Postural Control Activity Research Articles

Informing Clinical Practice Guidelines for Children and Youth With Down Syndrome: A Survey of Key Partners.

The purpose of this work was to describe input from key partners to inform the scope and priorities for a clinical practice guideline (CPG) pertaining to physical therapy services provided to children and youth with Down syndrome (DS). A 68-item survey was completed by interventionists and parents (n = 296) of children and youth with DS. The most prevalent physical therapy interventions currently being performed included tummy time, postural control activities, activity-based interventions, and play-based interventions. Key partners agreed on the importance of specific clinical outcomes, needing guidance on frequency and dosage of interventions, common barriers to physical therapy intervention, and needing information for discharge criteria in a future CPG. The results of this survey have given the CPG committee the necessary information to inform the CPG process for children and youth with DS.

Effects of seat back height and posture on 3D vibration transmission to pelvis, trunk and head

Vibration transmission is essential in the design of comfortable vehicle seats but knowledge is lacking on 3D trunk and head motion and the role of seat back and posture. We hypothesized that head motion is reduced when participants’ upper back is unsupported, as this stimulates active postural control. We developed an experimental methodology to evaluate 3D vibration transmission from compliant seats to the human body. Wide-band (0.1–12 Hz) motion stimuli were applied in fore-aft, lateral and vertical direction to evaluate the translational and rotational body response in pelvis, trunk and head. A standard car seat was equipped with a configurable and compliant back support to test 3 support heights and 3 sitting postures (erect, slouched, and preferred) where we also tested head down looking at a smartphone.Seat back support height and sitting posture substantially affected vibration transmission and affected low frequency responses in particular for body segment rotation. According to our hypothesis a low support height proved beneficial in reducing head motion. Relevance to industryOur methodology effectively evaluates 3D wide-band vibration transmission from compliant seats to the human body. The lowest back support height reduced head motion but was perceived as least comfortable. This calls for seat designs which support but do not so much constrain the upper back. The head down posture enlarged head motion, pleading for computer system integration allowing heads up postures in future automated cars. The biomechanical data will serve to validate human models supporting the design of comfortable (automated) vehicles.

New Training Tasks for Stepwise Loading in Isometric Bodyweight Squat with Active Posture Control

Isometric bodyweight squats are fundamental exercises in athletic training and rehabilitation. Previously, we measured muscle activity in a normal squat posture (NSP) and a squat posture with the center of foot pressure (COP) intentionally shifted forward as far as possible (forward-shifted posture: FSP), and the muscle activity patterns varied significantly according to the COP location. This study focused on stepwise loading as a training strategy. Ten healthy male participants performed isometric bodyweight squats in a previous study, adopting the NSP and FSP, with three knee flexion angles (30°, 60°, and 90°). The muscle activities of the vastus medialis (VM), semitendinosus, tibialis anterior (TA), and gastrocnemius muscle lateral head were measured using surface electromyogram. This study further explored the relationship between COP shifting and knee flexion angles on electromyogram changes using three-dimensional diagrams. In one-way repeated measures analysis of variance by ranks, knee flexion angles affected the muscle activities of the VM and TA in the NSP and muscle activities of the VM in the FSP. Combining these findings, stepwise loading tasks were created to train individual target muscles. The ten male participants examined all the tasks, and the feasibility was confirmed accordingly.

Acceleration and Jerk After a Jump Stabilization Task in Individuals With and Without Chronic Ankle Instability.

Studies have demonstrated that individuals with chronic ankle instability (CAI) have diminished dynamic stability. Jerk-based measures have been utilized to examine dynamic balance because of their ability to quantify changes in acceleration and may provide an understanding of the postural corrections that occur during stabilizing following a jumping task. The purpose of this study was to compare acceleration and jerk following a jump stabilization task between individuals with CAI and the uninjured controls. Thirty-nine participants volunteered to participate in this case control study. Participants completed a jump stabilization task requiring them to jump off 2 feet, touch a marker set at 50% of their maximal vertical jump height, land on a single limb, and maintain balance for 3seconds. Acceleration was calculated as the second derivative, and jerk was calculated as the third derivative of the displacement of the resultant vector position. Participants with CAI had greater acceleration (mean difference = 55.6cm/s2; 95% confidence interval, 10.3 to 100.90; P = .017) and jerk compared with the uninjured controls (mean difference = 1804.5cm/s3; 95% confidence interval, 98.7 to 3510.3; P = .039). These results suggest that individuals with CAI made faster and more frequent active postural control corrections to regain balance following a jump compared with the uninjured controls.

