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Elie OS, Franz JR, Selgrade BP. The Effects of Optical Flow Perturbations on Standing Balance in People With Multiple Sclerosis. J Appl Biomech 2024; 40:122-128. [PMID: 37963452 DOI: 10.1123/jab.2022-0089] [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: 04/08/2022] [Revised: 08/22/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023]
Abstract
Multiple sclerosis is a neurodegenerative disease that causes balance deficits, even in early stages. Evidence suggests that people with multiple sclerosis (PwMS) rely more on vision to maintain balance, and challenging balance with optical flow perturbations may be a practical screening for balance deficits. Whether these perturbations affect standing balance in PwMS is unknown. Therefore, the purpose of this study was to examine how optical flow perturbations affect standing balance in PwMS. We hypothesized that perturbations would cause higher variability in PwMS compared with matched controls during standing and that standing balance would be more susceptible to anterior-posterior (A-P) perturbations than medial-lateral (M-L) perturbations. Thirteen PwMS and 13 controls stood under 3 conditions: unperturbed, M-L perturbation, and A-P perturbations. A-P perturbations caused significantly higher A-P trunk sway variability in PwMS than controls, although both groups had similar center-of-pressure variability. Both perturbations increased variability in A-P trunk sway and center of pressure. Trunk variability data supported the hypothesis that PwMS were more susceptible to optical flow perturbations than controls. However, the hypothesis that A-P perturbations would affect balance more than M-L perturbations was partially supported. These results suggest potential for optical flow perturbations to identify balance deficits in PwMS.
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Affiliation(s)
- Olivia S Elie
- Department of Sports Medicine and Human Performance, Westfield State University, Westfield, MA, USA
| | - Jason R Franz
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
| | - Brian P Selgrade
- Department of Sports Medicine and Human Performance, Westfield State University, Westfield, MA, USA
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Tacchino A, Skjerbæk AG, Podda J, Prada V, Monti Bragadin M, Bergamaschi V, Susini A, Hvid LG, Pedullà L, Brichetto G. The role of sensory systems in the association between balance and walking in people with multiple sclerosis. Mult Scler Relat Disord 2024; 83:105440. [PMID: 38219298 DOI: 10.1016/j.msard.2024.105440] [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: 09/26/2023] [Revised: 12/09/2023] [Accepted: 01/08/2024] [Indexed: 01/16/2024]
Abstract
BACKGROUND In Multiple Sclerosis, it has been demonstrated that balance is related to performances in walking tasks at different levels of complexity. However, it is unknown how the different sensory systems involved in balance control contribute to walking. This observational study investigates the associations between somatosensory, vestibular, and visual systems and measures of self-reported walking and walking capacity at different complexity levels (i.e. low, medium, and high). METHODS People with MS with EDSS<6 were assessed through the Sensory Organization Test (SOT), 12-Item MS Walking Scale (MSWS-12), Timed 25-Foot Walk (T25FW), Timed Up-and-Go Test (TUG), and Six-Spot-Step-Test (SSST). T25FW, TUG and SSST are measures of low, medium and high walking capacity, respectively. RESULTS Forty-five PwMS were enrolled (EDSS: 3.4 ± 1.3). Capacity/ability walking measures were moderate-to-highly significantly associated (p < 0.01). Balance measures from SOT showed significant correlation (p < 0.05) between vestibular system and all the walking measures; between visual system and T25FW, SSST and MSWS-12; between the degree to which the patient relies on the visual system to maintain balance with conflicting visual surroundings information (VIS PREF) and T25FW and TUG. In the multivariate analyses, only VIS PREF significantly correlated (p < 0.05) with T25FW (std. Beta=0.42) and TUG (std. Beta=0.38). CONCLUSIONS Vestibular and visual systems are associated with walking capacity. However, tasks with higher complexity levels require more visual attention towards ground obstacles, as often seen in real-life activities, whereas simpler walking tasks seem to require visual attention towards the surroundings.
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Affiliation(s)
- Andrea Tacchino
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy.
