Postural Control

A number of investigators have employed linear and rotational displacements of the visual scene to study the mechanics by which visual cues influence postural orientation and the perception of motion in humans. Surprisingly, however, they have found that the latency of the involuntary responses evoked by such displacements (circular and linear vection after approximately 1 sec 2,8; changes in subjective vertical after 1-2 sec4; changes in EMG activity in leg muscles associated with postural sway after 0.5-2 sec 9) were significantly longer than the fastest known visual-motor reaction times. In contrast, hip muscle EMG activity began within 100-140 msec of a visual command when standing human subjects responded voluntarily by raising an arm as rapidly as possible 5. Animal experiments also showed physiological evidence suppoI ting the existence of potentially fast-acting visual-spinal pathways 1,1°. This study advances an explanation by showing that visual displacements can indeed modulate the involuntary EMG activity of human leg muscles within 100 msec of the perturbation. To achieve this rapid effect, visual displacements were imposed within a 'natural' context, which combined the visual with other non-visual motion stimuli.

This study investigated the influence of attention on the sensory integration component of postural control in young and older adults. Eighteen young and 18 older healthy subjects performed information-processing tasks during different postural challenge conditions. Postural conditions included seated, standing on a firm surface, standing on a sway-referenced floor, and standing on a sway-referenced floor while viewing a sway-referenced scene. During each condition, reaction time (RT) was measured during two simple and one inhibitory RT tasks. For the inhibitory task, the time required to inhibit an action was derived, termed the inhibitory time (IT). Performing a RT task was associated with increased postural sway in older subjects, but not in young subjects. The greatest influence of RT task on sway of older subjects was found during the sway-referenced floor/sway-referenced scene condition. Conversely, postural condition had an influence on RT task performance in both young and older subjects. The IT was increased in both young and older subjects only during the sway-referenced floor/scene condition. These results suggest that the sensory integration component of postural control in particular seems to require attention. Further, our data suggest that attentional processes related to inhibitory control are engaged when sensory integration requirements are high.

Affective states, anxiety in particular, have been shown to negatively influence human postural control efficiency as measured by posturographic means, while exposure to a full-length mirror image of one's body exerts a stabilizing effect. We tested the hypothesis that body image concerns and preoccupations would relate negatively to this stabilising effect. Sixty-six healthy students, who screened negative for psychiatric disorders, completed rating scales for anxiety, depression and body image concerns. Posturography recordings of body sway were taken under three conditions: with eyes closed, looking at a vertical bar and looking at a full-length mirror. The Eyes Open/Mirror Stabilometric Quotient [EOMQ=(sway path with eyes closed/sway path looking at the mirror)x100], an index of how much postural control is stabilized by mirror feedback in comparison to the visual vertical bar condition, was significantly inversely related to body image concerns and preoccupations, and to trait anxiety. This finding confirms the impact of emotional factors on human postural control, which warrant further studies. If confirmed in clinical populations characterized by high levels of body image disturbances, e.g. eating disorders, it could lead to developments in the assessment and monitoring of these patients.

falls, standing balance and obstacle avoidance performance, and balance confi dence scores. Results: The number of falls in the exercise group decreased by 46% (incidence rate ratio (IRR) 0.54, 95% confi dence interval (CI) 0.36-0.79) compared to the number of falls during the baseline period and by 46% (IRR 0.54, 95% CI 0.34-0.86) compared to the control group. Obstacle avoidance success rates improved signifi cantly more in the exercise group (on average 12%) compared to the control group (on average 6%). Quiet stance and weight-shifting measures did not show signifi cant effects of exercise. The exercise group also had a 6% increase of balance confi dence scores. Conclusion: The Nijmegen Falls Prevention Program was effective in reducing the incidence of falls in otherwise healthy elderly. There was no evidence of improved control of posture as a mechanism underlying this result. In contrast, an obstacle avoidance task indicated that subjects improved their performance. Laboratory obstacle avoidance tests may therefore be better instruments to evaluate future fall prevention studies than posturographic balance assessments.