Early aging and postural control while listening and responding.

It is not unusual for communication to take place while people are involved in another activity. This paper describes a study that measures the impact of listening while also completing an active postural control task. The focus was on whether the combination of listening and balancing was more detrimental to middle-aged adults than it was to younger adults as age-related changes in both hearing and postural control can occur within this age range. Speech understanding in the presence of noise and speech maskers was measured when participants (n = 15/group) were simply standing still, as well as when they were asked to complete a balancing-with-feedback postural control task, requiring different levels of effort. Performance on the postural control task also was measured in isolation. Results indicated that dual-task costs for postural control were larger when the masker was speech (vs noise) for the middle-aged group but not for the younger group. Dual-task costs in postural control increased with degree of high-frequency hearing loss even when age was controlled. Overall, results suggest that postural control in middle-aged adults can be compromised when individuals are communicating in challenging environments, perhaps reflecting an increased need for cognitive resources to successfully understand messages.

Design and Posture Control of a Wheel-Legged Robot With Actively Passively Transformable Suspension System

Abstract This paper presents a novel solution for the posture control and ride comfort between the proposed wheel-legged robot (four wheel-legged robot (FWLR)) and the unstructured terrain by means of an actively passively transformable suspension system. Unlike most traditional robots, each leg of FWLR is independent of each other with a spring-damping system (passive system) is connected in series with an actuator (active system), so the posture control and ride comfort in complex terrain can be realized by the combination between active and passive systems. To verify the performance of posture control in complex terrain, a prototype and complex terrain are established first, then a posture control model, algorithm, and controller considering the suspension system are proposed and verified by the comparison between co-simulation and experiment, the results showed that the pitch angle and roll angles in complex terrain can be controlled. To show the impact of the actively passively transformable suspension system on ride comfort (vibration isolation performance), different dynamic models with different degree-of–freedom (DOF) are established, the co-simulation results showed that the passive system and active posture control system can also effectively improve the ride comfort of FWLR in complex terrain. The research results of this paper have important reference significance and practical value for enriching and developing the mechanism design and theoretical research of wheel-legged robot and promoting the engineering application of all-terrain robot.

Posture control in land plants: growth, position sensing, proprioception, balance, and elasticity.

The colonization of the atmosphere by land plants was a major evolutionary step. The mechanisms that allow for vertical growth through air and the establishment and control of a stable erect habit are just starting to be understood. A key mechanism was found to be continuous posture control to counterbalance the mechanical and developmental challenges of maintaining a growing upright structure. An interdisciplinary systems biology approach was invaluable in understanding the underlying principles and in designing pertinent experiments. Since this discovery previously held views of gravitropic perception had to be reexamined and this has led to the description of proprioception in plants. In this review, we take a purposefully pedagogical approach to present the dynamics involved from the cellular to whole-plant level. We show how the textbook model of how plants sense gravitational force has been replaced by a model of position sensing, a clinometer mechanism that involves both passive avalanches and active motion of statoliths, granular starch-filled plastids, in statocytes. Moreover, there is a transmission of information between statocytes and other specialized cells that sense the degree of organ curvature and reset asymmetric growth to straighten and realign the structure. We give an overview of how plants have used the interplay of active posture control and elastic sagging to generate a whole range of spatial displays during their life cycles. Finally, a position-integrating mechanism has been discovered that prevents directional plant growth from being disrupted by wind-induced oscillations.

The influence of wearing ski-boots with different rigidity characteristics on postural control

External supports that reduce ankle joint mobility such as ski-boots can impair postural control of healthy participants. Although this disruptive effect has been attributed to the rigidity of the external supports, the results remained controversial and no study has been conducted in order to evaluate the influence of ski-boots rigidity. Hence, the question about the influence of ankle support rigidity on postural control remains open. This study was therefore undertaken in order to investigate the effect of ski-boots rigidity on postural control. Ten healthy active participants were recruited. The wearing of soft and rigid ski-boots was compared to barefoot while standing on a seesaw generating mediolateral and anteroposterior instability. Centre of pressure displacements were sampled with a force platform. The surface electromyographic activity of the main muscles from the leg, thigh and trunk was recorded. A motion analysis system was also used to calculate the ankle, knee and hip angles. The results did not reveal any negative influence of ski-boot rigidity on postural control but rather suggest a less active postural control with the rigid ski-boots which offered a higher mechanical contribution.

