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 55 records · Page 3Linked to original sources

PubMed1988

Postural control in single-limb stance.

Postural control in single-limb stance has previously been shown to be impaired among soccer players with functional instability (FI) of the ankle joint. The aim of the present study was to further study the role of the ankle in postural control. A dynamic method was used involving optoelectronic movement recordings of body segments and force-plate recordings of the reaction ground force. Surface electromyography was recorded for the peroneus longus muscle. Thirty physically active men were selected. Fifteen of them had FI of the ankle chosen for recording. The results show that different patterns exist for maintaining equilibrium in single-limb stance. The ankle has a central role for postural corrections. The position of center of pressure is highly correlated to the position of the ankle and peroneal muscle activity. When the body was in disequilibrium, corrections were made at the hip. It is proposed that a change from an inverted pendulum model to a multisegmental chain model takes place when adjustments at the ankle joint no longer suffice to maintain postural control. The men with FI showed impaired postural control associated with increased upper segmental corrections.

Adolescent↗

PubMed2003

Nonlinear analysis of the development of sitting postural control.

The development of sitting postural control in five normal infants was examined longitudinally at three stages of sitting: Stage 1, when infants could hold up their head and upper trunk, but could not sit independently; Stage 2, when infants began to sit independently briefly; and Stage 3, when infants could sit independently. Methods from nonlinear dynamics were used to analyze center of pressure (COP) data during sitting in terms of stability of the neuromuscular system (Lyapunov Exponent), movement dimensionality (Correlation Dimension), and complexity/regularity (Approximate Entropy). Results indicated significant changes in the nonlinear measures over time, with increased stability and increased regularity revealing a more stable and periodic strategy of maintaining postural control. Dimensionality decreased from Stage 1 to 2, indicating a constraint of the degrees of freedom. Subsequently, dimensionality increased from Stage 2 to 3, indicating a release of the degrees of freedom as sitting independence emerged. Nonlinear analysis of the COP time series supports the perspective that the development of postural control is a dynamic process whereby the infant learns to control the body's degrees of freedom to achieve the sitting posture.

Child Development↗

PubMed1985

The growth of stability: postural control from a development perspective.

This study compared central nervous system organizational processes underlying balance in children of three age groups: 15-31 months, 4-6 years, and 7-10 years, using a movable platform capable of antero-posterior (A-P) displacements or dorsi-plantar flexing rotations of the ankle joint. A servo system capable of linking platform rotations to A-P sway angle allowed disruption of ankle joint inputs, to test the effects of incongruent sensory inputs on response patterns. Surface electromyography was used to quantify latency and response patterns. Surface electromyography was used to quantify latency and amplitude of the gastrocnemius, hamstrings, tibialis anterior, and quadriceps muscle responses. Cinematography provided biomechanical analysis of the sway motion. Results demonstrated that while directionally specific response synergies are present in children under the age of six, structured organization of the synergies is not yet fully developed since variability in timing and amplitude relationships between proximal and distal muscles is high. Transition from immature to mature response patterns was not linear but stage-like with greatest variability in the 4- to 6- year-old children. Results from balance tests under altered sensory conditions (eyes closed and/or ankle joint inputs altered) suggested that: (a) with development a shift in controlling inputs to posture from visual dependence to more adult-like dependence on a combination of ankle joint and visual inputs occurred in the 4- to 6-year-old, and reached adult form in the 7- to 10-year-old age group. It is proposed that the age 4-6 is a transition period in the development of posture control. At this time the nervous system (a) uses visual-vestibular inputs to fine tune ankle-joint proprioception in preparation for its increased importance in posture control and (b) fine tunes the structural organization of the postural synergies themselves.

Journal Article↗

PubMed2006

Bilateral subthalamic nucleus deep brain stimulation improves certain aspects of postural control in Parkinson's disease, whereas medication does not.

