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Balaban CD, Williams E, Holland CL, Kiderman A, Kontos AP, Hoffer ME. Statistical Considerations for Subjective Visual Vertical and Subjective Visual Horizontal Assessment in Normal Subjects. OTOLOGY & NEUROTOLOGY OPEN 2023; 3:e044. [PMID: 38516545 PMCID: PMC10950168 DOI: 10.1097/ono.0000000000000044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 11/01/2023] [Indexed: 03/23/2024]
Abstract
Objectives Judgments of the subjective visual vertical (SVV) and subjective visual horizontal (SVH) while seated upright are commonly included in standard clinical test batteries for vestibular function. We examined SVV and SVH data from retrospective control to assess their statistical distributions and normative values for magnitudes of the preset effect, sex differences, and fixed-head versus head-free device platforms for assessment. Methods Retrospective clinical SVV and SVH data from 2 test platforms, Neuro-otologic Test Center (NOTC) and the Neurolign Dx 100 (I-Portal Portable Assessment System Nystagmograph) were analyzed statistically (SPSS and MATLAB software) for 408 healthy male and female civilians and military service members, aged 18-50 years. Results No prominent age-related effects were observed. The preset angle effects for both SVV and SVH, and their deviations from orthogonality, agree in magnitude with previous reports. Differences attributable to interactions with device type and sex are of small magnitude. Analyses confirmed that common clinical measure for SVV and SVH, the average of equal numbers of clockwise and counterclockwise preset trials, was not significantly affected by the test device or sex of the subject. Finally, distributional analyses failed to reject the hypothesis of underlying Gaussian distributions for the clinical metrics. Conclusions z scores based on these normative findings can be used for objective detection of outliers from normal functional limits in the clinic.
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Affiliation(s)
- Carey D. Balaban
- Departments of Otolaryngology, Neurobiology, Communication Sciences and Disorders, Bioengineering, and Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA
| | | | - Cynthia L. Holland
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA and Concussion Research Laboratory, UPMC Sports Medicine Concussion Program, University of Pittsburgh Medical Center, Pittsburgh, PA
| | | | - Anthony P. Kontos
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA and Concussion Research Laboratory, UPMC Sports Medicine Concussion Program, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Michael E. Hoffer
- Departments of Otolaryngology
- Neurological Surgery
- Sports Performance and Wellness Institute, University of Miami, Miami, FL
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Cheng Y, Zhang Y, Chen F, Chen Z, Xue T, Zhang Q, Xu M. Virtual reality for the measurement of SVV and SVH during static head tilt in healthy adults: a novel vestibular test. Acta Otolaryngol 2022; 142:291-297. [PMID: 35382691 DOI: 10.1080/00016489.2022.2058082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND AND OBJECTIVE Few previous studies have used virtual-reality (VR) technology to measure subjective visual vertical (SVV) and subjective visual horizontal (SVH) during static head tilt (0°, 30°, 45°, 60° and 90°). We propose a novel vestibular test for measuring the normal range of SVV and SVH during static head tilt in healthy adults. METHODS Eighty healthy adults were included in the study. SVV and SVH were calculated in nine head positions. RESULTS With head tilt 90° to the right, SVV skewed to the right, and SVH skewed upward. With head tilt 90° to the left, SVV skewed to the left, and SVH skewed downward. SVV was asymmetrical only at a head tilt of 90°. SVV and SVH were similar at all degrees of head tilt, except for 30° to the right, 45° to the left, and 0°. CONCLUSIONS VR measurements showed that SVV and SVH differed at various degrees of static head tilt. The standardized protocol proposed here may be used to establish a reference range for utricle function when evaluating acute, unilateral vestibular lesions.
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Affiliation(s)
- Ying Cheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
| | - Yuzhong Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
| | - Feiyun Chen
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
| | - Zichen Chen
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
| | - Tingting Xue
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
| | - Qing Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
- Xinhua Hospital of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Min Xu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China
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Which way is down? Visual and tactile verticality perception in expert dancers and non-experts. Neuropsychologia 2020; 146:107546. [PMID: 32610097 PMCID: PMC7534035 DOI: 10.1016/j.neuropsychologia.2020.107546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/07/2020] [Accepted: 06/22/2020] [Indexed: 11/21/2022]
Abstract
Gravity provides an absolute verticality reference for all spatial perception, allowing us to move within and interact effectively with our world. Bayesian inference models explain verticality perception as a combination of online sensory cues with a prior prediction that the head is usually upright. Until now, these Bayesian models have been formulated for judgements of the perceived orientation of visual stimuli. Here, we investigated whether judgements of the verticality of tactile stimuli follow a similar pattern of Bayesian perceptual inference. We also explored whether verticality perception is affected by the postural and balance expertise of dancers. We tested both the subjective visual vertical (SVV) and the subjective tactile vertical (STV) in ballet dancers and non-dancers. A robotic arm traced downward-moving visual or tactile stimuli in separate blocks while participants held their head either upright or tilted 30° to their right. Participants reported whether these stimuli deviated to the left (clockwise) or right (anti-clockwise) of the gravitational vertical. Tilting the head biased the SVV away from the longitudinal head axis (the classical E-effect), consistent with a failure to compensate for the vestibulo-ocular counter-roll reflex. On the contrary, tilting the head biased the STV toward the longitudinal head axis (the classical A-effect), consistent with a strong upright head prior. Critically, tilting the head reduced the precision of verticality perception, particularly for ballet dancers' STV judgements. Head tilt is thought to increase vestibular noise, so ballet dancers seem to be surprisingly susceptible to degradation of vestibular inputs, giving them an inappropriately high weighting in verticality judgements.