Three experiments examined interactions between posture control in upright stance and a concurrent location memory task. Healthy young participants stood upright and memorized the locations of dots presented on a computer screen. In the retrieval phase, they indicated whether arrows presented on the screen would pass through any of the memorized locations. Postural sway variability was measured either during the retention period or during retrieval. Relative to not performing the memory task, pos- tural sway variability increased in the retention period when the eyes were closed, but remained unaVected when the eyes were open. During retrieval, postural sway vari- ability was reduced relative to the no-memory-task condi- tion. Results were interpreted in terms of dual-task costs associated with maintaining multiple frames of reference.

In the present study, we examined the effects of the time lag between visual scene and the head movement in the virtual reality (VR) world on motion sickness and postural control in healthy volunteers. After immersion in VR with additional time lags (from 0 to 0.8 s) to the inherent delay (about 250 ms), the visual-vestibular conflict induced a slight motion sickness in experimental subjects, but no change was noticed in the body sway path with eyes open and closed. However, Romberg ratio of body sway path with eyes closed divided by that with eyes open after immersion in VR was significantly decreased in comparison with that before immersion in VR. Since Romberg ratio is an index of visual dependency on postural control, this finding indicates that the immersion in VR decreases the visual dependency on postural control. It is suggested that adaptation to visual-vestibular conflict in VR immersion increases the contribution of vestibular and somatosensory inputs to postural control by ignoring the conflicting delayed visual input in the VR world. VR may be a promising treatment for visual vertigo in vestibular patients with unsuccessful compensation by its ability to induce vestibular and somatosensory reweighing for postural control.

Gymnasts are known to practice and compete although suffering from injuries and pain. Pain may change strategies for postural control. The primary aim of the present study was to investigate how center of pressure (COP) measurements are influenced by low back pain and lower extremity injury in top-level female gymnasts. A secondary aim was to study the reliability of these measurements using a test-retest design, and how this depends on the duration of the test. Fifty-seven top-level gymnasts were included in four groups: non-injured (NI, n=18), low back pain (LBP, n=11), lower extremity injury (LEI, n=17) and a multiple injury group (MI, n=11). COP excursion during quiet stance was measured on a force platform, during 120s: (1) hard surface/eyes open, (2) hard surface/eyes closed, (3) foam surface/eyes open and (4) foam surface/eyes closed. The COP excursion increased, for all groups, during the foam surface/eyes closed measurement compared to the other three tests. Furthermore, the LBP group showed a 49% (p=0.01) larger COP area compared to the LEI group in the foam surface/eyes closed condition. Measurements on foam surface were in general more reliable than tests on hard surface and tests with eyes closed were more reliable than tests with eyes open. Tests during 120s were in most cases more reliable than tests during 60s. In conclusion the COP excursion is influenced by injury location. Quiet stance measurements on foam surface with eyes closed seems to be reliable and sensitive in young female gymnasts.

This study evaluated the effects of a creative movement program on balance of preschool children. Fifty preschool children (21 boys and 29 girls) were randomly assigned to either the Intervention Group (n = 25) or the Control Group (n = 25). The Intervention Group took part in a creative movement program that lasted 5 weeks (10 sessions, twice a week), while the Control Group participated in the activities of the nursery curriculum. Prior to and after the intervention, the children were assessed for static balance (two-legged stance on a forceplate), dynamic balance (walking on balance beams), and functional dynamic balance (Timed Up and Go test, TUG). The results showed that the Intervention Group performed significantly better on dynamic balance and Timed-up and Go test compared to the Control Group. No significant differences were found for static balance (peak-to-peak amplitude of center of pressure in the medio/lateral and anterior/posterior direction). According to the findings of the study, the two-legged stance test may not be suitable to measure the static balance of preschool children. It may be concluded that a creative movement program constitutes an attractive and effective method for the development of preschool children's balance.

