The Examination of Body Sway in Normal Subjects and Patients with M�ni�re�s Disease or Cerebellar Dysfunction

2015 ◽  
pp. 166-172 ◽  
Author(s):  
H. Ishizaki ◽  
K. Umemura ◽  
H. Mineta ◽  
M. Nozue ◽  
I. Matsuoka ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Body Sway ◽  
Cerebellar Dysfunction

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.

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)

Cerebellar dysmetria at the elbow, wrist, and fingers

1991 ◽  
Vol 65 (3) ◽  
pp. 563-571 ◽  
Author(s):  
J. Hore ◽  
B. Wild ◽  
H. C. Diener
Keyword(s):  
Small Amplitude ◽  
Peak Velocity ◽  
Normal Subjects ◽  
The Other ◽  
Emg Activity ◽  
Agonist Activity ◽  
Cerebellar Dysfunction ◽  
Antagonist Activity ◽  
Delayed Onset ◽  
The Asymmetry

1. The objective was to investigate in cerebellar patients with dysmetria the kinematic and electromyographic (EMG) characteristics of large and small movements at the elbow, wrist, and finger and thereby to determine the nature of cerebellar dysmetria at distal as well as proximal joints. Flexions were made as fast as possible by moving relatively heavy manipulanda for each joint to the same end position through 5, 30, and 60 degrees. 2. In normal subjects flexions at all joints were accompanied by similar triphasic EMG activity. Movements of increasing amplitude were made with increasing movement durations and increasing durations and magnitudes of initial agonist EMG activity. Antagonist activity often appeared to have two components: one coactive with the initial agonist burst but starting later, the other reaching its peak at about peak velocity. 3. Cerebellar patients with dysmetria showed hypermetria followed by tremor at all three joints when movements were made with the manipulanda. Hypermetria was most marked for aimed movements of small amplitude (5 degrees) at all joints. 4. A characteristic of cerebellar disordered movements, which could be present at all amplitudes and all joints, was an asymmetry with decreased peak accelerations and increased peak decelerations compared to normal movements. Both the asymmetry and the hypermetria for small amplitude movements could be used clinically as sensitive indicators of cerebellar dysfunction. 5. The EMG abnormalities accompanying hypermetria and asymmetry were a more gradual buildup and a prolongation of agonist activity and delayed onset of antagonist activity.(ABSTRACT TRUNCATED AT 250 WORDS)

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

New Neurotological Test for Detecting Cerebellar Dysfunction

1981 ◽  
Vol 90 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Toshiaki Yagi ◽  
Shuji Sekine ◽  
Motohiro Shimizu ◽  
Tomokazu Kamio
Keyword(s):  
Normal Subjects ◽  
High Gain ◽  
Cerebellar Dysfunction ◽  
Ocular Reflex ◽  
Different Types ◽  
Cerebellar Lesions ◽  
Adaptation Task

Adaptation of the vestibule-ocular reflex (VOR) was studied in 26 normal subjects and 15 patients with cerebellar lesions, using horizontal vision-reversal prisms. In normal subjects, adaptation of gain after wearing prisms for one hour was approximately 50% of the VOR value in the dark. In contrast to this, patients with cerebellar lesions showed less adaptation, approximately 20% after a one-hour forced adaptation task. These cases showed three different types of abnormalities: 1) high gain before wearing prisms and normal adaptation, 2) high gain before wearing prisms and reduction of adaptation, 3) normal gain and reduction of adaptation. From these results, it is suggested that observation of the effect of vision-reversal prisms on the VOR may permit the detection of cerebellar lesions of a type or subtlety which escape established tests.

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.

Sensorimotor Integration in Human Postural Control

2002 ◽  
Vol 88 (3) ◽  
pp. 1097-1118 ◽  
Author(s):  
R. J. Peterka
Keyword(s):  
Control System ◽  
Time Delay ◽  
Feedback Control ◽  
Sensorimotor Integration ◽  
Normal Subjects ◽  
Body Sway ◽  
Support Surface ◽  
Stimulus Amplitude ◽  
Stimulus Response ◽  
Response Data

It is generally accepted that human bipedal upright stance is achieved by feedback mechanisms that generate an appropriate corrective torque based on body-sway motion detected primarily by visual, vestibular, and proprioceptive sensory systems. Because orientation information from the various senses is not always available (eyes closed) or accurate (compliant support surface), the postural control system must somehow adjust to maintain stance in a wide variety of environmental conditions. This is the sensorimotor integration problem that we investigated by evoking anterior-posterior (AP) body sway using pseudorandom rotation of the visual surround and/or support surface (amplitudes 0.5–8°) in both normal subjects and subjects with severe bilateral vestibular loss (VL). AP rotation of body center-of-mass (COM) was measured in response to six conditions offering different combinations of available sensory information. Stimulus-response data were analyzed using spectral analysis to compute transfer functions and coherence functions over a frequency range from 0.017 to 2.23 Hz. Stimulus-response data were quite linear for any given condition and amplitude. However, overall behavior in normal subjects was nonlinear because gain decreased and phase functions sometimes changed with increasing stimulus amplitude. “Sensory channel reweighting” could account for this nonlinear behavior with subjects showing increasing reliance on vestibular cues as stimulus amplitudes increased. VL subjects could not perform this reweighting, and their stimulus-response behavior remained quite linear. Transfer function curve fits based on a simple feedback control model provided estimates of postural stiffness, damping, and feedback time delay. There were only small changes in these parameters with increasing visual stimulus amplitude. However, stiffness increased as much as 60% with increasing support surface amplitude. To maintain postural stability and avoid resonant behavior, an increase in stiffness should be accompanied by a corresponding increase in damping. Increased damping was achieved primarily by decreasing the apparent time delay of feedback control rather than by changing the damping coefficient (i.e., corrective torque related to body-sway velocity). In normal subjects, stiffness and damping were highly correlated with body mass and moment of inertia, with stiffness always about 1/3 larger than necessary to resist the destabilizing torque due to gravity. The stiffness parameter in some VL subjects was larger compared with normal subjects, suggesting that they may use increased stiffness to help compensate for their loss. Overall results show that the simple act of standing quietly depends on a remarkably complex sensorimotor control system.

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