The effects of tandem skiing on posture and heart rate in children with profound intellectual and multiple disabilities

ABSTRACTPurpose: The objective of study was to determine the effect of tandem ski (TS) activity on postural control and cardiac activity in children with profound intellectual and multiple disabilities (PIMDs).Method: Twenty children with PIMD and 20 age-matched controls (typically developed (TD) children) participated. Body segment movements were measured with inertial sensors (Physilog®) placed on the head, C7, trunk (including ECG) and pelvis with a seat reference. Each participant was measured during a 12-turn slalom pattern.Results: In each group, significant differences were observed between the head vs. trunk and head vs. pelvis angular speeds (p<0.001). In both groups, heart rate differed significantly during rest (PIMD 99 bpm, TD 97 bpm), exercise (PIMD 140 bpm, TD 139 bpm; rest vs. exercise p<0.001) and recovery (PIMD 101 bpm, TD 107 bpm; exercise vs. recovery p<0.001).Conclusions: In children with PIMD, TS elicits active postural control associated with cardiac activities similar to that of the controls.

Kinematic, kinetic, and electromyographic characteristics during quiet standing on a balance exercise assist robot.

[Purpose] The balance exercise assist robot is a training device based on a personal transport assistance robot ridden in the standing position. The personal transport assistance robot uses an inverted pendulum control system and moves in response to movements of the user’s center of gravity. The purpose of this study was to describe the characteristics of postural control during the action of stopping the personal transport assistance robot. [Participants and Methods] Eleven healthy male participants were required to maintain a standing position for 30 s; each task was performed 10 times. The measurement conditions were as follows: (1) on the floor; (2) on the robot, touching the handlebars; and (3) on the robot, not touching the handlebars. [Results] During the robotic tasks, the total locus lengths of the center of gravity and total joint momentums of the hip, knee, and ankle joints were larger, and the amount of displacement of the center of pressure was smaller than that during the floor task. Posture control on the robot was performed actively by mechanical interaction of the ankle, knee, and hip joints within a small base of support. [Conclusion] The balance exercise assist robot can be useful for postural control exercises because maintaining a standing position on the personal transport assistance robot required active postural control.

A Trunk Support System to Identify Posture Control Mechanisms in Populations Lacking Independent Sitting.

Populations with moderate-to-severe motor control impairments often exhibit degraded trunk control and/or lack the ability to sit unassisted. These populations need more research, yet their underdeveloped trunk control complicates identification of neural mechanisms behind their movements. The purpose of this study was to overcome this barrier by developing the first multi-articulated trunk support system to identify visual, vestibular, and proprioception contributions to posture in populations lacking independent sitting. The system provided external stability at a user-specific level on the trunk, so that body segments above the level of support required active posture control. The system included a tilting surface (controlled via servomotor) as a stimulus to investigate sensory contributions to postural responses. Frequency response and coherence functions between the surface tilt and trunk support were used to characterize system dynamics and indicated that surface tilts were accurately transmitted up to 5 Hz. Feasibility of collecting kinematic data in participants lacking independent sitting was demonstrated in two populations: two typically developing infants, [Formula: see text] months, in a longitudinal study (eight sessions each) and four children with moderate-to-severe cerebral palsy (GMFCS III-V). Adaptability in the system was assessed by testing 16 adults (ages 18-63). Kinematic responses to continuous pseudorandom surface tilts were evaluated across 0.046-2 Hz and qualitative feedback indicated that the trunk support and stimulus were comfortable for all subjects. Concepts underlying the system enable both research for, and rehabilitation in, populations lacking independent sitting.

2A1-R05 ヒトを活動的にする移動支援ロボット : 高い運動性能を実現する機構・姿勢制御の提案(車輪型/クローラ型移動ロボット(1))

This paper presents a novel personal robot assisting transportation to support active human life. The personal robot can bring the luggage and follow the human being automatically. Therefore, the robot encourages the elder people to go to outside for shopping, airing, and visiting friends. The robot should achieve both small footprint for coexistence in human community and high traveling performance to follow the human being. For achievement of these requirements, active posture control for roll and pitch angle is an essential technology. In this paper, the structure and control approach for posture control is proposed to realize the following the human being. The effectiveness of the proposed approach is verified by experiment using a new prototype robot.