We describe the treatment of two patients with peripheral vestibular dysfunction using a novel, staged exercise program. Response to treatment was documented. The first patient, a 62-year-old woman with unilateral vestibular dysfunction (UVD) and a 6-month history of disequilibrium following herpes zoster oticus resulting in damage to the right inner ear, was treated with an 8-week course of vestibular physical therapy. During the 8 weeks, the patient attended weekly physical therapy sessions and was trained to perform vestibular adaptation exercises on a daily basis at home. The second patient, a 53-year-old woman with progressive disequilibrium secondary to profound bilateral vestibular hypofunction (BVH), was treated with a 16-week course of vestibular physical therapy. During the first 8 weeks, the patient attended weekly physical therapy sessions and was trained to perform vestibular adaptation and substitution exercises on a daily basis at home. During the second 8 weeks, the ...

Movements of the whole-body center of mass during quiet standing have been estimated from measurements of body segment movements. These whole-body center of mass movements have been compared with movements of the center of mass as predicted from a simple inverted-pendulum model of standing. However, the total body center of mass is a weighted average of the center of mass of all individual body segments. The question arises as to how well the total body center of mass represents the individual segments and lower limb joint angles. This study focuses on the validity of how well the individual segments and lower limb angles temporally and spatially synchronize with the total body center of mass. Eleven healthy university students volunteered to participate. Kinematic data were collected using a 3D optoelectronic camera system; kinetic data were collected using a 3D force plate. Participants stood quietly, with eyes open, for 120 s. Segment and whole body centers of mass were calculated from a 14 segment, 3D bilateral model. Segment and joint angles were calculated for the lower limbs, bilaterally, and the trunk. Segment center of mass root-mean-square displacements were strongly correlated with center of mass height relative to the ankle joint and were synchronized, or temporally locked, to the movement of the whole body center of mass. Sagittal plane ankle angular displacements were highly correlated to sagittal plane center of mass movement; stronger correlations between body center of mass and lower limb angular displacement were observed, the result of compensatory knee joint angular displacements. These data support and extend the use of an inverted pendulum model to represent quiet standing postural control.

Standing, walking, and running are sensorimotor tasks that develop during childhood. Thereafter they function automatically as a result of a supraspinal network that controls spinal pattern generators. The present study used functional magnetic resonance imaging (fMRI) to investigate age-dependent changes in the supraspinal locomotor and postural network of normal subjects during mental imagery of locomotion and stance. Sixty healthy subjects (ages: 24 -78 years), who had undergone a complete neurological, neuro-ophthalmological, and sensory examination to rule out disorders of balance and gait, were trained for the conditions lying, standing, walking, and running in order to imagine these conditions on command in 20-second sequences with the eyes closed while lying supine in an magnetic resonance imaging (MRI) scanner. The following blood oxygen level-dependent (BOLD) signal changes during locomotion and stance were found to be independent of age: (1) prominent activations in the supplementary motor areas, the caudate nuclei, visual cortical areas, vermal, and paravermal cerebellum; (2) significant deactivations in the multisensory vestibular cortical areas (posterior insula, parietoinsular vestibular gyrus, superior temporal gyrus), and the anterior cingulate during locomotion. The following differences in brain activation during locomotion and stance were age-dependent: relative increases in the cortical BOLD signals in the multisensory vestibular cortices, motion-sensitive visual cortices (MT/V5), and somatosensory cortices (right postcentral gyrus). In advanced age this multisensory activation was most prominent during standing, less during walking, and least during running. In conclusion, the functional activation of the basic locomotor and postural network, which includes the prefrontal cortex, basal ganglia, brainstem, and cerebellar locomotor centers, is preserved in the elderly. Two major age-dependent aspects of brain activation during locomotion and stance were found: the mechanism of cortical inhibitory reciprocal interaction between sensory systems during locomotion and stance declines in advanced age; and consequently, multisensory cortical control of locomotion and stance increases with age. These findings may indicate a more conscious locomotor and postural strategy in the elderly. (A. Zwergal). xxx www.elsevier.com/locate/neuaging 0197-4580/$ -see front matter

Two experiments examined postural responses of 3-to 6-year-old children to visual informarion for oscillation. In Experiment 1, children saw oscillations of the surround, with these movements ranging in frequency between 0.2 and 0.8 Hz. Analyses of anterior-posterior postural sway revealed that, similar to previous developmental investigations, the frequency of sway matched the frequency of oscillations. Analyses of sway amplitude and timing, however, revealed patterns of results more in keeping with research on adults. Experiment 2 extended these findings, presenting oscillations in which the frequency changed during the trial. Analyses of anterior--posterior sway revealed that sway frequency matched both speeds of movement. In contrast, amplitude and timing measures were again in line with adult data. These results suggest that the postural sway of children contains both adultlike and nonadultlike parameters of balance control.