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[The subjective perception of the vertical-a valuable parameter for determination of peripheral vestibular disorder in Menière's disease in the chronic phase?]. HNO 2019; 67:282-292. [PMID: 30725124 DOI: 10.1007/s00106-019-0626-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The perception of verticality is mainly based on utricular afferent signals and central processing of the transmitted signals. However, there are also extracranial receptors that make a considerable contribution to the perception of verticality. With the subjective visual vertical (SVV) for the utricle and the subjective trunk vertical (STV), two different parameters are available that are not fully understood in terms of their response to physiologic and pathologic changes. The aim of this work was to determine SVV and STV under certain positions of the head and trunk as well as under the influence of Menière's disease (MD) as a chronic vestibular disease. In a prospective clinical study, 26 patients with MD and 39 healthy volunteers were recruited. Subjects were examined with C‑SVV glasses and with the three-dimensional trunk excursion chair, while head and torso positions were varied. In both groups, SVV determination is clearly more accurate with an earth-vertical head alignment than with a lateral head tilt (right: MM and control group: p = 0.001; left: MM p = 0.001, control group p = 0.000). If the torso is deflected laterally and the head is held straight, the SVV is significantly more accurate (left p = 0.003, right p = 0.015). The SRV was not affected by the presence of unilateral MD, while pathologic SVV values, if present, indicated the affected side. The results of our study support the assumption that in addition to SVV, SRV is an independent parameter for verticality perception and differs from the SVV in terms of lateralizing a peripheral vestibular deficit. These results suggest that the STV may depend not only on utricular function but also on extracranial afferent signals, and not be significantly altered by the presence of a hydropic peripheral vestibular lesion.
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The habitual motor vertical of humans depends on gravicentric and egocentric cues, but only little on visual cues. Exp Brain Res 2018; 236:2545-2552. [DOI: 10.1007/s00221-018-5316-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/17/2018] [Indexed: 11/26/2022]
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Kheradmand A, Winnick A. Perception of Upright: Multisensory Convergence and the Role of Temporo-Parietal Cortex. Front Neurol 2017; 8:552. [PMID: 29118736 PMCID: PMC5660972 DOI: 10.3389/fneur.2017.00552] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022] Open
Abstract
We inherently maintain a stable perception of the world despite frequent changes in the head, eye, and body positions. Such "orientation constancy" is a prerequisite for coherent spatial perception and sensorimotor planning. As a multimodal sensory reference, perception of upright represents neural processes that subserve orientation constancy through integration of sensory information encoding the eye, head, and body positions. Although perception of upright is distinct from perception of body orientation, they share similar neural substrates within the cerebral cortical networks involved in perception of spatial orientation. These cortical networks, mainly within the temporo-parietal junction, are crucial for multisensory processing and integration that generate sensory reference frames for coherent perception of self-position and extrapersonal space transformations. In this review, we focus on these neural mechanisms and discuss (i) neurobehavioral aspects of orientation constancy, (ii) sensory models that address the neurophysiology underlying perception of upright, and (iii) the current evidence for the role of cerebral cortex in perception of upright and orientation constancy, including findings from the neurological disorders that affect cortical function.
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Affiliation(s)
- Amir Kheradmand
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Otolaryngology – Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ariel Winnick
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Fraser LE, Makooie B, Harris LR. The Subjective Visual Vertical and the Subjective Haptic Vertical Access Different Gravity Estimates. PLoS One 2015; 10:e0145528. [PMID: 26716835 PMCID: PMC4696803 DOI: 10.1371/journal.pone.0145528] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/04/2015] [Indexed: 11/18/2022] Open
Abstract
The subjective visual vertical (SVV) and the subjective haptic vertical (SHV) both claim to probe the underlying perception of gravity. However, when the body is roll tilted these two measures evoke different patterns of errors with SVV generally becoming biased towards the body (A-effect, named for its discoverer, Hermann Rudolph Aubert) and SHV remaining accurate or becoming biased away from the body (E-effect, short for Entgegengesetzt-effect, meaning “opposite”, i.e., opposite to the A-effect). We compared the two methods in a series of five experiments and provide evidence that the two measures access two different but related estimates of gravitational vertical. Experiment 1 compared SVV and SHV across three levels of whole-body tilt and found that SVV showed an A-effect at larger tilts while SHV was accurate. Experiment 2 found that tilting either the head or the trunk independently produced an A-effect in SVV while SHV remained accurate when the head was tilted on an upright body but showed an A-effect when the body was tilted below an upright head. Experiment 3 repeated these head/body configurations in the presence of vestibular noise induced by using disruptive galvanic vestibular stimulation (dGVS). dGVS abolished both SVV and SHV A-effects while evoking a massive E-effect in the SHV head tilt condition. Experiments 4 and 5 show that SVV and SHV do not combine in an optimally statistical fashion, but when vibration is applied to the dorsal neck muscles, integration becomes optimal. Overall our results suggest that SVV and SHV access distinct underlying gravity percepts based primarily on head and body position information respectively, consistent with a model proposed by Clemens and colleagues.
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Affiliation(s)
- Lindsey E. Fraser
- Center for Vision Research, York University, Toronto, Ontario, Canada
- * E-mail:
| | - Bobbak Makooie
- Center for Vision Research, York University, Toronto, Ontario, Canada
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Bury N, Bock O. Role of gravitational versus egocentric cues for human spatial orientation. Exp Brain Res 2015; 234:1013-8. [PMID: 26706040 DOI: 10.1007/s00221-015-4526-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/06/2015] [Indexed: 11/30/2022]
Abstract
Our perception of the vertical depends on allocentric information about the visual surrounds, egocentric information about the own body axis and gravicentric information about the pull of gravity. Previous work has documented that some individuals rely strongly on allocentric information, while others do not, and the present work scrutinizes the existence of yet another dichotomy: We hypothesize that in the absence of allocentric cues, some individuals rely strongly on gravicentric information, while others do not. Twenty-four participants were tested at three angles of body pitch (0° = upright, -90° = supine, -110° = head down) after eliminating visual orientation cues. When asked to adjust a rotating tree '…such that the tree looks right,' nine persons set the tree consistently parallel to gravity, eight consistently parallel to their longitudinal axis and seven switched between these two references; responses mid-between gravity and body axis were rare. The outcome was similar when tactile cues were masked by body vibration, as well as when participants were asked to adjust the tree '… such that leaves are at the top and roots are at the bottom'; the incidence of gravicentric responses increased with the instruction to set the tree '… such that leaves are at the top and roots are at the bottom in space, irrespective of your own position.' We conclude that the perceived vertical can be anchored in gravicentric or in egocentric space, depending on instructions and individual preference.
