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Stasica M, Honekamp C, Streiling K, Penacchio O, van Dam L, Seyfarth A. Walking on Virtual Surface Patterns Leads to Changed Control Strategies. SENSORS (BASEL, SWITZERLAND) 2024; 24:5242. [PMID: 39204937 PMCID: PMC11359677 DOI: 10.3390/s24165242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/19/2024] [Accepted: 07/24/2024] [Indexed: 09/04/2024]
Abstract
Inclusive design does not stop at removing physical obstacles such as staircases. It also involves identifying architectural features that impose sensory burdens, such as repetitive visual patterns that are known to potentially cause dizziness or visual discomfort. In order to assess their influence on human gait and its stability, three repetitive patterns-random dots, repetitive stripes, and repetitive waves (Lisbon pattern)-were displayed in a coloured and greyscale variant in a virtual reality (VR) environment. The movements of eight participants were recorded using a motion capture system and electromyography (EMG). During all test conditions, a significant increase in the muscular activity of leg flexor muscles was identified just before touchdown. Further, an increase in the activity of laterally stabilising muscles during the swing phase was observed for all of the test conditions. The lateral and vertical centre of mass (CoM) deviation was statistically evaluated using a linear mixed model (LMM). The patterns did cause a significant increase in the CoM excursion in the vertical direction but not in the lateral direction. These findings are indicative of an inhibited and more cautious gait style and a change in control strategy. Furthermore, we quantified the induced discomfort by using both algorithmic estimates and self-reports. The Fourier-based methods favoured the greyscaled random dots over repetitive stripes. The colour metric favoured the striped pattern over the random dots. The participants reported that the wavey Lisbon pattern was the most disruptive. For architectural and structural design, this study indicates (1) that highly repetitive patterns should be used with care in consideration of their impact on the human visuomotor system and its behavioural effects and (2) that coloured patterns should be used with greater caution than greyscale patterns.
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Affiliation(s)
- Maximilian Stasica
- Lauflabor Locomotion Laboratory, Institute of Sports Science and Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Celine Honekamp
- Sensorimotor Control and Learning Lab, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Kai Streiling
- Sensorimotor Control and Learning Lab, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Olivier Penacchio
- Computer Science Department, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Loes van Dam
- Sensorimotor Control and Learning Lab, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - André Seyfarth
- Lauflabor Locomotion Laboratory, Institute of Sports Science and Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
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2
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Lavalle LK, Cleworth TW. The effect of modified optic flow gain on quiet stance. Neurosci Lett 2023; 797:137068. [PMID: 36641046 DOI: 10.1016/j.neulet.2023.137068] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/16/2022] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
Visual feedback provides critical information to support postural stability. Previous work has shown that magnifying visual feedback, such as by presenting individuals with biofeedback during balance tasks, can improve postural control. When studies manipulate the availability of optic flow directly, the conditions are often restricted to include an absence of visual feedback or sway referenced paradigms. Therefore, the aim of this study was to understand how manipulating the gain of optic flow contributes to quiet standing balance control among healthy adults. Optic flow was amplified or reduced relative to head motion using a virtual reality head-mounted display while participants stood quietly on either a firm or foam surface. Overall, when there was an increased reliance placed on the visual system by standing on foam, a tighter control of upright stance was observed as the gain of optic flow increased. Further, this study provided evidence that visual contributions to balance control may extend to higher frequencies of postural sway than previously theorized (greater than 0.1 Hz).
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Affiliation(s)
- Lisa K Lavalle
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada; Centre for Vision Research, York University, Toronto, ON, Canada; School of Medicine, Queen's University, Kingston, ON, Canada
| | - Taylor W Cleworth
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada; Centre for Vision Research, York University, Toronto, ON, Canada.