The reorganization of standing balance after a lower limb amputation is considered with emphasis on persons with an acquired un¡lateral amputation above the ankle and below the hip joint. ln the first section, three major peripheral motor and sensory impairments are discussed: (a) a lack of ankle torque generation to restore equilibrium in the sagittal plane, (b) a lack of weight-shifting capacity to control posture in the frontal plane, (c) a distorted somatosensory input from the síde of amputation. ln the second part of the paper, it is argued that a lower limb amputation, as any other seríous peripheral lesion, also affects the highest levels of the sensorimotor system, because the functional recovery after amputation requires a central adaptation to the alterations of peripheral motor and sensory conditions. A reduction in the cognitive regulation of posture as well as a decrease in visual dependency are proposed as two of the most critical parameters of the long-term central adaptation process and as relevant indicators of the restoration of (the safe performance of) gross-motor skills.

The present study investigates balance control mechanisms, their variations with the absence of visual input, and their development in children from 7 to 11 years old, in order to provide insights on the development of balance control in the pediatric population.

The study investigates the role of lateral muscles and body orientation in anticipatory postural adjustments (APAs). Subjects stood in front of an aluminum pendulum and were required to stop it with their right or left hand. An experimenter released the pendulum inducing similar body perturbations in all experimental series. The perturbation directions were manipulated by having the subjects standing on the force platform with different body orientations in relation to the pendulum movements. Consequently, perturbations were induced in sagittal, oblique, and frontal planes. Ground reaction forces and bilateral EMG activity of dorsal, ventral, and lateral trunk and leg muscles were recorded and quantified within the time intervals typical of APAs. Anticipatory postural adjustments were seen in all experimental conditions; their magnitudes depended on the body orientation in relation to the direction of perturbation. When the perturbation was produced in the lateral and oblique planes, APAs in the gluteus medius muscles were greater on the side opposite to the side of perturbation. Conversely, simultaneous anticipatory activation of the external obliques, rectus abdominis, and erector spinae muscles was observed on the side of perturbation when it was induced in the lateral plane. The results of the present study provide additional information on the directional specificity of anticipatory activation of ventral and dorsal muscles. The findings provide new data on the role of lateral muscles in feedforward postural control and stress the importance of taking into consideration their role in the control of upright posture.

In its simplest form, the human postural control system can be described as a closed-loop control system consisting of a plant (body segments and musculotendon actuators) and feedback. Previous efforts to understand the contributions of plant and feedback employed techniques to "open the loop" which is problematic with the study of posture because the plant is unstable without feedback. In

Seit der Veröffentlichung unserer ersten Zusammenstellung „Aktueller Arbeiten aus der Gleichgewichtsforschung“ 2009 ist eine Reihe von weiteren Berichten über Studien der Gleichgewichts-Leistungen im Zusammenhang mit supraposturalen Aufgaben erschienen (vgl. Tab. 4, im Anhang). Nicht alle Projekte, die wir uns da-mals vorgenommen hatten (Lippens & Nagel, 2009 c, S. 12), konnten wir aufgrund der unterschiedlichen beruflichen Arbeitsläufe verwirklichen. Dennoch scheint es jetzt angebracht, eine abschließende Bilanz unserer Arbeiten vorzulegen, die im Umfeld der Hamburger Inline-Skating Schule, Wissenschaftsförderverein am Insti-tut für Bewegungswissenschaft der Universität Hamburg entstanden sind, und im Zusammenhang theoretischer Überlegungen einzuordnen.

