Difference between Visual Feedback and Visual Suppression upon the Stabilization of Body Sway in Normal Subjects

ORL ◽  
1990 ◽  
Vol 52 (4) ◽  
pp. 226-231 ◽  
Author(s):  
N. Ohashi ◽  
M. Asai ◽  
H. Nakagawa ◽  
K. Mizukoshi
Keyword(s):  
Visual Feedback ◽  
Normal Subjects ◽  
Body Sway ◽  
Visual Suppression

EquiTest modification with shank and hip angle measurements: differences with age among normal subjects

1999 ◽  
Vol 9 (6) ◽  
pp. 435-444
Author(s):  
Rosemary A. Speers ◽  
Neil T. Shepard ◽  
Arthur D. Kuo
Keyword(s):  
Age Groups ◽  
Phase Relationship ◽  
Normal Subjects ◽  
Body Sway ◽  
Feedback Signal ◽  
Proprioceptive Information ◽  
Sensory Organization Test ◽  
Test Protocol ◽  
Ankle Motion ◽  
Sensory Organization

The Sensory Organization Test protocol of the EquiTest system (NeuroCom International, Clackamas Oregon) tests utilization of visual, vestibular, and proprioceptive sensors by manipulating the accuracy of visual and/or somatosensory inputs during quiet stance. In the standard Sensory Organization Test, both manipulation of sensory input (sway-referencing) and assessment of postural sway are based on ground reaction forces measured from a forceplate. The purpose of our investigation was to examine the use of kinematic measurements to provide a more direct feedback signal for sway-referencing and for assessment of sway. We compared three methods of sway-referencing: the standard EquiTest method based on ground reaction torque, kinematic feedback based on servo-controlling to shank motion, and a more complex kinematic feedback based on servo-controlling to follow position of the center of mass (COM) as calculated from a two-link biomechanical model. Fifty-one normal subjects (ages 20–79) performed the randomized protocol. When using either shank or COM angle for sway-referencing feedback as compared to the standard EquiTest protocol, the Equilibrium Quotient and Strategy Score assessments were decreased for all age groups in the platform sway-referenced conditions (SOT 4, 5, 6). For all groups of subjects, there were significant differences in one or more of the kinematic sway measures of shank, hip, or COM angle when using either of the alternative sway-referencing parameters as compared to the standard EquiTest protocol. The increased sensitivities arising from use of kinematics had the effect of amplifying differences with age. For sway-referencing, the direct kinematic feedback may enhance ability to reduce proprioceptive information by servo-controlling more closely to actual ankle motion. For assessment, kinematics measurements can potentially increase sensitivity for detection of balance disorders, because it may be possible to discriminate between body sway and acceleration and to determine the phase relationship between ankle and hip motion.

Assessment of transdiaphragmatic pressure in humans

1985 ◽  
Vol 58 (5) ◽  
pp. 1469-1476 ◽  
Author(s):  
D. Laporta ◽  
A. Grassino
Keyword(s):  
Pulmonary Disease ◽  
Visual Feedback ◽  
Random Order ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Disease Group ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Residual Capacity ◽  
Group 1

Maximal force developed by the diaphragm at functional residual capacity is a useful index to establish muscle weakness; however, great disparity in its reproducibility can be observed among reports in the literature. We evaluated five maneuvers to measure maximal transdiaphragmatic pressure (Pdimax) in order to establish best reproducibility and value. Thirty-five naive subjects, including 10 normal subjects (group 1), 12 patients with chronic obstructive pulmonary disease (group 2), and 13 patients with restrictive pulmonary disease (group 3), were studied. Each subject performed five separate maneuvers in random order that were repeated until reproducible values were obtained. The maneuvers were Mueller with (A) and without mouthpiece (B), abdominal expulsive effort with open glottis (C), two-step (maneuver C combined with Mueller effort) (D), and feedback [two-step with visual feedback of pleural (Ppl) and abdominal (Pab) pressure] (E). The greatest reproducible Pdimax values were obtained with maneuver E (P less than 0.01) (group 1: 180 +/- 14 cmH2O). The second best maneuvers were A, B, and D (group 1: 154 +/- 25 cmH2O). Maneuver C produced the lowest values. For all maneuvers, group 1 produced higher values than groups 2 and 3 (P less than 0.001), which were similar. The Ppl to Pdi ratio was 0.6 in maneuvers A and B, 0.4 in D and E, and 0.2 in C. We conclude that visual feedback of Ppl and Pab helped the subjects to elicit maximal diaphragmatic effort in a reproducible fashion. It is likely that the great variability of values in Pdimax previously reported are the result of inadequate techniques.

