ObjectiveAre people with a characteristically large physiological sway rendered particularly unstable when standing on a moving surface? Is postural sway in standing individuals idiosyncratic? In this study, we examine postural sway in individuals standing normally, and when subtle continuous sinusoidal disturbances are applied to their support platform. We calculate consistency between conditions to verify if sway can be considered characteristic of each individual. We also correlate two different aspects of participants’ responses to disturbance; their (...) sway velocity and their regulation of body orientation.MethodsNineteen healthy adults (age 29.2 ± 3.2 years) stood freely on footplates coaxially aligned with their ankles and attached to a motorized platform. They had their eyes closed, and hips and knees locked with a light wooden board attached to their body. Participants either stood quietly on a fixed platform or on a slowly tilting platform (0.1 Hz sinusoid; 0.2 and 0.4 deg). Postural sway size was separated into two entities: (1) the spontaneous sway velocity component (natural random relatively rapid postural adjustments, RMS body angular velocity) and (2) the evoked tilt gain component (much slower 0.1 Hz synchronous tilt induced by the movement of the platform, measured as peak-to-peak (p-p) gain, ratio of body angle to applied footplate rotation).ResultsThere was no correlation between the velocity of an individual’s sway and their evoked tilt gain (r= 0.34,p= 0.15 andr= 0.30,p= 0.22). However, when considered separately, each of the two measurements showed fair to good absolute agreement within conditions. Spontaneous sway velocity consistently increased as participants were subjected to increasing disturbance. Participants who swayed more (or less) did so across all conditions [ICC(3,k)= 0.95]. Evoked tilt gain also showed consistency between conditions [ICC(3,k)= 0.79], but decreased from least to most disturbed conditions.ConclusionThe two measurements remain consistent between conditions. Consistency between conditions of two very distinct unrelated measurements reflects the idiosyncratic nature of postural sway. However, sway velocity and tilt gain are not related, which supports the idea that the short-term regulation of stability and the longer-term regulation of orientation are controlled by different processes. (shrink)

Physical fatigue negatively affects postural control, resulting in impaired balance performance in young and older adults. Similar effects on postural control can be observed for mental fatigue mainly in older adults. Controversial results exist for young adults. There is a void in the literature on the effects of fatigue on balance and cortical activity. Therefore, this study aimed to examine the acute effects of PF and MF on postural sway and cortical activity. Fifteen healthy young adults (...) aged 28 ± 3 years participated in this study. MF and PF protocols comprising of an all-out repeated sit-to-stand task and a computer-based attention network test, respectively, were applied in random order. Pre and post fatigue, cortical activity and postural sway were tested during a challenging bipedal balance board task. Absolute spectral power was calculated for theta, alpha-2, beta-1, and beta-2 in frontal, central, and parietal regions of interest and baseline-normalized. Inference statistics revealed a significant time-by-fatigue interaction for CoPd and CoPv, and a significant main effect of time for CoP variability. Post hoc analyses showed a significant increase in CoPd and CoPv following PF but not MF. For cortical activity, a significant time-by-fatigue interaction was found for relative alpha-2 power in parietal areas. Post hoc tests indicated larger alpha-2 power increases after PF compared to MF. In addition, changes in parietal alpha-2 power and measures of postural sway did not correlate significantly, irrespective of the applied fatigue protocol. No significant changes were found for the other frequency bands, irrespective of the fatigue protocol and ROI under investigation. Thus, the applied PF protocol resulted in increased postural sway and CoP variability accompanied by enhanced alpha-2 power in the parietal ROI while MF led to increased CoP variability and alpha-2 power in our sample of young adults. Potential underlying cortical mechanisms responsible for the greater increase in parietal alpha-2 power after PF were discussed but could not be clearly identified as cause. Therefore, further future research is needed to decipher alternative interpretations. (shrink)

Previous works usually report greater postural stability in precise visual tasks than in stationary-gaze tasks. However, existing cognitive models do not fully support these results as they assume that performing an attention-demanding task while standing would alter postural stability because of the competition of attention between the tasks. Contrary to these cognitive models, attentional resources may increase to create a synergy between visual and postural brain processes to perform precise oculomotor behaviors. To test this hypothesis, we investigated (...) a difficult searching task and a control free-viewing task. The precise visual task required the 16 young participants to find a target in densely furnished images. The free-viewing task consisted of looking at similar images without searching anything. As expected, the participants exhibited significantly lower body displacements and a significantly higher cognitive workload in the precise visual task than in the free-viewing task. Most important, our exploration showed functional synergies between visual and postural processes in the searching task, that is, significant negative relationships showing lower head and neck displacements to reach more expended zones of fixation. These functional synergies seemed to involve a greater attentional demand because they were not significant anymore when the cognitive workload was controlled. In the free-viewing task, only significant positive relationships were found and they did not involve any change in cognitive workload. An alternative cognitive model and its potential subtended neuroscientific circuit are proposed to explain the supposedly cognitively grounded functional nature of vision–posture synergies in precise visual tasks. (shrink)

Postural instability in Parkinson’s disease (PD) is characterized by impaired postural responses to transient perturbations, increased postural sway in stance and difficulty transitioning between tasks. In addition, some studies suggest that loss of dopamine in the basal ganglia due to PD results in difficulty using proprioceptive information for motor control. Here, we quantify the ability of subjects with PD and age-matched control subjects to use and re-weight sensory information for postural control during steady-state conditions of (...) continuous rotations of the stance surface or visual surround. We measure the postural sway of subjects in response to a pseudorandom, surface-tilt stimulus with eyes closed, and in response to a pseudorandom, visual-tilt stimulus. We use a feedback control model of the postural control system to interpret our results, focusing on sensory weighting as a function of stimulus amplitude. We find that subjects with PD can re-weight their dependence upon sensory information in response to changes in surface- or visual-stimulus amplitude. Specifically, subjects with PD behaved like age-matched control subjects by decreasing proprioceptive contribution to stance control with increasing surface-tilt amplitude, and decreasing visual contribution with increasing visual-tilt amplitude. However, subjects with PD do not decrease their reliance on proprioception as much as age-matched controls for small increases in surface-stimulus amplitudes. Levodopa medication did not affect sensory re-weighting behaviors for postural control. The impairment in PD subject’s ability to respond differently to small changes in surface rotation amplitudes is consistent with an increased threshold for perceiving proprioceptive signals, which may result from decreased signal-to-noise in the dopaminergic pathways associated with sensory processing and/or sensory integration. (shrink)