„No functional movement, (  ), exists, except as embedded in a complex situa-tion and nested into a given postural setting. Both the environmental context and the postural context affect the nature and success of movements.’’(Reed, 1989)

Purpose: The purpose of this randomized controlled trial was to determine the effect of a 4-wk balance training program on static and dynamic postural control and self-reported functional outcomes in those with chronic ankle instability (CAI). Methods: Thirty-one young adults with self-reported CAI were randomly assigned to an intervention group (six males and 10 females) or a control group (six males and nine females). The intervention consisted of a 4-wk supervised balance training program that emphasized dynamic stabilization in single-limb stance. Main outcome measures included the following: self-reported disability on the Foot and Ankle Disability Index (FADI) and the FADI Sport scales; summary center of pressure (COP) excursion measures including area of a 95% confidence ellipse, velocity, range, and SD; time-to-boundary (TTB) measures of postural control in single-limb stance including the absolute minimum TTB, mean of TTB minima, and SD of TTB minima in the anteroposterior and mediolateral directions with eyes open and closed; and reach distance in the anterior, posteromedial, and posterolateral directions of the Star Excursion Balance Test (SEBT). Results: The balance training group had significant improvements in the FADI and the FADI Sport scores, in the magnitude and the variability of TTB measures with eyes closed, and in reach distances with the posteromedial and the posterolateral directions of the SEBT. Only one of the summary COP-based measures significantly changed after balance training. Conclusions: Four weeks of balance training significantly improved self-reported function, static postural control as detected by TTB measures, and dynamic postural control as assessed with the SEBT. TTB measures were more sensitive at detecting improvements in static postural control compared with summary COP-based measures.

Doubt about the role of stretch reflexes in movement and posture control has remained in part because the questions of reflex "usefulness" and the postural "set" have not been adequately considered in the design of experimental paradigms. The intent of this study was to discover the stabilizing role of stretch reflexes acting upon the ankle musculature while human subjects performed stance tasks requiring several different postural "sets". Task specific differences of reflex function were investigated by experiments in which the role of stretch reflexes to stabilize sway during stance could be altered to be useful, of no use, or inappropriate.

This study has focused upon the automatic components of posture and movement in a group of ten cerebral palsy children carefully selected to represent a spectrum of abnormalities relatively pure by clinical standards and ten age-matched normals. Each subject stood unsupported upon a movable platform and within a movable visual surround and was then exposed to external perturbations or was asked to pull with one arm upon a movable handle. In comparing the performance of cerebral palsy children in each clinical category with the agematched normals and with normal adults assessed in previous studies, the process of maintaining stance was subdivided into two component functions: substrates which determined the onset timing, direction and amplitude of postural actions from somatosensory, vestibular, and visual stimuli were termed "sensory organization", and those establishing temporal and spatial patterns of muscular contractions appropriate to produce effective movements were termed "muscle coordination". We found among seven of the ten cerebral palsy children a clear localization of dysfunction within either sensory organization or muscle coordination mechanisms. These results are providing some new insights into the organization of each of these processes as well as suggesting methods for developing a more systematic understanding of the abnormalities of movement control.

The present investigation examined the variability of sitting postural movement in relation to the development of perceived discomfort by means of linear and nonlinear analysis. Nine male subjects participated in this study. Discomfort ratings, kinetic and kinematics data were recorded during prolonged sitting. Body part discomfort index, displacement of the center of pressure (COP) in anteriorposterior and medial-lateral directions as well as lumbar curvature were calculated. Mean, standard deviation and sample entropy values were extracted from COP and lumbar curvature signals. Standard deviation and sample entropy were used to assess the degree of variability and complexity of sitting. A correlation analysis was performed to determine the correlation of each parameter with discomfort. There were no correlations between discomfort and any of the mean values. On the contrary, the standard deviations of the COP displacement in both directions and lumbar curvature were positively correlated to discomfort, whereas sample entropies were negatively correlated. The present study suggests that the increase in degree of variability and the decrease in complexity of sitting postural control are interrelated with the increase in perceived discomfort. Finally, the present study underlined the importance of quantifying motor variability for understanding the biomechanics of seated posture.