Postural control requires precise integration of sensory inputs and motor output, but clinical assessments of postural control do not differentiate between these. Previously, we found that this differentiation is important in Parkinson's disease (PD) as there was a dissociated effect of medication versus pallidotomy on sensory aspects of postural instability. In this study, we address several questions that emerged from that work in 28 different patients with PD off and on medication, before and after bilateral subthalamic nucleus deep brain stimulation (B-STN DBS): (1) In a different cohort is there still an unusually large percentage of patients with postural instability in sensory-deprived conditions? (2) Are more specific measures of motor aspects of postural control using dynamic posturography (postural movement velocity [MV] and reaction time [RT]) abnormal in PD as seen clinically using the Postural Instability and Gait Disorder score of the Unified Parkinson's Disease Rating Scale? (3) What is the effect of B-STN DBS versus medication on sensory versus motor aspects of postural instability in PD? The results included (1) substantially more patients (39%) versus controls (5%) exhibited postural instability in conditions of limited sensory feedback; (2) postural MV and postural RT were abnormal off medication preoperatively (N(subset) = 23; P < 0.001 for both); (3) B-STN DBS improved abnormal sensory aspects of postural instability (P < 0.05) and postural MV (P = 0.005), whereas medication did not. Neither B-STN DBS nor medication improved postural RT. For the group as a whole, STN DBS plus medication was better therapy than medication preoperatively for sensory aspects of postural control (P = 0.003).

Brain↗

PubMed2006

Neural bases of postural control.

The body posture during standing and walking is maintained due to the activity of a closed-loop control system. In the review, we consider different aspects of postural control: its functional organization, the distribution of postural functions in different parts of the central nervous system, and the activity of neuronal networks controlling posture.

Animals↗

PubMed2005

Detecting altered postural control after cerebral concussion in athletes with normal postural stability.

OBJECTIVE: To determine if approximate entropy (ApEn), a regularity statistic from non-linear dynamics, could detect changes in postural control during quiet standing in athletes with normal postural stability after cerebral concussion. METHODS: The study was a retrospective, case series analysis of centre of pressure (COP) data collected during the Sensory Organization Test (SOT) from NCAA Division I (USA) athletes prior to and within 48 h after injury. Subjects were 21 male and six female athletes from a variety of sports who sustained a cerebral concussion between 1997 and 2003. After injury, athletes displayed normal postural stability equivalent to preseason levels. For comparison, COP data also were collected from 15 male and 15 female healthy non-athletes on two occasions. ApEn values were calculated for COP anterior-posterior (AP) and medial-lateral (ML) time series. RESULTS: Compared to healthy subjects, COP oscillations among athletes generally became more regular (lower ApEn value) after injury despite the absence of postural instability. For AP time series, declines in ApEn values were much larger in SOT conditions 1 and 2 (approximately three times as large as the standard error of the mean) than for all other conditions. For ML time series, ApEn values declined after injury in all sensory conditions (F(1,55) = 6.36, p = 0.02). CONCLUSIONS: Athletes who demonstrated normal postural stability after concussion nonetheless displayed subtle changes in postural control. Changes in ApEn may have represented a clinically abnormal finding. ApEn analysis of COP oscillations may be a valuable supplement to existing concussion assessment protocols for athletes.

Adolescent↗

PubMed2005

Role of visual dysfunction in postural control in children with cerebral palsy.

INTRODUCTION: Deficient postural control is one of the key problems in cerebral palsy (CP). Little, however, is known about the specific nature of postural problems of children with CP, nor of the relation between abnormal posture and dysfunction of the visual system. AIM OF THE STUDY: To provide additional information on the association of abnormalities in postural control and visual dysfunction of the anterior or posterior part of the visual system. METHODS: Data resulting from ophthalmologic, orthoptic, neurological, neuro-radiological, and ethological investigations of more than 313 neurologically impaired children were retrospectively analyzed. RESULTS: Abnormal postural control related to ocular and ocular motor disorders consisted of anomalous head control and subsequent abnormal head posture and torticollis. The abnormal postural control related to retrochiasmatical damage of the visual system consisted of a torticollis combined with adjustment of the upper part of the body, as if at the same time adapting to a combination of defects and optimizing residual visual functions. CONCLUSION: Visual dysfunctions play a distinct role in the postural control of children with CP.