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Affiliation(s)
- Nils Bury
- Institute of Physiology and Anatomy, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
| | - Otmar Bock
- Institute of Physiology and Anatomy, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany
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9
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Abstract
Sensory systems encode the environment in egocentric (e.g., eye, head, or body) reference frames, creating inherently unstable representations that shift and rotate as we move. However, it is widely speculated that the brain transforms these signals into an allocentric, gravity-centered representation of the world that is stable and independent of the observer's spatial pose. Where and how this representation may be achieved is currently unknown. Here we demonstrate that a subpopulation of neurons in the macaque caudal intraparietal area (CIP) visually encodes object tilt in nonegocentric coordinates defined relative to the gravitational vector. Neuronal responses to the tilt of a visually presented planar surface were measured with the monkey in different spatial orientations (upright and rolled left/right ear down) and then compared. This revealed a continuum of representations in which planar tilt was encoded in a gravity-centered reference frame in approximately one-tenth of the comparisons, intermediate reference frames ranging between gravity-centered and egocentric in approximately two-tenths of the comparisons, and in an egocentric reference frame in less than half of the comparisons. Altogether, almost half of the comparisons revealed a shift in the preferred tilt and/or a gain change consistent with encoding object orientation in nonegocentric coordinates. Through neural network modeling, we further show that a purely gravity-centered representation of object tilt can be achieved directly from the population activity of CIP-like units. These results suggest that area CIP may play a key role in creating a stable, allocentric representation of the environment defined relative to an "earth-vertical" direction.
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10
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Clark TK, Newman MC, Oman CM, Merfeld DM, Young LR. Human perceptual overestimation of whole body roll tilt in hypergravity. J Neurophysiol 2014; 113:2062-77. [PMID: 25540216 DOI: 10.1152/jn.00095.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 12/22/2014] [Indexed: 12/11/2022] Open
Abstract
Hypergravity provides a unique environment to study human perception of orientation. We utilized a long-radius centrifuge to study perception of both static and dynamic whole body roll tilt in hypergravity, across a range of angles, frequencies, and net gravito-inertial levels (referred to as G levels). While studies of static tilt perception in hypergravity have been published, this is the first to measure dynamic tilt perception (i.e., with time-varying canal stimulation) in hypergravity using a continuous matching task. In complete darkness, subjects reported their orientation perception using a haptic task, whereby they attempted to align a hand-held bar with their perceived horizontal. Static roll tilt was overestimated in hypergravity, with more overestimation at larger angles and higher G levels, across the conditions tested (overestimated by ∼35% per additional G level, P < 0.001). As our primary contribution, we show that dynamic roll tilt was also consistently overestimated in hypergravity (P < 0.001) at all angles and frequencies tested, again with more overestimation at higher G levels. The overestimation was similar to that for static tilts at low angular velocities but decreased at higher angular velocities (P = 0.006), consistent with semicircular canal sensory integration. To match our findings, we propose a modification to a previous Observer-type canal-otolith interaction model. Specifically, our data were better modeled by including the hypothesis that the central nervous system treats otolith stimulation in the utricular plane differently than stimulation out of the utricular plane. This modified model was able to simulate quantitatively both the static and the dynamic roll tilt overestimation in hypergravity measured experimentally.
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Affiliation(s)
- Torin K Clark
- Man Vehicle Laboratory, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts; Charles Stark Draper Laboratory, Incorporated, Cambridge, Massachusetts;
| | - Michael C Newman
- National Aerospace Training and Research Center, Southampton, Pennsylvania; and
| | - Charles M Oman
- Man Vehicle Laboratory, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Daniel M Merfeld
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts
| | - Laurence R Young
- Man Vehicle Laboratory, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts
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Kheradmand A, Lasker A, Zee DS. Transcranial magnetic stimulation (TMS) of the supramarginal gyrus: a window to perception of upright. Cereb Cortex 2013; 25:765-71. [PMID: 24084127 DOI: 10.1093/cercor/bht267] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although the pull of gravity, primarily detected by the labyrinth, is the fundamental input for our sense of upright, vision and proprioception must also be integrated with vestibular information into a coherent perception of spatial orientation. Here, we used transcranial magnetic stimulation (TMS) to probe the role of the cortex at the temporal parietal junction (TPJ) of the right cerebral hemisphere in the perception of upright. We measured the perceived vertical orientation of a visual line; that is, the subjective visual vertical (SVV), after a short period of continuous theta burst stimulation (cTBS) with the head upright. cTBS over the posterior aspect of the supramarginal gyrus (SMGp) in 8 right-handed subjects consistently tilted the perception of upright when tested with the head tilted 20° to either shoulder (right: 3.6°, left: 2.7°). The tilt of SVV was always in the direction opposite to the head tilt. On the other hand, there was no significant tilt after sham stimulation or after cTBS of nearby areas. These findings suggest that a small area of cerebral cortex--SMGp--has a role in processing information from different sensory modalities into an accurate perception of upright.
