scholarly journals Velocity dependence of vestibular information for postural control on tilting surfaces

2016 ◽  
Vol 116 (3) ◽  
pp. 1468-1479 ◽  
Author(s):  
Fay B. Horak ◽  
JoAnn Kluzik ◽  
Frantisek Hlavacka
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Somatosensory System ◽  
The Body ◽  
Velocity Range ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Eyes Closed ◽  
Vestibular Information ◽  
Wide Range

Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities. However, with eyes closed, subjects with vestibular loss were most unstable within a critical tilt velocity range of 2 to 8 deg/s. Subjects with vestibular deficiency lost their balance in more than 90% of trials during the 4 deg/s condition, but never fell during slower tilts (0.25–1 deg/s) and fell only very rarely during faster tilts (16–32 deg/s). At the critical velocity range in which falls occurred, the body center of mass stayed aligned with respect to the surface, onset of ankle dorsiflexion was delayed, and there was delayed or absent gastrocnemius inhibition, suggesting that subjects were attempting to actively align their upper bodies with respect to the moving surface instead of to gravity. Vestibular information may be critical for stability at velocities of 2 to 8 deg/s because postural sway above 2 deg/s may be too fast to elicit stabilizing responses through the graviceptive somatosensory system, and postural sway below 8 deg/s may be too slow for somatosensory-triggered responses or passive stabilization from trunk inertia.

Bilateral Vestibular Loss in Cats Leads to Active Destabilization of Balance During Pitch and Roll Rotations of the Support Surface

2007 ◽  
Vol 97 (6) ◽  
pp. 4357-4367 ◽  
Author(s):  
Jane M. Macpherson ◽  
Dirk G. Everaert ◽  
Paul J. Stapley ◽  
Lena H. Ting
Keyword(s):  
Center Of Mass ◽  
The Body ◽  
Support Surface ◽  
Postural Response ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Automatic Postural Response ◽  
Vestibular Information ◽  
Body Center ◽  
Proprioceptive Inputs

Although the balance difficulties accompanying vestibular loss are well known, the underlying cause remains unclear. We examined the role of vestibular inputs in the automatic postural response (APR) to pitch and roll rotations of the support surface in freely standing cats before and in the first week after bilateral labyrinthectomy. Support surface rotations accelerate the body center of mass toward the downhill side. The normal APR consists of inhibition in the extensors of the uphill limbs and excitation in the downhill limbs to decelerate the body and maintain the alignment of the limbs with respect to earth-vertical. After vestibular lesion, cats were unstable during rotation perturbations and actively pushed themselves downhill rather than uphill, using a postural response that was opposite to that seen in the control trials. The extensors of the uphill rather than downhill limbs were activated, whereas those of the downhill limbs were inhibited rather than being excited. We propose that vestibular inputs provide an important reference to earth-vertical, which is critical to computing the appropriate postural response during active orientation to the vertical. In the absence of this vestibular information, subjects orient to the support surface using proprioceptive inputs, which drives the body downhill resulting in instability and falling. This is consistent with current models of sensory integration for computation of body posture and orientation.

Control of Stance and Developmental Coordination Disorder: The Role of Visual Information

2004 ◽  
Vol 21 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Eryk P. Przysucha ◽  
M. Jane Taylor
Keyword(s):  
Visual Information ◽  
Path Length ◽  
Developmental Coordination Disorder ◽  
Postural Sway ◽  
Quiet Standing ◽  
Eyes Closed ◽  
Total Path Length ◽  
Eyes Open ◽  
Stability Limits ◽  
Coordination Disorder

The purpose of this study was to compare the postural sway profiles of 20 boys with and without Developmental Coordination Disorder (DCD) on two conditions of a quiet standing task: eyes open and eyes closed. Anterior-posterior (AP) sway, medio-lateral sway (LAT), area of sway, total path length, and Romberg’s quotient were analyzed. When visual information was available, there was no difference between groups in LAT sway or path length. However, boys with DCD demonstrated more AP sway (p < .01) and greater area of sway (p < .03), which resulted in pronounced excursions closer to their stability limits. Analysis of Romberg’s quotient indicated that boys with DCD did not over-rely on visual information.

scholarly journals Can explicit visual feedback of postural sway efface the effects of sensory manipulations on mediolateral balance performance?

