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Render AC, Cusumano JP, Dingwell JB. Probability of lateral instability while walking on winding paths. J Biomech 2024; 176:112361. [PMID: 39395341 DOI: 10.1016/j.jbiomech.2024.112361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 09/29/2024] [Accepted: 10/03/2024] [Indexed: 10/14/2024]
Abstract
People with balance impairments often struggle performing turns or lateral maneuvers, which can increase risk of falls and injuries. Here we asked how people's mediolateral balance is impacted when walking on non-straight winding paths. Twenty-four healthy adults (12F / 12M; 25.8±3.5 yrs) participated. Each walked on each of six paths projected onto a treadmill, comprised of three pseudo-random path oscillation frequency combinations (straight, slowly-winding, quickly-winding), each presented at either wide or narrow width. We quantified stepping errors as the percent of steps taken off each path. We quantified minimum mediolateral Margin of Stability (MoSL) at each step and calculated means (μ) and standard deviations (σ) for each trial. We calculated lateral Probability of Instability (PoIL) as participants' statistical risk of taking unstable (MoSL < 0) steps. On narrower paths, participants made more stepping errors and walked with smaller μ(MoSL) for all path frequencies (p < 0.001), and exhibited increased PoIL on the straight and slowly-winding paths (p < 0.001). On winding paths, participants made progressively more stepping errors and walked with smaller μ(MoSL) as oscillation frequency increased on narrow paths (all p < 0.001) and on the wide quickly-winding paths (all p < 0.001). They also consistently walked with larger σ(MoSL), and increased PoILon higher sinuosity paths of both widths (all p < 0.001). Though many took numerous unstable steps, no participant fell. Our results demonstrate healthy adults' ability both to trade off increased risk of lateral instability for greater maneuverability, and to employ highly-versatile stepping strategies to maintain balance while walking.
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Affiliation(s)
- Anna C Render
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802 USA
| | - Joseph P Cusumano
- Department of Engineering Science & Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
| | - Jonathan B Dingwell
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802 USA.
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Chang JJ, Chen YC, Yeh SL, Tang PF, Tu CK. Impacts of audiovisual simultaneity perception on single-task and dual-task gaits in middle-aged and older adults. Gait Posture 2024; 113:99-105. [PMID: 38850854 DOI: 10.1016/j.gaitpost.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 05/18/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
BACKGROUND While dual-task walking requires the ability to integrate sensory information from multiple ongoing sources, it remains unknown whether dual-task walking is more affected than single-task walking by the multisensory integration ability. RESEARCH QUESTION How does the audiovisual temporal integration ability affect single-task and dual-task gaits in the aging population? METHODS One hundred and thirty healthy middle-aged and older adults (age = 64.7 ± 6.4 years) completed an audiovisual simultaneity judgment (AVSJ) task and underwent single-task, motor dual-task, and cognitive dual-task gait assessments. In the AVSJ task, participants judged whether a flash and an auditory stimulus presented at different stimulus onset asynchronies were simultaneous. The accuracy and precision of the AVSJ performance were assessed using the point of subjective simultaneity (PSS) and the temporal binding window (δ), respectively. A lower absolute PSS and δ indicated better performance. Participants held a cup of water and performed serial-7 subtraction for motor and cognitive dual-task gait assessments, respectively. The spatiotemporal gait parameters and their variability were calculated. The influences of PSS and δ on the gait parameters of the three gaits were examined with multiple hierarchical regressions. RESULTS Only the cognitive dual-task gait was significantly affected by PSS and δ. Greater PSS predicted a longer single support time (β = 0.195, p = 0.024) and its variability (β = 0.224, p = 0.011). Greater δ predicted greater step time variability (β = 0.198, p = 0.022). SIGNIFICANCE Declined perception of audiovisual simultaneity particularly degrades temporal control of cognitive dual-task walking, highlighting the importance of assessing and training this ability after midlife.