Does Posturography Differentiate Malingerers from Vertiginous Patients?

1995 ◽  
Vol 5 (2) ◽  
pp. 117-124
Author(s):  
Seija Uimonen ◽  
Kyösti Laitakari ◽  
Heikki Kiukaanniemi ◽  
Martti Sorri
Keyword(s):  
Normal Values ◽  
Normal Subjects ◽  
Vestibular Neuritis ◽  
Body Sway ◽  
Test Situation ◽  
Staff Members ◽  
Static Posturography ◽  
Test Conditions ◽  
The Subject ◽  
Analysis System

Voluntary, simulated vertigo and acute vertigo due to vestibular neuritis were examined by means of static posturography in 81 tests to evaluate the extent to which intentional malingering can be detected. Thirty healthy, normal subjects were first instructed to stand as still as possible on a static force platform and then to simulate dizziness. The true cases consisted of 21 patients with vestibular neuritis. The parameters analyzed included body sway velocity (BSV), body sway area of ellipse (BSE), and the Romberg quotient. Both the simulated and pathological posturographic BSV and BSE values differed from normal values under all test conditions, but they did not differ from each other, whereas the simulated values could be differentiated from the pathological ones with the Romberg quotient based on BSV. Five staff members of our audiological department were able to differentiate between the simulations and pathological cases quite well, with a median sensitivity of 0.77 and a specificity of 0.71 in a blinded test. A posturographic measurement, even performed once, can be useful to some extent for detecting simulation, but more investigation and development of the analysis system is required to obtain more specific results. For the present, the results obtained by trained observation of the subject in the test situation are at least as reliable as those obtained through the analysis of statistical measurements.

Cerebellar control of postural scaling and central set in stance

1994 ◽  
Vol 72 (2) ◽  
pp. 479-493 ◽  
Author(s):  
F. B. Horak ◽  
H. C. Diener
Keyword(s):  
Sensory Information ◽  
Normal Subjects ◽  
Anterior Lobe ◽  
Rate Of Change ◽  
Response Magnitude ◽  
Body Sway ◽  
Magnitude Scaling ◽  
Postural Responses ◽  
Surface Displacements ◽  
Central Set

1. The effects of cerebellar deficits in humans on scaling the magnitude of automatic postural responses based on sensory feedback and on predictive central set was investigated. Electromyographic (EMG) and surface reactive torques were compared in patients with anterior lobe cerebellar disorders and in normal healthy adults exposed to blocks of four velocities and five amplitudes of surface translations during stance. Correlations between the earliest postural responses (integrated EMG and initial rate of change of torque) and translation velocity provided a measure of postural magnitude scaling using sensory information from the current displacement. Correlations of responses with translation amplitude provided a measure of scaling dependent on predictive central set based on sequential experience with previous like displacements because the earliest postural responses occurred before completion of the displacements and because scaling to displacement amplitude disappeared when amplitudes were randomized in normal subjects. 2. Responses of cerebellar patients to forward body sway induced by backward surface displacements were hypermetric, that is, surface-reactive torque responses were two to three times larger than normal with longer muscle bursts resulting in overshooting of initial posture. Despite this postural hypermetria, the absolute and relative latencies of agonist muscle bursts at the ankle, knee, and hip were normal in cerebellar patients. 3. Although they were hypermetric, the earliest postural responses of cerebellar patients were scaled normally to platform displacement velocities using somatosensory feedback. Cerebellar patients, however, were unable to scale initial postural response magnitude to expected displacement amplitudes based on prior experience using central set. Randomization of displacement amplitudes eliminated the set effect of amplitude on initial responses in normal subjects, but responses to randomized and blocked trials were not different in cerebellar patients. 4. Cerebellar patients compensated for hypermetric responses and lack of anticipatory scaling of earliest gastrocnemius activity by scaling large, reciprocally activated tibialis and quadriceps antagonist activity with the displacement velocity and amplitude. Correlations between these antagonist EMG integrals and displacement amplitudes were preserved when amplitudes were randomized, suggesting that feedback-dependent and not set-dependent mechanisms were responsible for scaling of antagonists by cerebellar patients. Antagonist compensation for initial hypermetric responses also could be induced in normals when they overresponded to unexpectedly small amplitudes of surface displacements. 5. The major effects of anterior lobe cerebellar damage on human postural responses involves impairment of response magnitude based on predictive central set and not on use of velocity feedback or on the temporal synergic organization of multijoint postural coordination.(ABSTRACT TRUNCATED AT 400 WORDS)

