Nature of the Transition Between Two Modes of External Space Perception in Tilted Subjects

2005 ◽  
Vol 93 (6) ◽  
pp. 3356-3369 ◽  
Author(s):  
Ronald G. Kaptein ◽  
Jan A. M. Van Gisbergen
Keyword(s):  
Opposite Sign ◽  
Human Subjects ◽  
Space Perception ◽  
Body Tilt ◽  
Repeated Testing ◽  
Subjective Vertical ◽  
Inverted Position ◽  
Lateral Body ◽  
Visual Vertical ◽  
Response Modes

A striking feature of visual verticality estimates in the dark is undercompensation for lateral body tilt. Earlier studies and models suggest that this so-called Aubert (A) effect increases gradually to around 130° tilt and then decays smoothly on approaching the inverted position. By contrast, we recently found an abrupt transition toward errors of opposite sign (E effect) when body tilt exceeded 135°. The present study was undertaken to clarify the nature of this transition. We tested the subjective visual vertical in stationary roll-tilted human subjects using various rotation paradigms and testing methods. Cluster analysis identified two clearly separate response modes (A or E effect), present in all conditions, which dominated in different but overlapping tilt ranges. Within the overlap zone, the subjective vertical appeared bistable on repeated testing with responses in both categories. The tilt range where bistability occurred depended on the direction of the preceding rotation (hysteresis). The overlap zone shifted to a smaller tilt angle when testing was preceded by a rotation through the inverted position, compared with short opposite rotations from upright. We discuss the possibility that the A-E transition reflects a reference shift from compensating line settings for the head deviation from upright to basing them on the tilt deviation of the feet from upright. In this scenario, both the A and the E effect reflect tilt undercompensation. To explain the hysteresis and the bistability, we propose that the transition is triggered when perceived body tilt, a signal with known noise and hysteresis properties, crosses a fixed threshold.

Interpretation of a Discontinuity in the Sense of Verticality at Large Body Tilt

2004 ◽  
Vol 91 (5) ◽  
pp. 2205-2214 ◽  
Author(s):  
Ronald G. Kaptein ◽  
Jan A. M. Van Gisbergen
Keyword(s):  
Spatial Orientation ◽  
Human Subjects ◽  
Large Body ◽  
Body Tilt ◽  
Head Orientation ◽  
Subjective Visual Vertical ◽  
Egocentric Bias ◽  
Visual Vertical ◽  
Series Of Experiments ◽  
Tilt Signal

Results of earlier spatial-orientation studies focusing on the sense of verticality have emphasized an intriguing paradox. Despite evidence that nearly veridical signals for gravicentric head orientation and egocentric visual stimulus orientation are available, roll-tilted subjects err in the direction of the long body axis when adjusting a visual line to vertical in darkness (Aubert effect). This has led to the suggestion that a central egocentric bias signal with fixed strength and direction acts to pull the perceived vertical to the subjects' zenith (M-model). In the present study, the subjective visual vertical (SVV) was tested in six human subjects, across the entire 360° range. For comparison, body-tilt estimates from four subjects where collected in a separate series of experiments. For absolute tilts up to ∼135°, SVV responses showed a gradually increasing Aubert effect that could not be attributed to errors in perceived body tilt but was nicely in line with the M-model. At larger absolute tilts, SVV errors abruptly reversed sign, now showing a pattern concordant with errors in body-tilt estimates but incompatible with the M-model. These results suggest that, in the normal working range, the perception of external space and the perception of body posture are based on different processing of body-tilt signals. Beyond this range, both spatial-orientation tasks seem to rely mainly on a common tilt signal.