Adolescent↗

PubMed2004

Effect of training on postural control in figure skaters: a randomized controlled trial of neuromuscular versus basic off-ice training programs.

OBJECTIVES: To compare the effect of a neuromuscular training program and a basic exercise program on postural control in figure skaters. DESIGN: Two groups; parallel design; prospective, randomized controlled trial. SETTING: Postural control laboratory, arenas, September 2001 to December 2002. PARTICIPANTS: Forty-four young, healthy figure skaters (18 years +/- 3 years). INTERVENTIONS: Participants were randomly assigned to receive a neuromuscular training program (n = 22) or a basic exercise training program (n = 22). Both programs were completed 3 times per week for 4 weeks, and each session was supervised. MAIN OUTCOME MEASUREMENTS: Participants completed baseline and postintervention measures of postural control on a force plate. Postural control was quantified as the center of pressure (CoP) path length during tests of single-limb standing balance that mimicked figure skating skills and challenged the postural control system to varying degrees. The primary outcome measure was the CoP path length observed during a landing jump test completed with eyes closed. RESULTS: The post intervention CoP path lengths during the more challenging tests were significantly (P < 0.05) lower (indicating better postural control) for the neuromuscular trained group than for the basic exercise-trained group. For the landing jump test completed with eyes closed, the percent improvement in the neuromuscular trained group was significantly greater (mean = 21.0 +/- 22.0%) than the basic exercise trained group (mean = -4.9 +/- 24.9%; P < 0.05). The magnitude of improvement in the neuromuscular-trained group ranged from approximately 1% to 21%, depending on the specific postural control test used. CONCLUSIONS: The results suggest that off-ice neuromuscular training can significantly improve postural control in figure skaters, whereas basic exercise training does not.

Adolescent↗

PubMed2000

Postural control in horizontal benign paroxysmal positional vertigo.

Sixteen patients affected by benign paroxysmal positional vertigo of the horizontal semicircular canal (BPPV-HSC) were investigated by means of dynamic posturography (DP) and during bithermal caloric stimulation. Data were compared to data from 40 patients with benign paroxysmal positional vertigo of the posterior semicircular canal (BPPV-PSC) and 20 healthy controls. No postural deficit was observed before or after a liberative Lempert's manoeuvre when patients were compared to control subjects. BPPV-PSC postural scores were significantly impaired compared to scores from the BPPV-HSC group. A residual significant postural impairment was also observed after a successful liberative manoeuvre in the BPPV-PSC group. Electronystagmographic recordings before recovery revealed significant hypoexcitability of the affected ear in 8/16 patients of the BPPV-HSC group. After the liberative manoeuvre, a symmetric bilateral response to caloric stimulation was recorded in all patients. Three main conclusions can be drawn from the present data. First, disorders of the horizontal semicircular canal do not change postural control. Second, dynamic posturography can detect the postural imbalance due to posterior semicircular canal dysfunction even after resolution of paroxysmal vertigo attacks. Third, utricular dysfunction can be ruled out as a cause of the residual postural deficit observed in BPPV-PSC patients. Therefore the recovery delay observed even 1 month after the liberative manoeuvre in the BPPV-PSC-group might be due to the persistence of small amounts of residual debris in the canal, to paralysis of ampullar receptors, or to the time needed for central vestibular re-adaptation.

Caloric Tests↗

PubMed2005

Human standing posture control system depending on adopted strategies.

Control of the standing posture of humans involves at least two distinct modes of operation to restore the body balance in the sagittal plane: the ankle strategy and the hip strategy. The objective of the study was to estimate the contribution of vestibular, visual and somatosensory feedbacks to these distinct strategies. The body dynamics was described as the motion of two linked rigid segments that represented the legs and the rest of the body. The posture controller received the inclination angles of the two body segments as inputs and regulated the moments around the ankle and hip joints. The controller had four feedback paths that were characterised by transfer functions connecting the two inputs and the two outputs. To evoke the distinct strategies, the floor conditions were varied by narrowing the support surface under the feet. A continuous pseudo-random external disturbing force was applied to the waist and the thigh independently. The inclination angles of the body segments and the ground reaction force were measured, and the transfer functions of the controller were estimated with the maximum-likelihood system identification procedure. Six healthy male adult subjects participated in the experiment. When the hip strategy became evident under the narrow support surface conditions, the transfer function relating the leg inclination angle and the ankle joint moment decreased its DC gain (16%), whereas the other three transfer functions increased the gains (20-140%) (ANOVA, p < 0.05). Based on a criterion for simplicity in the modification of the posture controller, these changes suggest a new hypothesis that, when posture control becomes difficult, the central nervous system selectively activates the somatosensory feedback paths from the hip joint angle to the moments around the ankle and hip joints.