IntroductionAlthough a few studies suggest that young overweight to obese children and adolescents may have impaired postural control compared to young normal-weight peers, little information exists about how these two groups differ in the quality of the underlying balance strategies employed. Hence, the aim of the present study was a first comprehensive examination of the structural complexity of postural sways in these two cohorts during quiet bilateral standing.MethodsNineteen YO secondary school students were carefully matched to YN controls for (...) age, sex, height, and school. Mediolateral and anteriorposterior acceleration signals were recorded with an inertial measurement unit positioned at the trunk while standing barefoot in two conditions: firm and foam support surface. The magnitude of postural fluctuations was obtained using the root mean square. The temporal structure of the signals was analyzed via sample entropy, largest Lyapunov exponent, and detrended fluctuation analysis algorithm. Reliability was assessed using a test–retest design.ResultsIn both groups, foam standing caused higher postural fluctuations and reduced structural complexity. In comparison to YN, YO exhibited a higher RMSAP. Especially in ML direction, the acceleration signals of the YO had higher repeatability, greater long-range correlations, and lower local stability. However, these observations were largely independent of the task difficulty. Except for α-DFAAP, the IMU approach proved reliable to characterize posture control.DiscussionOur outcomes confirm postural control deficits in YO compared to their YN peers and indicate impaired regulatory mechanisms reflected as rigidity. Such less complex patterns usually reflect diverse pathologies, are detrimental to compensate for internal or external perturbations, and are attributed to lower adaptability and task performance. Without targeted balance stimuli, YO likely end in a lifelong vicious circle of mutually dependent poor balance regulation and low physical activity. (shrink)

Postural instability and balance impairment are disabling symptoms in patients with acute unilateral peripheral vestibular hypofunction. Vestibular rehabilitation is known to improve the vestibular compensation process, but its effect on posture recovery remains poorly understood, little is known about when VR must be done, and whether the degree of vestibular loss matters is uncertain. We analyzed posture control under static and dynamic postural tasks performed in different visual conditions [eye open ; eyes closed ; and optokinetic stimulation] using (...) dynamic posturography. Non-linear analyses of the postural performance were performed in two groups of patients with UVH subjected to the same VR program based on the unidirectional rotation paradigm and performed either early or later after vertigo attack. Distribution of the angular horizontal vestibulo-ocular reflex gain values recorded on the hypofunction side before rehabilitation differentiated two distinct sub-groups with aVOR gains below or above 0.20. The postural performance of the four sub-groups of patients with UVH tested before VR showed significantly altered postural parameters compared with healthy controls. Greater instability, higher energy to control posture, larger sway without feedback corrections, and lower time of automatic control of posture were observed in static conditions. The four sub-groups recovered near-normal postural performance after VR in the EO and EC conditions, but still exhibited altered postural performance with optokinetic stimulation. In dynamic posturography conditions and before VR, the percentage of patients able to perform the postural tasks with EC and optokinetic stimulation was significantly lower in the two sub-groups with aVOR gain <0.20. After VR, the improvement of the postural parameters depended on the stage of rehabilitation and the degree of vestibular hypofunction. The best balance function recovery was found in the sub-group with early VR and pre-rehabilitation aVOR gain above 0.20, the worst in the sub-group with late rehabilitation and aVOR gain below 0.20. These differences were seen when the vestibular input remains the main sensory cue to control balance, that is, on unstable support without vision or altered visual motion cues. These findings extend to dynamic balance recovery the crucial roles of early rehabilitation and degree of vestibular hypofunction which we have already highlighted for vestibulo-ocular reflex recovery. (shrink)

Dual task is known to affect postural stabilty in children. We explored the effect of visual tasks on postural control in dyslexic and in age-matched non-dyslexic children. Thirty dyslexic children (mean age: 9.80 ± 0.28 years) were compared with thirty non-dyslexic children (mean age: 9.92 ± 0.35 years). All children underwent ophthalmologic and optometric evaluation. Eye movements were recorded by a video-oculography system (EyeBrain ® T2) and postural sway was recorded simultaneously by a force platform (TechnoConept®). (...) Both groups of children performed fixations, pursuits, pro- and anti-saccades tasks. Dyslexic children showed significantly poor near fusional vergence ranges (convergence and divergence) with respect to the non-dyslexic children. During the postural task, quality of fixation and anti-saccade performance in dyslexic children were significantly worse compared to non-dyslexic children. In contrast, the number of catch-up saccades during pursuits and the latency of pro-and anti-saccades were similar in both groups of children examined. Concerning postural quality, dyslexic children were more unstable than age-matched non-dyslexic children. For both groups of children tested we also observed that executing saccades (pro- and anti-saccades) reduced postural values significantly in comparison with fixation and pursuit tasks. The impairment in convergence and divergence fusional capabilities could be due to an immaturity in cortical structures controlling the vergence system. The poor oculomotor performance reported in dyslexic children suggested a deficit in allocating visual attention and their postural instability observed is in line with the cerebellar impairment previously reported in dyslexic children. Finally, pro- or anti-saccades reduce postural values compared to fixation and pursuit tasks in both groups of children tested, suggesting a different influence of visual tasks on postural control according to their attentional demand. (shrink)

Fundamental movement skill proficiency does not develop solely due to maturation, but also via diverse perceptual-motor experiences across childhood. Practicing gymnastics has been shown to improve postural control. The purpose of the present study was to examine potential changes to postural control of children following a course of educational gymnastics. Two groups of children both completed 20 × 45-min physical education lessons; one group completed educational gymnastics lessons in school delivered by a professional coach, the other group completed (...) their typical PE classes. Unipedal balancing performance was assessed by calculating the percentage of successful trials made. Postural sway dynamics were explored by calculating center-of-pressure sample entropy, 95% ellipse sway area and sway velocity. Measurements were taken before the lessons began and immediately after the lessons were completed. The gymnastics group performed better than the typical PE group at unipedal balancing. Females outperformed males in both groups. Males made different changes to postural control compared to females across 3 months. Educational gymnastics enabled children in a critical period of development to make more rapid improvements to postural performance and control. Novel movement experiences, like those offered by educational gymnastics, may have a positive influence on postural control and importantly, physical literacy. Future work should examine how sex effects the development of postural control strategies in young children. (shrink)