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Affiliation(s)
- Jer-Jen Chang
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Chuan Chen
- Department of Medicine, Mackay Medical College, New Taipei City, Taiwan
| | - Su-Ling Yeh
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Psychology, College of Science, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan; Center for Artificial Intelligence and Robotics, National Taiwan University, Taipei, Taiwan
| | - Pei-Fang Tang
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan; Center for Artificial Intelligence and Robotics, National Taiwan University, Taipei, Taiwan; School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan.
| | - Chien-Kuang Tu
- School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan; Rehabilitation Department, Sin-Wu Branch, Tao-Yuan General Hospital, Ministry of Health and Welfare, Taiwan
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Barnes L, Davidson MJ, Alais D. The speed and phase of locomotion dictate saccade probability and simultaneous low-frequency power spectra. Atten Percept Psychophys 2024:10.3758/s13414-024-02932-4. [PMID: 39048846 DOI: 10.3758/s13414-024-02932-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2024] [Indexed: 07/27/2024]
Abstract
Every day we make thousands of saccades and take thousands of steps as we explore our environment. Despite their common co-occurrence in a typical active state, we know little about the coordination between eye movements, walking behaviour and related changes in cortical activity. Technical limitations have been a major impediment, which we overcome here by leveraging the advantages of an immersive wireless virtual reality (VR) environment with three-dimensional (3D) position tracking, together with simultaneous recording of eye movements and mobile electroencephalography (EEG). Using this approach with participants engaged in unencumbered walking along a clear, level path, we find that the likelihood of eye movements at both slow and natural walking speeds entrains to the rhythm of footfall, peaking after the heel-strike of each step. Compared to previous research, this entrainment was captured in a task that did not require visually guided stepping - suggesting a persistent interaction between locomotor and visuomotor functions. Simultaneous EEG recordings reveal a concomitant modulation entrained to heel-strike, with increases and decreases in oscillatory power for a broad range of frequencies. The peak of these effects occurred in the theta and alpha range for slow and natural walking speeds, respectively. Together, our data show that the phase of the step-cycle influences other behaviours such as eye movements, and produces related modulations of simultaneous EEG following the same rhythmic pattern. These results reveal gait as an important factor to be considered when interpreting saccadic and time-frequency EEG data in active observers, and demonstrate that saccadic entrainment to gait may persist throughout everyday activities.
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Affiliation(s)
- Lydia Barnes
- School of Psychology, The University of Sydney, Sydney, NSW, Australia
| | | | - David Alais
- School of Psychology, The University of Sydney, Sydney, NSW, Australia
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Norrbrand L, Johannesson B, Grönkvist M. Increased Metabolic Demand During Nighttime Walking in Hilly Forest Terrain While Wearing Night Vision Goggles. Mil Med 2024:usae317. [PMID: 38913444 DOI: 10.1093/milmed/usae317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/24/2024] [Accepted: 06/19/2024] [Indexed: 06/26/2024] Open
Abstract
INTRODUCTION Foot-borne soldiers sometimes carry out nighttime operations. It has previously been reported an elevated metabolic demand and impaired walking economy during outdoor walking on a gravel road in darkness wearing night vision goggles (NVG), compared with wearing a headlamp. The aim of the present study was to evaluate the effect of wearing NVG while walking in a hilly forest terrain and compare the results between experienced and inexperienced NVG users. MATERIALS AND METHODS At nighttime, two different groups, inexperienced (five men and six women) and experienced (nine men) NVG users, walked 1.1 km at a self-selected comfortable pace in a hilly forest. Part I was mainly uphill, and Part II was mainly downhill. Walks were performed wearing a headlamp (light), monocular NVG (mono), binocular NVG (bino), or mono with a 25 kg extra weight (backpack). Walking economy calculated from oxygen uptake in relation to body mass and covered distance (V̇O2 (mL/[kg · km])), heart rate, gait, and walking speed were measured. RESULTS In both groups, walking economy was deteriorated in all three conditions with limited vision (mono, bino, and backpack) compared to the light condition, both during Part I (mono/bino, experienced: +26/+25%, inexperienced: +34/+28%) and Part II (mono/bino, experienced: +44/+46%, inexperienced: +63/+49%). In the backpack condition, the relative change of walking economy was greater for the inexperienced group than the experienced group: Part I (experienced: +46%, inexperienced: +70%), Part II (experienced: +71%, inexperienced: +111%). Concurrently, the step length was shorter in all three conditions with limited vision during Part I (mono/bino/backpack, experienced: -7/-7/-15%, inexperienced: -12/-12/-19%) and Part II (mono/bino/backpack; experienced: -8/-8/-14%, inexperienced: -17/-15/-24%) than in the light condition. The experienced NVG users walked faster during all conditions, but there was no difference in heart rate between groups. CONCLUSIONS Despite that foveal vision using NVG is adequate, it appears that the mechanical efficiency during nighttime walking in hilly terrain was markedly lower while wearing NVG than with full vision, regardless of whether the soldier was an experienced or inexperienced NVG user. Moreover, the walking economy was even more affected when adding the 25-kg extra weight. It is probable that the deteriorated mechanical efficiency was partly due to the shorter step length in all three conditions with limited vision.