Adult↗

PubMed2003

Differential approach to strategies of segmental stabilisation in postural control.

The present paper attempts to clarify the between-subjects variability exhibited in both segmental stabilisation strategies and their subordinated or associated sensory contribution. Previous data have emphasised close relationships between the interindividual variability in both the visual control of posture and the spatial visual perception. In this study, we focused on the possible relationships that might link perceptual visual field dependence-independence and the visual contribution to segmental stabilisation strategies. Visual field dependent (FD) and field independent (FI) subjects were selected on the basis of their extreme score in a static rod and frame test where an estimation of the subjective vertical was required. In the postural test, the subjects stood in the sharpened Romberg position in darkness or under normal or stroboscopic illumination, in front of either a vertical or a tilted frame. Strategies of segmental stabilisation of the head, shoulders and hip in the roll plane were analysed by means of their anchoring index (AI). Our hypothesis was that FD subjects might use mainly visual cues for calibrating not only their spatial perception but also their strategies of segmental stabilisation. In the case of visual cue disturbances, a greater visual dependency to the strategies of segmental stabilisation in FD subjects should be validated by observing more systematic "en bloc" functioning (i.e. negative AI) between two adjacent segments. The main results are the following: 1. Strategies of segmental stabilisation differed between both groups and differences were amplified with the deprivation of either total vision and/or static visual cues. 2. In the absence of total vision and/or static visual cues, FD subjects have shown an increased efficiency of the hip stabilisation in space strategy and an "en bloc" operation of the shoulder-hip unit (whole trunk). The last "en bloc" operation was extended to the whole head-trunk unit in darkness, associated with a hip stabilisation in space. 3. The FI subjects have adopted neither a strategy of segmental stabilisation in space nor on the underlying segment, whatever the body segment considered and the visual condition. Thus, in this group, head, shoulder and hip moved independently from each other during stance control, roughly without taking into account the visual condition. The results, emphasising a differential weighting of sensory input involved in both perceptual and postural control, are discussed in terms of the differential choice and/or ability to select the adequate frame of reference common to both cognitive and motor spatial activities. We assumed that a motor-somesthetics "neglect" or a lack of mastering of these inputs/outputs rather than a mere visual dependence in FD subjects would generate these interindividual differences in both spatial perception and postural balance. This proprioceptive "neglect" is assumed to lead FD subjects to sensory reweighting, whereas proprioceptive dominance would lead FI subjects to a greater ability in selecting the adequate frame of reference in the case of intersensory disturbances. Finally, this study also provides evidence for a new interpretation of the visual field dependence-independence dimension in both spatial perception and postural control.

Adult↗

PubMed2004

Changes in postural control during a 48-hr. sleep deprivation period.

Sleep deprivation has detrimental effects on cognitive abilities; however, there has been limited investigation into the effects of sleep deprivation on postural control or influence of time of day on postural control measures. Therefore, we measured postural control on a force plate every 6 hr. in 24 subjects (11 women, 13 men; M age 20 +/- 2.1 yr.; M height 1.68+/-0.29 m; body mass 63.3 +/- 28.7 kg) participating in a 48-hr. dance marathon. During the first 24-hr. period, postural control significantly worsened. Rather than a steady decrease in postural control, during the second day of the event a repeating oscillatory trend of fluctuations in postural control was observed for both days of the event. We hypothesize that the repeating oscillation of postural control followed a circadian rhythm pattern, suggesting that sleep deprivation for 48 hr. does not influence measures of postural control in a consistent manner. The apparent influence of time of day on postural control measures warrants consideration of this factor when conducting studies with repeated measures of postural control across different days.

