Postural sway with earth-fixed and body-referenced finger contact in young and older adults

1999 ◽  
Vol 9 (2) ◽  
pp. 103-109
Author(s):  
Reginald L. Reginella ◽  
Mark S. Redfern ◽  
Joseph M. Furman
Keyword(s):  
Older Adults ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Sensory Information ◽  
Body Sway ◽  
Support Surface ◽  
Proprioceptive Information ◽  
Postural Control System ◽  
Fixed Reference ◽  
Older Subjects

Sensory information from lightly touching a reference with the hand is known to influence postural sway in young adults. The primary aim of this study was to compare the influence of finger contact (FC) with an earth-fixed reference to the influence of FC with a body-fixed reference. A second goal of this study was to determine if FC is used differently by older adults compared to younger adults. Using a force plate, center of pressure at the feet was recorded from blindfolded young and older subjects during several conditions. Subjects either did or did not lightly touch a force-sensitive plate that was either earth-fixed or moved forward and backward in synchrony with body sway (that is, sway-referenced). In addition, support surface conditions were also varied, including a fixed floor and a sway-referenced floor using an EquitestTM. Results showed that the type of FC, floor condition, and age each had an effect on postural sway. Touching an earth-fixed plate decreased postural sway as compared to no touching, while touching a sway-referenced plate incresased sway. This influence of FC was enhanced when the floor was sway-referenced. Although older subjects swayed more than young subjects overall, no age-FC interactions occurred, indicating that FC was not utilized differently between the age groups. This study suggests that FC cannot be disregarded as erroneous, especially when proprioceptive information from the legs is distorted. Further, FC is integrated with other sensory information by the postural control system similarly in young and older persons.

Haptic Stabilization of Posture: Changes in Arm Proprioception and Cutaneous Feedback for Different Arm Orientations

1999 ◽  
Vol 82 (6) ◽  
pp. 3541-3549 ◽  
Author(s):  
Ely Rabin ◽  
Simone B. Bortolami ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Postural Sway ◽  
Center Of Pressure ◽  
Body Position ◽  
Geometric Analysis ◽  
Body Sway ◽  
Proprioceptive Information ◽  
Foot Pressure ◽  
Somatosensory Information ◽  
Cutaneous Feedback ◽  
Postural Stabilization

Postural sway during quiet stance is attenuated by actively maintained contact of the index finger with a stationary surface, even if the level of applied force (<1 N) cannot provide mechanical stabilization. In this situation, changes in force level at the fingertip lead changes in center of foot pressure by ∼250 ms. These and related findings indicate that stimulation of the fingertip combined with proprioceptive information about the hand and arm can serve as an active sensor of body position relative to the point of contact. A geometric analysis of the relationship between hand and torso displacement during body sway led to the prediction that arm and hand proprioceptive and finger somatosensory information about body sway would be maximized with finger contact in the plane of body sway. Therefore, the most postural stabilization should be possible with such contact. To test this analysis, subjects touched a laterally versus anteriorly placed surface while in each of two stances: the heel-to-toe tandem Romberg stance that reduces medial-lateral stability and the heel-to-heel, toes-outward, knees-bent, “duck stance” that reduces fore-aft stability. Postural sway was always least with finger contact in the unstable plane: for the tandem stance, lateral fingertip contact was significantly more effective than frontal contact, and, for the duck stance, frontal contact was more effective than lateral fingertip contact. Force changes at the fingertip led changes in center of pressure of the feet by ∼250 ms for both fingertip contact locations for both test stances. These results support the geometric analysis, which showed that 1) arm joint angles change by the largest amount when fingertip contact is maintained in the plane of greatest sway, and 2) the somatosensory cues at the fingertip provide both direction and amplitude information about sway when the finger is contacting a surface in the unstable plane.

Adaptation and Reintegration of Proprioceptive Information in Young and Older Adults' Postural Control

2010 ◽  
Vol 104 (4) ◽  
pp. 1969-1977 ◽  
Author(s):  
Michail Doumas ◽  
Ralf Th. Krampe
Keyword(s):  
Older Adults ◽  
Postural Control ◽  
Path Length ◽  
Reference Conditions ◽  
Age Groups ◽  
Linear Feedback ◽  
Body Sway ◽  
Support Surface ◽  
Proprioceptive Information ◽  
Age Related

