources is one of the best methods for repetitive project resource management. This paper develops a resource leveling algorithm based on the backward controlling activity in line of balance. The backward controlling activity is a kind of special activity, and if its duration is prolonged the project duration could be reduced. It brings two advantages to the resource leveling: both the resource allocated on the backward activity and the project duration are reduced. A resource leveling algorithm is presented which permits the number of crews of the backward controlling activity to be reduced until the terminal situation is reached, where the backward controlling activity does not exist or the number of crews cannot be reduced. That adjustment enables the productivity of all activities to be consistent. An illustrative pipeline project demonstrates the improvement in resource leveling. And this study designed a MATLAB program to execute the design algorithm. The proposed model could help practitioners to achieve the goals of both resource leveling and project duration reduction without increasing any resource.

Defective balancing ability and hyperactivity in the CLX (circling behavior linked to the X-chromosome) mutant rat.

Science.gov (United States)

Fuji, Jun-ichiro; Tanabe, Hiroyuki; Fukuda, Ryo; Ooshima, Yojiro

2003-12-01

We have reported that the recently described circling behavior rat (CLX) is a hereditary mutant controlled by a single sex-linked recessive gene (gene symbol: clx). This mutant shows intermittent circle walking and/or running and head tossing with the neck twisted. The abnormal behavior begins to appear around weaning and continues throughout life. In the present study, behavioral tests were performed during the suckling and post-weaning periods and when the rats reached maturity, and the following peculiar abnormalities were revealed: (1) in the righting reflex test, the CLX young show a tendency to take a longer time to revert to normal posture; (2) in the negative geotaxis test, they had difficulty moving upward at 12 days of age; (3) in the air righting reflex test, they frequently fell on their backs or shoulders even after weaning; (4) almost none of the CLX rats showed nystagmus, which is invariably observed in normal rats after rotating stimulation, at 20 weeks of age; and (5) they showed hyperactivity in the open field test at the age of 5 or 6 weeks and a higher degree of locomotor activity in the home cage at the age of 7 and 15 weeks. These results suggest that CLX mutant rats may have some defect in vestibular function (balance sense) or abnormalities in an area of the central nervous system responsible for posture control, e.g., in the dopaminergic or GABAergic neurons.

[Developing team reflexivity as a learning and working tool for medical teams].

Science.gov (United States)

Riskin, Arieh; Bamberger, Peter

2014-01-01

Team reflexivity is a collective activity in which team members review their previous work, and develop ideas on how to modify their work behavior in order to achieve better future results. It is an important learning tool and a key factor in explaining the varying effectiveness of teams. Team reflexivity encompasses both self-awareness and agency, and includes three main activities: reflection, planning, and adaptation. The model of briefing-debriefing cycles promotes team reflexivity. Its key elements include: Pre-action briefing--setting objectives, roles, and strategies the mission, as well as proposing adaptations based on what was previously learnt from similar procedures; Post-action debriefing--reflecting on the procedure performed and reviewing the extent to which objectives were met, and what can be learnt for future tasks. Given the widespread attention to team-based work systems and organizational learning, efforts should be made toward ntroducing team reflexivity in health administration systems. Implementation could be difficult because most teams in hospitals are short-lived action teams formed for a particular event, with limited time and opportunity to consciously reflect upon their actions. But it is precisely in these contexts that reflexive processes have the most to offer instead of the natural impulsive collective logics. Team reflexivity suggests a potential solution to the major problems of iatorgenesis--avoidable medical errors, as it forces all team members to participate in a reflexive process together. Briefing-debriefing technology was studied mainly in surgical teams and was shown to enhance team-based learning and to improve quality-related outcomes and safety.

A tapetal-like fundus reflex in a healthy male

DEFF Research Database (Denmark)

Schatz, Patrik; Bregnhøj, Jesper; Arvidsson, Henrik

2012-01-01

To report on the retinal function and structure in a 37-year-old male who presented with a tapetal-like reflex (TLR) indistinguishable from that seen in female carriers of X-linked retinitis pigmentosa (XLRP).......To report on the retinal function and structure in a 37-year-old male who presented with a tapetal-like reflex (TLR) indistinguishable from that seen in female carriers of X-linked retinitis pigmentosa (XLRP)....

Deficits in medio-lateral balance control and the implications for falls in individuals with multiple sclerosis.

