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Ketterer J, Gehring D, Gollhofer A, Ringhof S. Sensory conflicts through short, discrete visual input manipulations: Identification of balance responses to varied input characteristics. Hum Mov Sci 2024; 93:103181. [PMID: 38301342 DOI: 10.1016/j.humov.2024.103181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 01/22/2024] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
Human balance control relies on various sensory modalities, and conflict of sensory input may result in postural instability. Virtual reality (VR) technology allows to train balance under conflicting sensory information by decoupling visual from somatosensory and vestibular systems, creating additional demands on sensory reweighting for balance control. However, there is no metric for the design of visual input manipulations that can induce persistent sensory conflicts to perturb balance. This limits the possibilities to generate sustained sensory reweighting processes and design well-defined training approaches. This study aimed to investigate the effects that different onset characteristics, amplitudes and velocities of visual input manipulations may have on balance control and their ability to create persistent balance responses. Twenty-four young adults were recruited for the study. The VR was provided using a state-of-the-art head-mounted display and balance was challenged in two experiments by rotations of the visual scene in the frontal plane with scaled constellations of trajectories, amplitudes and velocities. Mean center of pressure speed was recorded and revealed to be greater when the visual input manipulation had an abrupt onset compared to a smooth onset. Furthermore, the balance response was greatest and most persistent when stimulus velocity was low and stimulus amplitude was large. These findings show clear dissociation in the state of the postural system for abrupt and smooth visual manipulation onsets with no indication of short-term adaption to abrupt manipulations with slow stimulus velocity. This augments our understanding of how conflicting visual information affect balance responses and could help to optimize the conceptualization of training and rehabilitation interventions.
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Affiliation(s)
- Jakob Ketterer
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany.
| | - Dominic Gehring
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Albert Gollhofer
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Steffen Ringhof
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany; Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, 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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Mahmood I, Zia Ur Rahman M, Dehghani-Sanij AA. Modelling and analysis of orthoses generated whole-body vertical vibrations impact on limb stability and compliant dynamics in a ramp gait. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2022.104163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Abdul Yamin NAA, Basaruddin KS, Abu Bakar S, Salleh AF, Mat Som MH, Yazid H, Hoang TD. Quantification of Gait Stability During Incline and Decline Walking: The Responses of Required Coefficient of Friction and Dynamic Postural Index. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:7716821. [PMID: 36275397 PMCID: PMC9581656 DOI: 10.1155/2022/7716821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 09/13/2022] [Accepted: 09/29/2022] [Indexed: 11/04/2022]
Abstract
This study aims to investigate the gait stability response during incline and decline walking for various surface inclination angles in terms of the required coefficient of friction (RCOF), postural stability index (PSI), and center of pressure (COP)-center of mass (COM) distance. A customized platform with different surface inclinations (0°, 5°, 7.5°, and 10°) was designed. Twenty-three male volunteers participated by walking on an inclined platform for each inclination. The process was then repeated for declined platform as well. Qualysis motion capture system was used to capture and collect the trajectories motion of ten reflective markers that attached to the subjects before being exported to a visual three-dimensional (3D) software and executed in Matlab to obtain the RCOF, PSI, as well as dynamic PSI (DPSI) and COP-COM distance parameters. According to the result for incline walking, during initial contact, the RCOF was not affected to inclination. However, it was affected during peak ground reaction force (GRF) starting at 7.5° towards 10° for both walking conditions. The most affected PSI was found at anterior-posterior PSI (APSI) even as low as 5° inclination during both incline and decline walking. On the other hand, DPSI was not affected during both walking conditions. Furthermore, COP-COM distance was most affected during decline walking in anterior-posterior direction. The findings of this research indicate that in order to decrease the risk of falling and manage the inclination demand, a suitable walking strategy and improved safety measures should be applied during slope walking, particularly for decline and anterior-posterior orientations. This study also provides additional understanding on the best incline walking technique for secure and practical incline locomotion.