Lateropulsion After Hemispheric Stroke: A Form of Spatial Neglect Involving Graviception

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000011826
Author(s):  
Shenhao Dai ◽  
Céline Piscicelli ◽  
Emmanuelle Clarac ◽  
Monica Baciu ◽  
Marc Hommel ◽  
...  
Keyword(s):  
The Body ◽  
Spatial Neglect ◽  
Body Orientation ◽  
Body Tilt ◽  
Vertical Orientation ◽  
Lateral Body ◽  
Pusher Syndrome ◽  
Visual Vertical ◽  
Straight Ahead ◽  
Cardinal Sign

ObjectiveTo test the hypothesis that lateropulsion is an entity expressing an impaired body orientation with respect to gravity, in relation to a biased graviception and spatial neglect.MethodsData from the DOBRAS cohort (ClinicalTrials.gov:NCT03203109), were collected 30 days after a first hemisphere stroke. Lateral body tilt, pushing and resistance were assessed with the Scale for Contraversive Pushing.ResultsAmong 220 individuals, 72% were Upright and 28% showed lateropulsion (Tilters=14% less severe than Pushers=14%). The three signs had very high factor loadings (>0.90) on a same dimension, demonstrating that lateropulsion was effectively an entity comprising body tilt (cardinal sign), pushing and resistance. The factorial analyses also showed that lateropulsion was inseparable from the visual vertical (VV), a criterion referring to vertical orientation (graviception). Contralesional VV biases were frequent (44%), with a magnitude related to lateropulsion severity: Upright -0.6°(-2.9;2.4), Tilters -2.9°(-7;0.8), Pushers -12.3°(-15.4;-8.5). Ipsilesional VV biases were less frequent and milder (p<0.001). They did not deal with graviception, 84% being found in upright individuals. Multivariate, factorial, contingency, and prediction analyses congruently showed strong similarities between lateropulsion and spatial neglect, the latter encompassing the former.ConclusionsLateropulsion (pusher syndrome) is a trinity constituted by body tilt, pushing and resistance. It is a way to adjust the body orientation in the roll plane to a wrong reference of verticality. Referring to straight above, lateropulsion might correspond to a form of spatial neglect (referring to straight ahead), which would advocate for 3-D maps in the human brain involving the internal model of verticality.

Vestibular Influence on Human Auditory Space Perception

2000 ◽  
Vol 84 (2) ◽  
pp. 1107-1111 ◽  
Author(s):  
Jörg Lewald ◽  
Hans-Otto Karnath
Keyword(s):  
Cold Water ◽  
Human Subjects ◽  
Space Perception ◽  
Median Plane ◽  
Vestibular Stimulation ◽  
Whole Body ◽  
Interaural Level Difference ◽  
Auditory Periphery ◽  
Auditory Space ◽  
Sound Image

We investigated the effect of vestibular stimulation on the lateralization of dichotic sound by cold-water irrigation of the external auditory canal in human subjects. Subjects adjusted the interaural level difference of the auditory stimulus to the subjective median plane of the head. In those subjects in whom dizziness and nystagmus indicated sufficient vestibular stimulation, these adjustments were significantly shifted toward the cooled ear compared with the control condition (irrigation with water at body temperature); i.e., vestibular stimulation induced a shift of the sound image toward the nonstimulated side. The mean magnitude of the shift was 7.3 dB immediately after vestibular stimulation and decreased to 2.5 dB after 5 min. As shown by an additional control experiment, this effect cannot be attributed to a unilateral hearing loss induced by cooling of the auditory periphery. The results indicate the involvement of vestibular afferent information in the perception of sound location during movements of the head and/or the whole body. We thus hypothesize that vestibular information is used by central-nervous mechanisms generating a world-centered representation of auditory space.