| | - Anders Guldhammer Skjerbæk
- MS Hospitals in Denmark, Ry, Denmark; Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Jessica Podda
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy
| | - Valeria Prada
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy
| | - Margherita Monti Bragadin
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy; Italian Multiple Sclerosis Society (AISM) Rehabilitation Service of Liguria, Via Operai 30, Genoa 16149, Italy
| | - Valeria Bergamaschi
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy; Italian Multiple Sclerosis Society (AISM) Rehabilitation Service of Liguria, Via Operai 30, Genoa 16149, Italy
| | - Alessia Susini
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy
| | - Lars G Hvid
- MS Hospitals in Denmark, Ry, Denmark; Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Ludovico Pedullà
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy
| | - Giampaolo Brichetto
- Italian Multiple Sclerosis Foundation (FISM), Scientific Research Area, Via Operai 40, Genoa 16149, Italy; Italian Multiple Sclerosis Society (AISM) Rehabilitation Service of Liguria, Via Operai 30, Genoa 16149, Italy
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Shelton AD, McTaggart EM, Allen JL, Mercer VS, Crenshaw JR, Franz JR. Does the effect of walking balance perturbations generalize across contexts? Hum Mov Sci 2024; 93:103158. [PMID: 38029635 PMCID: PMC10925841 DOI: 10.1016/j.humov.2023.103158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 09/15/2023] [Accepted: 11/02/2023] [Indexed: 12/01/2023]
Abstract
Balance perturbations are used to study locomotor instability. However, these perturbations are designed to provoke a specific context of instability that may or may not generalize to a broader understanding of falls risk. The purpose of this study was to determine if the effect of balance perturbations on instability generalizes across contexts. 29 younger adults and 28 older adults completed four experimental trials, including unperturbed walking and walking while responding to three perturbation contexts: mediolateral optical flow, treadmill-induced slips, and lateral waist-pulls. We quantified the effect of perturbations as an absolute change in margin of stability from unperturbed walking. We found significant changes in mediolateral and anteroposterior margin of stability for all perturbations compared to unperturbed walking in both cohorts (p-values ≤ 0.042). In older adults, the mediolateral effects of lateral waist-pulls significantly correlated with those of optical flow perturbations and treadmill-induced slips (r ≥ 0.398, p-values ≤ 0.036). In younger adults but not in older adults, we found positive and significant correlations between the anteroposterior effect of waist-pull perturbations and optical flow perturbations, and the anteroposterior and mediolateral effect of treadmill-induced slips (r ≥ 0.428, p-values ≤ 0.021). We found no "goldilocks" perturbation paradigm to endorse that would support universal interpretations about locomotor instability. Building the most accurate patient profiles of instability likely requires a series of perturbation paradigms designed to emulate the variety of environmental contexts in which falls may occur.
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Affiliation(s)
- Andrew D Shelton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill & North Carolina State University, Chapel Hill, NC, USA
| | - Ellora M McTaggart
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill & North Carolina State University, Chapel Hill, NC, USA
| | - Jessica L Allen
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, USA
| | - Vicki S Mercer
- Division of Physical Therapy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jeremy R Crenshaw
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Jason R Franz
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill & North Carolina State University, Chapel Hill, NC, USA.
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Spomer AM, Conner BC, Schwartz MH, Lerner ZF, Steele KM. Audiovisual biofeedback amplifies plantarflexor adaptation during walking among children with cerebral palsy. J Neuroeng Rehabil 2023; 20:164. [PMID: 38062454 PMCID: PMC10704679 DOI: 10.1186/s12984-023-01279-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/01/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Biofeedback is a promising noninvasive strategy to enhance gait training among individuals with cerebral palsy (CP). Commonly, biofeedback systems are designed to guide movement correction using audio, visual, or sensorimotor (i.e., tactile or proprioceptive) cues, each of which has demonstrated measurable success in CP. However, it is currently unclear how the modality of biofeedback may influence user response which has significant implications if systems are to be consistently adopted into clinical care. METHODS In this study, we evaluated the extent to which adolescents with CP (7M/1F; 14 [12.5,15.5] years) adapted their gait patterns during treadmill walking (6 min/modality) with audiovisual (AV), sensorimotor (SM), and combined AV + SM biofeedback before and after four acclimation sessions (20 min/session) and at a two-week follow-up. Both biofeedback systems were designed to target plantarflexor activity on the more-affected limb, as these muscles are commonly impaired in CP and impact walking function. SM biofeedback was administered using a resistive ankle exoskeleton and AV biofeedback displayed soleus activity from electromyography recordings during gait. At every visit, we measured the time-course response to each biofeedback modality to understand how the rate and magnitude of gait adaptation differed between modalities and following acclimation. RESULTS Participants significantly increased soleus activity from baseline using AV + SM (42.8% [15.1, 59.6]), AV (28.5% [19.2, 58.5]), and SM (10.3% [3.2, 15.2]) biofeedback, but the rate of soleus adaptation was faster using AV + SM biofeedback than either modality alone. Further, SM-only biofeedback produced small initial increases in plantarflexor activity, but these responses were transient within and across sessions (p > 0.11). Following multi-session acclimation and at the two-week follow-up, responses to AV and AV + SM biofeedback were maintained. CONCLUSIONS This study demonstrated that AV biofeedback was critical to increase plantarflexor engagement during walking, but that combining AV and SM modalities further amplified the rate of gait adaptation. Beyond improving our understanding of how individuals may differentially prioritize distinct forms of afferent information, outcomes from this study may inform the design and selection of biofeedback systems for use in clinical care.