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Affiliation(s)
| | - Khairul Salleh Basaruddin
- Faculty of Mechanical Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
- Medical Devices and Health Sciences, Sports Engineering Research Center (SERC), Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
| | - Shahriman Abu Bakar
- Faculty of Mechanical Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
- Center of Excellence Automotive & Motorsport (MoTECH), Universiti Malaysia Perlis 02600 Pauh Putra, Perlis, Malaysia
| | - Ahmad Faizal Salleh
- Faculty of Electronic Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
- Medical Devices and Health Sciences, Sports Engineering Research Center (SERC), Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
| | - Mohd Hanafi Mat Som
- Faculty of Electronic Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
- Faculty of Mechanical Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
| | - Haniza Yazid
- Faculty of Electronic Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
- Faculty of Mechanical Engineering and Technology, Universiti Malaysia Perlis, Pauh Putra 02600, Perlis, Malaysia
| | - Tien-Dat Hoang
- Faculty of International Training, Thai Nguyen University of Technology, Thai Nguyen, Vietnam
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Sozzi S, Do MC, Schieppati M. Vertical ground reaction force oscillation during standing on hard and compliant surfaces: The “postural rhythm”. Front Neurol 2022; 13:975752. [PMID: 36119676 PMCID: PMC9475112 DOI: 10.3389/fneur.2022.975752] [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: 06/23/2022] [Accepted: 08/10/2022] [Indexed: 11/14/2022] Open
Abstract
When a person stands upright quietly, the position of the Centre of Mass (CoM), the vertical force acting on the ground and the geometrical configuration of body segments is accurately controlled around to the direction of gravity by multiple feedback mechanisms and by integrative brain centres that coordinate multi-joint movements. This is not always easy and the postural muscles continuously produce appropriate torques, recorded as ground reaction force by a force platform. We studied 23 young adults during a 90 s period, standing at ease on a hard (Solid) and on a compliant support (Foam) with eyes open (EO) and with eyes closed (EC), focusing on the vertical component of the ground reaction force (VGRF). Analysis of VGRF time series gave the amplitude of their rhythmic oscillations (the root mean square, RMS) and of their frequency spectrum. Sway Area and Path Length of the Centre of Pressure (CoP) were also calculated. VGRF RMS (as well as CoP sway measures) increased in the order EO Solid ≈ EC Solid < EO Foam < EC Foam. The VGRF frequency spectra featured prevailing frequencies around 4–5 Hz under all tested conditions, slightly higher on Solid than Foam support. Around that value, the VGRF frequencies varied in a larger range on hard than on compliant support. Sway Area and Path Length were inversely related to the prevailing VGRF frequency. Vision compared to no-vision decreased Sway Area and Path Length and VGRF RMS on Foam support. However, no significant effect of vision was found on VGRF mean frequency for either base of support condition. A description of the VGRF, at the interface between balance control mechanisms and sway of the CoP, can contribute information on how upright balance is maintained. Analysis of the frequency pattern of VGRF oscillations and its role in the maintenance of upright stance should complement the traditional measures of CoP excursions in the horizontal plane.