Increased Visual Dependence in Parkinson's Disease

2002 ◽  
Vol 95 (3_suppl) ◽  
pp. 1106-1114 ◽  
Author(s):  
Jean Philippe Azulay ◽  
Serge Mesure ◽  
Bernard Amblard ◽  
Jean Pouget
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Gait Analysis ◽  
Visual Information ◽  
Frontal Plane ◽  
Normal Subjects ◽  
Visual Control ◽  
Subjective Vertical ◽  
Visual Vertical ◽  
Visual Dependence

The present study tested the hypothesis that there is increased visual dependence perceptually in patients with Parkinson's disease. We also evaluated whether the visual control of posture and locomotion was related to perceptual visual field dependence. 21 patients with idiopathic Parkinson's disease and 22 age-matched normal subjects were compared on judgment of the visual vertical using the Rod-and-Frame test with visual perturbations in the frontal plane with a tilted frame. Patients had significantly larger errors than controls in the estimation of the subjective vertical. In the same experiment, we performed a posture and a gait analysis in both groups. Posturographic evaluation did not indicate significant differences in unsteadiness between patients and controls. Gait analysis indicated a typical pattern of reduced velocity, shortened stride length, and normal step width. A significant correlation of .89 was found only in the Parkinsonian group between their errors in estimating subjective visual vertical and the Romberg quotient evaluating visual contribution to postural control. No specific locomotor pattern was correlated with visual dependence. Considering our results and previous reports on the visual control of posture, we conclude that patients with Parkinson's disease showed a significantly increased dependence upon visual information both perceptually and motorically, with an increased perceptual visual dependence in the patients being predictive of an equivalent visual dependence or visual control of posture and equilibrium.

Perception of the Visual Horizontal during Lateral Body Tilt: Right-Left Asymmetries

1978 ◽  
Vol 47 (3) ◽  
pp. 715-720 ◽  
Author(s):  
Martin Bauermeister
Keyword(s):  
Body Tilt ◽  
Linear Effect ◽  
Non Linear Effect ◽  
Lateral Body ◽  
Non Linear ◽  
The Right

Subjects, 55 males and 45 females, indicated by means of a luminescent rod the visual horizontal under conditions of lateral body tilt ranging from 10° to 90° to the right and to the left. There was a non-linear effect of the angle of tilt on the degree of deviation of apparent from objective horizontal. With small angles of tilt the apparent horizontal tended to deviate opposite to the direction of body tilt, with larger angles, in the direction of tilt. Uncertainty of judgment increased with increasing angles of tilt.

Localization of the subjective vertical during roll, pitch, and recumbent yaw body tilt

2006 ◽  
Vol 173 (3) ◽  
pp. 364-373 ◽  
Author(s):  
Simone B. Bortolami ◽  
Alberto Pierobon ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Body Tilt ◽  
Subjective Vertical

Body-Tilt and Visual Verticality Perception During Multiple Cycles of Roll Rotation

2008 ◽  
Vol 99 (5) ◽  
pp. 2264-2280 ◽  
Author(s):  
R.A.A. Vingerhoets ◽  
W. P. Medendorp ◽  
J.A.M. Van Gisbergen
Keyword(s):  
Constant Velocity ◽  
Interaction Model ◽  
The Body ◽  
Body Tilt ◽  
Subjective Visual Vertical ◽  
Egocentric Bias ◽  
Leaky Integrator ◽  
Visual Vertical ◽  
Multiple Cycles ◽  
Roll Tilt

To assess the effects of degrading canal cues for dynamic spatial orientation in human observers, we tested how judgments about visual-line orientation in space (subjective visual vertical task, SVV) and estimates of instantaneous body tilt (subjective body-tilt task, SBT) develop in the course of three cycles of constant-velocity roll rotation. These abilities were tested across the entire tilt range in separate experiments. For comparison, we also obtained SVV data during static roll tilt. We found that as tilt increased, dynamic SVV responses became strongly biased toward the head pole of the body axis (A-effect), as if body tilt was underestimated. However, on entering the range of near-inverse tilts, SVV responses adopted a bimodal pattern, alternating between A-effects (biased toward head-pole) and E-effects (biased toward feet-pole). Apart from an onset effect, this tilt-dependent pattern of systematic SVV errors repeated itself in subsequent rotation cycles with little sign of worsening performance. Static SVV responses were qualitatively similar and consistent with previous reports but showed smaller A-effects. By contrast, dynamic SBT errors were small and unimodal, indicating that errors in visual-verticality estimates were not caused by errors in body-tilt estimation. We discuss these results in terms of predictions from a canal-otolith interaction model extended with a leaky integrator and an egocentric bias mechanism. We conclude that the egocentric-bias mechanism becomes more manifest during constant velocity roll-rotation and that perceptual errors due to incorrect disambiguation of the otolith signal are small despite the decay of canal signals.