Multiple sensory signals from visual, somatosensory and vestibular systems are used for human postural control. To maintain postural stability, the central nervous system keeps the center of mass (CoM) within the base of support. The influence of the stomatognathic motor system on postural control has been established under static conditions, but it has not yet been investigated during dynamic steady-state balance. The purpose of the study was to investigate the effects of controlled stomatognathic motor activity on the (...) control and stability of the CoM during dynamic steady-state balance. A total of 48 physically active and healthy adults were assigned to three groups with different stomatognathic motor conditions: jaw clenching, tongue pressing and habitual stomatognathic behavior. Dynamic steady-state balance was assessed using an oscillating platform and the kinematic data were collected with a 3D motion capturing system. The path length (PL) of the 3D CoM trajectory was used for quantifying CoM sway. Temporal dynamics of the CoM movement was assessed with a detrended fluctuation analysis (DFA). An uncontrolled manifold (UCM) analysis was applied to assess the stability and control of the CoM with a subject-specific anthropometric 3D model. The statistical analysis revealed that the groups did not differ significantly in PL, DFA scaling exponents or UCM parameters. The results indicated that deliberate jaw clenching or tongue pressing did not seem to affect the sway, control or stability of the CoM on an oscillating platform significantly. Because of the task-specificity of balance, further research investigating the effects of stomatognathic motor activities on dynamic steady-state balance with different movement tasks are needed. Additionally, further analysis by use of muscle synergies or co-contractions may reveal effects on the level of muscles, which were not visible on the level of kinematics. This study can contribute to the understanding of postural control mechanisms, particularly in relation to stomatognathic motor activities and under dynamic conditions. (shrink)

Persistent Postural-Perceptual Dizziness, also known as PPPD or 3PD, is a chronic functional vestibular disorder characterized by persistent sensation of rocking or swaying unsteadiness and/ or non-spinning dizziness without vertigo lasting at least 3 months. Symptoms typically worsen with upright posture, head or body motion and exposure to busy or visually rich environments. The article describes the application of Infra-Low Frequency Neurofeedback over 32 sessions on an unmedicated individual with symptoms related to PPPD that were still present 3 years (...) after the initial diagnosis. Along with significant reduction in those symptoms, other accompanying symptoms were markedly improved with ILF NFB. Consistent symptom tracking from session to session, as well as before and after CPT data were used to document reported changes with ILF NF. (shrink)

Instrumented assessments of quiet-stance postural control typically involve recording and analyzing of body sway signal, most often the center of pressure movement. It has been recently suggested that transient characteristics of body sway may offer additional information regarding postural control. In this study, we explored the relationship between whole-trial estimates of body sway and corresponding transient behavior indexes, as well as the effects of leg preference. A total of 705 healthy young athletes performed 30 s (...) single-leg body sway trials for both legs. It was found that the transient characteristics of the body sway are in negligible or weak correlation with the corresponding variables, averaged across the whole trial. All CoP variables showed transient characteristics, reflected in statistically significant decrease or increase throughout the trial. The preferred leg showed smaller body sway; however, the effect sizes were very small. Moreover, differences between the legs were also noted in terms of transient characteristics of body sway. In particular, the preferred leg showed earlier reduction in anterior–posterior body sway and larger reduction in medial–lateral body sway. Further studies should focus on examining the clinical utility of indexes of transient behavior of body sway, for instance, their sensitivity to aging-related changes and risk of falling. (shrink)

Many individuals with disabling conditions have difficulty with gait and balance control that may result in a fall. Exoskeletons are becoming an increasingly popular technology to aid in walking. Despite being a significant aid in increasing mobility, little attention has been paid to exoskeleton features to mitigate falls. To develop improved exoskeleton stability, quantitative information regarding how a user reacts to postural challenges while wearing the exoskeleton is needed. Assessing the unique responses of individuals to postural perturbations while (...) wearing an exoskeleton provides critical information necessary to effectively accommodate a variety of individual response patterns. This report provides kinematic and neuromuscular data obtained from seven healthy, college-aged individuals during posterior support surface translations with and without wearing a lower limb exoskeleton. A 2-min, static baseline standing trial was also obtained. Outcome measures included a variety of 0 dimensional measures such as center of pressure RMS, peak amplitude, velocities, pathlength, and electromyographic RMS, and peak amplitudes. These measures were obtained during epochs associated with the response to the perturbations: baseline, response, and recovery. T-tests were used to explore potential statistical differences between the exoskeleton and no exoskeleton conditions. Time series waveforms of the COP and EMG data were also analyzed. Statistical parametric mapping was used to evaluate the 1D COP and EMG waveforms obtained during the epochs with and without wearing the exoskeleton. The results indicated that during quiet stance, COP velocity was increased while wearing the exoskeleton, but the magnitude of sway was unchanged. The OD COP measures revealed that wearing the exoskeleton significantly reduced the sway magnitude and velocity in response to the perturbations. There were no systematic effects of wearing the exoskeleton on EMG. SPM analysis revealed that there was a range of individual responses; both behaviorally and among neuromuscular activation patterns. Using both the OD and 1D measures provided a more comprehensive representation of how wearing the exoskeleton impacts the responses to posterior perturbations. This study supports a growing body of evidence that exoskeletons must be personalized to meet the specific capabilities and needs of each individual end-user. (shrink)

Virtual reality enables individuals to be exposed to naturalistic environments in laboratory settings, offering new possibilities for research in human neuroscience and treatment of mental disorders. We used VR to study psychological, autonomic and postural reactions to heights in individuals with varying intensity of fear of heights. Study participants were immersed in a VR of an unprotected open-air elevator platform in an urban area, while standing on an unstable ground. Virtual elevation of the platform elicited robust and reliable psychophysiological (...) activation including increased distress, heart rate, and electrodermal activity, which was higher in individuals suffering from fear of heights. In these individuals, compared with individuals with low fear of heights, the VR height exposure resulted in higher velocity of postural movements as well as decreased low-frequency body sway oscillations. This indicates that individuals with strong fear of heights react to heights with maladaptive rigidity of posture due to increased weight of visual input for balance control, while the visual information is less reliable at heights. Our findings show that exposure to height in a naturalistic VR environment elicits a complex reaction involving correlated changes of the emotional state, autonomic activity, and postural balance, which are exaggerated in individuals with fear of heights. (shrink)