We investigated age-related changes in adaptation and sensory reintegration in postural control without vision. In two sessions, participants adapted their posture to sway reference and to reverse sway reference conditions, the former reducing (near eliminating) and the latter enhancing (near doubling) proprioceptive information for posture by means of support-surface rotations in proportion to body sway. Participants stood on a stable platform for 3 min (baseline) followed by 18 min of sway reference or reverse sway reference (adaptation) and finally again on a stable platform for 3 min (reintegration). Results showed that when inaccurate proprioception was introduced, anterior-posterior (AP) sway path length increased in comparable levels in the two age groups. During adaptation, young and older adults reduced postural sway at the same rate. On restoration of the stable platform in the reintegration phase, a sizeable aftereffect of increased AP path length was observed in both groups, which was greater in magnitude and duration for older adults. In line with linear feedback models of postural control, spectral analyses showed that this aftereffect differed between the two platform conditions. In the sway-referenced condition, a switch from low- to high-frequency COP sway marked the transition from reduced to normal proprioceptive information. The opposite switch was observed in the reverse sway referenced condition. Our findings illustrate age-related slowing in participants' postural control adjustments to sudden changes in environmental conditions. Over and above differences in postural control, our results implicate sensory reweighting as a specific mechanism highly sensitive to age-related decline.

Dynamic Regulation of Sensorimotor Integration in Human Postural Control

2004 ◽  
Vol 91 (1) ◽  
pp. 410-423 ◽  
Author(s):  
Robert J. Peterka ◽  
Patrick J. Loughlin
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Sensory Systems ◽  
Body Sway ◽  
Accurate Information ◽  
Support Surface ◽  
Proprioceptive Information ◽  
Postural Control System ◽  
Eyes Closed ◽  
Orientation Information

Upright stance in humans is inherently unstable, requiring corrective action based on spatial-orientation information from sensory systems. One might logically predict that environments providing access to accurate orientation information from multiple sensory systems would facilitate postural stability. However, we show that, after a period in which access to accurate sensory information was reduced, the restoration of accurate information disrupted postural stability. In eyes-closed trials, proprioceptive information was altered by rotating the support surface in proportion to body sway (support surface “sway-referencing”). When the support surface returned to a level orientation, most subjects developed a transient 1-Hz body sway oscillation that differed significantly from the low-amplitude body sway typically observed during quiet stance. Additional experiments showed further enhancement of the 1-Hz oscillation when the surface transitioned from a sway-referenced to a reverse sway-referenced motion. Oscillatory behavior declined with repetition of trials, suggesting a learning effect. A simple negative feedback-control model of the postural control system predicted the occurrence of this 1-Hz oscillation in conditions where too much corrective torque is generated in proportion to body sway. Model simulations were used to distinguish between two alternative explanations for the excessive corrective torque generation. Simulation results favor an explanation based on the dynamic reweighting of sensory contributions to postural control rather than a load-compensation mechanism that scales torque in proportion to a fixed combination of sensory-orientation information.

scholarly journals Firing properties of muscle spindles supplying the intrinsic foot muscles of humans in unloaded and freestanding conditions

2019 ◽  
Vol 121 (1) ◽  
pp. 74-84 ◽  
Author(s):  
T. P. Knellwolf ◽  
A. R. Burton ◽  
E. Hammam ◽  
V. G. Macefield
Keyword(s):  
Muscle Spindle ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Muscle Spindles ◽  
Medial Malleolus ◽  
Proprioceptive Information ◽  
Muscle Spindle Afferents ◽  
Tungsten Microelectrode ◽  
Firing Properties ◽  
Intrinsic Muscles

We recently developed an approach for recording from muscle spindles in the intrinsic muscles of the foot in freestanding humans by inserting a tungsten microelectrode into the posterior tibial nerve behind the medial malleolus of the ankle. Here we characterize the behavior of muscle spindles in the small muscles of the foot in 1) seated subjects with the leg horizontal and the foot naturally plantarflexed and 2) standing subjects. In the first study, recordings were made from 26 muscle spindle afferents located within flexor digiti minimi brevis ( n = 4), abductor digiti minimi ( n = 3), quadratus plantae ( n = 3), plantar interossei ( n = 4), flexor digitorum brevis ( n = 3), dorsal interossei ( n = 2), and lumbricals ( n = 2), with one each supplying abductor hallucis, adductor hallucis, and flexor hallucis brevis. The identity of another two muscle afferents was unknown. The majority of the units were silent at rest, only seven (27%) being spontaneously active. Because of the anatomic constraints of the foot, some spindles supplying muscles acting on the toes responded to movements of one or more digits. In the second study, 12 muscle spindle afferents were examined during standing. The ongoing discharge of eight spindle afferents covaried with changes in the center of pressure during postural sway. We conclude that the majority of spindle endings in the small muscles of the foot are silent at rest, which may allow them to encode changes in conformation of the foot when it is loaded during standing. Moreover, these muscle spindle afferents can provide useful proprioceptive information during standing and postural sway. NEW & NOTEWORTHY We have characterized the firing properties of muscle spindles in the intrinsic muscles of the human foot for the first time. The majority of the spindle endings are silent in seated subjects, and most fire tonically during standing, their discharge covarying with center of pressure during postural sway. We conclude that spindle endings in the intrinsic muscles of the foot provide useful proprioceptive information during free standing.