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3
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Assländer L, Albrecht M, Diehl M, Missen KJ, Carpenter MG, Streuber S. Estimation of the visual contribution to standing balance using virtual reality. Sci Rep 2023; 13:2594. [PMID: 36788259 PMCID: PMC9929338 DOI: 10.1038/s41598-023-29713-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Sensory perturbations are a valuable tool to assess sensory integration mechanisms underlying balance. Implemented as systems-identification approaches, they can be used to quantitatively assess balance deficits and separate underlying causes. However, the experiments require controlled perturbations and sophisticated modeling and optimization techniques. Here we propose and validate a virtual reality implementation of moving visual scene experiments together with model-based interpretations of the results. The approach simplifies the experimental implementation and offers a platform to implement standardized analysis routines. Sway of 14 healthy young subjects wearing a virtual reality head-mounted display was measured. Subjects viewed a virtual room or a screen inside the room, which were both moved during a series of sinusoidal or pseudo-random room or screen tilt sequences recorded on two days. In a between-subject comparison of 10 [Formula: see text] 6 min long pseudo-random sequences, each applied at 5 amplitudes, our results showed no difference to a real-world moving screen experiment from the literature. We used the independent-channel model to interpret our data, which provides a direct estimate of the visual contribution to balance, together with parameters characterizing the dynamics of the feedback system. Reliability estimates of single subject parameters from six repetitions of a 6 [Formula: see text] 20-s pseudo-random sequence showed poor test-retest agreement. Estimated parameters show excellent reliability when averaging across three repetitions within each day and comparing across days (Intra-class correlation; ICC 0.7-0.9 for visual weight, time delay and feedback gain). Sway responses strongly depended on the visual scene, where the high-contrast, abstract screen evoked larger sway as compared to the photo-realistic room. In conclusion, our proposed virtual reality approach allows researchers to reliably assess balance control dynamics including the visual contribution to balance with minimal implementation effort.
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Affiliation(s)
- Lorenz Assländer
- Human Performance Research Centre, University of Konstanz, 78464, Konstanz, Germany.
| | - Matthias Albrecht
- Human Performance Research Centre, University of Konstanz, 78464, Konstanz, Germany
- Department of Computer and Information Science, University of Konstanz, 78464, Konstanz, Germany
| | - Moritz Diehl
- Department of Mathematics, University of Freiburg, 79110, Freiburg, Germany
| | - Kyle J Missen
- School of Kinesiology, University of British Columbia, Vancouver, V6T 2A1, Canada
| | - Mark G Carpenter
- School of Kinesiology, University of British Columbia, Vancouver, V6T 2A1, Canada
| | - Stephan Streuber
- Department of Electrical Engineering and Computer Science, Coburg University of Applied Sciences and Arts, 96450, Coburg, Germany
- Zukunftskolleg, University of Konstanz, 78464, Konstanz, Germany
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4
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Lubetzky AV, Kelly JL, Harel D, Roginska A, Hujsak BD, Wang Z, Perlin K, Cosetti M. Insight into postural control in unilateral sensorineural hearing loss and vestibular hypofunction. PLoS One 2022; 17:e0276251. [PMID: 36251683 PMCID: PMC9576045 DOI: 10.1371/journal.pone.0276251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 10/03/2022] [Indexed: 12/05/2022] Open
Abstract
This pilot study aimed to identify postural strategies in response to sensory perturbations (visual, auditory, somatosensory) in adults with and without sensory loss. We tested people with unilateral peripheral vestibular hypofunction (N = 12, mean age 62 range 23-78), or with Unilateral Sensorineural Hearing Loss (USNHL, N = 9, 48, 22-82), or healthy controls (N = 21, 52, 28-80). Postural sway and head kinematics parameters (Directional Path in the anterior-posterior and medio-lateral directions (sway & head); pitch, yaw and roll (head) were analyzed in response to 2 levels of auditory (none, rhythmic sounds via headphones), visual (static, dynamic) and somatosensory cues (floor, foam) within a simulated, virtual 3-wall display of stars. We found no differences with the rhythmic auditory cues. The effect of foam was magnified in the vestibular group compared with controls for anterior-posterior and medio-lateral postural sway, and all head direction except for medio-lateral. The vestibular group had significantly larger anterior-posterior and medio-lateral postural sway and head movement on the static scene compared with controls. Differences in pitch, yaw and roll emerged between vestibular and controls only with sensory perturbations. The USNHL group did not increase their postural sway and head movement with the increased visual load as much as controls did, particularly when standing on the foam. They did not increase their medio-lateral sway with the foam as much as controls did. These findings suggest that individuals with USNHL employ a compensatory strategy of conscious control of balance, the functional implications of which need to be tested in future research.