Science.gov (United States)

Morrison, S; Rynders, C A; Sosnoff, J J

2016-09-01

A major health concern faced by individuals with Multiple Sclerosis (MS) is the heightened risk of falling. Reasons for this increased risk can often be traced back to declines in neurophysiological mechanisms underlying balance control and/or muscular strength. The aim of this study was to assess differences between persons with MS and age-matched healthy adults in regards to their falls risk, strength, reactions and directional control of balance. Twenty-two persons with multiple sclerosis (mean age 56.3±8.9 years) and 22 age-matched healthy adults (mean age 59.1±7.1 years) participated in the study. Assessments of falls risk, balance, fear of falling, lower limb strength, and reaction time were performed. Balance control was assessed under four conditions where the combined effects of vision (eyes open/closed) and standing surface (firm/pliable surface) were evaluated. Results demonstrated that, in comparison to healthy older adults, persons with MS had a significantly higher falls risk, slower reaction times, and weaker lower- limb strength. For balance, persons with MS exhibited greater overall COP motion in both the medio-lateral (ML) and anterior-posterior (AP) directions compared to older adults. Additionally, during more challenging balance conditions, persons from the MS group exhibited greater ML motion compared to sway in the AP direction. Overall, the results confirm that persons with MS are often at a heightened risk of falling, due to the multitude of neuromuscular changes brought about by this disease process. However, the increased ML sway for the MS group could reflect a decreased ability to control side-to-side motion in comparison to controlling AP sway. Copyright © 2016 Elsevier B.V. All rights reserved.

Adaptive control of structural balance for complex dynamical networks based on dynamic coupling of nodes

Science.gov (United States)

Gao, Zilin; Wang, Yinhe; Zhang, Lili

2018-02-01

In the existing research results of the complex dynamical networks controlled, the controllers are mainly used to guarantee the synchronization or stabilization of the nodes’ state, and the terms coupled with connection relationships may affect the behaviors of nodes, this obviously ignores the dynamic common behavior of the connection relationships between the nodes. In fact, from the point of view of large-scale system, a complex dynamical network can be regarded to be composed of two time-varying dynamic subsystems, which can be called the nodes subsystem and the connection relationships subsystem, respectively. Similar to the synchronization or stabilization of the nodes subsystem, some characteristic phenomena can be also emerged in the connection relationships subsystem. For example, the structural balance in the social networks and the synaptic facilitation in the biological neural networks. This paper focuses on the structural balance in dynamic complex networks. Generally speaking, the state of the connection relationships subsystem is difficult to be measured accurately in practical applications, and thus it is not easy to implant the controller directly into the connection relationships subsystem. It is noted that the nodes subsystem and the relationships subsystem are mutually coupled, which implies that the state of the connection relationships subsystem can be affected by the controllable state of nodes subsystem. Inspired by this observation, by using the structural balance theory of triad, the controller with the parameter adaptive law is proposed for the nodes subsystem in this paper, which may ensure the connection relationship matrix to approximate a given structural balance matrix in the sense of the uniformly ultimately bounded (UUB). That is, the structural balance may be obtained by employing the controlling state of the nodes subsystem. Finally, the simulations are used to show the validity of the method in this paper.

Automated data reduction workflows for astronomy. The ESO Reflex environment

Science.gov (United States)

Freudling, W.; Romaniello, M.; Bramich, D. M.; Ballester, P.; Forchi, V.; García-Dabló, C. E.; Moehler, S.; Neeser, M. J.

2013-11-01

Context. Data from complex modern astronomical instruments often consist of a large number of different science and calibration files, and their reduction requires a variety of software tools. The execution chain of the tools represents a complex workflow that needs to be tuned and supervised, often by individual researchers that are not necessarily experts for any specific instrument. Aims: The efficiency of data reduction can be improved by using automatic workflows to organise data and execute a sequence of data reduction steps. To realize such efficiency gains, we designed a system that allows intuitive representation, execution and modification of the data reduction workflow, and has facilities for inspection and interaction with the data. Methods: The European Southern Observatory (ESO) has developed Reflex, an environment to automate data reduction workflows. Reflex is implemented as a package of customized components for the Kepler workflow engine. Kepler provides the graphical user interface to create an executable flowchart-like representation of the data reduction process. Key features of Reflex are a rule-based data organiser, infrastructure to re-use results, thorough book-keeping, data progeny tracking, interactive user interfaces, and a novel concept to exploit information created during data organisation for the workflow execution. Results: Automated workflows can greatly increase the efficiency of astronomical data reduction. In Reflex, workflows can be run non-interactively as a first step. Subsequent optimization can then be carried out while transparently re-using all unchanged intermediate products. We found that such workflows enable the reduction of complex data by non-expert users and minimizes mistakes due to book-keeping errors. Conclusions: Reflex includes novel concepts to increase the efficiency of astronomical data processing. While Reflex is a specific implementation of astronomical scientific workflows within the Kepler workflow

Roles for Orexin/Hypocretin in the Control of Energy Balance and Metabolism.