Controlling Human Upright Posture: Velocity Information Is More Accurate Than Position or Acceleration

2004 ◽  
Vol 92 (4) ◽  
pp. 2368-2379 ◽  
Author(s):  
John Jeka ◽  
Tim Kiemel ◽  
Robert Creath ◽  
Fay Horak ◽  
Robert Peterka
Keyword(s):  
Postural Sway ◽  
Sensory Information ◽  
Accurate Information ◽  
Support Surface ◽  
Quiet Stance ◽  
Eyes Closed ◽  
Stance Control ◽  
Model Predictions ◽  
Velocity Information ◽  
Multisensory Information

The problem of how the nervous system fuses sensory information from multiple modalities for upright stance control remains largely unsolved. It is well established that the visual, vestibular, and somatosensory modalities provide position and rate (e.g., velocity, acceleration) information for estimation of body dynamics. However, it is unknown whether any particular property dominates when multisensory information is fused. Our recent stochastic analysis of postural sway during quiet stance suggested that sensory input provides more accurate information about the body's velocity than its position or acceleration. Here we tested this prediction by degrading major sources of velocity information through removal/attenuation of sensory information from vision and proprioception. Experimental measures of postural sway were compared with model predictions to determine whether sway behavior was indicative of a deficit in velocity information rather than position or acceleration information. Subjects stood with eyes closed on a support surface that was 1) fixed, 2) foam, or 3) sway-referenced. Six measures characterizing the stochastic structure of postural sway behaved in a manner consistent with model predictions of degraded velocity information. Results were inconsistent with the effect of degrading only position or acceleration information. These findings support the hypothesis that velocity information is the most accurate form of sensory information used to stabilize posture during quiet stance. Our results are consistent with the assumption that changes in sway behavior resulting from commonly used experimental manipulations (e.g., foam, sway-referencing, eyes closed) are primarily attributed to loss of accurate velocity information.

Impairments of Postural Balance in Surgically Treated Lumbar Disc Herniation Patients

2020 ◽  
Vol 36 (4) ◽  
pp. 228-234
Author(s):  
Ziva M. Rosker ◽  
Jernej Rosker ◽  
Nejc Sarabon
Keyword(s):  
Postural Balance ◽  
Center Of Pressure ◽  
Balance Control ◽  
The Body ◽  
Surface Velocity ◽  
Body Sway ◽  
Support Surface ◽  
Balance Task ◽  
Lateral Body ◽  
Unstable Support

Reports on body sway control following microdiscectomy lack reports on side-specific balance deficits as well as the effects of trunk balance control deficits on body sway during upright stances. About 3 weeks post microdiscectomy, the body sway of 27 patients and 25 controls was measured while standing in an upright quiet stance with feet positioned parallel on an unstable support surface, a tandem stance with the involved leg positioned in front or at the back, a single-leg stance with both legs, and sitting on an unstable surface. Velocity, average amplitude, and frequency-direction–specific parameters were analyzed from the center of pressure movement, measured by the force plate. Statistically significant differences between the 2 groups were observed for the medial–lateral body sway frequency in parallel stance on a stable and unstable support surface and for the sitting balance task in medial-lateral body sway parameters. Medium to high correlations were observed between body sway during sitting and the parallel stance, as well as between the tandem and single-legged stances. Following microdiscectomy, deficits in postural balance were side specific, as expected by the nature of the pathology. In addition, the results of this study confirmed the connection between proximal balance control deficits and balance during upright quiet balance tasks.

