PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Postural control”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2004

Effects of practice on cardiorespiratory responses during postural control.

The present study examined the effects of practice of a balance test on cardiorespiratory changes in response to a 1-min balance test performed by standing on one leg with eyes closed (SOLEC) in 30 females (n=15, 21+/-4 years, mean+/-SD, for the experimental group; n=15, 22+/-4 years for the control group). Blood pressure (BP), heart rate (HR), minute ventilation (VE), respiratory rate (RR), tidal volume (VT), expiratory duration (Te), inspiratory duration (Ti), and oxygen uptake (VO(2)) were measured during the balance test before and after 2 wk of daily practice. The experimental group was given a daily 15-min practice session for the balance test. In contrast, the control group was instructed not to do any special practice for the balance test. In both the experimental and control groups, SOLEC induced significant increases in BP, HR, VE, RR, and VO(2), and decreases in Te and Ti. Following the practice sessions, the balance time increased significantly in the experimental group (P<0.01). In addition, 2 wk of practice reduced the increases in BP (P<0.01), VE (P<0.05), and RR (P<0.01), and prolonged Te (P<0.01) during the SOLEC test. These results suggest that practice of a postural task affects cardiorespiratory responses to the balance test in addition to postural control.

Adult↗
PubMed1995

Frequency characteristics of postural control of children with and without visual impairment.

During quiet standing on a force platform, centre of pressure frequency characteristics of normal and visually impaired children were investigated under four conditions: normal surface, eyes open and closed; foam surface, eyes open and closed. Total power was calculated between 0 and 4Hz. Slopes of logarithmically transformed data were used to compare relative power at high and low frequencies. Younger children had greater total power and relatively more high frequency power. The results suggest that young children (four to six years) do not normally use immediate vision in postural control. Visually impaired children have greater instability than sighted children, with greatest differences between the two groups at 10 to 12 years.

Age Factors↗
PubMed1995

Impaired postural control in patients with cervico-brachial pain.

Dizziness and subjective balance disturbances are common complaints in cervical pain syndromes. We assessed balance function with posturography using vibration-induced and galvanically-induced body sway in consecutive patients (n = 116) with cervico-brachial pain syndrome of more than 3 months' duration. A total of 83% of the patients showed signs of cervical root compression on MRT scans. The incidence of complaints of vertigo was 50%. The patients manifested significantly poorer postural control than sex- and age-matched controls (n = 20). Disorders of the neck should be considered when assessing patients complaining of dizziness, vertigo and balance disturbances.

Afferent Pathways↗
PubMedDate not supplied

Postural control of patients with hemiparesis: force plates measurements based on the clinical sensory organization test.

Standing balance of hemiparetic patients is characterized by increased sway and an asymmetrical weight bearing distribution. The objectives of the study were to determine the feasibility of using a modified clinical sensory organization test with patients following a stroke and to evaluate the contribution of visual and somatosensory input to the standing balance of hemiparetic patients during the first two months following a stroke. Thirty patients with hemiparesis underwent functional and posturographic testing one and two months following their stroke. Testing was conducted in six stance conditions differing in somatosensory and visual input. Fifteen age-matched non-impaired subjects served as the control group. Sway Index (SI) representing the displacement of the subjects' center of pressure during stance, was generally affected by time (p = 0.003), visual input (p = 0.0001), and somatosensory input (p = 0.0061), with the effect of vision significantly greater in the patient group as compared with the control group (p = 0.0006). Despite significant functional gains in the Barthel Index and functional ambulation (p = 0.01), percentage of body weight on the involved extremity (%BW) by stance condition did not change over time. Posturographic testing is useful for determining the sensory organization abilities of stroke patients with moderate impairment and indicates that these patients are dependent on visual input for postural control. The decrease in %BW borne on the affected extremity does not change over time or with the varying of sensory input.

Aged↗
PubMed2001

The assessment of posture control in the elderly using the displacement of the center of pressure after forward platform translation.

We investigated the change of the center of pressure (COP) after forward platform translations in healthy subjects. These studies were performed on 26 normal young subjects and 20 healthy elderly subjects, who had a normal neurologic examination. Subjects stood barefoot on a three dimensional force plate on the platform, with feet parallel. The duration of the forward platform translations was 0.15s, and the displacements were 3.75, 7.5, 10, 15, 20, and 30 mm. Six trials were carried out at random. The COP data were recorded for 35s during standing, and were analyzed for 5s after translation. With the platform translation displacements from 3.75 to 15 mm, displacement of the COP showed a tendency to increase in all subjects. Whereas with the stimuli between 20 and 30 mm, the results were more varied. The elderly group showed significantly (p<0.05) larger sway than the young group. These results indicate that the individual ability of posture control may be assessed by means of measuring the sway of the center of gravity after platform translation. Electromyography was carried out simultaneously, it showed that elderly people contrary to young subjects used proximal biceps femoris and distal foot muscles at an early stage of the platform translation (p<0.05), suggesting lack of ankle stability with aging.