Science.gov (United States)

Goforth, Paulette B; Myers, Martin G

The neuropeptide hypocretin is also commonly referred to as orexin, since its orexigenic action was recognized early. Orexin/hypocretin (OX) neurons project widely throughout the brain and the physiologic and behavioral functions of OX are much more complex than initially conceived based upon the stimulation of feeding. OX most notably controls functions relevant to attention, alertness, and motivation. OX also plays multiple crucial roles in the control of food intake, metabolism, and overall energy balance in mammals. OX signaling not only promotes food-seeking behavior upon short-term fasting to increase food intake and defend body weight, but, conversely, OX signaling also supports energy expenditure to protect against obesity. Furthermore, OX modulates the autonomic nervous system to control glucose metabolism, including during the response to hypoglycemia. Consistently, a variety of nutritional cues (including the hormones leptin and ghrelin) and metabolites (e.g., glucose, amino acids) control OX neurons. In this chapter, we review the control of OX neurons by nutritional/metabolic cues, along with our current understanding of the mechanisms by which OX and OX neurons contribute to the control of energy balance and metabolism.

Desensitization of the cough reflex by exercise and voluntary isocapnic hyperpnea.

Science.gov (United States)

Lavorini, Federico; Fontana, Giovanni A; Chellini, Elisa; Magni, Chiara; Duranti, Roberto; Widdicombe, John

2010-05-01

Little is known about the effects of exercise on the sensory and cognitive aspects of coughing evoked by inhalation of tussigenic agents. The threshold for the cough reflex induced by inhalation of increasing nebulizer outputs of ultrasonically nebulized distilled water (fog), an index of cough reflex sensitivity, was assessed in twelve healthy humans in control conditions, during exercise and during voluntary isocapnic hyperpnea (VIH) at the same ventilatory level as the exercise. The intensity of the urge to cough (UTC), a cognitive component of coughing, was recorded throughout the trials on a linear scale. The relationships between inhaled fog nebulizer outputs and the correspondingly evoked UTC values, an index of the perceptual magnitude of the UTC sensitivity, were also calculated. Cough appearance was always assessed audiovisually. At an exercise level of 80% of anaerobic threshold, the median cough threshold was increased from a control value of 0.73 to 2.22 ml/min (PVIH, the threshold increased from 0.73 to 2.22 ml/min (PVIH compared with control, mean UTC values at cough threshold were unchanged, i.e., control, 3.83 cm; exercise, 3.12 cm; VIH, 4.08 cm. The relationship of the fog nebulizer output/UTC value was linear in control conditions and logarithmic during both exercise and VIH. The perception of the magnitude of the UTC seems to be influenced by signals or sensations arising from exercising limb and thoracic muscles and/or by higher nervous (cortical) mechanisms. The results indicate that the adjustments brought into action by exercise-induced or voluntary hyperpnea exert inhibitory influences on the sensory and cognitive components of fog-induced cough.

Balance training with multi-task exercises improves fall-related self-efficacy, gait, balance performance and physical function in older adults with osteoporosis: a randomized controlled trial.

Science.gov (United States)

Halvarsson, Alexandra; Franzén, Erika; Ståhle, Agneta

2015-04-01

To evaluate the effects of a balance training program including dual- and multi-task exercises on fall-related self-efficacy, fear of falling, gait and balance performance, and physical function in older adults with osteoporosis with an increased risk of falling and to evaluate whether additional physical activity would further improve the effects. Randomized controlled trial, including three groups: two intervention groups (Training, or Training+Physical activity) and one Control group, with a 12-week follow-up. Stockholm County, Sweden. Ninety-six older adults, aged 66-87, with verified osteoporosis. A specific and progressive balance training program including dual- and multi-task three times/week for 12 weeks, and physical activity for 30 minutes, three times/week. Fall-related self-efficacy (Falls Efficacy Scale-International), fear of falling (single-item question - 'In general, are you afraid of falling?'), gait speed with and without a cognitive dual-task at preferred pace and fast walking (GAITRite®), balance performance tests (one-leg stance, and modified figure of eight), and physical function (Late-Life Function and Disability Instrument). Both intervention groups significantly improved their fall-related self-efficacy as compared to the controls (p ≤ 0.034, 4 points) and improved their balance performance. Significant differences over time and between groups in favour of the intervention groups were found for walking speed with a dual-task (p=0.003), at fast walking speed (p=0.008), and for advanced lower extremity physical function (p=0.034). This balance training program, including dual- and multi-task, improves fall-related self-efficacy, gait speed, balance performance, and physical function in older adults with osteoporosis. © The Author(s) 2014.