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Affiliation(s)
- Stefania Sozzi
- Istituti Clinici Scientifici Maugeri IRCCS, Centro Studi Attività Motorie (CSAM), Pavia, Italy
| | - Manh-Cuong Do
- Complexité, Innovation, Activités Motrices et Sportives (CIAMS), Université Paris-Saclay, Orsay, France
- Complexité, Innovation, Activités Motrices et Sportives (CIAMS), Université d'Orléans, Orléans, France
| | - Marco Schieppati
- Istituti Clinici Scientifici Maugeri IRCCS, Centro Studi Attività Motorie (CSAM), Pavia, Italy
- *Correspondence: Marco Schieppati ;
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Oussou G, Magnani C, Bargiotas I, Lamas G, Tankere F, Vidal C. A New Sensitive Test Using Virtual Reality and Foam to Probe Postural Control in Vestibular Patients: The Unilateral Schwannoma Model. Front Neurol 2022; 13:891232. [PMID: 35693011 PMCID: PMC9174985 DOI: 10.3389/fneur.2022.891232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Vestibular schwannomas (VS) are benign tumors of the vestibular nerve that may trigger hearing loss, tinnitus, rotatory vertigo, and dizziness in patients. Vestibular and auditory tests can determine the precise degree of impairment of the auditory nerve, and superior and inferior vestibular nerves. However, balance is often poorly quantified in patients with untreated vestibular schwannoma, for whom validated standardized assessments of balance are often lacking. Balance can be quantified with the EquiTest. However, this device was developed a long time ago and is expensive, specific, and not sensitive enough to detect early deficits because it assesses balance principally in the sagittal plane on a firm platform. In this study, we assessed postural performances in a well-defined group of VS patients. We used the Dizziness Handicap Inventory (DHI) and a customized device consisting of a smartphone, a mask delivering a fixed or moving visual scene, and foam rubber. Patients were tested in four successive sessions of 25 s each: eyes open (EO), eyes closed (EC), fixed visual scene (VR0), and visual moving scenes (VR1) delivered by the HTC VIVE mask. Postural oscillations were quantified with sensors from an android smartphone (Galaxy S9) fixed to the back. The results obtained were compared to those obtained with the EquiTest. Vestibulo-ocular deficits were also quantified with the caloric test and vHIT. The function of the utricle and saccule were assessed with ocular and cervical vestibular-evoked myogenic potentials (o-VEMPs and c-VEMPs), respectively. We found that falls and abnormal postural oscillations were frequently detected in the VS patients with the VR/Foam device. We detected no correlation between falls or abnormal postural movements and horizontal canal deficit or age. In conclusion, this new method provides a simpler, quicker, and cheaper method for quantifying balance. It will be very helpful for (1) determining balance deficits in VS patients; (2) optimizing the optimal therapy indications (active follow-up, surgery, or gamma therapy) and follow-up of VS patients before and after treatment; (3) developing new rehabilitation methods based on balance training in extreme conditions with disturbed visual and proprioceptive inputs.
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Affiliation(s)
- Grâce Oussou
- Centre Borelli, CNRS UMR-9010, Université Paris Descartes, Paris, France
- Department of ENT, Salpetriere Hospital, Paris, France
| | - Christophe Magnani
- Centre Borelli, CNRS UMR-9010, Université Paris Descartes, Paris, France
| | - Ioannis Bargiotas
- Centre Borelli, CNRS UMR-9010, Université Paris Descartes, Paris, France
| | - Georges Lamas
- Department of ENT, Salpetriere Hospital, Paris, France
| | | | - Catherine Vidal
- Centre Borelli, CNRS UMR-9010, Université Paris Descartes, Paris, France
- Department of ENT, Salpetriere Hospital, Paris, France
- *Correspondence: Catherine Vidal
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7
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Abstract
Even for a stereotyped task, sensorimotor behavior is generally variable due to noise, redundancy, adaptability, learning or plasticity. The sources and significance of different kinds of behavioral variability have attracted considerable attention in recent years. However, the idea that part of this variability depends on unique individual strategies has been explored to a lesser extent. In particular, the notion of style recurs infrequently in the literature on sensorimotor behavior. In general use, style refers to a distinctive manner or custom of behaving oneself or of doing something, especially one that is typical of a person, group of people, place, context, or period. The application of the term to the domain of perceptual and motor phenomenology opens new perspectives on the nature of behavioral variability, perspectives that are complementary to those typically considered in the studies of sensorimotor variability. In particular, the concept of style may help toward the development of personalised physiology and medicine by providing markers of individual behaviour and response to different stimuli or treatments. Here, we cover some potential applications of the concept of perceptual-motor style to different areas of neuroscience, both in the healthy and the diseased. We prefer to be as general as possible in the types of applications we consider, even at the expense of running the risk of encompassing loosely related studies, given the relative novelty of the introduction of the term perceptual-motor style in neurosciences.