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Affiliation(s)
- Amir Kheradmand
- Department of Neurology Department of Otolaryngology-Head and Neck Surgery
| | | | - David S Zee
- Department of Neurology Department of Otolaryngology-Head and Neck Surgery Department of Ophthalmology Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Tarnutzer AA, Fernando DP, Kheradmand A, Lasker AG, Zee DS. Temporal constancy of perceived direction of gravity assessed by visual line adjustments. J Vestib Res 2012; 22:41-54. [PMID: 22699152 DOI: 10.3233/ves-2011-0436] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Here we investigated how well internal estimates of direction of gravity are preserved over time and if the subjective visual vertical (SVV) and horizontal (SVH) can be used inter-changeably. Fourteen human subjects repetitively aligned a luminous line to SVV, SVH or subjective visual oblique (± 45°) over 5 min in otherwise complete darkness and also in dim light. Both accuracy (i.e., the degree of veracity as reflected by the median adjustment error) and precision (i.e., the degree of reproducability as reflected by the trial-to-trial variability) of adjustments along the principle axes were significantly higher than along the oblique axes. Orthogonality was only preserved in a minority of subjects. Adjustments were significantly different between SVV vs. SVH (7/14 subjects) and between ±45° vs. -45° (12/14) in darkness and in 6/14 and 14/14 subjects, respectively, in dim light. In darkness, significant drifts over 5min were observed in a majority of trials (33/56). Both accuracy and precision were higher if more time was taken to make the adjustment. These results introduce important caveats when interpreting studies related to graviception. The test re-test reliability of SVV and SVH can be influenced by drift of the internal estimate of gravity. Based on spectral density analysis we found a noise pattern consistent with 1/fβ noise, indicating that at least part of the trial-to-trial dynamics observed in our experiments is due to the dependence of the serial adjustments over time. Furthermore, using results from the SVV and SVH inter-changeably may be misleading as many subjects do not show orthogonality. The poor fidelity of perceived ± 45° indicates that the brain has limited ability to estimate oblique angles.
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Affiliation(s)
- A A Tarnutzer
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Tarnutzer AA, Fernando DP, Lasker AG, Zee DS. How stable is perceived direction of gravity over extended periods in darkness? Exp Brain Res 2012; 222:427-36. [PMID: 23053369 DOI: 10.1007/s00221-012-3230-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/11/2012] [Indexed: 11/24/2022]
Abstract
Previous studies reported linear drift of perceived vertical for brief (≤10 min) observation periods. Here, we repeated estimates of direction of gravity up to 60 min to evaluate whether the drift is sustained, shows saturation or even reverses over time. Fifteen healthy human subjects repetitively adjusted a luminous line along subjective visual vertical (SVV) and horizontal (SVH) over periods of 5 min (constituting one block). We obtained seven blocks within 60 min in each subject for SVV and SVH. In between the first six blocks, subjects remained in darkness for 5 min each, whereas the lights were briefly turned on before block 7. We noted significantly (p < 0.05) increased errors in perceived direction of gravity by block 2 (SVV) and 3 (SVH). These increases disappeared after turning on the lights before block 7. Focusing on blocks 2-6, significant drift started from similar offset positions and pointed to the same direction in a majority of runs in 9/15 (SVV) and 11/15 (SVH) subjects. When pooling data from all blocks, orthogonality of errors was lost in all subjects. Trial-to-trial variability remained stable over the seven runs for SVV and SVH. Only when pooling all runs, precision was significantly (p < 0.05) higher for the SVH. Our findings suggest that perceived direction of gravity continues to fluctuate over extended recording periods with individuals showing unique patterns of direction-specific drift while variability remains stable. As subjects were upright during the entire experiment and as drift persisted over several blocks, sensory adaptation seems unlikely. We therefore favor a central origin of this kind of drift.
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Affiliation(s)
- A A Tarnutzer
- Department of Neurology, The Johns Hopkins University School of Medicine, Path 2-210, 600 N. Wolfe St., Baltimore, MD 21201, USA.
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Perception of subjective visual vertical and horizontal in patients with chronic neck pain: a cross-sectional observational study. ACTA ACUST UNITED AC 2011; 17:133-8. [PMID: 22182696 DOI: 10.1016/j.math.2011.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 10/31/2011] [Accepted: 11/08/2011] [Indexed: 11/21/2022]
Abstract
Previous studies have shown that chronic neck pain (CNP) patients have a larger spread of perceptual errors for subjective visual vertical (SVV) than those exhibited by asymptomatic controls. The current study investigated whether this was also the case for perception of subjective visual horizontal (SVH) and whether there was a correlation between the two measurements. Fifty patients with CNP were compared with a group of 50 age- and gender-matched controls. All subjects were required to complete a test to measure SVH as well as SVV using the computerised rod and frame (CRAF) test. These tests were conducted under various frame conditions. No difference was found between the errors of the CNP and control groups in the absence of a surrounding frame. When a tilted frame was added to the CRAF test, the range of errors observed in the CNP group increased for both SVV and SVH. In particular, significantly more CNP patients fell outside the reference range of errors and a subgroup of patients, characterised by higher neck pain disability indices, was identified who demonstrated higher than expected errors for both SVV and SVH. However no conclusion could be drawn with regards to the direction of error asymmetry and laterality of pain as those patients with unilateral pain exhibited errors both towards and away from the affected area.
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Postural configuration affects the perception of earth-based space during pitch tilt. Acta Psychol (Amst) 2011; 138:119-25. [PMID: 21664588 DOI: 10.1016/j.actpsy.2011.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 05/22/2011] [Accepted: 05/24/2011] [Indexed: 11/20/2022] Open
Abstract
This study investigates the relative contribution of body parts in the elaboration of a whole-body egocentric attraction phenomenon previously observed during earth-based judgments. This was addressed through a particular earth-based task requiring estimating the possibility of passing under a projected line, imagining a forward horizontal displacement. Different postural configurations were tested, involving whole-body tilt, trunk tilt alone or head tilt alone. Two legs positions relative to the trunk were manipulated. Results showed systematic deviations of the subjective "passability" toward the tilt, linearly related to the tilt magnitude. For each postural configuration, the egocentric influence appeared to be highly dependent on the position of trunk and head axes, whereas the legs position appeared not relevant. When compared to the whole-body tilt condition, tilting the trunk alone consistently reduced the amount of the deviation toward the tilt, whereas tilting the head alone consistently increased it. Our results suggest that several specific effects from multiple body parts can account for the global deviation of the estimates observed during whole-body tilt. Most importantly, we support that the relative contribution of the body segments could mainly depend on a reweighting process, probably based on the reliability of sensory information available for a particular postural set.
