1
|
Effect of optokinetic virtual reality scenes on a sitting-to-stand movement. Hum Mov Sci 2022; 83:102956. [DOI: 10.1016/j.humov.2022.102956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 12/21/2021] [Accepted: 04/28/2022] [Indexed: 11/19/2022]
|
2
|
Park JH, Cho SI, Choi J, Han J, Rah YC. Pupil responses associated with the perception of gravitational vertical under directional optic flows. Sci Rep 2021; 11:21303. [PMID: 34716355 PMCID: PMC8556311 DOI: 10.1038/s41598-021-00346-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/30/2021] [Indexed: 11/09/2022] Open
Abstract
This study assessed the pupil responses in the sensory integration of various directional optic flows during the perception of gravitational vertical. A total of 30 healthy participants were enrolled with normal responses to conventional subjective visual vertical (SVV) which was determined by measuring the difference (error angles) between the luminous line adjusted by the participants and the true vertical. SVV was performed under various types of rotational (5°/s, 10°/s, and 50°/s) and straight (5°/s and 10°/s) optic flows presented via a head-mounted display. Error angles (°) of the SVV and changes in pupil diameters (mm) were measured to evaluate the changes in the visually assessed subjective verticality and related cognitive demands. Significantly larger error angles were measured under rotational optic flows than under straight flows (p < 0.001). The error angles also significantly increased as the velocity of the rotational optic flow increased. The pupil diameter increased after starting the test, demonstrating the largest diameter during the final fine-tuning around the vertical. Significantly larger pupil changes were identified under rotational flows than in straight flows. Pupil changes were significantly correlated with error angles and the visual analog scale representing subjective difficulties during each test. These results suggest increased pupil changes for integrating more challenging visual sensory inputs in the process of gravity perception.
Collapse
Affiliation(s)
- Joo Hyun Park
- grid.416665.60000 0004 0647 2391Department of Otorhinolaryngology-Head and Neck Surgery, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Republic of Korea
| | - Sung Ik Cho
- grid.222754.40000 0001 0840 2678Department of Computer Science and Engineering, Korea University College of Informatics, Seoul, Republic of Korea
| | - June Choi
- grid.222754.40000 0001 0840 2678Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - JungHyun Han
- grid.222754.40000 0001 0840 2678Department of Computer Science and Engineering, Korea University College of Informatics, Seoul, Republic of Korea
| | - Yoon Chan Rah
- grid.222754.40000 0001 0840 2678Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Ansan Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
3
|
Diaz-Artiles A, Karmali F. Vestibular Precision at the Level of Perception, Eye Movements, Posture, and Neurons. Neuroscience 2021; 468:282-320. [PMID: 34087393 DOI: 10.1016/j.neuroscience.2021.05.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 11/18/2022]
Abstract
Precision and accuracy are two fundamental properties of any system, including the nervous system. Reduced precision (i.e., imprecision) results from the presence of neural noise at each level of sensory, motor, and perceptual processing. This review has three objectives: (1) to show the importance of studying vestibular precision, and specifically that studying accuracy without studying precision ignores fundamental aspects of the vestibular system; (2) to synthesize key hypotheses about precision in vestibular perception, the vestibulo-ocular reflex, posture, and neurons; and (3) to show that groups of studies that are thoughts to be distinct (e.g., perceptual thresholds, subjective visual vertical variability, neuronal variability) are actually "two sides of the same coin" - because the methods used allow results to be related to the standard deviation of a Gaussian distribution describing the underlying neural noise. Vestibular precision varies with age, stimulus amplitude, stimulus frequency, body orientation, motion direction, pathology, medication, and electrical/mechanical vestibular stimulation, but does not vary with sex. The brain optimizes precision during integration of vestibular cues with visual, auditory, and/or somatosensory cues. Since a common concern with precision metrics is time required for testing, we describe approaches to optimize data collection and provide evidence that fatigue and session effects are minimal. Finally, we summarize how precision is an individual trait that is correlated with clinical outcomes in patients as well as with performance in functional tasks like balance. These findings highlight the importance of studying vestibular precision and accuracy, and that knowledge gaps remain.
Collapse
Affiliation(s)
- Ana Diaz-Artiles
- Bioastronautics and Human Performance Laboratory, Department of Aerospace Engineering, Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843-3141, USA. https://bhp.engr.tamu.edu
| | - Faisal Karmali
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA; Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston MA, USA.