This study investigated the influence of fear of falling or postural threat on the control of posture and movement during a voluntary rise to toes task for 12 healthy young adults. Postural threat was modified through alterations to the surface height at which individuals stood (low or high platform) and changes in step restriction (away from or at the edge of the platform) creating four levels of postural threat: LOW AWAY, LOW EDGE, HIGH AWAY and HIGH EDGE. To rise to the toes, an initial postural adjustment must destabilise the body so that it can be moved forward and elevated to a new position of support over the toes. Centre of pressure and centre of mass profiles, as well as tibialis anterior (TA), soleus (SO) and gastrocnemius (GA) muscle activity patterns were used to describe this behaviour. The results showed that the performance of the rise to toes task was significantly modified when positioned at the edge of the high platform. In this situation, the central nervous system reduced the magnitude and rate of the postural adjustments and subsequent voluntary movement. Although the duration of the movement was lengthened for this most threatening condition, the sequencing and relative timing of TA, SO and GA muscle activity was preserved. These changes in rise to toes behaviour were accompanied by evidence of increased physiological arousal and participant reports of decreased confidence, increased anxiety and decreased stability. Evidence of fear of falling effects on anticipatory postural control is clinically relevant as it may explain deficits in this control observed in individuals with balance disorders. For example, individuals with Parkinson’s disease or cerebellar dysfunction demonstrate impaired performance on the rise to toes task as reflected in alterations of both the timing and magnitude of their anticipatory postural adjustments. Our findings suggest alterations in the magnitude of postural adjustments may be magnified by fear of falling while changes in the timing of postural adjustments may reflect underlying pathology.

The assumption that proprioceptive inputs from the lower legs are used to trigger balance and gait movements is questioned in this review (an outgrowth of discussions initiated during the Neural Control of Movement Satellite meeting held in Cozumel, Mexico, April 1997). Recent findings presented here suggest that trunk or hip inputs may be more important in triggering human balance corrections and that proprioceptive input from the lower legs mainly helps with the final shaping and intermuscular coordination of postural and gait movements. Three major questions were considered. First, what role, if any, do lower-leg proprioceptive inputs play in the triggering of normal balance corrections? If this role is negligible, which alternative proprioceptive inputs then trigger balance corrections? Second, what is the effect of proprioceptive loss on the triggering of postural and gait movements? Third, how does proprioceptive loss affect the output of central pattern generators in providing the final shaping of postural movements? The authors conclude that postural and gait movements are centrally organized at two levels. The first level involves the generation of the basic directionally-specific response pattern based primarily on hip or trunk proprioceptive input and secondarily on vestibular inputs. This pattern specifies the spatial characteristics of muscle activation, that is which muscles are primarily activated, as well as intermuscular timing, or the sequence in which muscles are activated. The second level is involved in the shaping of centrally set activation patterns on the basis of multi-sensorial afferent input (including proprioceptive input from all body segments and vestibular sensors) in order that movements can adapt to different task conditions.

The ageing neuromuscular system is affected by structural and functional changes that lead to a general slowing down of neuromuscular performance and an increased risk of falling. As a consequence, the process of ageing results in a reduced ability to develop maximal and explosive force, as well as in deficits in static and dynamic postural control. A decrease in the number and size of type II fibres in particular accounts for the age-related decline in muscle mass (sarcopaenia) and strength performance. Multiple denervation and re-innervation processes of muscle fibres seem to be responsible for the reduced number of muscle fibres. Recently, it has been suggested that it is not the decline in motoneurons that accounts for the loss in number of muscle fibres but the disturbed potential of fibre regeneration and re-innervation. Furthermore, an age-related reduction in the number of satellite cells has also been associated with sarcopaenia. The ability to compensate for platform and gait perturbations deteriorates with ageing as reflected in longer onset latencies and inefficient postural responses. All sites within the somatosensory system are affected by ageing and therefore contribute to postural instability. However, morphological changes of muscle spindles appear primarily to be responsible for the impaired ability to compensate for balance threats in old age. Given these neuromuscular limitations in old age, it is important to apply adequate training interventions that delay or even reverse the onset of these constraints. Strength training has the potential to enhance maximal as well as explosive force production capacity. This is accomplished by neural factors, including an improved recruitment pattern, discharge rate, and synchronization of motor units. Furthermore, an increase in number of satellite cells most likely accounts for training-induced muscle hypertrophy. Recent studies have investigated the impact of balance training in old age on the ability to develop maximal and explosive force. In addition, the effects of balance training on reflex activity during gait perturbations were also examined. Increases in maximal and explosive force production capacity and an improved ability to compensate for gait perturbations were observed. It is evident from the literature that researchers are increasingly studying the effects of more specifically designed training programmes on performance in populations of older adults. Thus, in the near future, strength training could be replaced by high-velocity forms of power training and balance training by perturbation-based training programmes. It is hypothesized that this new approach is more efficient in terms of fall prevention than the traditional approach.