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Schuler JR, Bockisch CJ, Straumann D, Tarnutzer AA. Precision and accuracy of the subjective haptic vertical in the roll plane. BMC Neurosci 2010; 11:83. [PMID: 20630097 PMCID: PMC2912915 DOI: 10.1186/1471-2202-11-83] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 07/14/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND When roll-tilted, the subjective visual vertical (SVV) deviates up to 40 degrees from earth-vertical and trial-to-trial variability increases with head roll. Imperfections in the central processing of visual information were postulated to explain these roll-angle dependent errors. For experimental conditions devoid of visual input, e.g. adjustments of body posture or of an object along vertical in darkness, significantly smaller errors were noted. Whereas the accuracy of verticality adjustments seems to depend strongly on the paradigm, we hypothesize that the precision, i.e. the inverse of trial-to-trial variability, is less influenced by the experimental setup and mainly reflects properties of the otoliths. Here we measured the subjective haptic vertical (SHV) and compared findings with previously reported SVV data. Twelve healthy right-handed human subjects (handedness assessed based on subjects' verbal report) adjusted a rod with the right hand along perceived earth-vertical during static head roll-tilts (0-360 degrees , steps of 20 degrees ). RESULTS SHV adjustments showed a tendency for clockwise rod rotations to deviate counter-clockwise and for counter-clockwise rod rotations to deviate clockwise, indicating hysteresis. Clockwise rod rotations resulted in counter-clockwise shifts of perceived earth-vertical up to -11.7 degrees and an average counter-clockwise SHV shift over all roll angles of -3.3 degrees (+/- 11.0 degrees ; +/- 1 StdDev). Counter-clockwise rod rotations yielded peak SHV deviations in clockwise direction of 8.9 degrees and an average clockwise SHV shift over all roll angles of 1.8 degrees (+/- 11.1 degrees ). Trial-to-trial variability was minimal in upright position, increased with increasing roll (peaking around 120-140 degrees ) and decreased to intermediate values in upside-down orientation. Compared to SVV, SHV variability near upright and upside-down was non-significantly (p > 0.05) larger; both showed an m-shaped pattern of variability as a function of roll position. CONCLUSIONS The reduction of adjustment errors by eliminating visual input supports the notion that deviations between perceived and actual earth-vertical in roll-tilted positions arise from central processing of visual information. The shared roll-tilt dependent modulation of trial-to-trial variability for both SVV and SHV, on the other hand, indicates that the perception of earth-verticality is dominated by the same sensory signal, i.e. the otolith signal, independent of whether the line/rod setting is under visual or tactile control.
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Affiliation(s)
- Jeanine R Schuler
- Department of Neurology, Zurich University Hospital, Zurich, Switzerland
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Lejeune L, Thouvarecq R, Anderson DJ, Caston J, Jouen F. Kinaesthetic and visual perceptions of orientations. Perception 2010; 38:988-1001. [PMID: 19764301 DOI: 10.1068/p6132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In the present study we compare the kinaesthetic and visual perception of the vertical and horizontal orientations (subjective vertical and subjective horizontal) to determine whether the perception of cardinal orientations is amodal or modality-specific. The influence of methodological factors on the accuracy of perception is also investigated by varying the stimulus position as a function of its initial tilt (clockwise or counterclockwise) and its angle (22 degrees, 45 degrees, 67 degrees, and 90 degrees) in respect to its physical orientation. Ten participants estimated the vertical and horizontal orientations by repositioning a rod in the kinaesthetic condition or two luminous points, forming a 'virtual line' in the visual condition. Results within the visual modality replicated previous findings by showing that estimation of the physical orientations is very accurate regardless of the initial position of the virtual line. In contrast, the perception of orientation with the kinaesthetic modality was less accurate and systematically influenced by the angle between the initial position of the rod and the required orientation. The findings question the assumption that the subjective vertical is derived from an internal representation of gravity and highlight the necessity of taking into account methodological factors in studies on subjective orientations.
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Affiliation(s)
- Laure Lejeune
- Information, Organisation et Action, EA 4260, UFR STAPS, University of Caen Basse Normandie, 14032 Caen Cedex, France.
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Docherty S, Bagust J. From line to dots: an improved computerised rod and frame system for testing subjective visual vertical and horizontal. BMC Res Notes 2010; 3:9. [PMID: 20205858 PMCID: PMC2826355 DOI: 10.1186/1756-0500-3-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 01/19/2010] [Indexed: 11/10/2022] Open
Abstract
Background Perception of subjective visual vertical (SVV) and horizontal (SVH) has traditionally been measured by rotating a mechanical rod either with or without a frame present. The computerised rod and frame (CRAF) system has previously only been used to measure SVV. We have expanded the use of this system by testing its feasibility to measure SVH. This was done by comparing two groups of subjects (n = 103) randomly assigned to be tested for SVV or SVH. Findings Preliminary results showed a higher than expected percentage of individuals with SVH errors < 0.5°. This was attributed to additional visual cues provided by the changing appearance of the rod as it approached the horizontal. A solution to this problem was sought by replacing the rod by two dots to mark its ends. In a second investigation 30 subjects were tested using both the "rod as line" and "rod as dots" presentation. Bland and Altman analysis showed no difference between the rod and dots presentations in the measurement of SVV, but confirmed a fixed error of -0.93° between rods and dots for SVH. Changing the rod from a line to dots in the computer system resulted in errors for both SVV and SVH that were comparable to previous studies using manual systems. Conclusions The computerized rod and frame system may be improved by replacement of the line with two dots. This reduces clues provided to the subject by the appearance of the rod on the screen.