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Affiliation(s)
- Pierre-Paul Vidal
- CNRS, SSA, ENS Paris Saclay, Université de Paris, Centre Borelli, 75005 Paris, France
- Institute of Information and Control, Hangzhou Dianzi University, Hangzhou, China
| | - Francesco Lacquaniti
- Department of Systems Medicine, Center of Space Biomedicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
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Karmali F, Goodworth AD, Valko Y, Leeder T, Peterka RJ, Merfeld DM. The role of vestibular cues in postural sway. J Neurophysiol 2021; 125:672-686. [PMID: 33502934 DOI: 10.1152/jn.00168.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Controlling posture requires continuous sensory feedback about body motion and orientation, including from the vestibular organs. Little is known about the role of tilt vs. translation vs. rotation vestibular cues. We examined whether intersubject differences in vestibular function were correlated with intersubject differences in postural control. Vestibular function was assayed using vestibular direction-recognition perceptual thresholds, which determine the smallest motion that can be reliably perceived by a subject seated on a motorized platform in the dark. In study A, we measured thresholds for lateral translation, vertical translation, yaw rotation, and head-centered roll tilts. In study B, we measured thresholds for roll, pitch, and left anterior-right posterior and right anterior-left posterior tilts. Center-of-pressure (CoP) sway was measured in sensory organization tests (study A) and Romberg tests (study B). We found a strong positive relationship between CoP sway and lateral translation thresholds but not CoP sway and other thresholds. This finding suggests that the vestibular encoding of lateral translation may contribute substantially to balance control. Since thresholds assay sensory noise, our results support the hypothesis that vestibular noise contributes to spontaneous postural sway. Specifically, we found that lateral translation thresholds explained more of the variation in postural sway in postural test conditions with altered proprioceptive cues (vs. a solid surface), consistent with postural sway being more dependent on vestibular noise when the vestibular contribution to balance is higher. These results have potential implications for vestibular implants, balance prostheses, and physical therapy exercises.NEW & NOTEWORTHY Vestibular feedback is important for postural control, but little is known about the role of tilt cues vs. translation cues vs. rotation cues. We studied healthy human subjects with no known vestibular pathology or symptoms. Our findings showed that vestibular encoding of lateral translation correlated with medial-lateral postural sway, consistent with lateral translation cues contributing to balance control. This adds support to the hypothesis that vestibular noise contributes to spontaneous postural sway.
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Affiliation(s)
- Faisal Karmali
- Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts.,Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts
| | - Adam D Goodworth
- Kinesiology Department, Westmont College, Santa Barbara, California
| | - Yulia Valko
- Departments of Ophthalmology and Neurology, University Hospital Zurich, University of Zurich, Switzerland
| | - Tania Leeder
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts
| | - Robert J Peterka
- Department of Neurology, Oregon Health and Science University, Portland, Oregon.,National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, Portland, Oregon
| | - Daniel M Merfeld
- Department of Otolaryngology - Head and Neck Surgery, The Ohio State University, Columbus, Ohio
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9
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Alizadehsaravi L, Bruijn SM, Maas H, van Dieën JH. Modulation of soleus muscle H-reflexes and ankle muscle co-contraction with surface compliance during unipedal balancing in young and older adults. Exp Brain Res 2020; 238:1371-1383. [PMID: 32266445 PMCID: PMC7286858 DOI: 10.1007/s00221-020-05784-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 03/14/2020] [Indexed: 11/25/2022]
Abstract
This study aimed to assess modulation of lower leg muscle reflex excitability and co-contraction during unipedal balancing on compliant surfaces in young and older adults. Twenty healthy adults (ten aged 18-30 years and ten aged 65-80 years) were recruited. Soleus muscle H-reflexes were elicited by electrical stimulation of the tibial nerve, while participants stood unipedally on a robot-controlled balance platform, simulating different levels of surface compliance. In addition, electromyographic data (EMG) of soleus (SOL), tibialis anterior (TA), and peroneus longus (PL) and full-body 3D kinematic data were collected. The mean absolute center of mass velocity was determined as a measure of balance performance. Soleus H-reflex data were analyzed in terms of the amplitude related to the M wave and the background EMG activity 100 ms prior to the stimulation. The relative duration of co-contraction was calculated for soleus and tibialis anterior, as well as for peroneus longus and tibialis anterior. Center of mass velocity was significantly higher in older adults compared to young adults ([Formula: see text] and increased with increasing surface compliance in both groups ([Formula: see text]. The soleus H-reflex gain decreased with surface compliance in young adults [Formula: see text], while co-contraction increased [Formula: see text]. Older adults did not show such modulations, but showed overall lower H-reflex gains [Formula: see text] and higher co-contraction than young adults [Formula: see text]. These results suggest an overall shift in balance control from the spinal level to supraspinal levels in older adults, which also occurred in young adults when balancing at more compliant surfaces.