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Affiliation(s)
- Lena Norrbrand
- Division of Environmental Physiology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Solna 171 65, Sweden
| | - Björn Johannesson
- Division of Environmental Physiology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Solna 171 65, Sweden
| | - Mikael Grönkvist
- Division of Environmental Physiology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Solna 171 65, Sweden
- Division of Health Informatics and Logistics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Flemingsberg 141 57, Sweden
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Davidson MJ, Verstraten FAJ, Alais D. Walking modulates visual detection performance according to stride cycle phase. Nat Commun 2024; 15:2027. [PMID: 38453900 PMCID: PMC10920920 DOI: 10.1038/s41467-024-45780-4] [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: 06/20/2023] [Accepted: 02/05/2024] [Indexed: 03/09/2024] Open
Abstract
Walking is among our most frequent and natural of voluntary behaviours, yet the consequences of locomotion upon perceptual and cognitive function remain largely unknown. Recent work has highlighted that although walking feels smooth and continuous, critical phases exist within each step for the successful coordination of perceptual and motor function. Here, we test whether these phasic demands impact upon visual perception, by assessing performance in a visual detection task during natural unencumbered walking. We finely sample visual performance over the stride cycle as participants walk along a smooth linear path at a comfortable speed in a wireless virtual reality environment. At the group-level, accuracy, reaction times, and response likelihood show strong oscillations, modulating at approximately 2 cycles per stride (~2 Hz) with a marked phase of optimal performance aligned with the swing phase of each step. At the participant level, Bayesian inference of population prevalence reveals highly prevalent oscillations in visual detection performance that cluster in two idiosyncratic frequency ranges (2 or 4 cycles per stride), with a strong phase alignment across participants.
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Affiliation(s)
| | | | - David Alais
- School of Psychology, The University of Sydney, Sydney, Australia
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6
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Kreter N, Fino PC. Consequences of changing planned foot placement on balance control and forward progress. J R Soc Interface 2024; 21:20230577. [PMID: 38350615 PMCID: PMC10864096 DOI: 10.1098/rsif.2023.0577] [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: 10/04/2023] [Accepted: 01/19/2024] [Indexed: 02/15/2024] Open
Abstract
While walking humans generally plan foot placement two steps in advance. However, it is often necessary to rapidly alter foot placement position just before stepping due to the appearance of a new obstacle. While humans are quite capable of rapidly altering foot placement position, such changes can have major effects on centre of mass dynamics. We investigated how rapid changes to planned foot placement impact centre of mass dynamics, and how such changes influence the control of balance and forward progress, during both straight- and turning-gait. Thirteen young adults walked along a virtually projected walkway with precision footholds oriented either in a straight line or with a single 60°, 90° or 120° turn. On a subset of trials, participants were required to rapidly avoid stepping on select footholds. We found that if the centre of mass was disrupted such that it interfered with task success (i.e. staying upright and continuing along the planned path), walkers were more likely to sacrifice forward progress than the upright stability. Further, walkers appear to control centre of mass dynamics differently following inhibited steps during step turns than during spin turns, which may reflect a larger threat to task success when spin turns are interrupted.