Adult↗
PubMed1996

Disturbed eye movements after whiplash due to injuries to the posture control system.

Self-reports after whiplash often indicate associations with vertigo and reading problems. Neuropsychological and otoneurological tests were applied to a group of whiplash patients (n = 26) and to a carefully matched control group. The whiplash group deviated from the control group on measures of eye movements during reading, on smooth pursuit eye movements with the head in normal position, and with the body turned to the left or to the right. Clinical, caloric, and neurophysiological tests showed no injury to the vestibular system or to the CNS. Test results suggest that injuries to the neck due to whiplash can cause distortion of the posture control system as a result of disorganized neck proprioceptive activity.

Adult↗
PubMed2005

[Postural control related to age in patients with benign positional paroxysmal vertigo].

OBJECTIVE: To study the relationship between age and posturography in patients with benign positional paroxysmal vertigo. MATERIAL AND METHODS: Prospective study performed in 65 patients with benign positional paroxysmal vertigo (BPPV) in any variant. Sensory Organization Test outcomes were recorded and compared with their equivalents in a control group by means of scatter-plot diagrams and regression line. For statistical study, Mann-Whitney's U-test was used. RESULTS: Slope for regression lines in composite was -0.0934 in group NORMAL; in group BPPV it was -0.4284. This difference is due to conditions 5 and 6. Results were statistically significative. CONCLUSIONS: BPPV patients have a worse postural control than control group. The difference is bigger the older the patient is. It is due to a failure in conditions 5 and 6, so it should be from a vestibular origin.

Adult↗
PubMed2003

[Influence of visual cues on upright postural control: differentiated effects of eyelids closure].

In most protocols aimed at testing balance abilities, patients are generally required to close their eyes in order to gain insight about proprioceptive cues and the way the central nervous system (CNS) uses this information. However, one should not exclude possible interaction with the physiological mechanisms involved in eyelid closure, thus leading to a biased neurological evaluation. To assess this possible involvement, 15 healthy adults were required to keep their eyes open in the dark (YOn), to close normally (YF) and forcibly their eyelids (YFF), respectively in random order. The analysis was focused on elementary motions computed from the complex center of pressure (CP) trajectories, i.e. the horizontal motions of the center of gravity (CG(h)) and the difference between the CP and the vertical projection of the center of gravity (CP-CG(v)). The former is recognized as the main variable in postural control whilst several interesting features can be extracted from the latter: their link with the horizontal accelerations communicated to the CG, the level of muscular activity and the implied ankle stiffness expressed by their frequential distribution. The results indicate that the amplitudes of the CP-CG(v) spectra are statistically reduced in YOn when compared to the YF condition, especially in the antero-posterior direction. On the other hand, no shift in the frequential bandwidth was observed on these spectra, signifying a constancy in ankle stiffness over all conditions. Interestingly, the CNS does not really seem to gain from these reduced horizontal accelerations at the CG level since the CG(h) amplitudes are only slightly reduced. However, it is important to emphasize that the CP trajectories alone are not able to demonstrate any statistical trend. It can thus be hypothesized that, despite the fact that visual information is still unavailable, the proprioceptive cues nonetheless continue to play a minor role in the detection-correction process aimed at controlling body sway. Past studies on the physiology of eyes blinking have suggested the probability that the cerebellar cortex or brain stem structures (such as the reticular formation) are involved in these commands. Because of its dual facilitating-inhibiting function, the latter is indeed a fair candidate for modulating the descending command operating through the postural muscles. These data are of interest for the practician in order to assess with precision the role played by proprioceptive and visual cues in possible balance disfunctioning.

Adult↗
PubMed1995

Upright, correlated random walks: A statistical-biomechanics approach to the human postural control system.

