Human Ocular Counterrolling During Roll‐Tilt and Centrifugation

MacDougall, Hamish G.; Curthoys, Ian S.; Betts, Grant A.; Burgess, Ann M.; Halmagyi, G. Michael

doi:10.1111/j.1749-6632.1999.tb09183.x

Cited by 38 publications

(23 citation statements)

References 13 publications

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“…OCR likely depends upon the integration of both utricular and saccular signals. Providing identical interaural shear to the otoliths but varying cranio-caudal shear by applying centrifugation or static head roll, centrifugation was found to yield larger ocular torsion (OT) (MacDougall et al 1999), supporting a saccular contribution to OT in humans. De Graaf and colleagues (1996), based on a variety of paradigms stimulating the otoliths, estimated that the utricular contribution to OCR is about three times greater than the saccular contribution.…”

Section: Introductionmentioning

confidence: 92%

Head roll dependent variability of subjective visual vertical and ocular counterroll

2009

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Head roll dependent variability of subjective visual vertical and ocular counterroll Tarnutzer Head roll dependent variability of subjective visual vertical and ocular counterroll AbstractWe compared the variability of the subjective visual vertical (SVV) and static ocular counterroll (OCR), and hypothesized a correlation between the measurements because of their shared macular input. SVV and OCR were measured simultaneously in various whole-body roll positions [upright, 45 degrees right-ear down (RED), and 75 degrees RED] in six subjects. Gains of OCR were -0.18 (45 degrees RED) and -0.12 (75 degrees RED), whereas gains of compensation for body roll in the SVV task were -1.11 (45 degrees RED) and -0.96 (75 degrees RED). Normalized SVV and OCR variabilities were not significantly different (P > 0.05), i.e., both increased with increasing roll. Moreover, a significant correlation (R (2) = 0.80, slope = 0.29) between SVV and OCR variabilities was found. Whereas the gain of OCR is different from the gain of SVV, trial-to-trial variability of OCR follows the same roll-dependent modulation observed in SVV variability. We propose that the similarities in variability reflect a common otolith input, which, however, is subject to distinct central processing for determining the gain of SVV and OCR.

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Section: Introductionmentioning

confidence: 92%

Head roll dependent variability of subjective visual vertical and ocular counterroll

2009

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“…As the saccular sensory epithelium is oriented vertically, activation of the saccule occurs with head rotation in the pitch plane [Fernandez and Goldberg, 1976;Fer- , 1972;MacDougall et al, 1999;Uchino, 1997]. Stimulation of the macula utriculi, lying in the horizontal plane, is elicited by head tilt in the roll direction [Ikegami et al, 1994;Uchino, 1997].…”

Section: Discussionmentioning

confidence: 99%

Otolith Function Assessed with the Subjective Postural Horizontal and Standardised Stance and Gait Tasks

Beule

Allum

2006

Audiol Neurotol

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If otolith function is essential to maintain upright standing while moving along slanted or uneven surfaces, subjects with an otolith deficit should have difficulty judging whether the inclination of the surface on which they are standing is tilted or not. We tested this judgement and compared it with the ability to control trunk sway during standardised stance and gait tests. Thirteen patients with unilateral vestibular nerve neurectomy at least 6 months prior to testing and 39 age-matched controls were asked to move a dynamic posturography platform on which they were standing back to their subjective ‘horizontal’ position after the platform had been slowly tilted at 0.4°/s to 5° in 8 different directions. Normal subjects left the platform deviated in pitch (forwards-backwards) at about 0.7° on describing the platform as levelled off for all directions of tilt. Patients showed larger deviations of about 1.3° in pitch with significant differences for forward right tilt (1.58 ± 0.73° compared to 0.73 ± 0.11° for normals; mean and SEM) and for forward left. Roll (lateral) deviations were about 0.4° for normals and 0.5° larger for the patients (for example, for backward left, 1.13 ± 0.24° compared to 0.4 ± 0.07° in normals). Except for a tendency towards greater deviations to the lesion side of patients with eyes closed, no differences were noted between tests under eyes open and closed conditions. However, for backward and roll tilts patients needed to steady themselves first by grasping a handrail when tested with eyes closed. Stance tests on foam showed increases in roll and pitch trunk sway with respect to controls. Patients had significantly larger trunk roll sway deviations during 1-legged stance tests and during gait trials. For stance trials, the patients lost their balance control prior to the end of the standard 20-second recording time. We conclude that a unilateral loss of otolith inputs due to nerve resection permanently impairs the ability to judge whether the support surface is horizontal, and leads to excessive trunk sway when standing on a compliant surface as well as excessive trunk roll sway during gait.

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“…MacDougall and colleagues compared ocular torsion evoked by two motion paradigms: roll-tilt motions on a tilt-chair and centripetal linear acceleration during constant velocity rotation on a fixed-chair centrifuge (MacDougall et al 1999). The magnitude of the y-axis force component was the same for both paradigms, but the z-axis forces were different.…”

Section: Introductionmentioning

confidence: 97%

Motion Perception During Variable-Radius Swing Motion in Darkness

Rader

Oman

Merfeld

2009

Journal of Neurophysiology

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Using a variable-radius roll swing motion paradigm, we examined the influence of interaural (y-axis) and dorsoventral (z-axis) force modulation on perceived tilt and translation by measuring perception of horizontal translation, roll tilt, and distance from center of rotation (radius) at 0.45 and 0.8 Hz using standard magnitude estimation techniques (primarily verbal reports) in darkness. Results show that motion perception was significantly influenced by both y- and z-axis forces. During constant radius trials, subjects' perceptions of tilt and translation were generally almost veridical. By selectively pairing radius (1.22 and 0.38 m) and frequency (0.45 and 0.8 Hz, respectively), the y-axis acceleration could be tailored in opposition to gravity so that the combined y-axis gravitoinertial force (GIF) variation at the subject's ears was reduced to approximately 0.035 m/s(2) - in effect, the y-axis GIF was "nulled" below putative perceptual threshold levels. With y-axis force nulling, subjects overestimated their tilt angle and underestimated their horizontal translation and radius. For some y-axis nulling trials, a radial linear acceleration at twice the tilt frequency (0.25 m/s(2) at 0.9 Hz, 0.13 m/s(2) at 1.6 Hz) was simultaneously applied to reduce the z-axis force variations caused by centripetal acceleration and by changes in the z-axis component of gravity during tilt. For other trials, the phase of this radial linear acceleration was altered to double the magnitude of the z-axis force variations. z-axis force nulling further increased the perceived tilt angle and further decreased perceived horizontal translation and radius relative to the y-axis nulling trials, while z-axis force doubling had the opposite effect. Subject reports were remarkably geometrically consistent; an observer model-based analysis suggests that perception was influenced by knowledge of swing geometry.

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Human Ocular Counterrolling During Roll‐Tilt and Centrifugation

Cited by 38 publications

References 13 publications

Head roll dependent variability of subjective visual vertical and ocular counterroll

Head roll dependent variability of subjective visual vertical and ocular counterroll

Otolith Function Assessed with the Subjective Postural Horizontal and Standardised Stance and Gait Tasks

Motion Perception During Variable-Radius Swing Motion in Darkness

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