| |
Collapse
|
4
|
An Implanted Vestibular Prosthesis Improves Spatial Orientation in Animals with Severe Vestibular Damage. J Neurosci 2021; 41:3879-3888. [PMID: 33731447 DOI: 10.1523/jneurosci.2204-20.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/10/2021] [Accepted: 03/08/2021] [Indexed: 11/21/2022] Open
Abstract
Gravity is a pervasive environmental stimulus, and accurate graviception is required for optimal spatial orientation and postural stability. The primary graviceptors are the vestibular organs, which include angular velocity (semicircular canals) and linear acceleration (otolith organs) sensors. Graviception is degraded in patients with vestibular damage, resulting in spatial misperception and imbalance. Since minimal therapy is available for these patients, substantial effort has focused on developing a vestibular prosthesis or vestibular implant (VI) that reproduces information normally provided by the canals (since reproducing otolith function is very challenging technically). Prior studies demonstrated that angular eye velocity responses could be driven by canal VI-mediated angular head velocity information, but it remains unknown whether a canal VI could improve spatial perception and posture since these behaviors require accurate estimates of angular head position in space relative to gravity. Here, we tested the hypothesis that a canal VI that transduces angular head velocity and provides this information to the brain via motion-modulated electrical stimulation of canal afferent nerves could improve the perception of angular head position relative to gravity in monkeys with severe vestibular damage. Using a subjective visual vertical task, we found that normal female monkeys accurately sensed the orientation of the head relative to gravity during dynamic tilts, that this ability was degraded following bilateral vestibular damage, and improved when the canal VI was used. These results demonstrate that a canal VI can improve graviception in vestibulopathic animals, suggesting that it could reduce the disabling perceptual and postural deficits experienced by patients with severe vestibular damage.SIGNIFICANCE STATEMENT Patients with vestibular damage experience impaired vision, spatial perception, and balance, symptoms that could potentially respond to a vestibular implant (VI). Anatomic features facilitate semicircular canal (angular velocity) prosthetics but inhibit approaches with the otolith (linear acceleration) organs, and canal VIs that sense angular head velocity can generate compensatory eye velocity responses in vestibulopathic subjects. Can the brain use canal VI head velocity information to improve estimates of head orientation (e.g., head position relative to gravity), which is a prerequisite for accurate spatial perception and posture? Here we show that a canal VI can improve the perception of head orientation in vestibulopathic monkeys, results that are highly significant because they suggest that VIs mimicking canal function can improve spatial orientation and balance in vestibulopathic patients.
Collapse
|
5
|
Wedtgrube A, Bockisch CJ, Straumann D, Tarnutzer AA. Prolonged Static Whole-Body Roll-Tilt and Optokinetic Stimulation Significantly Bias the Subjective Postural Vertical in Healthy Human Subjects. Front Neurol 2020; 11:595975. [PMID: 33178130 PMCID: PMC7593480 DOI: 10.3389/fneur.2020.595975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/07/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Prolonged static whole-body roll-tilt has been shown to bias estimates of the direction of gravity when assessed by static paradigms such as the subjective visual vertical and the subjective haptic vertical. Objective: We hypothesized that these shifts are paradigm-independent and thus predicted a post-tilt bias as well for self-adjustments along perceived vertical (subjective postural vertical, SPV). Likewise, rotatory optokinetic stimuli, which have been shown to shift the SPV when presented at the time of adjustments, may have an lasting effect on the SPV, predicting a shift in the perceived direction of gravity in the direction of the optokinetic rotatory stimulation. Methods: Self-adjustments along perceived vertical by use of a motorized turntable were recorded at baseline and after 5 min of static whole-body roll-tilt (orientation = ±90°, adaptation period) in 10 healthy human subjects. During adaptation subjects were either in darkness (no OKN stimulation) or were presented a full-field rotatory optokinetic stimulus (velocity = ±60°/s). Statistical analysis of adjustment errors for the different conditions was performed using a generalized linear model. Results: After 5 min of static whole-body roll-tilt in darkness, we observed significant (p < 0.001) shifts in the SPV averaging −2.8° (adaptation position: −90°) and 3.1° (+90°), respectively. Adding an optokinetic rotatory stimulus resulted in an additional, significant shift of SPV adjustments toward the direction of the previously presented optokinetic rotation (optokinetic clockwise rotation: 1.4°, p = 0.034; optokinetic counter-clockwise rotation: −1.3°, p = 0.037). Trial-to-trial variability of turntable adjustments was not significantly affected by adaptation. Conclusions: Prolonged static roll-tilt results in a significant post-tilt bias of the perceived direction of gravity when assessed by the SPV, confirming previous findings from other vision-dependent and vision-independent paradigms. This finding emphasizes the impact of recent whole-body roll orientations relative to gravity. Such adaptational shifts in verticality estimates may be explained in the context of Bayesian optimal observer theory with a bias of prior knowledge (i.e., expectation biased by experience). Our findings also have clinical implications, as the observed post-tilt bias may contribute to postural instability when standing up in the morning with an increasing risk for falls and fall-related injuries in humans with preexisting balance disorders.
Collapse
Affiliation(s)
- Andrea Wedtgrube
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - Christopher J Bockisch
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology, University Hospital Zurich, Zurich, Switzerland.,Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland.,Center of Clinical Neurosciences, University Hospital Zurich, Zurich, Switzerland
| | - Dominik Straumann
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland.,Center of Clinical Neurosciences, University Hospital Zurich, Zurich, Switzerland
| | - Alexander A Tarnutzer
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland.,Center of Clinical Neurosciences, University Hospital Zurich, Zurich, Switzerland.,Neurology, Cantonal Hospital of Baden, Baden, Switzerland
| |
Collapse
|
6
|
Bergmann J, Bardins S, Prawitz C, Keywan A, MacNeilage P, Jahn K. Perception of postural verticality in roll and pitch while sitting and standing in healthy subjects. Neurosci Lett 2020; 730:135055. [DOI: 10.1016/j.neulet.2020.135055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 10/24/2022]
|
7
|
Wedtgrube A, Bockisch C, Tarnutzer A. Effects of prolonged roll-tilt on the subjective visual and haptic vertical in healthy human subjects. J Vestib Res 2020; 30:1-16. [DOI: 10.3233/ves-200690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A. Wedtgrube
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - C.J. Bockisch
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
- Department of Otorhinolaryngology, University Hospital Zurich, Zurich, Switzerland
- Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Switzerland
- Center of Clinical Neurosciences, University Hospital Zurich, Switzerland
| | - A.A. Tarnutzer
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Switzerland
- Center of Clinical Neurosciences, University Hospital Zurich, Switzerland
- Cantonal Hospital of Baden, Baden, Switzerland
| |
Collapse
|