A variety of theoretical frameworks predict the resemblance of behaviors between two people engaged in communication, in the form of coordination, mimicry, or alignment. However, little is known about the time course of the behavior matching, even though there is evidence that dyads synchronize oscillatory motions (e.g., postural sway). This study examined the temporal structure of nonoscillatory actions—language, facial, and gestural behaviors—produced during a route communication task. The focus was the temporal relationship between matching behaviors in the interlocutors (...) (e.g., facial behavior in one interlocutor vs. the same facial behavior in the other interlocutor). Cross-recurrence analysis revealed that within each category tested (language, facial, gestural), interlocutors synchronized matching behaviors, at temporal lags short enough to provide imitation of one interlocutor by the other, from one conversational turn to the next. Both social and cognitive variables predicted the degree of temporal organization. These findings suggest that the temporal structure of matching behaviors provides low-level and low-cost resources for human interaction. (shrink)

Background: Lower limb spasticity after stroke is common that can affect the balance, increase the risk of falling, and reduces the quality of life.Objective: First, evaluate the effects of spasticity severity of ankle plantar flexors on balance of patients after stroke. Second, to determine the relationship between the spasticity severity with ankle proprioception, passive ankle dorsiflexion range of motion, and balance confidence.Methods: Twenty-eight patients with stroke based on the Modified Modified Ashworth Scale were divided into two groups: High Spasticity Group (...) or a Low Spasticity Group. The MMAS scores, Activities-Specific Balance Confidence Questionnaire, postural sway of both affected and non-affected limbs under the eyes open and eyes closed conditions, timed up and go test, passive ankle dorsiflexion ROM, and ankle joint proprioception were measured.Results: The ankle joint proprioception was significantly better in the LSG compared to the HSG. No significant differences were found between the LSG and HSG on all other outcome measures. There were no significant relationships between the spasticity severity and passive ankle dorsiflexion ROM, and balance confidence.Conclusion: The severity of ankle plantar flexor spasticity had no effects on balance of patients with stroke. However, the ankle joint proprioception was better in patients with low spasticity. Our findings suggest that the balance is affected regardless of the severity of the ankle plantar flexor spasticity in this group of participants with stroke. (shrink)

ObjectivesTo investigate the effect of combined balance and plyometric training on knee function and proprioception of elite badminton athletes.MethodsSixteen elite male badminton players volunteered to participate and were randomly assigned to a combined balance and plyometric training and plyometric group. The CT group performed balance combined with plyometric training three times a week over 6 weeks ; while the PT group undertook only plyometric training for the same period. Both groups had the same technical training of badminton.ResultsThe knee function and (...) proprioception were assessed at baseline and after the intervention by measuring the performance of single-legged hop tests, standing postural sway, and LSI of dominant leg and non-dominant leg. The results showed that as compared to PT, CT induced significantly greater improvements in LSIT and LSIS.ConclusionIn elite badminton players, intervention using CT holds great promise to augment the benefits for knee function compared to the intervention using PT only, and at the same time, with at least comparable benefits for proprioception. Future studies are needed to examine and confirm the results of this study. (shrink)

Postural instability marks a prevalent symptom of Parkinson’s disease. It often manifests in increased body sway, which is commonly assessed by tracking the Center of Pressure. Yet, in terms of postural control, the body’s Center of Mass, and not CoP is what is regulated in a gravitational field. The aim of this study was to explore the effect of early- to mid-stage PD on these measures of postural control in response to unpredictable visual perturbations. We investigated (...) three cohorts: 18 patients with early to mid-stage PD [Hoehn & Yahr stage ; 1.94 ± 0.70]; a group of 15 age-matched controls ; and a group of 12 young healthy adults. Participants stood on a force plate to track their CoP, while the movement of their entire body was recorded with a video-based motion tracking system to monitor their CoM. A moving room paradigm was applied through a head-mounted virtual reality headset. The stimulus consisted of a virtual tunnel that stretched in the anterior-posterior direction which either remained static or moved back and forth in an unpredictable fashion.We found differences in mean sway amplitude and mean velocities of CoP and CoM between the groups under both conditions, with higher MSA of CoP and CoM for PD and higher mean velocities of both variables for PD and ECT when compared with YCT. Visual perturbation increased mean CoP velocity in all groups but did not have effects on mean CoM velocity or MSA. While being significantly lower for the young adults, the net effect of visual perturbation on mean CoP velocity was similar between patients with PD and age-matched controls. There was no effect of the visual perturbation on mean CoM velocity for any of the groups.Our simultaneous assessment of CoP and CoM revealed that postural control is reflected differently in CoM and CoP. As the motion of CoM remained mostly unaffected, all groups successfully counteracted the perturbation and maintained their balance. Higher CoP velocity for PD and ECT revealed increased corrective motion needed to achieve this, which however was similar in both groups. Thus, our results suggest increased effort, expressed in CoP velocity, to be an effect of age rather than disease in earlier stages of PD. (shrink)

People coordinate body postures and gaze patterns during conversation. We review literature showing that (1) action embodies cognition, (2) postural coordination emerges spontaneously when two people converse, (3) gaze patterns influence postural coordination, (4) gaze coordination is a function of common ground knowledge and visual information that conversants believe they share, and (5) gaze coordination is causally related to mutual understanding. We then consider how coordination, generally, can be understood as temporarily coupled neuromuscular components that function as a (...) collective unit known as a coordinative structure in the motor control literature. We speculate that the coordination of gaze and body sway found in conversation may be understood as a cross‐person coordinative structure that embodies the goals of the joint action system. (shrink)