Soleus stretch reflex during cycling

DEFF Research Database (Denmark)

Grey, Michael James; Pierce, C. W.; Milner, T. E.

2001-01-01

The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions durin...

Low Incidence Of Extensor Plantar Reflex In Newborns In An ...

African Journals Online (AJOL)

Healthy term newborns with Apgar score of 8 and above at one minute were recruited into the study consecutively in a maternity hospital in Ibadan, Nigeria. The plantar reflex was elicited by stroking the lateral side of the sole with firm pressure, between 24 - 48 hours after delivery. Results Of 461 newborns, the plantar reflex ...

[The lombard reflex as a test of vocal function (author's transl)].

Science.gov (United States)

Schultz-Coulon, H J; Fues, C P

1976-06-01

Any impairment of audio-phonatory control by background noise is followed by an increase in both the intensity and pitch of the speaking voice (Lombard reflex, 1911), thus increasing vocal strain. As a consequence, it might be anticipated that persons reacting to noise with marked changes in voice might be more liable to develop dysphonia. 22 singers, 34 normal controls, and 22 patients with hyperfunctional dysphonia where studied. In all patients, both ears were gradually masked with white noise. The change of the mean intensity level and of the mean pitch level of the speaking voice were then measured objectively with a special fundamental frequency analyzer (Fedders and Schultz-Coulon, 1975). Results show that the increase of intensity is comparable in all subjects, whereas the elevation of the mean pitch level differs significantly: trained voices (singers) react with the least pitch increment whereas dysphonic patients react with the most. The following conclusions were made from the present investigation: 1. Extreme increments in pitch level can be considered to be a more significant etiological factor of dysphonia than intensity increments; 2. Vocal therapy and voice training may have a favorable effect on the Lombard reflex (probably by improvement of the kinesthetic control mechanism) so that the speaking voice in a noisy environment is raised less with less vocal strain. The study also indicates that measurement of pitch changes during binaural masking can provide important information for the diagnosis, therapy and prophylaxis of dysphonia.

Insulin controls food intake and energy balance via NPY neurons

Directory of Open Access Journals (Sweden)

Kim Loh

2017-06-01

Full Text Available Objectives: Insulin signaling in the brain has been implicated in the control of satiety, glucose homeostasis and energy balance. However, insulin signaling is dispensable in energy homeostasis controlling AgRP or POMC neurons and it is unclear which other neurons regulate these effects. Here we describe an ancient insulin/NPY neuronal network that governs energy homeostasis across phyla. Methods: To address the role of insulin action specifically in NPY neurons, we generated a variety of models by selectively removing insulin signaling in NPY neurons in flies and mice and testing the consequences on energy homeostasis. Results: By specifically targeting the insulin receptor in both fly and mouse NPY expressing neurons, we found NPY-specific insulin signaling controls food intake and energy expenditure, and lack of insulin signaling in NPY neurons leads to increased energy stores and an obese phenotype. Additionally, the lack of insulin signaling in NPY neurons leads to a dysregulation of GH/IGF-1 axis and to altered insulin sensitivity. Conclusions: Taken together, these results suggest that insulin actions in NPY neurons is critical for maintaining energy balance and an impairment of this pathway may be causally linked to the development of metabolic diseases. Keywords: Hypothalamus, NPY, Insulin, Obesity

Salinity controls on plant transpiration and soil water balance

Science.gov (United States)

Perri, S.; Molini, A.; Suweis, S. S.; Viola, F.; Entekhabi, D.