The task of maintaining erect stance involves a complex sensorimotor control system, the output of which can be highly irregular. Even when a healthy individual attempts to stand still, the center of gravity of his or her body and the center of pressure (COP) under his or her feet continually move about in an erratic fashion. In this study, we approach the problem of characterizing postural sway from the perspective of random-walk theory. Specifically, we analyze COP trajectories as one-dimensional and two-dimensional random walks. These analyses reveal that over short-term intervals of time during undisturbed stance the COP behaves as a positively correlated random walk, whereas over long-term intervals of time it resembles a negatively correlated random walk. We interpret this novel finding as an indication that during quiet standing the postural control system utilizes open-loop and closed-loop control schemes over short-term and long-term intervals, respectively. From this perspective, our approach, known as stabilogram-diffusion analysis, has the advantage that it leads to the extraction of COP parameters which can be directly related to the steady-state behavior and functional interaction of the neuromuscular mechanisms underlying the maintenance of erect stance. (c) 1995 American Institute of Physics.

Journal Article↗
PubMed2000

Effect of resistive knee extension training on postural control measures in middle aged and elderly persons.

The purpose of the present study was to determine whether knee extension strength gain in middle-aged and elderly persons is associated with improvement in the limits of stability when leaning his/her body in various directions. The resistance training group (EXT; 4 males, 17 females) completed two bilateral knee extension training sessions, consisting of one set of exercises, per week for 10 weeks. The non-training control group (CONT; 4 males, 3 females) were instructed not to train their legs during the 10-week control period. One set of exercises consisted of 8-12 repetitions of a dynamic resistance exercise until volitional fatigue for knee extension. The initial load for training was set at 70% of the one-repetition maximum (1-RM). The thickness of the rectus femoris (RF) and vastus lateralis (VL) muscles were measured using a B-mode ultrasound apparatus. The postural control measures, obtained using the Balance Master system, included the percentage limits-of-stability (%LOS) and path length (%Path). The 1-RM in EXT was increased significantly by resistance training (p < 0.001). In addition, significant differences were observed between the percentage increase of 1-RM in EXT and those in CONT at wk 5 and at wk 10 of resistance training (p < 0.001). However, no significant increase in muscle thickness of RF or VL was found in EXT. The %LOS to the rear target in EXT was increased significantly by resistance training (p < 0.05-0.01). In addition, the percentage change in %Path was decreased significantly by resistance training (p < 0.001). Therefore, strength gain in quadriceps femoris appears to be associated with improvement in the %LOS and %Path for the rear. In conclusion, strength gain in quadriceps femoris is thought to possibly enable accurate movement of the COG farther from the center target towards the rear, suggesting that strength gain has a positive influence on a person's perception of their ability to avoid falls.

Adult↗
PubMed1997

Ankle trauma significantly impairs posture control--a study in basketball players and controls.

Both ankle and hip movements are used to maintain balance in strategies defined as bottom up and top down models. This suggests that pathological impairment of either of these articulations could modify the parameters of balance control. In order to appreciate the bearing of ankle damage on the proper control of equilibrium, posturographic recordings were compared, in a static and two dynamic tests, between 15 professional national basketball players, with histories of 10 to 15 ankle sprains, and 50 controls. In statokinesigrams obtained with eyes open or closed, center of foot pressure displacements were of similar length (way) between controls and players, while the area covered was increased for the latter and related to the history of ankle trauma. In a toes-up dynamic test (4 degrees, 50 degrees/s) coupled with electromyographic recordings, the short latency response (myotatic reflex in the triceps surae muscle) normalized to one meter body height, was shorter in players without relationship to histories of ankle damage. In a prolonged sinusoidal dynamic test, players with the largest number of ankle trauma showed greater difficulties in maintaining posture control. These data pinpoint the role of ankles in the control of both static and dynamic balance and demonstrate that the role of the hip joints becomes more important (top down strategy) in the case of damaged ankles.

Adolescent↗
PubMed1997

Comparison of postural control of children with Down syndrome and those with other forms of mental retardation.

To confirm the 1994 findings of Okuzumi, Haishi, and Kokubun, the displacement of the center of foot pressure, one-foot balance and head sway were measured in children with Down syndrome (n = 11) compared to those with other types of mental retardation (n = 17). The magnitudes of the displacement of the center of foot pressure and head sway were not significantly different between the Down group and other forms of mental retardation, whereas the performance of one-foot balance was significantly lower in the Down group. The mean frequencies of sway waves were generally higher in the Down group, and the differences between the two groups were significant except for sagittal head sway. The results generally supported the prior findings. We proposed that it was not the magnitude of the displacement of the center of foot pressure but rather the manner of the whole body's sway which might be related to postural control.

Adolescent↗
PubMed2004

Postural control as a function of self- and object-motion perception.