The purpose of this follow-up one and four years post stroke was to nd out whether the initial physiotherapy approach had had any long-term effects on mortality, motor function, postural control, activities of daily living, life quality, follow-up from community services and living conditions. Design: A randomized controlled trial of rst time ever stroke patients. Group 1 (n = 33) and group 2 (n = 28) had initial physiotherapy according to the Motor Relearning Programme and Bobath, respectively. Main outcome measures: The Motor Assessment Scale (MAS), the Sødring Motor Evaluation Scale (SMES), the Barthel ADL Index, the Nottingham Health Pro le (NHP) and Berg Balance Scale were used. The following parameters were also registered: incidence of new strokes, other diseases, use of assistive devices, the patient's accommodation and use of services from the community.

This study was designed to examine the role of foot type, height, leg length, and range of motion (ROM) measurements on excursion distances while performing the Star Excursion Balance Test (SEBT), a test of dynamic postural control. Participants (n = 30) performed 3 trials of the SEBT in each of the 8 directions while balancing on the right and left

This paper reviews studies on neurophysiological and behavioral methods used to evaluate motor imagery accuracy. These methods can be used when performed in the field and are based on recordings of peripheral indices such as autonomic nervous system or electromyographic activities, mental chronometry and psychological tests. Providing physiological signs that correlate to these types of mental processes may be considered an objective approach for motor imagery analysis. However, although autonomic nervous system activity recording has been shown to match motor imagery in real time, to evaluate its accuracy qualitatively and the individual ability to form mental images, the relationship between physiological responses and mental processes remains an inference. Moreover, electromyographic recordings may be associated with postural control data, but due to inconsistent results, they remain insufficient to solely evaluate motor imagery accuracy. Other techniques traditionally used in psychology and cognitive psychology are questionnaires, ''debriefing'' with subjects and mental chronometry. Although such methods lead to interesting results, there remains an important part of subjectivity as subjects perform an autoevaluation of motor imagery accuracy. Similarly, mental chronometry gives information on the ability to preserve temporal organization of movement but does not allow the evaluation of the vividness of mental images. Thus, several methods should be combined to analyze motor imagery accuracy in greater detail. Neurophysiological recordings cannot therefore be considered an alternative but rather a complementary technique to behavioral and psychological methods. The advantages and inconvenient of each technique and the hypotheses that could be tested are discussed. D

We reviewed research on the effect of adaptive seating on sitting posture/postural control in children with cerebral palsy. Second, we examined whether changes in postural control related to changes in other aspects of functioning. Methods: Electronic database/hand searches were undertaken to locate studies published in English. Reviewers screened studies for inclusion criteria, extracted data, indexed outcomes to the International Classification of Functioning, Disability and Health, assigned levels of evidence, and assessed study quality. Results: Thirteen of 14 articles used group designs and the other a single-subject design. Conflicting findings were reported for saddle seats and optimal seat/back angle for improving sitting posture/ postural control. Significant improvements were reported with seat inserts, external supports, and modular seating systems. Evidence supporting effects of postural control on functional abilities was limited. Conclusions: Future studies on the effects of adaptive seating should describe participants with standardized classification systems and employ stronger research designs. (Pediatr Phys Ther 2008;20:303-317) Key words: adaptive seating, assistive device, child, cerebral palsy/physiopathology, cerebral palsy/therapy, human movement system, infant equipment, movement disorders/physiopathology, movement disorders/therapy, musculoskeletal equilibrium/physiology, orthoses, physical therapy/methods, state of the art review, treatment outcome