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Affiliation(s)
- Anat V. Lubetzky
- Department of Physical Therapy, Steinhardt School of Culture, Education and Human Development, New York University, New York, NY, United States of America
- * E-mail:
| | - Jennifer L. Kelly
- Vestibular Rehabilitation, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States of America
| | - Daphna Harel
- Department of Applied Statistics, Social Science and Humanities, Steinhardt School of Culture Education and Human Development, New York University, New York, NY, United States of America
| | - Agnieszka Roginska
- Department of Music and Performing Arts Professions, Steinhardt School of Culture, Education and Human Development, New York University, New York, NY, United States of America
| | - Bryan D. Hujsak
- Vestibular Rehabilitation, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States of America
| | - Zhu Wang
- Computer Science Department, Courant Institute of Mathematical Sciences, New York University, New York, NY, United States of America
| | - Ken Perlin
- Computer Science Department, Courant Institute of Mathematical Sciences, New York University, New York, NY, United States of America
| | - Maura Cosetti
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States of America
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5
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Nielsen EI, Cleworth TW, Carpenter MG. Exploring emotional-modulation of visually evoked postural responses through virtual reality. Neurosci Lett 2022; 777:136586. [PMID: 35331814 DOI: 10.1016/j.neulet.2022.136586] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/08/2022] [Accepted: 03/18/2022] [Indexed: 11/19/2022]
Abstract
Exposure to postural threat has been documented to influence the sensory contributions of proprioceptive and vestibular information in standing balance control. Contributions from the visual system to balance are also crucial, yet the degree to which postural threat may modulate visual control of balance is not well characterized. Therefore, the aims of this study were to assess the feasibility of eliciting visual evoked postural responses (VEPRs) using head-mounted virtual reality (VR) and use this method to examine the potential influence of virtual postural threat on the visual control of balance. 36 healthy young adults were exposed to a pseudorandom, translational visual stimulus of a real-world environment in VR. The visual stimulus was presented in virtual conditions of LOW and HIGH postural threat in which participants stood at ground level, and on a 7m elevated platform, respectively. VEPRs were successfully produced in both postural threat conditions. When exposed to the visual stimulus while at an elevated surface height, participants demonstrated significant changes to their physiological arousal and emotional state. Despite significant coherence across the stimulus' frequency range, stimulus correlated VEPRs were not significantly modulated during exposure to the visual stimulus under virtual postural threat. This study supports the future utility of VR head-mounted displays in examining emotional influences on the visual control of balance.
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Affiliation(s)
- Emma I Nielsen
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada; Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Taylor W Cleworth
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada; School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Mark G Carpenter
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada.