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Affiliation(s)
- Nicholas Kreter
- Department of Health and Kinesiology, University of Utah, Salt Lake City, UT 84112, USA
| | - Peter C. Fino
- Department of Health and Kinesiology, University of Utah, Salt Lake City, UT 84112, USA
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Davidson MJ, Keys RT, Szekely B, MacNeilage P, Verstraten F, Alais D. Continuous peripersonal tracking accuracy is limited by the speed and phase of locomotion. Sci Rep 2023; 13:14864. [PMID: 37684285 PMCID: PMC10491677 DOI: 10.1038/s41598-023-40655-y] [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: 05/04/2023] [Accepted: 08/16/2023] [Indexed: 09/10/2023] Open
Abstract
Recent evidence suggests that perceptual and cognitive functions are codetermined by rhythmic bodily states. Prior investigations have focused on the cardiac and respiratory rhythms, both of which are also known to synchronise with locomotion-arguably our most common and natural of voluntary behaviours. Compared to the cardiorespiratory rhythms, walking is easier to voluntarily control, enabling a test of how natural and voluntary rhythmic action may affect sensory function. Here we show that the speed and phase of human locomotion constrains sensorimotor performance. We used a continuous visuo-motor tracking task in a wireless, body-tracking virtual environment, and found that the accuracy and reaction time of continuous reaching movements were decreased at slower walking speeds, and rhythmically modulated according to the phases of the step-cycle. Decreased accuracy when walking at slow speeds suggests an advantage for interlimb coordination at normal walking speeds, in contrast to previous research on dual-task walking and reach-to-grasp movements. Phasic modulations of reach precision within the step-cycle also suggest that the upper limbs are affected by the ballistic demands of motor-preparation during natural locomotion. Together these results show that the natural phases of human locomotion impose constraints on sensorimotor function and demonstrate the value of examining dynamic and natural behaviour in contrast to the traditional and static methods of psychological science.
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Affiliation(s)
| | | | - Brian Szekely
- Department of Psychology, University of Nevada, Reno, USA
| | | | - Frans Verstraten
- School of Psychology, The University of Sydney, Sydney, Australia
| | - David Alais
- School of Psychology, The University of Sydney, Sydney, Australia
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8
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Ellmers TJ, Wilson MR, Kal EC, Young WR. The perceived control model of falling: developing a unified framework to understand and assess maladaptive fear of falling. Age Ageing 2023; 52:afad093. [PMID: 37466642 PMCID: PMC10355179 DOI: 10.1093/ageing/afad093] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND fear of falling is common in older adults and can have a profound influence on a variety of behaviours that increase fall risk. However, fear of falling can also have potentially positive outcomes for certain individuals. Without progressing our understanding of mechanisms underlying these contrasting outcomes, it is difficult to clinically manage fear of falling. METHODS this paper first summarises recent findings on the topic of fear of falling, balance and fall risk-including work highlighting the protective effects of fear. Specific focus is placed on describing how fear of falling influences perceptual, cognitive and motor process in ways that might either increase or reduce fall risk. Finally, it reports the development and validation of a new clinical tool that can be used to assess the maladaptive components of fear of falling. RESULTS we present a new conceptual framework-the Perceived Control Model of Falling-that describes specific mechanisms through which fear of falling can influence fall risk. The key conceptual advance is the identification of perceived control over situations that threaten one's balance as the crucial factor mediating the relationship between fear and increased fall risk. The new 4-item scale that we develop-the Updated Perceived Control over Falling Scale (UP-COF)-is a valid and reliable tool to clinically assess perceived control. CONCLUSION this new conceptualisation and tool (UP-COF) allows clinicians to identify individuals for whom fear of falling is likely to increase fall risk, and target specific underlying maladaptive processes such as low perceived control.