Background and Aim: Benign paroxysmal positional vertigo (BPPV) is most common type of vertigo in general population. Epley maneuver is the most effective treatment technique. However, there is no clinically valid test to verify effectiveness of maneuver quickly after treatment in the same session. Modified clinical test of sensory interaction on balance (mCTSIB) is considered as a quick and simple test. This study aimed to use mCTSIB for assessing effectiveness of Epley maneuver in BPPV patients. Methods: The study was carried out on 44 patients (36 female and 8 male, mean age of 53.11 (SD=7.09) diagnosed with posterior semi-circular canals BPPV in Dix-Hallpike test and no other vestibular disorders. mCTSIB in four conditions was assessed, before and after Epley maneuver. Balance time, lateral and anterior-posterior sway were recorded. mCTSIB repeated after three weeks to assess reliability. Results: The time for balance control in mCTSIB after maneuver did not change significantly relative to before maneuver (p>0.05). Lateral sway changes in conditions 2, 3 and 4 in mCTSIB significantly reduced after maneuver

Postural stability is crucial in maintaining body balance during quiet standing, locomotion, and any activities that require a high degree of balance performance, such as participating in sports and dancing. Research has shown that there is a relationship between stability and body mass. The aims of this study were to examine the impact that two variables had on static postural control: body mass index (BMI) and gender. Eighty healthy young adults (age¼ 21.7 7 1.8 yr; height ¼ 1.65 7 0.09 m; mass ¼67.5 719.0 kg) participated in the study and the static postural control was assessed using the Biodex Balance System, with a 20 Hz sampling rate in the bipedic stance (BLS) and unipedic stance (ULS) for 30 s. Five test evaluations were performed for each balance test. Postural control was found to be negatively correlated with increased adiposity, as the obese BMI group performed significantly poorer than the underweight, normal weight and overweight groups during BLS and ULS tests. The underweight, normal weight and overweight groups exhibited greater anterior-posterior stability in postural control during quiet stance. In addition, female displayed a trend of having a greater postural sway than male young adults, although it was evidenced in only some BMI groups. This study revealed that BMI do have an impact on postural control during both BLS and ULS. As such, BMI and genderspecific effects should be taken into consideration when selecting individuals for different types of sporting activities, especially those that require quiet standing.

DEFINICIÓN CUANDO HABLAMOS DE CONTROL POSTURAL, HABLAMOS DE LA COORDINACIÓN DE VARIOS SISTEMAS QUE SE ORGANIZAN SEGÚN LA TAREA QUE SE REALIZARÁ Y SEGÚN LOS FACTORES AMBIENTALES QUE NOS RODEAN. PARA REALIZAR LO ANTES MENCIONADO, NECESITAMOS CONTROLAR LA POSICIÓN DE CUERPO EN EL ESPACIO PARA MANTENER LA ESTABILIDAD Y LA ORIENTACIÓN Y ESTOS 2 COMPONENTES VAN A VARIAR DEPENDIENDO DE LA ACTIVIDAD QUE SE DESEMPEÑARÁ MÁS EL ENTORNO.

In order to understand how age, culture, and problems in motor coordination impact the performance of activities of daily living, we used focus groups and in-depth interviews with Australian and Canadian parents to examine activities of daily living of younger (5-7 years of age) and older (8-9 years of age) children with and without DCD. By comparison with their typically developing age group, children with DCD had more difficulty with dressing, personal hygiene, and eating skills. Difficulties with postural control and fine-motor skills were reported to contribute to poorer performance of activities of daily living. As expected, competence in the performance of activities of daily living improved in the older children with and without DCD and there were few differences in the performance of daily living tasks between typical children in Australia and Canada. Overall, the motor difficulties of children with DCD had a significant impact on performance of a wide range of daily activities.