Haptic touch reduces sway by increasing axial tone

It is unclear how haptic touch with a stable surface reduces postural sway. We hypothesized that haptic input enhances postural stability due to alterations in axial postural tone. We measured the influence of heavy and light touch (LT) of the hands on a stable bar on axial postural tone and postural sway during stance in 14 healthy adults. A unique “Twister” device measured hip torque by fixing the upper body in space while oscillating the surface in yaw ±10 at 1 deg/s. Subjects were tested while: (1) standing quietly with their arms at their sides, (2) lightly touching a rigid bar in front of them and (3) firmly gripping the bar. Horizontal and vertical sway was not restricted by the device's yaw fixation, therefore, the subjects remained in a state of active postural control during the three touch conditions. Haptic touch significantly increased hip postural tone by 44% during light touch, from 2.5±0.9 to 3.6±1.0 Nm ( P=0.005), and by 40% during firm grip to 3.5±0.8 Nm ( P=0.005). Increases in hip postural tone were associated with a reduction in postural sway ( r=−0.55, P=0.001). This is the first study showing that axial postural tone can be modified by remote somatosensory input and provides a potential explanation for how light touch improves postural stability. Changes in subjects' perception from trunk to surface rotation when changing from no touch (NT) to haptic touch, suggests that the CNS changes from using a global, to a local, trunk reference frame for control of posture during touch. The increase of hip postural tone during touching and gripping can be explained as a suppression of hip muscle shortening reactions that normally assist axial rotation.

Axial kinesthesia is impaired in Parkinson's disease: Effects of levodopa

Integration of sensory and motor inputs has been shown to be impaired in appendicular muscles and joints of Parkinson's disease (PD) patients. As PD advances, axial symptoms such as gait and balance impairments appear, which often progresses to complete inability stand or walk unaided. The current study evaluates kinesthesia in the axial musculature of PD patients during active postural control to determine whether impairments similar to those found in the appendages are also present in the hip and trunk. Using axial twisting, we quantified the detection threshold and directional accuracy of the hip relative to the feet (i.e. Hip Kinesthesia) and the hip relative to the shoulders (i.e. Trunk Kinesthesia). The relation of kinesthetic threshold to disease progression as measured by UPDRS and the effect of levodopa treatment on kinesthesia were assessed in 12 PD compared to age-matched controls. Subjects stood unaided while passively twisted at a very low constant rotational velocity (1°/s). The results showed that accuracy in determining the direction of axial twisting was reduced in PD relative to healthy control subjects in the hip (PD-ON: 81%; PD-OFF: 91%; CTL = 96%) and trunk (PD-ON: 81%; PD-OFF: 88%; CTL = 95%). Thresholds for perception of axial twisting were increased when PD subjects were ON levodopa versus OFF in both the hip ( p < 0.01) and the trunk ( p < 0.05). The magnitude of decrease in sensitivity due to being ON levodopa was significantly correlated with the increase in UPDRS motor scores (Hip: r = 0.90, p < 0.01 and Trunk: r = 0.60, p < 0.05). This effect was not significantly correlated with equivalent levodopa dosage. PD subjects with disease onset on the left side of their body showed significantly higher axial thresholds than subjects with right PD onset ( p < 0.05). In conclusion, deficits in axial kinesthesia seem to contribute to the functional impairments of posture and locomotion in PD. Although levodopa has been shown to improve appendicular kinesthesia, we observed the opposite in the body axis. These findings underscore the dissociable neurophysiological circuits and dopaminergic pathways that are known to innervate these functionally distinct muscle groups.