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Affiliation(s)
- Alyssa M Spomer
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
- Gillette Children's, 200 University Avenue East, Stop 490105, St. Paul, MN, 55101, USA.
| | - Benjamin C Conner
- College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Michael H Schwartz
- Department of Orthopedic Surgery, University of Minnesota, Minneapolis, MN, USA
- Gillette Children's, 200 University Avenue East, Stop 490105, St. Paul, MN, 55101, USA
| | - Zachary F Lerner
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
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Riem L, Beardsley SA, Obeidat AZ, Schmit BD. Visual oscillation effects on dynamic balance control in people with multiple sclerosis. J Neuroeng Rehabil 2022; 19:90. [PMID: 35978431 PMCID: PMC9382748 DOI: 10.1186/s12984-022-01060-0] [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: 03/16/2022] [Accepted: 06/15/2022] [Indexed: 12/03/2022] Open
Abstract
Background People with multiple sclerosis (PwMS) have balance deficits while ambulating through environments that contain moving objects or visual manipulations to perceived self-motion. However, their ability to parse object from self-movement has not been explored. The purpose of this research was to examine the effect of medial–lateral oscillations of the visual field and of objects within the scene on gait in PwMS and healthy age-matched controls using virtual reality (VR). Methods Fourteen PwMS (mean age 49 ± 11 years, functional gait assessment score of 27.8 ± 1.8, and Berg Balance scale score 54.7 ± 1.5) and eleven healthy controls (mean age: 53 ± 12 years) participated in this study. Dynamic balance control was assessed while participants walked on a treadmill at a self-selected speed while wearing a VR headset that projected an immersive forest scene. Visual conditions consisted of (1) no visual manipulations (speed-matched anterior/posterior optical flow), (2) 0.175 m mediolateral translational oscillations of the scene that consisted of low pairing (0.1 and 0.31 Hz) or (3) high pairing (0.15 and 0.465 Hz) frequencies, (4) 5 degree medial–lateral rotational oscillations of virtual trees at a low frequency pairing (0.1 and 0.31 Hz), and (5) a combination of the tree and scene movements in (3) and (4). Results We found that both PwMS and controls exhibited greater instability and visuomotor entrainment to simulated mediolateral translation of the visual field (scene) during treadmill walking. This was demonstrated by significant (p < 0.05) increases in mean step width and variability and center of mass sway. Visuomotor entrainment was demonstrated by high coherence between center of mass sway and visual motion (magnitude square coherence = ~ 0.5 to 0.8). Only PwMS exhibited significantly greater instability (higher step width variability and center of mass sway) when objects moved within the scene (i.e., swaying trees). Conclusion Results suggest the presence of visual motion processing errors in PwMS that reduced dynamic stability. Specifically, object motion (via tree sway) was not effectively parsed from the observer’s self-motion. Identifying this distinction between visual object motion and self-motion detection in MS provides insight regarding stability control in environments with excessive external movement, such as those encountered in daily life.
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Affiliation(s)
- Lara Riem
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA
| | - Scott A Beardsley
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA
| | - Ahmed Z Obeidat
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Brian D Schmit
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA.
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THE EFFECT OF VIRTUAL REALITY-BASED THERAPY ON FEAR OF FALLING IN MULTIPLE SCLEROSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS. Mult Scler Relat Disord 2022; 63:103791. [DOI: 10.1016/j.msard.2022.103791] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/25/2022] [Accepted: 04/01/2022] [Indexed: 11/19/2022]
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Bilek F, Demir CF. Validity and reliability of the 3-meter backward walk test in mildly disabled persons with multiple sclerosis. Mult Scler Relat Disord 2022; 58:103532. [PMID: 35066275 DOI: 10.1016/j.msard.2022.103532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/12/2021] [Accepted: 01/14/2022] [Indexed: 01/22/2023]
Abstract
BACKGROUND One of the biggest problems for persons with Multiple Sclerosis (PwMS) is dizziness, poor posture, and balance problems that cause injury-causing falls. The aim of our study was to reveal the test-retest reliability and validity of the 3-Meter Backward Walk Test (3MBWT) in mildly disabled PwMS. METHODS This study included a total of 93 mildly disabled PwMS with mean EDSS of 1.89. 3MBWT, Functional Access Test (FRT), Dynamic Gait Index (DGI), Timed 25-Foot Walk (T25FW), and Timed-Up and Go (TUG) were applied to the patients. To measure test-retest reliability, a second evaluation was performed three days after the first evaluation. RESULTS Cronbach's alpha coefficient was found to be 0.998 (excellent). For intra-rater agreement, the ICC values in the individual test were 0.998. The SEM value was 0.18, the MDC value was found to be 0.50. A very strong correlation was revealed between the 3MBWT and FRT (r: -0.931, p: 0.001), TUG (r: 0.968, p: 0.001), T25FW (r: 0.879, p: 0.001), DGI (r: -0.871, p: 0.001) and falling history (r: 0.932, p: 0.001). CONCLUSION The 3MBWT was observed to be valid and reliable in mildly disabled PwMS. 3MBWT is an effective and reliable tool for measuring ability to walk backward in mildly disabled PwMS.
