Sway Values Research Articles

Postural stability of normal subjects measured by sway magnetometry: pathlength and area for the age range 15 to 64 years

Fifty-eight subjects with no known vestibular pathology, postural problems or cerebrovascular disease were studied to determine the range of sway values in a normal working-age population. Sway was measured with a magnetometry system, previously shown to be highly successful in distinguishing sway with and without the eyes open in individual subjects. 30 subjects were aged 15-29 years and 28 aged 30-64 years. With the subject standing on a firm base the pathlength and area enclosed by movement of the hips in the horizontal plane were measured over 30 second periods with eyes open and eyes closed. There were no significant differences between the two age ranges. We obtained the following upper limits of normal values for the age range 15 to 64 years: pathlength with eyes open 140 mm, pathlength with eyes closed 200 mm, area with eyes open , and area with eyes closed . The mean and standard deviation of the Romberg coefficient (sway with eyes open/sway with eyes closed) was for pathlength measurement and for area measurement. Keywords: balance, posturography, magnetometry, normal limits

Automatic and voluntary lateral weight shifts in rehabilitation of hemiparetic patients

One of the main objectives of exercise therapy for hemiparetic patients is the rehabilitation of their impaired ability to accept and bear bodyweight on the involved lower extremity. The purpose of this study was to compare two types of therapeutic exercises, automatic and voluntary weight shifts, used as treatment for this problem. Thirteen hemiparetic patients and nine age-matched healthy controls participated in the study. Criterion variables were four: (1) body sway; (2) location of the centre of pressure; (3) activation pattern of the gluteus medius and medial gastrocnemius muscles; and (4) magnitude of activation of these two muscles. Each subject was tested three times: (1) during static stance; (2) while standing on a moving platform that imposed automatic lateral weight shifts; and (3) while standing on a stationary base and voluntarily shifting bodyweight from one lower limb to the other. Values of sway and location of the centre of pressure on the mediolateral axis were collected by the Chattecx balance system; magnitude and modulation of the muscular activity in both lower extremities were recorded with surface electromyography. The findings showed significant differences between patients and controls in all four variables. Regarding differences between exercise modes, the main finding pointed to larger sways in voluntary as compared to automatic weight shifts. Presumably, body fixation during automatic perturbations was manifested in a decreased body sway. Stance symmetry and the EMG activation profile of the paretic muscles were not improved by either exercise mode.

Cyclic: a laboratory software package for the analysis of electromyographic patterns in cyclic movements

Static posturography can serve as an easy and fast way to determine whether a child possesses sufficient balance control in different sensory conditions. Therefore, the aim of this review is to map age-related differences in postural sway during childhood in typically developing children, using static posturography and to provide an overview of the available (age-specific) reference values in scientific literature.The search strategy was performed in five databases (Pubmed, Web of Science, ScienceDirect, Cochrane Clinical Trials, Medline (Ovid)) November 2nd 2014 and updated twice: March 16th 2015 and July 20th 2015. The following keywords were used: (children OR child) AND (“postural control” OR “postural stability” OR equilibrium OR posture OR “postural balance”[mesh]) AND (“quiet stance” OR standing OR stance OR “quiet stance” OR static) AND (“postural sway” OR posturography OR “body sway” OR stabilography OR “trunk sway” OR “medio-lateral sway” OR “antero-posterior sway”). Relevant studies were identified using predefined selection criteria, applied on title and abstract (phase 1) and on full text (phase 2), supplemented with reference screening after the second phase.A total of 14 studies met the criteria. This review showed three main findings: 1) during natural bipedal stance with the eyes open, all studies reported a decrease in postural sway with increasing age, with conflicting results on the (non-)linearity of its development, 2) with eyes closed, all children show more sway than with eyes open and 3) only four studies reported numeric sway values that could serve as reference values, mainly focusing on children aged five and older.Considerable disagreement exists on the (non-)linearity of the development of postural sway in children. By choosing arbitrary age categories, it remains unclear between which age groups differences are situated. Future research is necessary to determine for which age groups age-specific reference values are relevant.

Estimation of two-joint muscle length

Static posturography can serve as an easy and fast way to determine whether a child possesses sufficient balance control in different sensory conditions. Therefore, the aim of this review is to map age-related differences in postural sway during childhood in typically developing children, using static posturography and to provide an overview of the available (age-specific) reference values in scientific literature.The search strategy was performed in five databases (Pubmed, Web of Science, ScienceDirect, Cochrane Clinical Trials, Medline (Ovid)) November 2nd 2014 and updated twice: March 16th 2015 and July 20th 2015. The following keywords were used: (children OR child) AND (“postural control” OR “postural stability” OR equilibrium OR posture OR “postural balance”[mesh]) AND (“quiet stance” OR standing OR stance OR “quiet stance” OR static) AND (“postural sway” OR posturography OR “body sway” OR stabilography OR “trunk sway” OR “medio-lateral sway” OR “antero-posterior sway”). Relevant studies were identified using predefined selection criteria, applied on title and abstract (phase 1) and on full text (phase 2), supplemented with reference screening after the second phase.A total of 14 studies met the criteria. This review showed three main findings: 1) during natural bipedal stance with the eyes open, all studies reported a decrease in postural sway with increasing age, with conflicting results on the (non-)linearity of its development, 2) with eyes closed, all children show more sway than with eyes open and 3) only four studies reported numeric sway values that could serve as reference values, mainly focusing on children aged five and older.Considerable disagreement exists on the (non-)linearity of the development of postural sway in children. By choosing arbitrary age categories, it remains unclear between which age groups differences are situated. Future research is necessary to determine for which age groups age-specific reference values are relevant.