2017-12-01

Soil salinization and aridification represent a major threat for the food security and sustainable development of drylands. The two problems are deeply connected, and their interplay is expected to be further enhanced by climate change and projected population growth. Salt-affected land is currently estimated to cover around 1.1 Gha, and is particularly widespread in semi-arid to hyper-arid climates. Over 900 Mha of these saline/sodic soils are potentially available for crop or biomass production. Salt-tolerant plants have been recently proposed as valid solution to exploit or even remediate salinized soils. However the effects of salinity on evapotranspiration, soil water balance and the long-term salt mass balance in the soil, are still largely unexplored. In this contribution we analyze the feedback of evapotranspiration on soil salinization, with particular emphasis on the role of vegetation and plant salt-tolerance. The goal is to introduce a simple modeling framework able to shed some light on how (a) soil salinity controls plant transpiration, and (b) salinization itself is favored/impeded by different vegetation feedback. We introduce at this goal a spatially lumped stochastic model of soil moisture and salt mass dynamics averaged over the active soil depth, and accounting for the effect of salinity on evapotranspiration. Here, the limiting effect of salinity on ET is modeled through a simple plant response function depending on both salt concentration in the soil and plant salt-tolerance. The coupled soil moisture and salt mass balance is hence used to obtain the conditional steady-state probability density function (pdf) of soil moisture for given salt tolerance and salinization level, Our results show that salinity imposes a limit in the soil water balance and this limit depends on plant salt-tolerance mainly through the control of the leaching occurrence (tolerant plants exploit water more efficiently than the sensitive ones). We also analyzed the

Contribution of the maculo-ocular reflex to gaze stability in the rabbit.

Science.gov (United States)

Pettorossi, V E; Errico, P; Santarelli, R M

1991-01-01

The contribution of the maculo-ocular reflex to gaze stability was studied in 10 pigmented rabbits by rolling the animals at various angles of sagittal inclination of the rotation and/or longitudinal animal axes. At low frequencies (0.005-0.01 Hz) of sinusoidal stimulation the vestibulo-ocular reflex (VOR) was due to macular activation, while at intermediate and high frequencies it was mainly due to ampullar activation. The following results were obtained: 1) maculo-ocular reflex gain decreased as a function of the cosine of the angle between the rotation axis and the earth's horizontal plane. No change in gain was observed when longitudinal animal axis alone was inclined. 2) At 0 degrees of rotation axis and with the animal's longitudinal axis inclination also set at 0 degrees, the maculo-ocular reflex was oriented about 20 degrees forward and upward with respect to the earth's vertical axis. This orientation remained constant with sagittal inclinations of the rotation and/or longitudinal animal axes ranging from approximately 5 degrees upward to 30 degrees downward. When the longitudinal animal axis was inclined beyond these limits, the eye trajectory tended to follow the axis inclination. In the upside down position, the maculo-ocular reflex was anticompensatory, oblique and fixed with respect to orbital coordinates. 3) Ampullo-ocular reflex gain did not change with inclinations of the rotation and/or longitudinal animal axes. The ocular responses were consistently oriented to the stimulus plane. At intermediate frequencies the eye movement trajectory was elliptic because of directional differences between the ampullo- and maculo-ocular reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of reflex-based self-defence training on police performance in simulated high-pressure arrest situations

NARCIS (Netherlands)

Renden, Peter G.; Savelsbergh, Geert J. P.; Oudejans, Raoul R. D.

2017-01-01

We investigated the effects of reflex-based self-defence training on police performance in simulated high-pressure arrest situations. Police officers received this training as well as a regular police arrest and self-defence skills training (control training) in a crossover design. Officers’

The influence of diabetic peripheral neuropathy on local postural muscle and central sensory feedback balance control.

Directory of Open Access Journals (Sweden)

Nima Toosizadeh

Full Text Available Poor balance control and increased fall risk have been reported in people with diabetic peripheral neuropathy (DPN. Traditional body sway measures are unable to describe underlying postural control mechanism. In the current study, we used stabilogram diffusion analysis to examine the mechanism under which balance is altered in DPN patients under local-control (postural muscle control and central-control (postural control using sensory cueing. DPN patients and healthy age-matched adults over 55 years performed two 15-second Romberg balance trials. Center of gravity sway was measured using a motion tracker system based on wearable inertial sensors, and used to derive body sway and local/central control balance parameters. Eighteen DPN patients (age = 65.4±7.6 years; BMI = 29.3±5.3 kg/m2 and 18 age-matched healthy controls (age = 69.8±2.9; BMI = 27.0±4.1 kg/m2 with no major mobility disorder were recruited. The rate of sway within local-control was significantly higher in the DPN group by 49% (healthy local-controlslope = 1.23±1.06×10-2 cm2/sec, P<0.01, which suggests a compromised local-control balance behavior in DPN patients. Unlike local-control, the rate of sway within central-control was 60% smaller in the DPN group (healthy central-controlslope-Log = 0.39±0.23, P<0.02, which suggests an adaptation mechanism to reduce the overall body sway in DPN patients. Interestingly, significant negative correlations were observed between central-control rate of sway with neuropathy severity (rPearson = 0.65-085, P<0.05 and the history of diabetes (rPearson = 0.58-071, P<0.05. Results suggest that in the lack of sensory feedback cueing, DPN participants were highly unstable compared to controls. However, as soon as they perceived the magnitude of sway using sensory feedback, they chose a high rigid postural control strategy, probably due to high concerns for fall, which may increase the energy cost during extended period of standing; the adaptation