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Affiliation(s)
| | - Mark R Wilson
- Department of Public Health and Sports Sciences, University of Exeter, Exeter, UK
| | - Elmar C Kal
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
| | - William R Young
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
- Department of Public Health and Sports Sciences, University of Exeter, Exeter, UK
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9
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Zipser-Mohammadzada F, Scheffers MF, Conway BA, Halliday DM, Zipser CM, Curt A, Schubert M. Intramuscular coherence enables robust assessment of modulated supra-spinal input in human gait: an inter-dependence study of visual task and walking speed. Exp Brain Res 2023; 241:1675-1689. [PMID: 37199775 DOI: 10.1007/s00221-023-06635-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 05/11/2023] [Indexed: 05/19/2023]
Abstract
Intramuscular high-frequency coherence is increased during visually guided treadmill walking as a consequence of increased supra-spinal input. The influence of walking speed on intramuscular coherence and its inter-trial reproducibility need to be established before adoption as a functional gait assessment tool in clinical settings. Here, fifteen healthy controls performed a normal and a target walking task on a treadmill at various speeds (0.3 m/s, 0.5 m/s, 0.9 m/s, and preferred) during two sessions. Intramuscular coherence was calculated between two surface EMG recordings sites of the Tibialis anterior muscle during the swing phase of walking. The results were averaged across low-frequency (5-14 Hz) and high-frequency (15-55 Hz) bands. The effect of speed, task, and time on mean coherence was assessed using three-way repeated measures ANOVA. Reliability and agreement were calculated with the intra-class correlation coefficient and Bland-Altman method, respectively. Intramuscular coherence during target walking was significantly higher than during normal walking across all walking speeds in the high-frequency band as obtained by the three-way repeated measures ANOVA. Interaction effects between task and speed were found for the low- and high-frequency bands, suggesting that task-dependent differences increase at higher walking speeds. Reliability of intramuscular coherence was moderate to excellent for most normal and target walking tasks in all frequency bands. This study confirms previous reports of increased intramuscular coherence during target walking, while providing first evidence for reproducibility and robustness of this measure as a requirement to investigate supra-spinal input.Trial registration Registry number/ClinicalTrials.gov Identifier: NCT03343132, date of registration 2017/11/17.
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Affiliation(s)
| | - Marjelle Fredie Scheffers
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Faculty of Medicine, Utrecht University, Utrecht, The Netherlands
| | - Bernard A Conway
- Biomedical Engineering, University of Strathclyde, Glasgow, G4 0NW, UK
| | - David M Halliday
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, UK
- York Biomedical Research Institute, University of York, York, UK
| | - Carl Moritz Zipser
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Armin Curt
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
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10
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Pieruccini-Faria F, Hassan Haddad SM, Bray NW, Sarquis-Adamson Y, Bartha R, Montero-Odasso M. Brain Structural Correlates of Obstacle Negotiation in Mild Cognitive Impairment: Results from the Gait and Brain Study. Gerontology 2023; 69:1115-1127. [PMID: 37166343 DOI: 10.1159/000530796] [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: 07/05/2022] [Accepted: 04/17/2023] [Indexed: 05/12/2023] Open
Abstract
INTRODUCTION Mild cognitive impairment (MCI) affects obstacle negotiation capabilities, potentially increasing the risk of falls in older adults. However, it is unclear whether smaller brain volumes typically observed in older individuals with MCI are related to the observed hazardous obstacle negotiation in this population. METHODS A total of 93 participants (71.9 ± 5.36 years of age; MCI = 53/control = 40) from the Gait and Brain Study were analyzed. Gray matter (GM) volumes from the frontal, temporal, and parietal lobes were entered in the analysis. Gait performance was recorded using a 6-m electronic walkway during two cognitive load conditions while approaching and stepping over an obstacle: (1) single-task and (2) while counting backwards by 1s from 100 (dual-task). Anticipatory adjustments in gait performance to cross an "ad hoc" obstacle were electronically measured during pre-crossing phases: early (3 steps before the late phase) and late (3 steps before obstacle). Association between the percentage of change in average gait speed and step length from early to late (i.e., anticipatory adjustments) and GM volumes was investigated using multivariate models adjusted for potential confounders. RESULTS Anticipatory adjustments in gait speed (Wilks' lambda: 0.35; Eta2: 0.64; p = 0.01) and step length (Wilks' lambda: 0.33; Eta2: 0.66; p = 0.01) during dual-task conditions were globally associated with GM volumes in MCI. Individuals with MCI with smaller GM volumes in the left inferior frontal gyrus, left hippocampus, right hippocampus, and right entorhinal cortex made significantly fewer anticipatory gait adjustments prior to crossing the obstacle. CONCLUSION Frontotemporal atrophy may affect obstacle negotiation capabilities potentially increasing the risk of falls in MCI.