2016 ◽  
Vol 115 (2) ◽  
pp. 907-914 ◽  
Author(s):  
L. Eduardo Cofré Lizama ◽  
Mirjam Pijnappels ◽  
N. Peter Reeves ◽  
Sabine M. P. Verschueren ◽  
Jaap H. van Dieën
Keyword(s):  
Visual Feedback ◽  
Repeated Measures ◽  
Visual Information ◽  
Postural Sway ◽  
Center Of Mass ◽  
The Body ◽  
Body Center ◽  
Explicit Feedback ◽  
Dominant Frequencies ◽  
Visual Conditions

Explicit visual feedback on postural sway is often used in balance assessment and training. However, up-weighting of visual information may mask impairments of other sensory systems. We therefore aimed to determine whether the effects of somatosensory, vestibular, and proprioceptive manipulations on mediolateral balance are reduced by explicit visual feedback on mediolateral sway of the body center of mass and by the presence of visual information. We manipulated sensory inputs of the somatosensory system by transcutaneous electric nerve stimulation on the feet soles (TENS) of the vestibular system by galvanic vestibular stimulation (GVS) and of the proprioceptive system by muscle-tendon vibration (VMS) of hip abductors. The effects of these manipulations on mediolateral sway were compared with a control condition without manipulation under three visual conditions: explicit feedback of sway of the body center of mass (FB), eyes open (EO), and eyes closed (EC). Mediolateral sway was quantified as the sum of energies in the power spectrum and as the energy at the dominant frequencies in each of the manipulation signals. Repeated-measures ANOVAs were used to test effects of each of the sensory manipulations, of visual conditions and their interaction. Overall, sensory manipulations increased body sway compared with the control conditions. Absence of normal visual information had no effect on sway, while explicit feedback reduced sway. Furthermore, interactions of visual information and sensory manipulation were found at specific dominant frequencies for GVS and VMS, with explicit feedback reducing the effects of the manipulations but not effacing these.

Effect of Head Orientation on Human Postural Stability Following Unilateral Vestibular Ablation

1991 ◽  
Vol 1 (2) ◽  
pp. 153-160
Author(s):  
Charles R. Fox ◽  
Gary D. Paige
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Postural Sway ◽  
Normal Subjects ◽  
Head Orientation ◽  
Support Surface ◽  
Eyes Closed ◽  
Vestibular Information ◽  
Postural Equilibrium ◽  
Vestibular Pathology

Effective interpretation of vestibular inputs to postural control requires that orientation of head on body is known. Postural stability might deteriorate when vestibular information and neck information are not properly coupled, as might occur with vestibular pathology. Postural sway was assessed in unilateral vestibulopathic patients before and acutely, 1,4, and 18+ months after unilateral vestibular ablation (UVA) as well as in normal subjects. Postural equilibrium with eyes closed was quantified as scaled pk-pk sway during 20 s trials in which the support surface was modulated proportionally with sway. Subjects were tested with the head upright and facing forward, turned 45∘ right, and 45∘ left. Equilibrium was uninfluenced by head orientation in normal subjects. In contrast, patients after UV A showed both a general reduction in stability and a right/left head orientation-dependent asymmetry. These abnormalities adaptively recovered with time. It is concluded that vestibular inputs to postural control are interpreted within a sensory-motor context of head-on-body orientation.

The role of vestibular and somatosensory systems in intersegmental control of upright stance

2008 ◽  
Vol 18 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Rob Creath ◽  
Tim Kiemel ◽  
Fay Horak ◽  
John J. Jeka
Keyword(s):  
Support Surface ◽  
Light Touch ◽  
Upright Stance ◽  
Rotating Platform ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Eyes Closed ◽  
Intersegmental Dynamics ◽  
Somatosensory Information ◽  
Leg Coordination

Upright stance was perturbed using sinusoidal platform rotations to see how vestibular and somatosensory information are used to control segment and intersegmental dynamics in subjects with bilateral vestibular loss (BVL) and healthy controls (C). Subjects stood with eyes closed on a rotating platform (±1.2° for frequencies ranging from 0.01–0.4 Hz in the presence and absence of light fingertip touch. Trunk movement relative to the platform of BVLs was higher than Cs at higher platform frequencies whereas leg movement relative to the platform was similar for both groups. With the addition of light touch, both groups showed similar trunk and leg segment movement relative to the platform. Trunk-leg coordination was in-phase for frequencies below 1 Hz and anti-phase above 1 Hz. Interestingly, BVLs showed evidence of a "legs-leading-trunk" relationship in the shift from in-phase to anti-phase around 1 Hz. Controls showed no preference for either segment to lead the coordinative shift from in- to anti-phase. The results suggest that the balance instability of BVL subjects stems from high variability of the trunk, rather than the legs. The high trunk variability may emerge from the "legs-leading" intersegmental relationship upon which BVLs rely. Because BVLs derive information about self-orientation primarily from the support surface when their eyes are closed, the legs initiate the shift to anti-phase trunk-leg coordination that is necessary for stable upright stance control. Higher trunk variability suggests that this strategy results in lower overall postural stability. Light touch substitutes for vestibular information, leading to lower trunk variability along with a trunk-leg phase shift similar to controls, without a preference for either segment to lead the shift. The results suggest that vestibulospinal control acts primarily to stabilize the trunk in space and to facilitate intersegmental dynamics.