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6
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Student J, Engel D, Timmermann L, Bremmer F, Waldthaler J. Visual Perturbation Suggests Increased Effort to Maintain Balance in Early Stages of Parkinson’s to be an Effect of Age Rather Than Disease. Front Hum Neurosci 2022; 16:762380. [PMID: 35308620 PMCID: PMC8924037 DOI: 10.3389/fnhum.2022.762380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 02/02/2022] [Indexed: 12/01/2022] Open
Abstract
Postural instability marks a prevalent symptom of Parkinson’s disease (PD). It often manifests in increased body sway, which is commonly assessed by tracking the Center of Pressure (CoP). Yet, in terms of postural control, the body’s Center of Mass (CoM), and not CoP is what is regulated in a gravitational field. The aim of this study was to explore the effect of early- to mid-stage PD on these measures of postural control in response to unpredictable visual perturbations. We investigated three cohorts: (i) 18 patients with early to mid-stage PD [Hoehn & Yahr stage (1–3); 1.94 ± 0.70]; (ii) a group of 15 age-matched controls (ECT); and (iii) a group of 12 young healthy adults (YCT). Participants stood on a force plate to track their CoP, while the movement of their entire body was recorded with a video-based motion tracking system to monitor their CoM. A moving room paradigm was applied through a head-mounted virtual reality headset. The stimulus consisted of a virtual tunnel that stretched in the anterior-posterior direction which either remained static or moved back and forth in an unpredictable fashion.We found differences in mean sway amplitude (MSA) and mean velocities of CoP and CoM between the groups under both conditions, with higher MSA of CoP and CoM for PD and higher mean velocities of both variables for PD and ECT when compared with YCT. Visual perturbation increased mean CoP velocity in all groups but did not have effects on mean CoM velocity or MSA. While being significantly lower for the young adults, the net effect of visual perturbation on mean CoP velocity was similar between patients with PD and age-matched controls. There was no effect of the visual perturbation on mean CoM velocity for any of the groups.Our simultaneous assessment of CoP and CoM revealed that postural control is reflected differently in CoM and CoP. As the motion of CoM remained mostly unaffected, all groups successfully counteracted the perturbation and maintained their balance. Higher CoP velocity for PD and ECT revealed increased corrective motion needed to achieve this, which however was similar in both groups. Thus, our results suggest increased effort, expressed in CoP velocity, to be an effect of age rather than disease in earlier stages of PD.
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Affiliation(s)
- Justus Student
- Department of Neurophysics, University of Marburg, Marburg, Germany
- Department of Neurology, University Hospital of Marburg, Marburg, Germany
- *Correspondence: Justus Student
| | - David Engel
- Department of Neurophysics, University of Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University of Gießen, Marburg, Germany
| | - Lars Timmermann
- Department of Neurology, University Hospital of Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University of Gießen, Marburg, Germany
| | - Frank Bremmer
- Department of Neurophysics, University of Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University of Gießen, Marburg, Germany
| | - Josefine Waldthaler
- Department of Neurology, University Hospital of Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University of Gießen, Marburg, Germany
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7
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Lubetzky AV, Coker E, Arie L, Aharoni MMH, Krasovsky T. Postural Control under Cognitive Load: Evidence of Increased Automaticity Revealed by Center-of-Pressure and Head Kinematics. J Mot Behav 2021; 54:466-479. [PMID: 34902292 DOI: 10.1080/00222895.2021.2013768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
How postural responses change with sensory perturbations while also performing a cognitive task is still debatable. This study investigated this question via comprehensive assessment of postural sway, head kinematics and their coupling. Twenty-three healthy young adults stood in tandem with eyes open or wearing the HTC Vive Head-Mounted Display (HMD) with a static or dynamic (i.e., movement in the anterior-posterior direction at 5 mm or 32 mm at 0.2 Hz) 3-wall stars display. On half of the trials, participants performed a cognitive serial subtraction task. Medio-lateral center-of-pressure (COP) path significantly increased with the cognitive task, particularly with dynamic visuals whereas medio-lateral variance decreased with the cognitive task. Head path and velocity significantly increased with the cognitive task in both directions while variance decreased. Head-COP cross-correlations ranged between 0.78 and 0.66. These findings, accompanied by frequency analysis, suggest that postural control switched to primarily relying on somatosensory input under challenging cognitive load conditions. Several differences between head and COP suggest that head kinematics contribute an important additional facet of postural control and the relationship between head and COP may depend on task and stance position. The potential of HMDs for clinical assessments of balance needs to be further explored.