The gait and balance of patients with diabetes can be improved: a randomised controlled trial.

NARCIS (Netherlands)

Allet, L.; Armand, S.; Bie, R.A. de; Golay, A.; Monnin, D.; Aminian, K.; Staal, J.B.; Bruin, E.D. de

2010-01-01

AIMS/HYPOTHESIS: Gait characteristics and balance are altered in diabetic patients. Little is known about possible treatment strategies. This study evaluates the effect of a specific training programme on gait and balance of diabetic patients. METHODS: This was a randomised controlled trial (n=71)

VizieR Online Data Catalog: RefleX : X-ray-tracing code (Paltani+, 2017)

Science.gov (United States)

Paltani, S.; Ricci, C.

2017-11-01

We provide here the RefleX executable, for both Linux and MacOSX, together with the User Manual and example script file and output file Running (for instance): reflex_linux will produce the file reflex.out Note that the results may differ slightly depending on the OS, because of slight differences in some implementations numerical computations. The difference are scientifically meaningless. (5 data files).

Motricidade reflexa na morte cerebral The reflex activity in the brain death

Directory of Open Access Journals (Sweden)

Wilson L. Sanvito

1972-03-01

Full Text Available O diagnóstico de morte cerebral está baseado em critérios clínicos, eletrencefalográficos e angiográficos. Do ponto de vista clínico deve ser evidenciado o seguinte quadro: coma profundo, midríase paralítica bilateral, ausência de reação a qualquer estímulo externo, apnéia, arreflexia superficial e profunda. Do ponto de vista eletrencefalográfico são necessários dois registros, separados por um intervalo de 24 horas, evidenciando traçados iselétricos. No presente trabalho são estudados 15 pacientes com morte cerebral comprovada do ponto de vista clínico e eletrencefalográfico. Em 8 pacientes havia persistência de atividade reflexa durante a fase de morte cerebral (reflexos profundos e/ou superficiais. Fenômenos de automatismos medulares também foram verificados em 3 pacientes.The diagnosis of brain death is based in clinical, electroencephalographic and angiographic data. The criteria for diagnosis of brain death are: deep coma with unreceptivity and unresponsiveness, no movements or breathing (the patient's respiration must be maintained artificially, bilateral dilated and fixed pupils, absence of corneal reflexes, no response to caloric test, absence of deep tendon reflexes and of the superficial abdominal and plantar reflexes, isoelectric EEG maintained for twenty-four hours. The purpose of this study was to observe the natural clinical courses of 15 patients with brain death, specially the data concerning the deep and superficial reflexes. From 15 patients fulfilling the criteria of brain death, 8 maintained spinal reflexes up to the time of cardiac arrest; in five of these patients the superficial abdominal reflexes were present and the reflexes of spinal automatism could be elicited. These results show that the absence of deep and superficial reflexes can't be considered as essencial for the diagnosis of brain death.

A task dependent change in the medium latency component of the soleus stretch reflex

DEFF Research Database (Denmark)

Grey, Michael James; Larsen, Birgit; Sinkjær, Thomas

2002-01-01

In comparison to the H-reflex, the task dependency of the human stretch reflex during locomotive and postural tasks has not received a great deal of attention in the literature. The few studies on reflex task dependency that have been performed to date have concentrated on either the group Ia...

Erecting Closets and Outing Ourselves: Uncomfortable Reflexivity and Community-Based Research

Science.gov (United States)

Reed, Sarah J.; Miller, Robin Lin; Nnawulezi, Nkiru; Valenti, Maria T.