Plegic limb classification using cluster analysis

Static posturography can serve as an easy and fast way to determine whether a child possesses sufficient balance control in different sensory conditions. Therefore, the aim of this review is to map age-related differences in postural sway during childhood in typically developing children, using static posturography and to provide an overview of the available (age-specific) reference values in scientific literature.The search strategy was performed in five databases (Pubmed, Web of Science, ScienceDirect, Cochrane Clinical Trials, Medline (Ovid)) November 2nd 2014 and updated twice: March 16th 2015 and July 20th 2015. The following keywords were used: (children OR child) AND (“postural control” OR “postural stability” OR equilibrium OR posture OR “postural balance”[mesh]) AND (“quiet stance” OR standing OR stance OR “quiet stance” OR static) AND (“postural sway” OR posturography OR “body sway” OR stabilography OR “trunk sway” OR “medio-lateral sway” OR “antero-posterior sway”). Relevant studies were identified using predefined selection criteria, applied on title and abstract (phase 1) and on full text (phase 2), supplemented with reference screening after the second phase.A total of 14 studies met the criteria. This review showed three main findings: 1) during natural bipedal stance with the eyes open, all studies reported a decrease in postural sway with increasing age, with conflicting results on the (non-)linearity of its development, 2) with eyes closed, all children show more sway than with eyes open and 3) only four studies reported numeric sway values that could serve as reference values, mainly focusing on children aged five and older.Considerable disagreement exists on the (non-)linearity of the development of postural sway in children. By choosing arbitrary age categories, it remains unclear between which age groups differences are situated. Future research is necessary to determine for which age groups age-specific reference values are relevant.

Prolonged Peroneal Reaction Time in Ankle Instability

The peroneal reflex time to sudden ankle inversion and the postural control of 15 athletes with functionally instable ankles were compared with 15 stable controls. A trapdoor produced sudden ankle inversion. Surface electrodes recorded electromyographic activity of the peroneal muscles. Postural sway was expressed by a transverse sway value obtained during single limb stance on a force plate. Increased postural sway was found in subjects with functional instability (p less than 0.01). This is in accordance with previous studies. Functionally instable subjects also displayed an increased peroneal reaction time (p less than 0.01) supporting the theory that functional instability is induced by a proprioceptive reflex defect. Nine of the 15 instable subjects were unilaterally instable and showed lower peroneal reaction time and postural sway values for the stable ankle, but the difference was not significant. There was a high degree of correlation between postural sway and peroneal reaction time (Spearman's rho = .92). In ten functionally instable athletes tested with and without ankle taping, it could not be verified that a reflex enhancing effect of taping occurs through stimulation of cutaneous afferents.

Falls, sway, and symmetry of weight-bearing after stroke

This study examines the relationship between falls, postural sway, stance symmetry, and length of hospital admission after stroke. Side of stroke, age, and sex differences are noted. A consecutive sample of 92 stroke patients underwent two assessments, four months apart, at between two and nine months post-stroke. Measurements of weight distribution and sway were made on the Nottingham Balance Platform. Any falls were recorded. A significant relationship was found between sway values at the first assessment and the number of falls (r = 0.27, p less than 0.01). Sway values improved with recovery (z = 2.9, p less than 0.01). Stance symmetry was significantly related to length of stay (r = 0.27, p less than 0.01) and age (r = 0.28, p less than 0.01), but not to falls. A significant difference was found between the weight distribution of right- and left-sided hemiplegias (t = 8.2, p less than 0.001) and stance symmetry improved with recovery (z = 2.9, p less than 0.01). No sex differences were apparent. This suggests that stance symmetry is another index of stroke severity, but that sway and falls frequency are not. However, an important relationship between sway and falls was revealed.

Stabilizing and destabilizing effects of vision and foot position on body sway of healthy young subjects: a posturographic study.

A total of 800 posturographic measurements--each characterized by four values (sway path, sway area, anteroposterior sway and lateral sway)--was carried out for this study. Eight different conditions (interfoot distances of 0, 4, 10 and 20 cm, each with eyes open and eyes closed) were compared by statistical means. All sway values were diminished by vision in small interfoot distances. At large interfoot distances, however, the presence of visual control resulted in an increase of lateral sway. Comparing the different foot positions, an increase of anteroposterior sway and a decrease of all other components were found at large interfoot distances no matter whether the eyes were open or closed.

Complex environmental exposures and hearing functions

This study deals with changes in TTS2 values, cardiovascular functions, haemodynamic activity, upright body sway, ratios of urinary catecholamines, and correlations between these changes in complex exposure situations. The study was based on a factorial experimental design with a total of 12 exposure combinations. Each individual experiment took 6 h with a pause of 1 h at noon. The subjects (n = 60) were exposed to noise and whole‐body vibration at two different dry bulb temperatures. The changes were dependent on the combinations of noise, vibration, and temperature to which the subjects were exposed. The TTS2 values at 4 kHz were associated with the haemodynamic index (HDI) values when the subjects were exposed simultaneously to noise and stochastic vibration at 35°C. The TTS2 values at 6 kHz were associated most strongly with the HDI values after exposure to a combination of noise, stochastic, or sinusoidal vibration, and a temperature of 20°C. The TTS2 values at 4 and 6 kHz correlated positively with the noradrenaline/adrenaline (NA/A) ratio when subjects were exposed to noise at 35°C. The association between the TTS2 values and the 10A/NA ratio and especially the A/NA ratio was very strong when subjects had been simultaneously exposed to noise and sinusoidal or stochastic vibration at 35°C. Furthermore, the highest positive correlation coefficients were found between the TTS2 values at 4 kHz and the upright body sway values in the X direction when the subjects had been exposed to noise and sinusoidal vibration at 20°C.