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Affiliation(s)
- Anat V Lubetzky
- Department of Physical Therapy, Steinhardt School of Culture Education and Human Development, New York University, New York, New York, USA
| | - Elizabeth Coker
- Department of Dance, Tisch School of the Arts, New York University, New York, New York, USA
| | - Liraz Arie
- Department of Physical Therapy, Steinhardt School of Culture Education and Human Development, New York University, New York, New York, USA
| | - Moshe M H Aharoni
- Physical Therapy Department, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Tal Krasovsky
- Physical Therapy Department, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel.,Pediatric Rehabilitation Department, Sheba Medical Center, Ramat Gan, Israel
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8
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Engel D, Student J, Schwenk JCB, Morris AP, Waldthaler J, Timmermann L, Bremmer F. Visual perturbation of balance suggests impaired motor control but intact visuomotor processing in Parkinson's disease. J Neurophysiol 2021; 126:1076-1089. [PMID: 34469704 DOI: 10.1152/jn.00183.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Postural instability marks one of the most disabling features of Parkinson's disease (PD), but it only reveals itself after affected brain areas have already been significantly damaged. Thus there is a need to detect deviations in balance and postural control before visible symptoms occur. In this study, we visually perturbed balance in the anterior-posterior direction using sinusoidal oscillations of a moving room in virtual reality at different frequencies. We tested three groups: individuals with PD under dopaminergic medication, an age-matched control group, and a group of young healthy adults. We tracked their center of pressure and their full-body motion, from which we also extracted the center of mass. We investigated sway amplitudes and applied newly introduced phase-locking analyses to investigate responses across participants' bodies. Patients exhibited significantly higher sway amplitudes as compared with the control subjects. However, their sway was phase locked to the visual motion like that of age-matched and young healthy adults. Furthermore, all groups successfully compensated for the visual perturbation by phase locking their sway to the stimulus. As frequency of the perturbation increased, distribution of phase locking (PL) across the body revealed a shift of the highest PL values from the upper body toward the hip region for young healthy adults, which could not be observed in patients and elderly healthy adults. Our findings suggest an impaired motor control, but intact visuomotor processing in early stages of PD, while less flexibility to adapt postural strategy to different perturbations revealed to be an effect of age rather than disease.NEW & NOTEWORTHY A better understanding of visuomotor control in Parkinson's disease (PD) potentially serves as a tool for earlier diagnosis, which is crucial for improving patient's quality of life. In our study, we assess body sway responses to visual perturbations of the balance control system in patients with early-to-mid stage PD, using motion tracking along with recently established phase-locking techniques. Our findings suggest patients at this stage have an impaired muscular stability but intact visuomotor control.
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Affiliation(s)
- David Engel
- Department of Neurophysics, Philipps-Universität Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, Germany
| | - Justus Student
- Department of Neurology, University Hospital Giessen and Marburg, Marburg, Germany
| | - Jakob C B Schwenk
- Department of Neurophysics, Philipps-Universität Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, Germany
| | - Adam P Morris
- Neuroscience Program, Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria, Australia.,Data Science and Artificial Intellegience Platform, Monash eResearch Centre, Monash University, Clayton, Victoria, Australia
| | - Josefine Waldthaler
- Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, Germany.,Department of Neurology, University Hospital Giessen and Marburg, Marburg, Germany
| | - Lars Timmermann
- Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, Germany.,Department of Neurology, University Hospital Giessen and Marburg, Marburg, Germany
| | - Frank Bremmer
- Department of Neurophysics, Philipps-Universität Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, Germany
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9
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Engel D, Schwenk JCB, Schütz A, Morris AP, Bremmer F. Multi-segment phase coupling to oscillatory visual drive. Gait Posture 2021; 86:132-138. [PMID: 33721690 DOI: 10.1016/j.gaitpost.2021.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/04/2021] [Accepted: 03/05/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND It has been shown that humans adapt their postural sway to oscillatory, visually simulated self-motion. However, little is still known about the way individual body segments contribute to this adjustment of body sway and how this contribution varies with different environmental conditions. RESEARCH QUESTION How do the centre of pressure (COP) and individual body segments phase-lock to a sinusoidal visual drive depending on the frequency of stimulation? METHODS In this study, we introduce phase coupling as a method for assessing full body motion in response to visual stimuli presented in virtual reality (VR). 12 participants (mean age: 31 ± 9 years) stood inside a virtual tunnel which oscillated sinusoidally in the anterior-posterior direction at a frequency of 0.2 Hz, 0.8 Hz or 1.2 Hz. Primary outcome measures were the trajectories of their COP as well as of 25 body segments obtained by a motion tracking system. RESULTS Subjects significantly coupled the phase of their COP and body segments to the visual drive. Our analysis yielded significant phase coupling of the COP to the stimulus for all tested frequencies. The phase coupling of body segments revealed a shift in postural response as a function of frequency. At the low frequency of 0.2 Hz, we found strong and significant phase coupling homogeneously distributed across the body. At the higher frequencies of 0.8 Hz and 1.2 Hz, however, overall phase coupling became weaker and was centred around the lower torso and hip segments. SIGNIFICANCE Information on how the visual percept of self-motion affects balance control is crucial for understanding visuomotor processing in health and disease. Our setup and methods constitute a reliable tool for assessing perturbed balance control, which can be utilized in future clinical trials.