A Mathematical Model to Examine Issues Associated With Using Portable Force-Measurement Technologies to Collect Infant Postural Data

2020 ◽  
Vol 8 (1) ◽  
pp. 14-37 ◽  
Author(s):  
James R. Chagdes ◽  
Joshua J. Liddy ◽  
Amanda J. Arnold ◽  
Laura J. Claxton ◽  
Jeffrey M. Haddad
Keyword(s):  
Mathematical Model ◽  
Center Of Pressure ◽  
Force Measurement ◽  
Low Cost ◽  
Body Sway ◽  
Support Surface ◽  
Experimental Setup ◽  
Mathematical Simulations ◽  
Additional Support

Portable force-measurement technologies are becoming increasingly popular tools to examine the maturation of postural motor milestones, such as sitting and standing, in infants. These convenient, low-cost devices provide numerous opportunities to characterize postural development outside of the laboratory. However, it is important to understand the unique challenges and technical limitations associated with collecting center of pressure (CoP) data using portable force-measurement technologies in infant populations. This study uses a mathematical model to examine issues that emerge when using portable force-measurement technologies to collect sitting and standing postural data in infants. The results of our mathematical simulations demonstrate that the CoP errors from portable force-measurement technologies depend on the posture examined (e.g., sitting vs. standing), the anthropometrics of the person (e.g., height and weight), the frequency of body sway, and the experimental setup (e.g., an additional support surface being placed on top of the device). Recommendations are provided for developmental researchers interested in adopting these technologies in infant populations.

scholarly journals Effects of light touch on balance in patients with stroke

Open Medicine ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 259-263
Author(s):  
Tae-sung In ◽  
Jin-Hwa Jung ◽  
Sang-hun Jang ◽  
Kyung-hun Kim ◽  
Kyoung-sim Jung ◽  
...  
Keyword(s):  
Postural Sway ◽  
Center Of Pressure ◽  
Force Plate ◽  
Cross Sectional Study ◽  
Support Surface ◽  
Light Touch ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Surface Conditions ◽  
Hemiparetic Stroke

AbstractLight touch is the combination of cutaneous and kinesthetic inputs. The literature suggests that light touch compensates for a reduced amount of center of pressure information in older peoples, blind subjects and patients with neurological disorder. This study investigated the effects of light touch applied to an external bar, on the postural sway in individuals with hemiparetic stroke. We used a cross sectional study, fifteen individuals with stroke and 15 healthy age-matched adults stood as still as possible on a force plate. Experimental trials (duration, 30 s) included two visual conditions (open eyes and closed eyes), two somatosensory conditions (no touch and light touch) and two support surface conditions (firm and foam surfaces). The area of center of pressure (COP) and the mean velocity of COP in the medio-lateral and anterior-posterior directions were assessed. For both groups, COP velocity and area decreased with light touch regardless of the visual or surface conditions. The effects of light touch were similar in both groups. In addition, results show that the effectiveness of light touch in reducing postural sway was greater on a foam surface than on a firm surface. Our findings indicate that light touch could be beneficial in postural control for individuals with hemi-paretic stroke

scholarly journals Effects of orthopedic insoles on static balance of older adults wearing thick socks

2018 ◽  
Vol 42 (3) ◽  
pp. 357-362 ◽  
Author(s):  
Christina Zong-Hao Ma ◽  
Duo Wai-Chi Wong ◽  
Anson Hong-Ping Wan ◽  
Winson Chiu-Chun Lee
Keyword(s):  
Older Adults ◽  
Study Design ◽  
Plantar Pressure ◽  
Repeated Measures ◽  
Postural Balance ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Cost Effective ◽  
The Elderly ◽  
Orthopedic Insoles

Background: The wearing of socks and insoles may affect the ability of the foot to detect tactile input influencing postural balance. Objectives: The aim of this study was to investigate whether (1) thick socks adversely affected the elderly postural balance and (2) orthopedic insoles could improve the elderly postural balance while wearing thick socks. Study design: Repeated-measures study design. Methods: In total, 14 healthy older adults were recruited. A monofilament test was conducted to evaluate foot plantar sensation with and without thick socks. Subjects then performed the Romberg tests under three conditions: (1) barefoot, (2) with socks only, and (3) with both socks and insoles. Postural balance was assessed by measuring the center of pressure movement during standing in each experimental condition. Results: Thick socks significantly decreased the monofilament score ( p < 0.001), suggesting reduction in ability to detect external forces. All center of pressure parameters increased significantly while wearing thick socks ( p < 0.017), implying reduction of postural stability. They then decreased significantly with the additional use of insoles ( p < 0.017). Conclusion: Previous studies have documented the changes in plantar pressure distribution with the use of orthopedic insoles. This study further suggests that such changes in contact mechanics could produce some balance-improving effects, which appears not to have been reported earlier. Clinical relevance Wearing thick socks reduces plantar pressure sensitivity and increases postural sway which may increase risk of falls. Orthopedic insoles and footwear with similar design could potentially be a cost-effective method in maintaining postural balance when wearing thick socks.

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