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Tarnutzer AA, Bockisch CJ, Straumann D. Roll-dependent modulation of the subjective visual vertical: contributions of head- and trunk-based signals. J Neurophysiol 2009; 103:934-41. [PMID: 20018837 DOI: 10.1152/jn.00407.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Precision and accuracy of the subjective visual vertical (SVV) modulate in the roll plane. At large roll angles, systematic SVV errors are biased toward the subject's body-longitudinal axis and SVV precision is decreased. To explain this, SVV models typically implement a bias signal, or a prior, in a head-fixed reference frame and assume the sensory input to be optimally tuned along the head-longitudinal axis. We tested the pattern of SVV adjustments both in terms of accuracy and precision in experiments in which the head and the trunk reference frames were not aligned. Twelve subjects were placed on a turntable with the head rolled about 28 degrees counterclockwise relative to the trunk by lateral tilt of the neck to dissociate the orientation of head- and trunk-fixed sensors relative to gravity. Subjects were brought to various positions (roll of head- or trunk-longitudinal axis relative to gravity: 0 degrees , +/-75 degrees ) and aligned an arrow with perceived vertical. Both accuracy and precision of the SVV were significantly (P < 0.05) better when the head-longitudinal axis was aligned with gravity. Comparing absolute SVV errors for clockwise and counterclockwise roll tilts, statistical analysis yielded no significant differences (P > 0.05) when referenced relative to head upright, but differed significantly (P < 0.001) when referenced relative to trunk upright. These findings indicate that the bias signal, which drives the SVV toward the subject's body-longitudinal axis, operates in a head-fixed reference frame. Further analysis of SVV precision supports the hypothesis that head-based graviceptive signals provide the predominant input for internal estimates of visual vertical.
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Affiliation(s)
- A A Tarnutzer
- Neurology Department, Zurich University Hospital, Frauenklinikstrasse 26, CH-8091 Zurich, Switzerland.
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Pagarkar W, Bamiou D, Ridout D, Luxon L. Repeatability of the Subjective Visual Vertical and Horizontal. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/16513860500239580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Carriot J, DiZio P, Nougier V. Vertical frames of reference and control of body orientation. Neurophysiol Clin 2008; 38:423-37. [DOI: 10.1016/j.neucli.2008.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 09/10/2008] [Indexed: 11/28/2022] Open
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Goonetilleke SC, Mezey LE, Burgess AM, Curthoys IS. On the relation between ocular torsion and visual perception of line orientation. Vision Res 2008; 48:1488-96. [DOI: 10.1016/j.visres.2008.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 03/20/2008] [Accepted: 03/25/2008] [Indexed: 10/22/2022]
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23
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Bortolami SB, Pierobon A, DiZio P, Lackner JR. Localization of the subjective vertical during roll, pitch, and recumbent yaw body tilt. Exp Brain Res 2006; 173:364-73. [PMID: 16628401 DOI: 10.1007/s00221-006-0385-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 01/13/2006] [Indexed: 10/24/2022]
Abstract
Localization of the subjective vertical during body tilt in pitch and in roll has been extensively studied because of the relevance of these axes for aviation and control of posture. Studies of yaw orientation relative to gravity are lacking. Our goal was to perform the first thorough evaluation of static orientation in recumbent yaw and to collect as efficiently as possible roll and pitch orientation data which would be consistent with the literature, using the same technique as our yaw tests. This would create the first comprehensive, coherent data set for all three axes suitable for quantitative tri-dimensional modeling of spatial orientation. We tested localization of the vertical for subjects tilted in pitch (-100 degrees to +130 degrees ), in roll (-90 degrees to +90 degrees ), and in yaw while recumbent (-80 degrees to +80 degrees ). We had subjects point a gravity-neutral probe to the gravitational vertical (haptically indicated vertical) and report verbally their perceived tilt. Subjects underestimated their body tilts in recumbent yaw and pitch and overestimated their tilts in roll. The haptic settings for pitch and roll were consistent with data in the literature obtained with haptic and visual indications. Our data constitute the first tri-dimensional assessment of the subjective vertical using a common measurement procedure and provide the basis for the tri-axial modeling of vestibular function presented in the companion paper.
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Affiliation(s)
- Simone B Bortolami
- Ashton Graybiel Spatial Orientation Laboratory, MS 033, Brandeis University, Waltham, MA 02454-9110, USA.
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24
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Bertulis A, Bulatov A. Distortions in length perception: visual field anisotropy and geometrical illusions. ACTA ACUST UNITED AC 2005; 35:423-34. [PMID: 15929571 DOI: 10.1007/s11055-005-0043-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Psychometric experiments were performed to study the effects of visual field anisotropy and geometrical illusions on the accuracy of comparison of objects in terms of length. Stimuli consisting of V-shaped symbols were used, made up of three light spots or one spot plus components of illusory figures, which were pairs of Müller-Layer wings or an interval of the Oppel-Kundt figure filled with spots of light. Relationships between the length comparison errors and the orientations of the reference and test parts of the stimulus were obtained. The experimental data showed that the simultaneous appearance of illusions and visual field anisotropy can be summed algebraically.
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Affiliation(s)
- A Bertulis
- Kaunas Medical University, 9 Mitskyavichaus, Kaunas 3000, Lithuania
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25
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26
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Hafström A, Fransson PA, Karlberg M, Magnusson M. Idiosyncratic compensation of the subjective visual horizontal and vertical in 60 patients after unilateral vestibular deafferentation. Acta Otolaryngol 2004; 124:165-71. [PMID: 15072418 DOI: 10.1080/00016480410016630] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To investigate long-term compensation mechanisms of utricular function after translabyrinthine surgery for vestibular schwannoma. Correlations between the subjective visual horizontal (SVH) and subjective visual vertical (SVV) and other parameters of vestibular compensation were studied. The correlation between the SVH and SVV was also investigated to see whether these measurements are compatible for patients. MATERIAL AND METHODS Sixty consecutive patients were investigated 3 months before and 6 months after surgery by means of electronystagmography and SVH and SVV tests. Tumor size was measured using MRI. RESULTS The SVH and SVV increased significantly towards the ipsilesional side postoperatively. Preoperative tilt correlated with age. Postoperative tilt correlated weakly with preoperative caloric sensitivity and inversely with tumor size. The correlation between the SVH and SVV was high both before and after surgery (r(s) > 0.74; p < 0.001). CONCLUSIONS The long-term compensation of static tilt perception was dependent on age and not on dynamic canal functions. We propose an idiosyncrasy in the SVH and SVV compensation after unilateral vestibular deafferentation, incongruous with the general course of vestibular compensation. The results suggest a probable dependence on non-vestibular information, i.e. proprioception, in facilitating compensation of static vestibular deficits. The similarity between the SVH and SVV measurements confirms that either test can be used clinically for patients with vestibular lesions.