The goals of this study were to examine the visual information influence on body sway as a function of self- and object-motion perception and visual information quality. Participants that were aware (object-motion) and unaware (self-motion) of the movement of a moving room were asked to stand upright at five different distances from its frontal wall. The visual information effect on body sway decreased when participants were aware about the sensory manipulation. Moreover, while the visual influence on body sway decreased as the distance increased in the self-motion perception, no effects were observed in the object-motion mode. The overall results indicate that postural control system functioning can be altered by prior knowledge, and adaptation due to changes in sensory quality seem to occur in the self- but not in the object-motion perception mode.

Adult↗
PubMed1998

A double-inverted pendulum model for studying the adaptability of postural control to frequency during human stepping in place.

In order to analyze the influence of gravity and body characteristics on the control of center of mass (CM) oscillations in stepping in place, equations of motion in oscillating systems were developed using a double-inverted pendulum model which accounts for both the head-arms-trunk (HAT) segment and the two-legged system. The principal goal of this work is to propose an equivalent model which makes use of the usual anthropometric data for the human body, in order to study the ability of postural control to adapt to the step frequency in this particular paradigm of human gait. This model allows the computation of CM-to-CP amplitude ratios, when the center of foot pressure (CP) oscillates, as a parametric function of the stepping in place frequency, whose parameters are gravity and major body characteristics. Motion analysis from a force plate was used to test the model by comparing experimental and simulated values of variations of the CM-to-CP amplitude ratio in the frontal plane versus the frequency. With data from the literature, the model is used to calculate the intersegmental torque which stabilizes the HAT when the Leg segment is subjected to a harmonic torque with an imposed frequency.

Biomechanical Phenomena↗
PubMed1988

Postural control in siblings to scoliosis patients and scoliosis patients.

The etiologic importance of postural dysfunction, as shown by many authors in adolescent idiopathic scoliosis (AIS), has been under great debate. The authors' hypothesis was that a factor that is involved in the development of the scoliotic curvature, would be present also in nonscoliotic siblings to scoliosis patients, as AIS is a hereditary transmitted disease. Postural function in 100 siblings to scoliotic children was investigated by means of stabilometry, and compared with a matched control group of healthy children, as well as a group of scoliotic children. The siblings showed a postural control function that was significantly different from both of the other groups. The siblings had a postural sway that was less than the sway measured in both controls and scoliosis patients. The sway was also more asymmetrical than in the two other groups. In the authors' opinion, the presence of this postural aberration in siblings indicates that it is a factor in the etiology of AIS.

Adolescent↗
PubMed1989

[Model studies of muscle postural control in children with spastic hemiparesis: pathophysiologic and clinical relevance].

By means of a biocybernetic method the transfer behaviour of postural motor control system was characterized in children with spastic hemiparesis and matched healthy subjects. There were significant differences between the initial reactions of the postural motor systems of both examination groups to pseudorandom torque sequences (fig. 3, tab. 1). Considering these results we created a postural motor control model for both examinations groups (model see fig. 2). From this model it is possible to estimate separately the biomechanical effect of augmented segmental reflex activity and muscle-inherent dysfunctions in patients with spastic syndrome (fig. 4). The determination of these disturbed functions enables us to give instructions on a focused treatment of spastic syndrome according to the dominant dysfunction quantified.

Brain Damage, Chronic↗
PubMed2006

Stimulus-dependent changes in the vestibular contribution to human postural control.

Humans maintain stable stance in a wide variety of environments. This robust behavior is thought to involve sensory reweighting whereby the nervous system adjusts the relative contribution of sensory sources used to control stance depending on environmental conditions. Based on prior experimental and modeling results, we developed a specific quantitative representation of a sensory reweighting hypothesis that predicts that a given reduction in the contribution from one sensory system will be accompanied by a corresponding increase in the contribution from different sensory systems. The goal of this study was to test this sensory-reweighting hypothesis using measures that quantitatively assess the relative contributions of the proprioceptive and graviceptive (vestibular) systems to postural control during eyes-closed stance in different test conditions. Medial/lateral body sway was evoked by side-to-side rotation of the support surface (SS) while simultaneously delivering a pulsed galvanic vestibular stimulus (GVS) through electrodes behind the ears. A model-based interpretation of sway evoked by SS rotations provided estimates of the proprioceptive weighting factor, Wp, and showed that Wp declined with increasing SS amplitude. If the sensory-reweighting hypothesis is true, then the decline in Wp should be accompanied by a corresponding increase in Wp, the graviceptive weighting factor, and responses to the GVS should increase in proportion to the value of Wp derived from responses to SS rotations. Results were consistent with the predictions of the proposed sensory-reweighting hypothesis. GVS-evoked sway increased with increasing SS amplitude, and Wp measures derived from responses to GVS and from responses to SS rotations were highly correlated.

Adult↗