Adult↗

PubMed2006

Postural control following a self-initiated reaching task in type 2 diabetic patients and age-matched controls.

Although the postural stability of diabetic patients is affected in the presence of polyneuropathy, it has been suggested that diabetes per se has no effect on balance control during quiet standing. However, recent studies have reported muscular mechanical deficits in patients with type 2 diabetes (T2D) that may be highlighted during a more destabilizing task than quiet standing. Therefore, the objective of this study was to compare non-diabetic and T2D subjects during a modified version of the functional reach (FR) test in order to discriminate differences in postural control associated with diabetes per se. Thirty subjects (15 non-diabetic and 15 T2D) were requested to stand on a force platform and to perform the FR test. Center of pressure velocity (V(COP)), root-mean-square (RMS) amplitude and range of the COP were calculated in the anterior-posterior direction during three specific periods of the FR performance: namely "before", "on-going" and "after". No significant difference between the non-diabetic subjects and the T2D subjects was found for the FR performance. However, T2D subjects had significantly higher V(COP), RMS and range of COP displacements for the "after" period compared to the non-diabetic group (p<0.05). These results suggest that T2D subjects without peripheral neuropathy may have difficulties regaining their stability after a self-initiated reaching task. Therefore, diabetes mellitus per se, could have a direct effect on postural control during standing after a self-induced forward reaching movement.

Arm↗

PubMed2003

Lumbar paraspinal muscle function, perception of lumbar position, and postural control in disc herniation-related back pain.

STUDY DESIGN: A follow-up study evaluating postural control, lumbar movement perception, and paraspinal muscle reflexes in disc herniation-related chronic low back pain (LBP) before and after discectomy. OBJECTIVES: To assess the effect of discectomy on postural control, lumbar perception, and reflex activation of paraspinal muscles during sudden upper limb loading. SUMMARY OF BACKGROUND DATA: Impaired muscle function, postural control, and lumbar proprioception have been observed in LBP. However, they have not been studied in sciatica patients after surgery. METHODS: The study included 20 patients selected for an operation for chronic LBP caused by disc herniation and 15 controls without chronic LBP. The paraspinal muscle responses for upper limb loading during unexpected and expected conditions were measured by surface electromyography. The ability to sense lumbar rotation was assessed in a previously validated motorized trunk rotation unit in the seated position. The postural control was measured with a vertical force platform. Pain, disability, and depression scores were recorded. RESULTS: Patients had poorer lumbar perception (P = 0.012) and postural control (P < 0.05) than did healthy controls. The postural control remained unchanged, but lumbar perception (P = 0.054) and the lumbar feed-forward control (P = 0.043) improved after the surgery. CONCLUSIONS: The results demonstrate impaired lumbar proprioception and postural control in sciatica patients. During short-term follow-up after operative treatment, postural control does not seem to change, but impaired lumbar proprioception and feed-forward control of paraspinal muscles seem to recover.

Chronic Disease↗

PubMedDate not supplied

Effects of visual and support surface orientation references upon postural control in vestibular deficient subjects.

Assessment of postural control in vestibular deficient subjects with and without visual and ankle joint sway information permitted: 1) a quantitative assessment of the overall vestibular information used by the individual patient for control of upright posture; 2) an estimate of the extent to which the vestibular deficient subject can appropriately "select" and alternatively use visual and ankle joint somatosensory information for compensatory postural control and 3) quantification of adaptive changes in postural responses to visual and somatosensory inputs. Results from this study support the hypothesis that abnormal vestibular function disrupts the subject's reference to gravity (earth) vertical. This loss of an absolute spatial reference normally provided by vestibular input prevents the resolution of conflicting or inaccurate visual and somatosensory spatial references which may occur during active or passive body movements.

Ear, Inner↗

PubMed1990

Postural control in elderly subjects.