2012-01-01

Feminist scholars and community psychologists have argued that reflexivity is a necessary component to conducting socially conscious research. Reflexivity, however, is rarely evident in community psychology. In this article, we share the uncomfortable realities that surfaced during a community-based research project in which we adapted and…

A critical reflexive Perspective on othering in collaborative knowledge production

DEFF Research Database (Denmark)

Jakobsen, Helle Nordentoft; Olesen, Birgitte Ravn

2018-01-01

Purpose The purpose of the article is to show power mechanisms of in- and exclusion in moments where certain participants appeared to be othered in two collaborative research and development projects in a health care setting. Design/methodology/approach The article contributes to critical......-reflexive analyses of reflexive processes within collaborative knowledge production We use an analytical framework combining Bakhtin and Foucault to investigate processes of inclusion and exclusion in the interplay between dominant and subordinated voices in a moment-by-moment analysis of two incidents from...... interdisciplinary workshops. Findings The analysis illuminates how differences between voices challenge participants’ reflexive awareness and lead to the reproduction of contextual power and knowledge hierarchies and the concomitant silencing of particular participants. Thus, the findings draw attention...

Wii Fit balance training or progressive balance training in patients with chronic stroke: a randomised controlled trial

Science.gov (United States)

Yatar, Gozde Iyigun; Yildirim, Sibel Aksu

2015-01-01

[Purpose] The aim of this study was to compare the effects of Wii Fit balance training (WBT) and progressive balance training (PBT) approaches on balance functions, balance confidence, and activities of daily living in chronic stroke patients. [Subjects] A total of 30 patients were randomized into the WBT (n=15) and PBT (n=15) groups. [Methods] All of the subjects received exercise training based on a neurodevelopemental approach in addition to either Wii Fit or progressive balance training for total of 1 hour a day, 3 days per week for 4 weeks. Primary measurements were static balance function measured with a Wii Balance Board and dynamic balance function assessed with the Berg Balance Scale, Timed Up and Go test, Dynamic Gait Index, and Functional Reach Test. Secondary measures were balance confidence assessed with the Activities-specific Balance Confidence scale and activities of daily living evaluated with the Frenchay Activity Index. [Results] There was not remarkable difference between the two treatments in dynamic balance functions, balance confidence, and activities of daily living. [Conclusion] Although both of the approaches were found to be effective in improving the balance functions, balance confidence, and activities of daily living, neither of them were more preferable than the other for the treatment of balance in patients with chronic stroke. PMID:25995576

Wii Fit balance training or progressive balance training in patients with chronic stroke: a randomised controlled trial.

Science.gov (United States)

Yatar, Gozde Iyigun; Yildirim, Sibel Aksu

2015-04-01

[Purpose] The aim of this study was to compare the effects of Wii Fit balance training (WBT) and progressive balance training (PBT) approaches on balance functions, balance confidence, and activities of daily living in chronic stroke patients. [Subjects] A total of 30 patients were randomized into the WBT (n=15) and PBT (n=15) groups. [Methods] All of the subjects received exercise training based on a neurodevelopemental approach in addition to either Wii Fit or progressive balance training for total of 1 hour a day, 3 days per week for 4 weeks. Primary measurements were static balance function measured with a Wii Balance Board and dynamic balance function assessed with the Berg Balance Scale, Timed Up and Go test, Dynamic Gait Index, and Functional Reach Test. Secondary measures were balance confidence assessed with the Activities-specific Balance Confidence scale and activities of daily living evaluated with the Frenchay Activity Index. [Results] There was not remarkable difference between the two treatments in dynamic balance functions, balance confidence, and activities of daily living. [Conclusion] Although both of the approaches were found to be effective in improving the balance functions, balance confidence, and activities of daily living, neither of them were more preferable than the other for the treatment of balance in patients with chronic stroke.

A condição obscura: Reflexões sobre as políticas de imigração e controle de estrangeiros em Portugal

Directory of Open Access Journals (Sweden)

Igor José de Renó Machado

2012-11-01

Full Text Available O artigo propõe uma reflexão antropológica sobre as leis portuguesas de controle da imigração e concessão de nacionalidade. Ao mesmo tempo que procuram estabilizar um contingente de imigrantes numa condição vulnerável, as leis, como um todo, compartilham uma noção de aversão à diferença radical, procurando sempre aportuguesar os estrangeiros. Os diferentes mecanismos construídos para atingir esse objetivo são analisados em detalhe.