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Affiliation(s)
- Leila Alizadehsaravi
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Institute for Brain and Behaviour Amsterdam and Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
| | - Sjoerd M Bruijn
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Institute for Brain and Behaviour Amsterdam and Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
| | - Huub Maas
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Institute for Brain and Behaviour Amsterdam and Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands
| | - Jaap H van Dieën
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Institute for Brain and Behaviour Amsterdam and Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands.
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Mahmood I, Martinez-Hernandez U, Dehghani-Sanij AA. A model identification approach to quantify impact of whole-body vertical vibrations on limb compliant dynamics and walking stability. Med Eng Phys 2020; 80:8-17. [PMID: 32451270 DOI: 10.1016/j.medengphy.2020.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/26/2020] [Accepted: 04/05/2020] [Indexed: 11/18/2022]
Abstract
Extensive research is ongoing in the field of orthoses/exoskeleton design for efficient lower limbs assistance. However, despite wearable devices reported to improve lower limb mobility, their structural impacts on whole-body vertical dynamics have not been investigated. This study introduced a model identification approach and frequency domain analysis to quantify the impacts of orthosis-generated vibrations on limb stability and contractile dynamics. Experiments were recorded in the motion capture lab using 11 unimpaired subjects by wearing an adjustable ankle-foot orthosis (AFO). The lower limb musculoskeletal structure was identified as spring-mass (SM) and spring-mass-damper (SMD) based compliant models using the whole-body centre-of-mass acceleration data. Furthermore, Nyquist and Bode methods were implemented to quantify stabilities resulting from vertical impacts. Our results illustrated a significant decrease (p < 0.05) in lower limb contractile properties by wearing AFO compared with a normal walk. Also, stability margins quantified by wearing AFO illustrated a significant variance in terms of gain-margins (p < 0.05) for both loading and unloading phases whereas phase-margins decreased (p < 0.05) only for the respective unloading phases. The methods introduced here provide evidence that wearable orthoses significantly affect lower limb vertical dynamics and should be considered when evaluating orthosis/prosthesis/exoskeleton effectiveness.