Performance and control of upright bipedal posture requires a constant and dynamic integration of relative contributions of different sensory inputs (i. e., sensory reweighting) to enable effective adaptations as individuals face environmental changes and perturbations. Children with gymnastic experience showed balance performance closer to that of adults during and after proprioceptive alteration than children without gymnastic experience when their center of pressure (COP) was analyzed. However, a particular COP sway can be achieved through performing and coordinating different postural (...) movements. The aim of this study was to assess how children and adults of different gymnastic experience perform and control postural movements while they have to adjust balance during and after bilateral tendon vibration. All participants were equipped with spherical markers attached to their skin and two vibrators strapped over the Achilles tendons. Bipedal stance was performed in three 45-s trials in two visual conditions (eyes open, EO, and eyes closed, EC) ordered randomly in which vibration lasted 10 s. Posture movements were analyzed by a principal component analysis (PCA) calculated on normalized and weighted markers coordinates. The relative standard deviation of each principal movement component (principal position, PP-rSTD) quantified its contribution to the whole postural movements, i.e., quantified the coordinative structure. The first (principal velocities, PV-rSTD) and second (principal accelerations, PA-rSTD) time-derivatives characterized the rate-dependent sensory information associated with and the neuromuscular control of the postural movements, respectively. Children without gymnastic experience showed a different postural coordinative structure and different sensory-motor control characteristics. They used less ankle movements in the anterior-posterior direction but increased ankle movements in medio-lateral direction, presented larger hip and trunk velocities, and exhibited more hip actions. Gymnastic experience during childhood seemed to benefit the development of proprioceptive reweighting processes in children, leading to a more mature form of coordinating and controlling posture similarly to adults. (shrink)

Vision is known to improve human postural responses to external perturbations. This study investigates the role of vision for the responses to continuous pseudorandom support surface translations in the body sagittal plane in three visual conditions: with the eyes closed, in stroboscopic illumination and with eyes open in continuous illumination with the room as static visual scene. In the frequency spectrum of the translation stimulus we distinguished on the basis of the response patterns between a low-frequency, mid-frequency, and high-frequency (...) range. With EC, subjects’ mean sway response gain was very low in the LFR. On average it increased with EO/SI and more so with EO/CI. In contrast, the average gain in the MFR decreased from EC to EO/SI and further to EO/CI. In the HFR, all three visual conditions produced, similarly, high gain levels. A single inverted pendulum model controlling center of mass balancing about the ankle joints formally described the EC response as being strongly shaped by a resonance phenomenon arising primarily from the control’s proprioceptive feedback loop. The effect of adding visual information in these simulations lies in a reduction of the resonance, similar as in the experiments. Extending the model to a double inverted pendulum suggested in addition a biomechanical damping effective from trunk sway in the hip joints on the resonance. (shrink)

It can be tempting to think of affect as a matter of the present moment – a reaction, a feeling, an experience or engagement that unfolds right now. This paper will make the case that affect is better thought of as not only temporally extended but as saturated with temporality, especially with the past. In and through affectivity, concrete, ongoing history continues to weigh on present comportment. In order to spell this out, I sketch a Heidegger-inspired perspective. It revolves around (...) two claims. The first is that we should understand what Heidegger calls 'Befindlichkeit' (findingness) as radical situatedness. Affectivity is a matter of 'finding oneself' constellated – thrown – into the world in ways that outrun what an individual or collective might grasp and process. The second claim is that the temporal dimension, as a relatedness to the past, takes precedence in affect's situatedness. Key to affect is the way in which the past continues to hold sway over present comportment, collectively and individually. In order to articulate this perspective, it is important to overcome the idea that affect must be understood mainly in terms of feeling or experiential states of other kinds. Better suited to grasp the idea of findingness is the concept of 'disclosive posture', as proposed by Katherine Withy. I suggest that this notion should be put at the fore of a phenomenological approach to situated affectivity. (shrink)

Is Reason a Neutral Tool in Comparative Philosophy? In his answer to the symposium’s question, Jonardon Ganeri develops a »Manifesto for [a] Re:emergent Philosophy.« Tracking changes in the understanding of ›comparative philosophy,‹ he sketches how today’s world of academic philosophy seems to be set to enter an »age of re:emergence« in which world philosophies will be studied through modes of global participation. In their responses, the symposium’s discussants tease out implications of this Manifesto for different issues: While Mustafa Abu (...) class='Hi'>Sway suggests that comparative philosophy be understood as an intra-philosophical dialogue, whose aim depends on its participants, Paul Boghossian questions whether there can be conflicting, yet equally valid, ways of arriving at justified beliefs about the world. For her part, Georgina Stewart draws out the similarities between Ganeri’s understanding of comparative philosophy and the ethical stance involved in studying Maori science. In his Reply, Ganeri fleshes out his understanding of a pluralistic realism. Only an epistemic culture, which is open to a plurality of epistemic stances, he contends, can propel polycentric modes of knowledge production. (shrink)

Schumaker (philosophy, science and technology department, Rensselaer Polytechnic Institute) examines how the terms of posture encompass all the major disciplines and investigates a variety of philosophical topics: abstract thought, ...

Emotion can be communicated through multiple distinct modalities. However, an often-ignored channel of communication is posture. Recent research indicates that bodily posture plays an important role in the perception of emotion. However, research examining postural communication of emotion is limited by the variety of validated emotion poses and unknown cohesion of categorical and dimensional ratings. The present study addressed these limitations. Specifically, we examined individuals’ (1) categorization of emotion postures depicting 5 discrete emotions (joy, sadness, fear, anger, and disgust), (...) (2) categorization of different poses depicting the same discrete emotion, and (3) ratings of valence and arousal for each emotion pose. Findings revealed that participants successfully categorized each posture as the target emotion, including disgust. Moreover, participants accurately identified multiple distinct poses within each emotion category. In addition to the categorical responses, dimensional ratings of valence and arousal revealed interesting overlap and distinctions between and within emotion categories. These findings provide the first evidence of an identifiable posture for disgust and instantiate the principle of equifinality of emotional communication through the inclusion of distinct poses within emotion categories. Additionally, the dimensional ratings corroborated the categorical data and provide further granularity for future researchers to consider in examining how distinct emotion poses are perceived. (shrink)