scholarly journals Correlation between body weight and postural control in healthy individuals using sway meter

2019 ◽  
Vol 16 (2) ◽  
pp. 36-41
Author(s):  
Tharani G ◽  
Vedha Varshini M G ◽  
Senthil Nathan C V ◽  
Mohan Kumar G ◽  
Kamatchi K
Keyword(s):  
Body Weight ◽  
Postural Control ◽  
Body Mass ◽  
Strong Correlation ◽  
Daily Living ◽  
Postural Sway ◽  
The Body ◽  
Healthy Individuals ◽  
Eyes Closed ◽  
Anterior Posterior

BACKGROUND: Postural control is critical for ensuring a safety activity of daily living. Individuals with poor stability are more prone to fall while doing activities of daily living. A certain level of sway is essentially present due to small perturbation within the body during shifting body weight from one to other foot, breathing, etc. The purpose of this study was to analyze the correlation between body mass and postural control in normal, lean and obese individual. AIMS: to analyze the correlation between body mass and postural control in healthy individuals using sway meter. MATERIALS AND METHODS: This is an observational study done with 75 participants. Both male and female healthy individuals between 18-23 years were included in this study. Individuals with any musculoskeletal injuries, neurological conditions, peripheral artery disease and pregnant women were excluded from the study. BMI of each participant was calculated and assigned into three groups. Group A-lean, group B-normal and group C-obese. Postural control was analyzed for each group by using sway meter; level of postural sway was compared between groups A, B C. RESULTS: On comparing mean values of groups A, B and C there was a positive association and strong correlation between body mass index and postural control with eye open and eye closed in anterior, posterior and postural sway towards left between the groups at (P 0.05). However, there was a negative association and weak correlation between BMI and postural control with eye open eye closed in postural sway towards right between the groups at (P 0.05). CONCLUSIONS: This study reveals that there is strong correlation between BMI and postural control. Subjects in eyes closed and eyes opened conditions showed sway in anterior, posterior and left directions but there was less sway towards right side direction.

Bilateral Vestibular Loss Leads to Active Destabilization of Balance During Voluntary Head Turns in the Standing Cat

2006 ◽  
Vol 95 (6) ◽  
pp. 3783-3797 ◽  
Author(s):  
Paul J. Stapley ◽  
Lena H. Ting ◽  
Chen Kuifu ◽  
Dirk G. Everaert ◽  
Jane M. Macpherson
Keyword(s):  
Vertical Axis ◽  
The Body ◽  
Head Turn ◽  
Vestibular Input ◽  
Ipsilateral Side ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Postural Responses ◽  
Postural Imbalance ◽  
Lateral Head

The purpose of this study was to determine the source of postural instability in labyrinthectomized cats during lateral head turns. Cats were trained to maintain the head in a forward orientation and then perform a rapid, large-amplitude head turn to left or right in yaw, while standing freely on a force platform. Head turns were biomechanically complex with the primary movement in the yaw plane accompanied by an ipsilateral ear-down roll and nose-down pitch. Cats used a strategy of pushing off by activating extensors of the contralateral forelimb while using all four limbs to produce a rotational moment of force about the vertical axis. After bilateral labyrinthectomy, the initial components of the head turn and accompanying postural responses were hypermetric, but otherwise similar to those produced before the lesion. However, near the time of peak yaw velocity, the lesioned cats produced an unexpected burst in extensors of the contralateral limbs that thrust the body to the ipsilateral side, leading to falls. This postural error was in the frontal (roll) plane, even though the primary movement was a rotation in the horizontal (yaw) plane. The response error decreased in amplitude with compensation but did not disappear. We conclude that lack of vestibular input results in active destabilization of balance during voluntary head movement. We postulate that the postural imbalance arises from the misperception that the trunk was rolling contralaterally, based on signals from neck proprioceptors in the absence of vestibular inputs.

Precision contact of the fingertip reduces postural sway of individuals with bilateral vestibular loss

1999 ◽  
Vol 126 (4) ◽  
pp. 459-466 ◽  
Author(s):  
J. R. Lackner ◽  
Paul DiZio ◽  
John Jeka ◽  
F. Horak ◽  
David Krebs ◽  
...  
Keyword(s):  
Postural Sway ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss

scholarly journals POSTURAL SWAY IN LOWER EXTREMITY AMPUTEES AND OLDER ADULTS MAY SUGGEST INCREASED FALL RISK IN AMPUTEES

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Hamid Bateni
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Lower Extremity ◽  
Frequency Domain ◽  
Visual Information ◽  
Fall Risk ◽  
Postural Sway ◽  
Proprioceptive Information ◽  
Eyes Closed ◽  
Eyes Open