The Reflexive Principle of Sociological Theorization

Directory of Open Access Journals (Sweden)

R T Ubaidullayeva

2013-12-01

Full Text Available The article attempts to describe the reflexive principle in theory-making, which integrates the basic modern methodological paradigms and lays the foundation for the development of sociology. On the basis of the theoretical ideas of P. Bourdieu, A. Giddens and P. Ricoeur the author defines the concept of social reflexion and reveals its peculiarities in sociology as compared to reflexion in philosophy. According to the author, the fulfillment of reflexive functions in sociology is connected with the task of analyzing the complex structure of the polysemantic object, considering the specific quality of the subjects and their various trends of development. The presence of the poles — objectivity-subjectivity, rationality-irrationality, consciousness-unconsciousness etc, requires a reproduction of the dichotomies engendering them in social life and development of cognitive methods for their study in sociology.

Grounded theory research: literature reviewing and reflexivity.

Science.gov (United States)

McGhee, Gerry; Marland, Glenn R; Atkinson, Jacqueline

2007-11-01

This paper is a report of a discussion of the arguments surrounding the role of the initial literature review in grounded theory. Researchers new to grounded theory may find themselves confused about the literature review, something we ourselves experienced, pointing to the need for clarity about use of the literature in grounded theory to help guide others about to embark on similar research journeys. The arguments for and against the use of a substantial topic-related initial literature review in a grounded theory study are discussed, giving examples from our own studies. The use of theoretically sampled literature and the necessity for reflexivity are also discussed. Reflexivity is viewed as the explicit quest to limit researcher effects on the data by awareness of self, something seen as integral both to the process of data collection and the constant comparison method essential to grounded theory. A researcher who is close to the field may already be theoretically sensitized and familiar with the literature on the study topic. Use of literature or any other preknowledge should not prevent a grounded theory arising from the inductive-deductive interplay which is at the heart of this method. Reflexivity is needed to prevent prior knowledge distorting the researcher's perceptions of the data.

Collaborative Research in Contexts of Inequality: The Role of Social Reflexivity

Science.gov (United States)

Leibowitz, Brenda; Bozalek, Vivienne; Farmer, Jean; Garraway, James; Herman, Nicoline; Jawitz, Jeff; McMillan, Wendy; Mistri, Gita; Ndebele, Clever; Nkonki, Vuyisile; Quinn, Lynn; van Schalkwyk, Susan; Vorster, Jo-Anne; Winberg, Chris

2017-01-01

This article reports on the role and value of social reflexivity in collaborative research in contexts of extreme inequality. Social reflexivity mediates the enablements and constraints generated by the internal and external contextual conditions impinging on the research collaboration. It fosters the ability of participants in a collaborative…

Effect of joint mobilization on the H Reflex amplitude in people with spasticity

OpenAIRE

Pérez Parra, Julio Ernesto; Henao Lema, Claudia Patricia

2011-01-01

Objective: To determine the effect of ankle joint mobilization on the H reflex amplitude of thesoleus muscle in people with spasticity. Materials and methods: A quasi-experimental study withcrossover design and simple masking was conducted in 24 randomized subjects to initiate thecontrol or experimental group. Traction and rhythmic oscillation were applied for five minutesto the ankle joint. H wave amplitude changes of Hoffmann reflex (electrical equivalent of themonosynaptic spinal reflex) w...

A closed-loop energy price controlling method for real-time energy balancing in a smart grid energy market

International Nuclear Information System (INIS)

Alagoz, B. Baykant; Kaygusuz, Asim; Akcin, Murat; Alagoz, Serkan

2013-01-01

Future smart grids will require a flexible, observable, and controllable network for reliable and efficient energy delivery under uncertain generation and demand conditions. One of the mechanisms for efficient and reliable energy generation is dynamic demand-responsive generation management based on energy price adjustments that creates a balance in energy markets. This study presents a closed-loop PID (proportional–integral–derivative) controller-based price control method for autonomous and real-time balancing of energy demand and generation in smart grid electricity markets. The PID control system can regulate energy prices online to respond dynamically and instantaneously to the varying energy demands of grid consumers. Independent energy suppliers in the smart grid decide whether to sell their energy to the grid according to the energy prices declared by the closed-loop PID controller system. Energy market simulations demonstrate that PID-controlled energy price regulation can effectively maintain an energy balance for hourly demand fluctuations of consumers. - Highlights: • This study presents a control theoretic approach for management of energy balance. • A closed-loop PID controller-based price controlling method is used in smart grid. • The simulation results demonstrate advantages of PID-based energy price control. • This method is appropriate for demand responsive management of smart grid markets