The question of postures is a relatively recent concern for the actors involved in teacher education. It is important for the teacher educator to identify the postures he adopts so that the student teacher can learn to practice his profession independently and develop his professional singularity. In the same way, the mentor during the induction period, by adopting certain postures, plays a major role in the professional development of the beginning teacher. These aspects have been the subject of a doctoral (...) research conducted through a qualitative multiple-case study in a context of teacher induction. From the conversations between the mentors and the beginning teachers, several postures were identified. In addition, semi-structured interviews with the mentors revealed their conceptions relating to the accompaniment, which gave an orientation to the postures adopted. Once the theoretical framework of the accompaniment postures exposed, this paper states the link between these and the ethical principles underlying their practice, the vision of their role and their position towards the beginner. (shrink)

_Postures of the Mind _was first published in 1985. Minnesota Archive Editions uses digital technology to make long-unavailable books once again accessible, and are published unaltered from the original University of Minnesota Press editions. Annette Baier develops, in these essays, a posture in philosophy of mind and in ethics that grows out of her reading of Hume and the later Wittgenstein, and that challenges several Kantian or analytic articles of faith. She questions the assumption that intellect has authority over all (...) human feelings and traditions; that to recognize order we must recognize universal laws—descriptive or prescriptive; that the essential mental activity is representing; and that mental acts can be analyzed into discrete basic elements, combined according to statable rules of synthesis. In the first group of essays—"Varieties of Mental Postures"—Baier evaluates the positions taken by philosophers ranging from Descartes to Dennett and Davidson. Among her topics are remembering, intending, realizing, caring, representing, changing one's mind, justifying one's actions and feelings, and having conflicting reasons for them. The second group of essays—"Varieties of Moral Postures" - explores the sort of morality we get when all of these capacities become reflective and self-corrective. Some deal with particular moral issues—our treatment of animals, our policies regarding risk to human life, our contractual obligations; others, with more general questions on the role of moral philosophers and the place of moral theory. These essays respond to the theories of Hobbes, Kant, Rawls, and MacIntyre, but Baier's most positive reaction is to David Hume; _Postures of the Mind _ affirms and cultivates his version of a moral reflection that employs feeling and tradition as well as reason. (shrink)

_Postures of the Mind _was first published in 1985. Minnesota Archive Editions uses digital technology to make long-unavailable books once again accessible, and are published unaltered from the original University of Minnesota Press editions. Annette Baier develops, in these essays, a posture in philosophy of mind and in ethics that grows out of her reading of Hume and the later Wittgenstein, and that challenges several Kantian or analytic articles of faith. She questions the assumption that intellect has authority over all (...) human feelings and traditions; that to recognize order we must recognize universal laws—descriptive or prescriptive; that the essential mental activity is representing; and that mental acts can be analyzed into discrete basic elements, combined according to statable rules of synthesis. In the first group of essays—"Varieties of Mental Postures"—Baier evaluates the positions taken by philosophers ranging from Descartes to Dennett and Davidson. Among her topics are remembering, intending, realizing, caring, representing, changing one's mind, justifying one's actions and feelings, and having conflicting reasons for them. The second group of essays—"Varieties of Moral Postures" - explores the sort of morality we get when all of these capacities become reflective and self-corrective. Some deal with particular moral issues—our treatment of animals, our policies regarding risk to human life, our contractual obligations; others, with more general questions on the role of moral philosophers and the place of moral theory. These essays respond to the theories of Hobbes, Kant, Rawls, and MacIntyre, but Baier's most positive reaction is to David Hume; _Postures of the Mind _ affirms and cultivates his version of a moral reflection that employs feeling and tradition as well as reason. (shrink)

A journey into the hidden psychological influences that derail our decision-making. Why is it so difficult to end a doomed relationship? Why do we listen to advice just because it came from someone "important"? Why are we more likely to fall in love when there's danger involved? Here, organizational thinker Ori Brafman and his brother, psychologist Rom Brafman, answer these questions and more. Drawing on research from the fields of social psychology, behavioral economics, and organizational behavior, Sway reveals forces (...) that influence every aspect of our personal and business lives, including loss aversion, the diagnosis bias, and the "chameleon effect." The Brafmans not only uncover rational explanations for a wide variety of irrational behaviors, but also point readers toward ways to avoid succumbing to their pull.--From publisher description. (shrink)

One hundred and twenty-seven college students were recruited for an experimental investigation of the effect of body posture on religious attitudes. Roughly half of the participants were placed in lower, contractive body postures while the other half were placed in higher, expansive body postures. After five minutes in these postures, all were asked to fill out a measure of religious attitudes. As expected, participants in the lower, contractive positions expressed more agreement with conventional religious beliefs than those in the higher, (...) expansive positions. (shrink)

This article builds on collaborative research (observations, interviews, and writing and reflection workshops) conducted on Early Childhood Educators (ECEs). The text studies the inclusive education efforts of ECEs within early childhood centers. In this setting, the educational and care work carried out raises the question of encounters with others. Inclusive education places children, families, and ECE in liminal or in-between spaces. ECEs have to reconcile the similarities and differences between young children and their parents within early childhood centers. As a (...) result, certain points of rupture and convergence emerge between ECEs and families. The active involvement of ECEs appears to be a key component of this professional posture so conducive to inclusive education. (shrink)

Inspired by Adriana Cavarero’s recent work on maternal inclinations as a postural term, the overall purpose of this article is to seek out a geometry of the educational relation that is alien to the masculine myth of the ‘economic man’. Drawing on Jan Masschelein and Maarten Simons’s critique of the marketization of education, reading their giving ‘shape and form’ to the scholastic school through the geometry of Cavarero’s ‘maternal inclinations’, the article shows how images and metaphors associated with the (...) posture of rectitude infuse the scholastic model of the school. At the same time, we argue, it testifies to a geometry of an inclined subject and, in doing so, it offers an opening for recovering the significance of the feminine and maternal to educational theory. Affirming this opening, the paper makes a shift of emphasis from scholastic techniques to educational postures. (shrink)