Vestibulo-Ocular (VOR) Abnormalities at High Rotational Frequencies in Patients with Meniere' Disease

1988 ◽  
Vol 98 (3) ◽  
pp. 211-214 ◽  
Author(s):  
V.S. Dayal ◽  
M. Mai ◽  
R.D. Tomlinson
Keyword(s):  
Visual Feedback ◽  
Low Frequency ◽  
Normal Subjects ◽  
Steady Increase ◽  
Apparent Difference ◽  
Rapid Rise ◽  
Frequency Range ◽  
Meniere Disease ◽  
High Frequencies ◽  
Gaze Stability

Although visual feedback is required to maintain gaze stability during low-frequency rotations (below 1 Hz) because of suboptimal VOR gain in this frequency range, such behavior is not as evident at higher frequencies. Benson1 and Hydén et al.2 noted a steady increase in VOR gain in the higher-frequency range (2 to 5 Hz), where visual feedback has little effect. Similar behavior has also been reported in the monkey models. Eleven patients with diagnoses of Meniere's disease had tests of VOR and VOR cancellations performed with the use of pseudorandom oscillations as high as 5 Hz. The reponses at various frequencies were compared with normal data from 17 subjects. The VOR gain in patients exhibited a more rapid rise at high frequencies than that observed in normal subjects. For example, at 3.5 Hz the normal gain was 1.09, whereas patients exhibited a gain of 1.35 (mean of 11 subjects). When the performance during VOR cancellation tasks was compared, Meniere's patients appeared to be less able to perform these tasks; however, when the values were compared by use of a cancellation index that compensates for any difference in VOR gain, this apparent difference disappeared.

Caloric-Eye Tracking Pattern Test: I. Visual Suppression and the Possibility of Simplified Differential Diagnosis between Peripheral and Central Vertigo

1976 ◽  
Vol 85 (2) ◽  
pp. 261-267 ◽  
Author(s):  
E. Sakata ◽  
Y. Umeda
Keyword(s):  
Differential Diagnosis ◽  
Eye Tracking ◽  
Normal Subjects ◽  
Vestibular Nystagmus ◽  
View Point ◽  
Vestibular Disorder ◽  
Stationary Target ◽  
Visual Suppression ◽  
Suppression Mechanism ◽  
Caloric Nystagmus

During the examination of patients who complain of vertigo or who have equilibrium disorders, it is often difficult to determine the etiology of the disorders, that is, to determine whether it is dependent on a peripheral or central vestibular disorder. To attempt to guess the etiology in these cases, we devised a new method: the caloric eye-tracking pattern test. In normal subjects and in patients with peripheral disorders, as is well known, caloric nystagmus has little influence on the eye-tracking pattern. In contrast, in patients with central vestibular disorders, caloric nystagmus evoked abnormalities on the eye-tracking pattern, either superimposed or saccades, in spite of the fact that the eye-tracking pattern before the caloric stimulation is normal. These findings result from the visual suppression mechanism to the vestibular nystagmus. We can say that the visual suppression to the vestibular nystagmus is evoked more strongly by pursuing a moving visual stimulus than by gazing at a stationary target. These results are interesting, not only from the physiological view point, but also from the clinical view point. There is a possibility of the differential diagnosis between peripheral and central vertigo.