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Affiliation(s)
- Anna Hafström
- Department of Otorhinolaryngology, Head and Neck Surgery, Lund University Hospital, Sweden.
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27
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Mezey LE, Curthoys IS, Burgess AM, Goonetilleke SC, MacDougall HG. Changes in ocular torsion position produced by a single visual line rotating around the line of sight––visual “entrainment” of ocular torsion. Vision Res 2004; 44:397-406. [PMID: 14659966 DOI: 10.1016/j.visres.2003.09.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A large- or full-field visual stimulus slowly rotating around the naso-occipital axis of an observer causes both eyes to tort, and many of the factors controlling this optokinetic torsional response have been identified. The present study reports that a single line rotating about the line of sight can cause both eyes to tort in the same direction as the stimulus but with a low gain. We have used the term 'entrainment' to describe this torsional response. This paper reports some of the factors associated with entrainment. Video measures of 3-d eye position were recorded while the subject made settings of a simple visual line to subjective visual horizontal (SVH) and vertical (SVV) using the standard method-of-adjustment paradigm. The visual line was composed of 11 light-emitting diodes; the line subtended a visual angle of 19 degrees, and moved at a constant speed of 4.8 degrees /s. Settings were made in an otherwise darkened room, and also in the light. Subjects were required to maintain fixation of the central LED while making settings from starting positions 10 or 20 degrees either side of gravitational horizontal or vertical. We show that entrainment of ocular torsion by the single moving visual line is low in gain but a reliable and repeatable effect and that (1) there are considerable individual differences between subjects but within-subject consistency, (2) all subjects show larger and more consistent torsional entrainment for lines moving to SVH than lines moving to SVV, (3) the strongest entrainment generally occurs within about 10 degrees of the target position, and (4) entrainment is also present in the light, though with slightly reduced gain.
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Affiliation(s)
- Laura E Mezey
- School of Psychology, A19, University of Sydney, Sydney, NSW 2006, Australia
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28
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Hoppenbrouwers M, Wuyts FL, Van de Heyning PH. Suppression of the E-effect during the subjective visual vertical test. Neuroreport 2004; 15:325-7. [PMID: 15076762 DOI: 10.1097/00001756-200402090-00023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The subjective visual vertical was measured in 38 healthy subjects. The head was alternately roll-tilted to the right and to the left, and the start position of the light bar was alternately set clockwise and counterclockwise. When the head is tilted less than 60-70 degrees a deviation of the subjective visual vertical in the opposite direction to the head tilt is expected. This phenomenon has been reported in various studies as the E-effect. The present study demonstrates however that the E-effect is suppressed if the start position of the light bar is presented relatively parallel to the length axis of the tilted head.
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Affiliation(s)
- Mieke Hoppenbrouwers
- Vestibular Function Laboratory, Dept of ENT, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem, Belgium
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29
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McKenna GJ, Peng GCY, Zee DS. Neck muscle vibration alters visually perceived roll in normals. J Assoc Res Otolaryngol 2003; 5:25-31. [PMID: 14569429 PMCID: PMC2538369 DOI: 10.1007/s10162-003-4005-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2003] [Accepted: 07/24/2003] [Indexed: 12/20/2022] Open
Abstract
The objective of this study was to determine whether vibration of dorsal neck muscles or of the mastoid bone or of both modified the perception of visual orientation in the head roll-tilt plane in normal subjects. Measurements of the subjective visual vertical (SVV) were obtained from 26 normal human subjects. Subjects reported the SVV in the upright and in the left and right 30 degrees static head roll-tilt positions. Subjects then reported the SVV while vibration was applied to the left or right dorsal neck or left or right mastoid. Both head position and vibration independently modified settings of the SVV. In head-tilted positions, vibration of the upper dorsal neck muscles (on the side of the head opposite to the head tilt) caused a significantly greater shift of the SVV in the opposite direction of head roll-tilt compared to vibration of the lower dorsal neck muscles or of the mastoid. These results support a role for cervical somatosensory information in perception of visual orientation in the roll plane. Our findings may help explain the differences observed in visual orientation perception in normal subjects between head alone and whole-body roll-tilt. Finally, vibration of neck muscles in the head roll-tilted plane may be a useful method to test cervical somatosensory function possibly by increasing their response to external stimulation.
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Affiliation(s)
- George J McKenna
- Department of Neurology, National Naval Medical Center, Bethesda, MD 20889, USA.