The postural stability of 23 subjects aged 85 years or over was studied with a force platform. The sensory function of the lower limbs was disturbed with small vibrators placed on both calf muscles and/or by placing the subjects on a platform covered with foam plastic. When compared with a group (n = 100) of 50-60-year-old subjects, the elderly subjects had significantly higher sway velocities even during nonperturbed conditions. The perturbation of muscle spindles with vibration and/or pressoreceptor function with foam plastic did not increase the postural instability of the elderly subjects. Visual deprivation had a significant effect on postural stability, and the visual influx contributed about 50% of the postural stability. Postural control is reduced as a result of loss of sensory cues of pressoreceptors and also deterioration in function of stretch reflexes initiated from muscle spindles. The very elderly seem to rely on visual control of posture; this is slow, which can be one reason for susceptibility to falls.

Age Factors↗

PubMed1989

Hierarchy of different muscles in postural control.

The effects of muscle spindle activation on different postural muscles were examined in eight volunteers, using a force platform technique. Small electrical vibrators were placed symmetrically over the muscles concerned and the effects of vibration frequencies of 20, 40, 60, 80 and 100 Hz were studied at a constant amplitude of 0.4 mm (peak-to-peak). Significant responses were observed in most muscles. The responses were observed (in maximum response order) from: the neck, triceps surae, gluteus, abdominal, hamstring, quadriceps, lumbar and tibialis anterior muscles. The response direction did not follow anatomical gonistic vis-à-vis antagonistic distribution of the muscles studied, indicating that it is the functional properties of the muscles that determine posture stabilization. The large inter-individual variability in responses, but the consistency in intra-individual muscle responses indicates that the subjects used afferent muscles to a varying extent in postural control. The vibration-induced activation of the muscles was presumably derived by activation of stretch-sensitive secondary endings of muscle spindles that control postural stability.

Adult↗

PubMed1998

One-footed and externally disturbed two-footed postural control in patients with chronic low back pain and healthy control subjects. A controlled study with follow-up.

STUDY DESIGN: A study of postural control during one-footed and externally disturbed two-footed stance among healthy control subjects and patients with chronic low back pain at the beginning of a functional back restoration program and 6 months later at follow-up examination. OBJECTIVES: To study postural control cross-sectionally among control subjects and patients with low back pain, and to evaluate the effects of functional restoration on the postural control parameters in a follow-up examination. SUMMARY OF BACKGROUND DATA: Deficits of motor skills and coordination have been reported in association with musculoskeletal disorders. It has been found that patients with chronic low back pain have impaired psychomotor control, but the impairment is reversible with successful low back rehabilitation. It is insufficiently known how functional activation and intensive physical training affect postural control. METHODS: Sixty-one healthy volunteers (32 men, 29 women) and altogether 99 patients with low back pain participated in the study. Sixty-eight patients (33 men, 35 women) had moderate and 31 (18 men, 13 women) had severe low back pain. Postural stability was measured with a force platform. In two-footed stance, vibration stimulation on calf and back muscles was used to disturb the balance. Center point of force-velocity (cm/sec), average position shift in anteroposterior direction (cm), and maximal position shift in lateral direction (cm) were used as the parameters. RESULTS: Reliability of all tests was acceptable. Center point of force-velocity was the most sensitive parameter and the one-footed measurement the most sensitivetest for evaluating postural stability. At the beginning, the patients with severe low back pain had poorer one-footed postural control compared with the control subjects (P = 0.0003). The subgroup of patients with moderate low back pain participated in the restoration program. The outcome of the restoration program was considered good if the disability because of low back pain (Oswestry index) decreased during the restoration program and poor if the disability increased or did not change. The one-footed postural stability remained primarily at the same level as the initial results in the control and good outcome groups, but became significantly poorer in the poor outcome group. The difference between poor outcome and control groups was statistically significant (P = 0.04). CONCLUSIONS: Impaired postural stability seems to be one factor in multidimensional symptomatology of patients with chronic low back trouble. Postural stability is easily disturbed in case of impairment in strength, coordination, or effective coupling of muscles in the lumbar and pelvic area. Patients with chronic low back pain seem to experience impairment in these functions, which should be taken into consideration when back rehabilitation programs are planned.

Adult↗