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Affiliation(s)
- Furkan Bilek
- Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Fırat University, Elazığ, Turkey.
| | - Caner Feyzi Demir
- Department of Neurology, Faculty of Medical, Fırat University, Elazığ, Turkey
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Ehrhardt A, Hostettler P, Widmer L, Reuter K, Petersen JA, Straumann D, Filli L. Fall-related functional impairments in patients with neurological gait disorder. Sci Rep 2020; 10:21120. [PMID: 33273488 PMCID: PMC7712911 DOI: 10.1038/s41598-020-77973-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/17/2020] [Indexed: 11/08/2022] Open
Abstract
Falls are common in patients with neurological disorders and are a primary cause of injuries. Nonetheless, fall-associated gait characteristics are poorly understood in these patients. Objective, quantitative gait analysis is an important tool to identify the principal fall-related motor characteristics and to advance fall prevention in patients with neurological disorders. Fall incidence was assessed in 60 subjects with different neurological disorders. Patients underwent a comprehensive set of functional assessments including instrumented gait analysis, computerized postural assessments and clinical walking tests. Determinants of falls were assessed by binary logistic regression analysis and receiver operator characteristics (ROC). The best single determinant of fallers was a step length reduction at slow walking speed reaching an accuracy of 67.2% (ROC AUC: 0.669; p = 0.027). The combination of 4 spatio-temporal gait parameters including step length and parameters of variability and asymmetry were able to classify fallers and non-fallers with an accuracy of 81.0% (ROC AUC: 0.882; p < 0.001). These findings suggest significant differences in specific spatio-temporal gait parameters between fallers and non-fallers among neurological patients. Fall-related impairments were mainly identified for spatio-temporal gait characteristics, suggesting that instrumented, objective gait analysis is an important tool to estimate patients' fall risk. Our results highlight pivotal fall-related walking deficits that might be targeted by future rehabilitative interventions that aim at attenuating falls.
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Affiliation(s)
- Angela Ehrhardt
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland.
| | - Pascal Hostettler
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Lucas Widmer
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Katja Reuter
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | | | - Dominik Straumann
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Linard Filli
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Swiss Center for Clinical Movement Analysis (SCMA), Balgrist Campus AG, Zurich, Switzerland
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Desmet DM, Westbrook AD, Grabiner MD. Treadmill-belt width, but not feedback from the lower visual field, influences the noise characteristics of step width time series. J Biomech 2020; 109:109943. [PMID: 32807305 DOI: 10.1016/j.jbiomech.2020.109943] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 06/18/2020] [Accepted: 07/02/2020] [Indexed: 10/23/2022]
Abstract
Step kinematic variability, which has been associated with gait-related fall risk, is thought to be attributed to neuromotor noise. Altered neuromotor control of step kinematics would be expected to manifest as changes in the noise-related characteristics of the step kinematic time series. This study determined the effects of eliminating feedback from the lower visual field and reducing treadmill-belt width on the noise characteristics of step width time series and statistical measures of step width variability during treadmill walking. We hypothesized that eliminating feedback from the lower visual field and reducing treadmill-belt width would both alter the noise characteristics of step width time series, reflected by decreased fractal scaling, and increase statistical measures of step width variability. Eighteen young adults performed four randomly ordered walking trials during which we manipulated visual feedback from the lower visual field (normal and obstructed) and treadmill-belt width (wide and narrow). Reducing treadmill-belt width, but not eliminating feedback from the lower visual field, significantly reduced the fractal scaling of step width time series, indicating a shift towards white, uncorrelated noise. These results suggest that accounting for the influence of treadmill-belt width on step width time series may be an important consideration in both laboratory and clinical settings. Further work is needed to clarify the effects of vision on measures of step width, identify the mechanism(s) underlying the observed shift towards white, uncorrelated noise associated with reduced treadmill-belt width, and to assess the potential relationship between the noise characteristics of step width time series and fall risk.
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Affiliation(s)
- David M Desmet
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, United States.
| | - Aaron D Westbrook
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Mark D Grabiner
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, United States
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