scholarly journals Trunk stabilization during sagittal pelvic tilt: from trunk-on-pelvis to trunk-in-space due to vestibular and visual feedback

2016 ◽  
Vol 115 (3) ◽  
pp. 1381-1388 ◽  
Author(s):  
Paul van Drunen ◽  
Frans C. T. van der Helm ◽  
Jaap H. van Dieën ◽  
Riender Happee
Keyword(s):  
Visual Feedback ◽  
Pelvic Tilt ◽  
Sagittal Plane ◽  
Task Instruction ◽  
Body Sway ◽  
Low Back ◽  
Flexion Extension ◽  
Trunk Sway ◽  
Eyes Open ◽  
Trunk Stabilization

The goal of this study was to investigate the human ability to stabilize the trunk in space during pelvic tilt. Upper body sway was evoked in kneeling-seated healthy subjects by angular platform perturbations with a rotation around a virtual low-back pivot point between the L4 and L5 vertebrae. To investigate motor control modulation, variations in task instruction (balance naturally or minimize trunk sway), vision (eyes open or closed), and perturbation bandwidth (from 0.2 up to 1, 3, or 10 Hz) were applied. Cocontraction and proprioceptive muscle spindle feedback were associated with minimizing low-back flexion/extension (trunk-on-pelvis stabilization), while vestibular and visual feedback were supposed to contribute to trunk-in-space stabilization. Trunk-in-space stabilization was only observed with the minimize trunk sway task instruction, while the task instruction to balance naturally led to trunk-on-pelvis stabilization with trunk rotations even exceeding the perturbations. This indicates that vestibular feedback is used when minimizing trunk sway but has only a minor contribution during natural trunk stabilization in the sagittal plane. The eyes open condition resulted in reduced global trunk rotations and increased global trunk reflexive responses, demonstrating effective visual contributions to trunk-in-space stabilization. On the other hand, increasing perturbation bandwidth caused a decreased feedback contribution leading to deteriorated trunk-in-space stabilization.

Posturography frequency analysis of sound-evoked body sway in normal subjects

2006 ◽  
Vol 263 (3) ◽  
pp. 248-252 ◽  
Author(s):  
Marco Alessandrini ◽  
Roberto Lanciani ◽  
Ernesto Bruno ◽  
Bianca Napolitano ◽  
Stefano Girolamo
Keyword(s):  
Frequency Analysis ◽  
Normal Subjects ◽  
Body Sway

A simple technique to measure body sway in normal subjects and patients with dizziness

1995 ◽  
Vol 109 (3) ◽  
pp. 189-192 ◽  
Author(s):  
N. J. Roland ◽  
C. A. Smith ◽  
I. W. Miller ◽  
A. S. Jones ◽  
T. H. Lesser
Keyword(s):  
Objective Assessment ◽  
Normal Subjects ◽  
Body Sway ◽  
Moving Force ◽  
Ocular Reflex ◽  
Eyes Closed ◽  
Lateral Body ◽  
Vestibulo Ocular Reflex ◽  
Balance Disorder ◽  
Vestibulospinal Reflex

AbstractFor many years vestibular testing has relied on measurements of the vestibulo-ocular reflex (VOR). More recently quantified assessment of balance, using fixed or moving force platforms and magnetometry have been applied to clinical research. These are objective attempts to quantify the vestibulospinal reflex (VSR). This study evaluates whether SwayWeigh, a simple device which measures lateral body sway, can provide an objective assessment of balance dysfunction. Forty patients with a balance disorder and 31 subjects with normal balance were tested with eyes opened and eyes closed whilst they were standing on a flat surface and then on an air bed. The lateral sway in patients with a balance disorder was compared to that in the normal subjects and highly significant differences (p<0.0001) were observed. The results also confirmed the importance of vision and proprioception in the maintenance of posture.The Sway Weigh balance platform is a simple and economical device which objectively measures balance dysfunction.

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