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Affiliation(s)
- Imran Mahmood
- Institute of Design, Robotics, and Optimisation, School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Uriel Martinez-Hernandez
- Department of Electronics and Electrical Engineering, Faculty of Engineering and Design, University of Bath, Bath, United Kingdom
| | - Abbas A Dehghani-Sanij
- Institute of Design, Robotics, and Optimisation, School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
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11
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Patikas DA, Papavasileiou A, Ekizos A, Hatzitaki V, Arampatzis A. Swaying slower reduces the destabilizing effects of a compliant surface on voluntary sway dynamics. PLoS One 2019; 14:e0226263. [PMID: 31826026 PMCID: PMC6905565 DOI: 10.1371/journal.pone.0226263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 11/24/2019] [Indexed: 11/18/2022] Open
Abstract
The ability to control weight shifting (voluntary sway) is a crucial factor for stability during standing. Postural tracking of an oscillating visual target when standing on a compliant surface (e.g. foam) is a challenging weight shifting task that may alter the stability of the system and the muscle activation patterns needed to compensate for the perturbed state. The purpose of this study was to examine the effects of surface stability and sway frequency on the muscle activation of the lower limb, during visually guided voluntary postural sway. Seventeen volunteers performed a 2-min voluntary sway task in the anterior-posterior direction following with their projected center of pressure (CoPAP) a periodically oscillating visual target on a screen. The target oscillated at a frequency of 0.25 Hz or 0.125 Hz, while the participants swayed on solid ground (stable surface) or on a foam pad (unstable surface), resulting in four experimental conditions. The electromyogram (EMG) of 13 lower limb muscles was measured and the target–CoPAP coupling was evaluated with coherence analysis, whereas the difference in the stability of the system between the conditions was estimated by the maximum Lyapunov exponent (MLE). The results showed that slower oscillations outperformed the faster in terms of coherence and revealed greater stability. On the other hand, unstable ground resulted in an undershooting of the CoPAP to the target and greater MLE. Regarding the EMG data, a decreased triceps surae muscle activation at the low sway frequency compared to the higher was observed, whereas swaying on foam induced higher activation on the tibialis anterior as well. It is concluded that swaying voluntarily on an unstable surface results in reduced CoPAP and joint kinematics stability, that is accomplished by increasing the activation of the distal leg muscles, in order to compensate for this perturbation. The reduction of the sway frequency limits the effect of the unstable surface, on the head and upper body, improves the temporal component of coherence between CoP and target, whereas EMG activity is decreased. These findings might have implications in rehabilitation programs.
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Affiliation(s)
- Dimitrios A. Patikas
- School of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
- * E-mail:
| | - Anastasia Papavasileiou
- School of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Antonis Ekizos
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin School of Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Vassilia Hatzitaki
- School of Physical Education and Sport Science, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Adamantios Arampatzis
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin School of Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
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12
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Hafström A. Perceived and Functional Balance Control Is Negatively Affected by Diminished Touch and Vibration Sensitivity in Relatively Healthy Older Adults and Elderly. Gerontol Geriatr Med 2018; 4:2333721418775551. [PMID: 29900186 PMCID: PMC5990875 DOI: 10.1177/2333721418775551] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 03/07/2018] [Accepted: 03/19/2018] [Indexed: 11/17/2022] Open
Abstract
Background: Severe diminished foot somatosensation, for example, caused by neuropathies and advanced aging, contributes to balance deficits and increased fall risk. However, little is known about somatosensory impairment and functional and subjective balance problems in relatively healthy elderly. Method: Vibration perception thresholds (VPTs) were assessed with a biothesiometer and tactile pressure sensation thresholds (TPSTs) with 20 monofilaments in 34 relatively healthy community-dwelling older adults (M = 69.4 years). Balance was evaluated with functional balance tests and questionnaires. A stepwise regression analysis was performed to determine the extent to which VPTs, TPSTs, and age could explain balance impairments. Results: High VPTs had negative effects on Berg Balance Scale and Dizziness Handicap Inventory scores (p ≤ .011), as did high TPSTs on walking speed and Figure-8 test (p ≤ .001). With visual information available, one-leg standing time (OLST) was significantly affected by ipsilateral VPTs on solid and TPSTs on compliant surface (p ≤ .002). Without visual information, age was the only factor with a main effect on OLST (p < .001). Age had no significant correlations with TPSTs or VPTs. Discussion: Somatosensation appears to be very important for perceived as well as functional balance control in older adults. Our findings have important clinical implications when assessing balance impairment and impending fall risk.
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Balance Training Does Not Alter Reliance on Visual Information during Static Stance in Those with Chronic Ankle Instability: A Systematic Review with Meta-Analysis. Sports Med 2017; 48:893-905. [DOI: 10.1007/s40279-017-0850-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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