POSTURES ET PRATIQUES DE L'HOMME Libéralisme, philosophie non-standard et pensée japonaise Jordanco SEKULOVSKI Nous, les sans-philosophie ASIE Japon -/- La philosophie véhicule des distinctions dualistes dont la conflictualité affaiblit gravement notre sentiment de solidarité humaine ; affronter la philosophie sur son propre terrain mène à une impasse, toute objection à son règne métaphysique devant, pour être reçue, se formuler dans les termes mêmes de la métaphysique... Il s'agit donc de changer de terrain, ou de chemin... L'auteur s'appuie sur le kâta (...) japonais qui forme la base des techniques de soi et façonne la pensée et les pratiques sociétales : une alternative crédible à la pensée-monde occidentale aujourd'hui dans l'impasse. -/- - format : 135 x 215 cm ISBN : 978-2-343-00792-2 • septembre 2013 • 222 pages EAN13 : 9782343007922 EAN PDF : 9782336322865. (shrink)

Cross-linguistic strategies for mapping lexical and spatial relations from body partonym systems to external object meronymies (as in English ‘table leg’, ‘mountain face’) have attracted substantial research and debate over the past three decades. Due to the systematic mappings, lexical productivity and geometric complexities of body-based meronymies found in many Mesoamerican languages, the region has become focal for these discussions, prominently including contrastive accounts of the phenomenon in Zapotec and Tzeltal, leading researchers to question whether such systems should be explained (...) as global metaphorical mappings from bodily source to target holonym or as vector mappings of shape and axis generated “algorithmically”. I propose a synthesis of these accounts in this paper by drawing on the species-specific cognitive affordances of human upright posture grounded in the reorganization of the anatomical planes, with a special emphasis on antisymmetrical relations that emerge between arm-leg and face-groin antinomies cross-culturally. Whereas Levinson argues that the internal geometry of objects “stripped of their bodily associations” (1994: 821) is sufficient to account for Tzeltal meronymy, making metaphorical explanations entirely unnecessary, I propose a more powerful, elegant explanation of Tzeltal meronymic mapping that affirms both the geometric-analytic and the global-metaphorical nature of Tzeltal meaning construal. I do this by demonstrating that the “algorithm” in question arises from the phenomenology of movement and correlative body memories—an experiential ground which generates a culturally selected pair of inverse contrastive paradigm sets with marked and unmarked membership emerging antithetically relative to the transverse anatomical plane. These relations are then selected diagrammatically for the classification of object orientations according to systematic geometric iconicities. Results not only serve to clarify the case in question but also point to the relatively untapped potential that upright posture holds for theorizing the emergence of human cognition, highlighting in the process the nature, origins and theoretical validity of markedness and double scope conceptual integration. (shrink)

How is it that metaphors are meaningful, yet we have so much trouble saying exactly what they mean? I argue that metaphoric thought is an act of imagination, mediated by the contingent form of human embodiment. Metaphoric cognition is an example of the productive interplay between intentional imagery and the body scheme, a process of imaginal modeling. The case of metaphor marks the intersection of linguistic and psychological processes and demonstrates the need for a multi-disciplinary approach not only in philosophy (...) of language, but in cognitive science and consciousness studies as well. (shrink)

Here, we describe how Casas Grandes Medio period (AD 1200 to 1450) shamanic practices of the North American Southwest used tobacco shamanism, a ritual stance called the Tennessee Diviner (TD) posture, and cultural expectations to generate trance experiences of soul flight and divination. We introduce a conceptual model that holds that specific trance experiences are the emergent result of human minds interacting with additional factors including entheogens, cultural expectations, physiological states, postures/movement, and sound/stimulation. Experimental and ethnographic evidence indicates initiating trance (...) with either tobacco intoxication or the TD posture accompanied with a rapidly beating drum or rattle corresponds with perceptions of soul flight, transformation, and divination/information acquisition. Both have similar results but pairing them together as they were during the Medio period likely helped ensure the culturally desired trance experiences. This practice of mutually reinforcing factors was likely part of tobacco‐based shamanism found in other New World cultures as well. We suggest our general model can be applied to other contexts to examine how various aspects of trance induction interact to produce the cultural patterns (and resulting cosmological and spiritual frameworks) anthropologists have documented in other cultures. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Dining Posture in Ancient Rome: Bodies, Values, and StatusJeremy RossiterMatthew B. Roller. Dining Posture in Ancient Rome: Bodies, Values, and Status. Princeton: Princeton University Press, 2006. xvi + 219 pp. 8 color plates. 18 black-and-white figs. Cloth, $39.50.As the author of this volume is quick to point out, a book-length study focusing solely on how the Romans sat, or reclined, at table might not seem like the most (...) compelling reading, even for a specialist reader. Could something so abstruse really warrant such an extensive study? Clearly the author thinks so, and to support his view he starts with some bold claims of what the book promises to accomplish. One of the key aims of the book is to redefine our understanding of Roman dining practices; to challenge the orthodox views presented in the "handbooks" (by which the author seems to mean principally the second edition of Marquardt and Mau's Das Privatleben der Römer, Leipzig 1886) and to replace them with a more measured interpretation of the evidence, not just of the few familiar texts that are often cited in the handbooks but rather of the full range of texts, images, and other source material that contribute in one way or another to what we know about Roman dining. Why do this? Because, Roller argues, the orthodox view is wrong. It depends on too little information, it pays too little attention to the evidence of images, and it fails to see the important link between dining custom and social values. These are bold assertions, the credibility of which can only be judged by comparing the orthodox view of Roman dining practices with the "new" picture of Roman dining given by Roller and by evaluating the methodology he uses to reach his conclusions.What then is the orthodox view of Roman dining posture? Roller summarizes it as follows (4–5): free adult males reclined, free adult women sat (during the Republic) but later reclined (during the Empire), free children sat, and slaves stood. Fast forward to the end of the book (177) and we find a rather different assessment: "persons of any age, sex or status might actually assume, or be represented as assuming, various positions under different circumstances." What Roller does here is to deconstruct the simplistic assertions of the handbooks and replace them with a more nuanced interpretation of the evidence. However, his conclusions, although different from the standard view, are not an entirely radical departure. As he admits, "normal" dining practices can be detected: "certain postures attach persistently to certain categories of person" (178). Free adult males are "normally" represented as reclining, free adult women and children are "commonly" shown either sitting or reclining, and slaves "normally" stand. But the point Roller makes is that these dining postures are not rigid; they are not rules. Indeed there are so many exceptions to the norms, both in the texts and in the images, that one has to question the veracity of these so-called "normal" patterns of behavior. The more important question, as Roller is at pains to emphasize, is to determine the ideology that underlies the texts and images. Why do the sources show what they show? What is their intended message?One of the recurring arguments of this book is that reclining as a dining posture in Roman times always marked social privilege. It was a sign of otium. It [End Page 596] singled the diner out as a member of the elite, as someone with wealth, leisure, and access to "the good life." References in literature and art to reclining diners provide reinforcement of this privileged status. Elite males set the standard for everyone else. Those who did not belong to this class, particularly the subelites, the people just below the upper crust of Roman society, could express their aspirations to elite status by depicting themselves as reclining at dinner, regardless of whether they actually did so in practice.A large part of this book is devoted to the question of women at table. It is here that the evidence is the most convoluted; equally it is here that Roller offers some challenging new insights. He argues... (shrink)