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Affiliation(s)
- David Engel
- Department of Neurophysics, University of Marburg, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University, Gießen, Germany.
| | - Jakob C B Schwenk
- Department of Neurophysics, University of Marburg, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University, Gießen, Germany
| | - Adrian Schütz
- Department of Neurophysics, University of Marburg, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University, Gießen, Germany
| | - Adam P Morris
- Neuroscience Program, Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria, Australia; Data Science and AI Platform, Monash eResearch Centre, Monash University, Clayton, Victoria, Australia
| | - Frank Bremmer
- Department of Neurophysics, University of Marburg, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University, Gießen, Germany
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10
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Ralston JD, Raina A, Benson BW, Peters RM, Roper JM, Ralston AB. Physiological Vibration Acceleration (Phybrata) Sensor Assessment of Multi-System Physiological Impairments and Sensory Reweighting Following Concussion. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2020; 13:411-438. [PMID: 33324120 PMCID: PMC7733539 DOI: 10.2147/mder.s279521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/02/2020] [Indexed: 11/23/2022] Open
Abstract
Objective To assess the utility of a head-mounted wearable inertial motion unit (IMU)-based physiological vibration acceleration (“phybrata”) sensor to support the clinical diagnosis of concussion, classify and quantify specific concussion-induced physiological system impairments and sensory reweighting, and track individual patient recovery trajectories. Methods Data were analyzed from 175 patients over a 12-month period at three clinical sites. Comprehensive clinical concussion assessments were first completed for all patients, followed by testing with the phybrata sensor. Phybrata time series data and spatial scatter plots, eyes open (Eo) and eyes closed (Ec) phybrata powers, average power (Eo+Ec)/2, Ec/Eo phybrata power ratio, time-resolved phybrata spectral density (TRPSD) distributions, and receiver operating characteristic (ROC) curves are compared for individuals with no objective impairments and those clinically diagnosed with concussions and accompanying vestibular impairment, other neurological impairment, or both vestibular and neurological impairments. Finally, pre- and post-injury phybrata case report results are presented for a participant who was diagnosed with a concussion and subsequently monitored during treatment, rehabilitation, and return-to-activity clearance. Results Phybrata data demonstrate distinct features and patterns for individuals with no discernable clinical impairments, diagnosed vestibular pathology, and diagnosed neurological pathology. ROC curves indicate that the average power (Eo+Ec)/2 may be utilized to support clinical diagnosis of concussion, while Eo and Ec/Eo may be utilized as independent measures to confirm accompanying neurological and vestibular impairments, respectively. All 3 measures demonstrate area under the curve (AUC), sensitivity, and specificity above 90% for their respective diagnoses. Phybrata spectral analyses demonstrate utility for quantifying the severity of concussion-induced physiological impairments, sensory reweighting, and subsequent monitoring of improvements throughout treatment and rehabilitation. Conclusion Phybrata testing assists with objective concussion diagnosis and provides an important adjunct to standard concussion assessment tools by objectively ascertaining neurological and vestibular impairments, guiding targeted rehabilitation strategies, monitoring recovery, and assisting with return-to-sport/work/learn decision-making.
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Affiliation(s)
| | - Ashutosh Raina
- Center of Excellence for Pediatric Neurology, Rocklin, CA 95765, USA.,Concussion Medical Clinic, Rocklin, CA 95765, USA
| | - Brian W Benson
- Benson Concussion Institute, Calgary, Alberta T3B 6B7, Canada.,Canadian Sport Institute Calgary, Calgary, Alberta T3B 5R5, Canada
| | - Ryan M Peters
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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