Analysis of Evoked and Ongoing Electrical Activity at the Scalp of Human Subjects

1965 ◽  
Vol 8 (4) ◽  
pp. 371-387 ◽  
Author(s):  
Donald C. Teas
Keyword(s):  
Electrical Activity ◽  
Background Activity ◽  
Human Subjects ◽  
Low Frequency ◽  
Wide Band ◽  
Repeated Testing ◽  
Eyes Closed ◽  
Band Noise ◽  
The Subject ◽  
Wide Band Noise

Electrical activity at two locations on the scalp (Vertex and Vertex-3 cm, midline) for an experimental design suitable to clinical application, was recorded on magnetic tape. Data from 5 subjects with normal hearing, for 3 testing days, were processed. Average evoked responses to bursts of wide-band noise (30 dB and 50 dB SL) for two conditions (“eyes closed” and “reading”) were computed. The ongoing background activity was processed by computing its interval histogram. The percentage of ongoing activity within the frequency range 1.5 cps to 17 cps was extracted, and the magnitude of the N 1 -P 2 component of average responses was measured. These measures at the two electrode sites were analyzed by calculating analyses of variance for each of the four sets of data. Percentage of low-frequency background activity and N 1 -P 2 magnitude were positively related only for Day 1. A strong habituation effect appeared for Day 2 and Day 3. Habituation reduced differences between the two conditions and also differences between the two signal strengths for the average responses. Maximum N 1 -P 2 magnitude should be recorded for a single test with the subject relaxed and with his “eyes closed.” For repeated testing a discrimination between signals should be required to offset the attenuation of responses by habituation.

scholarly journals Evaluation of subjective vertical perception among stroke patients: a systematic review

2021 ◽  
Vol 79 (11) ◽  
pp. 1026-1034
Author(s):  
Luana Ribeiro Ferreira ◽  
Flávio José Pereira De Almeida Ferreira ◽  
Fernanda Aparecida Campos ◽  
Gustavo José Luvizutto ◽  
Luciane Aparecida Pascucci Sande De Souza
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Web Of Science ◽  
High Variability ◽  
Cochrane Library ◽  
Subjective Visual Vertical ◽  
Stroke Patients ◽  
Subjective Vertical ◽  
Visual Vertical ◽  
Crucial Information

Abstract Background: Verticality misperception is relatively common among patients after stroke, and it may be evaluated in terms of (a) subjective visual vertical (SVV), (b) subjective haptic vertical (SHV) and (c) subjective postural vertical (SPV). To better understand these assessment methods, we conducted a systematic review of the methodological characteristics of different protocols for evaluating SVV, SHV and SPV among individuals after stroke. Objective: To standardize the methodological characteristics of protocols for evaluating verticality perception after stroke. Methods: We searched the following databases: PUBMED, regional BVS portal (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index and LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Cochrane Library and PEDro. Two review authors independently used the QUADAS method (Quality Assessment of Diagnostic Accuracy Studies) and extracted data. Results: We included 21 studies in the review: most (80.9%) used SVV, eight (38.1%) used SPV and four (19.0%) used SHV. We observed high variability in assessments of verticality perception, due to patient positions, devices used, numbers of repetitions and angle of inclination for starting the tests. Conclusion: This systematic review was one of the first to explore all the methods of assessing verticality perception after stroke, and it provides crucial information on how to perform the tests, in order to guide future researchers/clinicians.

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