Based on our empirical research on global meaning in people with spinal cord injury and people with stroke, we formulated ‘inner posture’ as a concept in rehabilitation. Inner posture, as we concluded from our empirical data, refers to the way in which people bear what cannot be changed. It helps them to live with their injury. Considering that much has already been written about meaning from a variety of disciplines, the question arises whether the concept of inner posture adds something (...) new to the existing literature, or is just another name for a phenomenon that has already been described before in different terms. In this paper, we aim to investigate this and to clarify our conceptualization, by comparing the concept of inner posture with influential concepts in healthcare literature which seem to be more or less related. In the work of Puchalski regarding spirituality, Pargament regarding religion, Eliott regarding hope and Frankl regarding attitude, we found definitions and descriptions that seemed to come close to the phenomenon we refer to as inner posture. Because these concepts have various theoretical backgrounds, the comparison can help to better understand our concept of inner posture, through a process of dialogue between traditions, following Gadamer’s notion of dialogue as fusion of horizons of understanding. We conclude that inner posture differs from the other concepts in several ways. Some of these differences are more fundamental, other are partial. This suggests that we identified a new perspective on a phenomenon partially described earlier. The comparison also inspired us to slightly adjust our definition and to formulate new research questions. (shrink)

This study is to explore the gesture recognition and behavior tracking in swimming motion images under computer machine vision and to expand the application of moving target detection and tracking algorithms based on computer machine vision in this field. The objectives are realized by moving target detection and tracking, Gaussian mixture model, optimized correlation filtering algorithm, and Camshift tracking algorithm. Firstly, the Gaussian algorithm is introduced into target tracking and detection to reduce the filtering loss and make the acquired motion (...) posture more accurate. Secondly, an improved kernel-related filter tracking algorithm is proposed by training multiple filters, which can clearly and accurately obtain the motion trajectory of the monitored target object. Finally, it is proposed to combine the Kalman algorithm with the Camshift algorithm for optimization, which can complete the tracking and recognition of moving targets. The experimental results show that the target tracking and detection method can obtain the movement form of the template object relatively completely, and the kernel-related filter tracking algorithm can also obtain the movement speed of the target object finely. In addition, the accuracy of Camshift tracking algorithm can reach 86.02%. Results of this study can provide reliable data support and reference for expanding the application of moving target detection and tracking methods. (shrink)

Aristotle’s concept of dynamis (potentiality) is distinct from the modern concept of energy. Both concepts have problematic limitations. We need a third alternative that is here called “sway.”.

Remise en cause de la théorie d’Einstein, de celle de Darwin, créationnisme et fondamentalismes, cosmologies païennes, mouvements technofascistes, idéologies radicales anti-science… Pourquoi des personnes formées à la science en viennent-elles à adopter une attitude en opposition virulente à la science de leur époque? Comment mobilisent-elles leur capacité de raisonnement au service de dogmes et d’idéologies sans rapport avec la science? Peut-on tirer un fil historique entre ces postures depuis la naissance de la science moderne au XVIe siècle? De nos jours, (...) quel est l’impact sur les rapports entre science et société de ces attitudes, diffusées et multipliées par le canal de l’Internet? Rejet de la science contemporaine, de la spécialisation et de l’abstraction mathématique ; appel au bon sens et à une science globale ; vitupération pouvant aller jusqu’à l’invocation de la théorie du complot ; instrumentalisation de la science à des fins idéologiques ou religieuses : voilà les principales caractéristiques des mouvements ou des individus étudiés dans cet ouvrage. Alexandre Moatti, ingénieur en chef des Mines, est chercheur associé en histoire des sciences et des idées à l’université Paris-VII-Denis-Diderot. Il est notamment l’auteur deEinstein, un siècle contre lui (2007). (shrink)

On peut voir l’apparition de la radicalité politique contemporaine avec l’émergence de l’Internationale situationniste et sa lecture du marxisme. Celle-ci, fortement influencée par Lukacs, Korsch, mais aussi Lefèbvre, et en réaction à Althusser, s’appuie néanmoins sur les textes de l’Idéologie allemande et s’engouffre dans la faille « épistémologique » séparant les deux Marx. Les postures de la radicalité qui en découlent, s’appuient sur la centralité sociale et anthropologique du travail don...

Recent research on body and head positions has shown that postural changes may induce varying degrees of changes on acoustic speech signals and articulatory gestures. While the preservation of formant profiles across different postures is suitably accounted for by the two-tube model and perturbation theory, it remains unclear whether it is resulted from the accommodation of tongue postures. Specifically, whether the tongue accommodates the changes in head angle to maintain the target acoustics is yet to be determined. The present (...) study examines vowel acoustics and their correspondence with the articulatory maneuvers of the tongue, including both tongue postures and movements of the tongue center, across different head angles. The results show that vowel acoustics, including pitch and formants, are largely unaffected by upward or downward tilting of the head. These preserved acoustics may be attributed to the lingual gestures that compensate for the effects of gravity. Our results also reveal that the tongue postures in response to head movements appear to be vowel-dependent, and the tongue center may serve as an underlying drive that covariates with the head angle changes. These results imply a close relationship between vowel acoustics and tongue postures as well as a target-oriented strategy for different head angles. (shrink)