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30
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Pavlou M, Wijnberg N, Faldon ME, Bronstein AM. Effect of semicircular canal stimulation on the perception of the visual vertical. J Neurophysiol 2003; 90:622-30. [PMID: 12649316 DOI: 10.1152/jn.00960.2002] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
UNLABELLED The subjective visual vertical (SVV) is usually considered a measure of otolith function. Herewith we investigate the influence of semicircular canal (SCC) stimulation on the SVV by rotating normal subjects in yaw about an earth-vertical axis, with velocity steps of +/- 90 degrees /s, for 60 s. SVV was assessed by setting an illuminated line to perceived earth vertical in darkness, during a per- and postrotary period. Four head positions were tested: upright, 30 degrees backward (chin up) or forward, and approximately 40 degrees forward from upright. During head upright/backward conditions, a significant SVV tilt (P < 0.01) in the direction opposite to rotation was found that reversed during postrotary responses. The rotationally induced SVV tilt had a time constant of decay of approximately 30 s. Rotation with the head 30 degrees forward did not affect SVV, whereas the 40 degrees forward tilt caused a direction reversal of SVV responses compared with head upright/backward. Spearman correlation values (Rho) between individual SCC efficiencies in different head positions and mean SVV tilts were 0.79 for posterior, 0.34 for anterior, and - 0.80 for horizontal SCCs. Three-dimensional video-oculography showed that SVV and torsional eye position measurements were highly correlated (0.83) and in the direction opposite to the slow phase torsional vestibuloocular reflex. IN CONCLUSION 1) during yaw axis rotation without reorientation of the head with respect to gravity, the SVV is influenced by SCC stimulation; 2) this effect is mediated by the vertical SCCs, particularly the posterior SCCs; 3) rotationally induced SVV changes are due to torsional ocular tilt; 4) SVV and ocular tilts occur in the "anticompensatory," fast phase direction of the torsional nystagmus; and 5) clinically, abnormal SVV tilts cannot be considered a specific indication of otolith system dysfunction.
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Affiliation(s)
- Marousa Pavlou
- Academic Department of Neuro-Otology, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, Imperial College London, Charing Cross Hospital, London W6 8RF, United Kingdom
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Jaggi-Schwarz K, Hess BJM. Influence of dynamic tilts on the perception of earth-vertical. Exp Brain Res 2003; 149:340-50. [PMID: 12632236 DOI: 10.1007/s00221-002-1343-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2002] [Accepted: 11/06/2002] [Indexed: 11/28/2022]
Abstract
The aim of this study was to test the hypothesis that optimal activation of both the semicircular canals and the otoliths provides reliable vestibular cues about self-orientation in space. For this, we measured the ability of subjects to estimate the subjective vertical immediately, 20 s and 90 s after a rapid tilt (180 degrees /s(2)) from upright into different roll positions between 90 degrees left and right side down. Subjects had to estimate the earth-vertical and earth-horizontal direction in the dark by (a) setting a luminous line, (b) performing saccades, and (c) verbally declaring body position relative to gravity. The mean error curves from the three paradigms showed consistent E (Müller)- and A (Aubert)-effects, which did not significantly change over time. Horizontal and vertical saccade tasks exhibited different response characteristics, as previously reported by others, which likely reflect different computation mechanisms. The verbal estimation paradigm yielded complementary results to those of the luminous line paradigm and vertical saccade task. The E-effect of the luminous line and the vertical saccade paradigm might be explained by a bias towards earth-vertical due to interactions of vestibular and neck afferent signals. The invariably small A-effect of the luminous line and the vertical saccade paradigm probably reflects somatosensory signals that had relatively weak influence in our experiments. We conclude that phasic activation of the vestibular system reduces the influence of non-vestibular cues observed in low tilt velocity or static experiments. Although this activation generates an E-effect, the total error in the range of +/-90 degrees is reduced.
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Mast FW, Berthoz A, Kosslyn SM. Mental imagery of visual motion modifies the perception of roll-vection stimulation. Perception 2001; 30:945-57. [PMID: 11578080 DOI: 10.1068/p3088] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
When viewing a wide-angle visual display, which rotates in the frontoparallel plane around the line of sight, observers experience an illusory shift of the direction of gravity; this shift leads to an apparent tilt of the body and displaces allocentric space coordinates. In this study, subjects adjusted an indicator to the apparent horizontal while viewing a rotating display. To determine whether top down processes could affect the illusion, the subjects were asked to visualize a rotating configuration of dots onto a blank central portion of the moving visual field. Visualizing dots and actually viewing the dots deflected the spatial judgment in very similar ways. These results demonstrate that top down processing can affect allocentric space coordinates.
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Affiliation(s)
- F W Mast
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA.
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33
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Van Beuzekom AD, Van Gisbergen J. Properties of the Internal Representation of Gravity Inferred From Spatial-Direction and Body-Tilt Estimates. J Neurophysiol 2000. [DOI: 10.1152/jn.2000.84.1.11] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- A. D. Van Beuzekom
- Department of Medical Physics and Biophysics, University of Nijmegen, 6500 HB Nijmegen, The Netherlands
| | - J.A.M. Van Gisbergen
- Department of Medical Physics and Biophysics, University of Nijmegen, 6500 HB Nijmegen, The Netherlands
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Herdman SJ, Blatt PJ, Schubert MC. Vestibular rehabilitation of patients with vestibular hypofunction or with benign paroxysmal positional vertigo. Curr Opin Neurol 2000; 13:39-43. [PMID: 10719648 DOI: 10.1097/00019052-200002000-00008] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Since the initial introduction of exercises as a treatment for patients with vestibular deficits, there have been numerous clinical reports on the benefits of treatment. Clinical reports, however, are of limited use as a basis for treatment because, without a control group, they offer only interesting descriptions of the patient populations. Fortunately, several prospective, randomized studies on the treatment of patients with vestibular hypofunction or with benign paroxysmal positional vertigo have been published recently, adding to the small number of previous publications. This review will examine the information provided by those studies. Advances in the use of outcome measures, assessment of otolith function and treatment of related balance problems are also presented.
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Affiliation(s)
- S J Herdman
- Department of Orthopaedics and Rehabilitation, University of Miami, Florida, USA.
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Abstract
The subjective visual horizontal and vestibular-evoked myogenic potentials are simple, robust, and reproducible tests of otolith dysfunction that can prove clinically useful diagnostic information in patients with vertigo and other balance disorders. While they appear to have high specificity for unilateral otolith dysfunction, further clinical research will be required to establish their sensitivity.
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Affiliation(s)
- G M Halmagyi
- Department of Neurology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
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