Integração de informação e reativação da memória: impacto positivo de uma intervenção cognitivo-motora em bebês

OBJETIVO: Investigar os efeitos de uma intervenção cognitivo-motora na integração de informação e reativação da memória de bebês. MÉTODOS: Participaram do estudo 40 bebês de seis a oito meses de idade, nascidos a termo e matriculados em creches, permanecendo nelas sete horas por dia com relação educador/bebê de 1/6, provenientes de famílias numerosas e de baixa renda que não participavam de programas interventivos. Uma intervenção cognitivo-motora foi propiciada ao Grupo Interventivo com atividades de perseguição visual, manipulação de brinquedo e controle postural. Para o Grupo Controle, nenhuma intervenção foi propiciada. As atividades da rotina da creche foram mantidas para os dois grupos. Três atividades de manipulação foram avaliadas no início do programa, um mês depois (retenção) e três dias após a retenção. Para a análise dos dados, foram utilizados o teste do qui-quadrado com correção de Yates, o teste exato de Fisher e o de Cochran. RESULTADOS: O Grupo Interventivo demonstrou desempenho significativamente superior ao Grupo Controle em evocar informações da memória na retenção e pós-retenção em duas atividades. Mudanças significativas e positivas também foram observadas para o Grupo Interventivo no fator tempo. Os bebês mais velhos do Grupo Interventivo demonstraram melhor capacidade de evocar informação em relação aos mais jovens. Essa tendência não foi observada para o Grupo Controle. CONCLUSÕES: Para potencializar o desenvolvimento global de bebês, as intervenções deveriam ser organizadas implementando tarefas diversificadas com intervalos de aprendizagem apropriados, os quais levem em consideração a capacidade dos bebês de manterem a informação e integrarem essa informação a novos desafios

Postural Control after Vestibular Schwannoma Resection Measured with Visual Feedback Posturography

Background: Vestibular symptoms after surgery diminish rapidly, but the simultaneous progress in active postural control has not been fully addressed. Objectives: The aim was to evaluate the progress in postural control in operated vestibular schwannoma (VS) patients with visual feedback posturography (VFP). Methods: 36 consecutive patients with unilateral VS were studied with the VFP pre-operatively, 1 month and 3 months after the surgery. The accuracy and velocity of active postural control movements to distant targets in VFP was measured and compared to that of healthy controls. Results: The hold percentage within the targets was significantly reduced in the VS patients compared to the controls (pre-operatively p = 0.005; postoperatively at 1 month p = 0.002 and at 3 months p = 0.017). The sway velocity (SV) within the targets among patients with VS was significantly increased pre-operatively (p = 0.009), at the 1-month (p = 0.004) and at the 3-month follow-up visits (p = 0.016). All the postural control parameters except SV tended to improve slightly postoperatively. The consecutive VFP measurements in individual VS patients correlated statistically significantly (p < 0.001 for all parameters). The abnormality in the pre-operative VFP results correlated statistically significantly with that of postoperative VFP (p = 0.001). Conclusions: The VFP is an objective and repeatable method, which can be used to assess and follow up the active postural control in individual patients with VS. Persisting abnormality in the VFP seems to be an indication for more aggressive vestibular rehabilitation to normalize the disturbed postural control.

Postural Control Measured by Visual Feedback Posturography

The objective was to study the applicability and repeatability of visual feedback posturography (VFP) in assessing postural control of 23 healthy subjects. The subjects had to move their center of gravity (COG) marker on a computer screen to chosen targets by leaning their body on the platform, and the accuracy, velocity, and side difference of these movements were measured. The intraclass correlation coefficients for all parameters during repeated tests were significant (r = 0.93–0.96; p < 0.01). Hold percentage within the targets and COG marker velocity to the targets did not change significantly during repeated tests. Balance index and hit delay were significantly smaller during the 4th and 5th than during the 1st test session (p < 0.05), but they did not change significantly between the other test sessions. The normative limit for side difference in postural control was 22%. VFP can be used to follow active postural control due to its high test-retest repeatability. However, learning effects in some parameters must be taken into account when applying VFP repeatedly in different patient populations to assess the progress in postural control.

Active Posture Control during Experimental Motion Sickness in Guinea-Pigs

This study evaluated active posture control in guinea-pigs under motion sickness stimulation. Twelve guinea-pigs, which received training to stay on a moving perch, were divided into two groups: a motion sickness stimulation group and a control group. The motion sickness group was given a combined stimulation of turntable rotation and optokinetic drum rotation, and the control group was given turntable stimulation alone. Motion sickness was evaluated by conditioned taste aversion to saccharin solution. Active posture control was evaluated by the angle of nose tip displacement and the staying duration (length of time that guinea-pigs stayed on the turntable). The consumption of saccharin solution increased in the control group but did not increase in the motion sickness group. The motion sickness group showed a significant increase in the mean angle of nose tip displacement and a significant decrease in the staying duration on the turntable. These results indicate that active posture control was disturbed by motion sickness stimulation.