BACKGROUND: Falls can be detrimental to overall health and quality of life for lower extremity amputees. Most previous studies of postural steadiness focus on quantification of time series variables extracted from postural sway signals. While it has been suggested that frequency domain variables can provide more valuable information, few current studies have evaluated postural sway in amputees using frequency domain variables. OBJECTIVE: To determine time and frequency domain variables of postural sway among lower extremity amputees vs. healthy young and older adult controls. METHODOLOGY: Participants were assigned to 3 groups:  lower extremity amputation (n=6), healthy young adults (n=10), and healthy older adults (n=10). Standing barefoot on a force platform, each individual completed 3 trials of each of 3 standing conditions: eyes open, eyes closed, and standing on a foam balance pad. Time and frequency domain variables of postural sway were computed and analyzed. RESULTS: Comparison of older adults, younger adults, and amputees on the three conditions of standing eyes open, eyes closed, and on foam revealed significant differences between groups. Mean mediolateral (ML) sway distance from the center of pressure (COP), total excursions and sway velocity was significantly higher for amputees and older adults when compared to young adults (p<0.05). Furthermore, power of sway signal was substantially lower for both amputees and older adults. When compared to that of older adults, postural steadiness of amputees was more affected by the eyes closed condition, whereas older adults’ was more affected when sensory and proprioceptive information was perturbed by standing on foam.  CONCLUSION: Our findings showed that fall risk is greater in amputees than in young adults without amputation. Additionally, amputees may rely more heavily on visual information than proprioceptive information for balance, in contrast to older and young adults without amputation.  Layman's Abstract Falls can be detrimental to overall health and quality of life for lower extremity amputees. We evaluated postural sway and concluded that amputees have an increased fall risk and may rely more heavily on visual information for balance than do individuals without amputation. Article PDF Link:https://jps.library.utoronto.ca/index.php/cpoj/article/view/33804/26600 How To Cite: Bateni H. Postural sway in lower extremity amputees and older adults may suggest increased fall risk in amputees. Canadian Prosthetics & Orthotics Journal. 2020;Volume 3, Issue 2, No.4. https://doi.org/10.33137/cpoj.v3i2.33804 Corresponding Author: Hamid Bateni, PhD Physical Therapy Program, School of Allied Health and Communicative Disorders, Northern Illinois University, DeKalb, Illinois, USA.E-mail: [email protected]: https://orcid.org/0000-0001-9083-1817

scholarly journals Vestibulo-sympathetic reflex in patients with bilateral vestibular loss

2019 ◽  
Vol 127 (5) ◽  
pp. 1238-1244
Author(s):  
O. Kuldavletova ◽  
P. Denise ◽  
G. Quarck ◽  
M. Toupet ◽  
H. Normand
Keyword(s):  
Normal Subjects ◽  
Head Position ◽  
Neck Flexion ◽  
Vascular Effect ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Eyes Closed ◽  
Head Positions ◽  
Sympathetic Effect ◽  
Sensory Compensation

This study assessed cardiovascular control during head-down neck flexion (HDNF) in a group of patients suffering from total bilateral idiopathic vestibular loss (BVL) for 7 ± 2 yr. Nine adult patients (age 54 ± 6 yr) with BVL were recruited. Calf blood flow (CBF), mean arterial pressure (MAP), and heart rate (HR) were measured with subjects’ eyes closed in two lying body positions: ventral prone (VP) and lateral (LP) on the left side. Vascular resistance (CVR) was calculated as MAP/CBF. The HDNF protocol consisted in passively changing the head position: head up (HU)–head down (HD)–HU. Measurements were taken twice at each head position. In VP CBF significantly decreased in HD (3.65 ± 0.65 mL·min−1·100 mL−1) vs. HU (4.64 ± 0.71 mL·min−1·100 mL−1) ( P < 0.002), whereas CVR in VP significantly rose in HD (31.87 ± 6.93 arbitrary units) vs. HU (25.61 ± 6.36 arbitrary units) ( P < 0.01). In LP no change in CBF or CVR was found between the two head positions. MAP and HR presented no difference between HU and HD in both body positions. Age of patients did not significantly affect the results. The decrease in CBF of the BVL patients was similar to the decrease observed with the same HDNF protocol in normal subjects. This suggests a sensory compensation for the lost vestibular inputs that could originate from the integration of inputs from trunk graviceptors and proprioceptive and cutaneous receptors. Another possibility is that the HDNF vascular effect is evoked mostly by nonlabyrinthine sensors. NEW & NOTEWORTHY The so-called vestibulo-sympathetic reflex, as demonstrated by the head-down neck flexion (HDNF) protocol, is present in patients with total bilateral vestibular idiopathic loss, equally in young and old subjects. The origin of the sympathetic effect of HDNF is questioned. Moreover, the physiological significance of the vestibulo-sympathetic reflex remains obscure, because it acts in opposition to the orthostatic baroreflex. It may serve to inhibit the excessively powerful baroreflex.

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