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Affiliation(s)
- Frederico Pieruccini-Faria
- Division of Geriatric Medicine, Department of Medicine, Western University, London, Ontario, Canada
- Gait and Brain Lab, Parkwood Institute and Lawson Health Research Institute, London, Ontario, Canada
| | | | - Nickolas W Bray
- Gait and Brain Lab, Parkwood Institute and Lawson Health Research Institute, London, Ontario, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Yanina Sarquis-Adamson
- Gait and Brain Lab, Parkwood Institute and Lawson Health Research Institute, London, Ontario, Canada
| | - Robert Bartha
- Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Manuel Montero-Odasso
- Division of Geriatric Medicine, Department of Medicine, Western University, London, Ontario, Canada
- Gait and Brain Lab, Parkwood Institute and Lawson Health Research Institute, London, Ontario, Canada
- Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada
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11
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Shoja O, Towhidkhah F, Hassanlouei H, Levin MF, Bahramian A, Nadeau S, Zhang L, Feldman AG. Reaction of human walking to transient block of vision: analysis in the context of indirect, referent control of motor actions. Exp Brain Res 2023; 241:1353-1365. [PMID: 37010540 DOI: 10.1007/s00221-023-06593-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 03/05/2023] [Indexed: 04/04/2023]
Abstract
Human locomotion may result from monotonic shifts in the referent position, R, of the body in the environment. R is also the spatial threshold at which muscles can be quiescent but are activated depending on the deflection of the current body configuration Q from R. Shifts in R are presumably accomplished with the participation of proprioceptive and visual feedback and responsible for transferring stable body balance (equilibrium) from one place in the environment to another, resulting in rhythmic activity of multiple muscles by a central pattern generator (CPG). We tested predictions of this two-level control scheme. In particular, in response to a transient block of vision during locomotion, the system can temporarily slow shifts in R. As a result, the phase of rhythmical movements of all four limbs will be changed for some time, even though the rhythm and other characteristics of locomotion will be fully restored after perturbation, a phenomenon called long-lasting phase resetting. Another prediction of the control scheme is that the activity of multiple muscles of each leg can be minimized reciprocally at specific phases of the gait cycle both in the presence and absence of vision. Speed of locomotion is related to the rate of shifts in the referent body position in the environment. Results confirmed that human locomotion is likely guided by feedforward shifts in the referent body location, with subsequent changes in the activity of multiple muscles by the CPG. Neural structures responsible for shifts in the referent body configuration causing locomotion are suggested.
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Affiliation(s)
- Otella Shoja
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Farzad Towhidkhah
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Hamidollah Hassanlouei
- Department of Motor Behaviour, Faculty of Sport Science and Health, Shahid Beheshti University, Tehran, Iran
| | - Mindy F Levin
- School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
| | - Alireza Bahramian
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Sylvie Nadeau
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
- Faculté de Médecine-École de Réadaptation, Montreal, QC, Canada
| | - Lei Zhang
- Institute for Neural Computation, Ruhr University Bochum, Bochum, Germany
| | - Anatol G Feldman
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada.
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada.
- Institut de réadaptation Gingras-Lindsay-de-Montréal (IRGLM), 6300 Darlington, Montreal, QC, H3S 2J4, Canada.
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12
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Hunt R, Mills C, Frost G, Blackmore T, Miller-Dicks M. The visual control of locomotion when stepping onto moving surfaces: A comparison of younger and older adults. Exp Gerontol 2023; 174:112117. [PMID: 36758648 DOI: 10.1016/j.exger.2023.112117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/27/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023]
Abstract
Stepping between static and moving surfaces presents a locomotor challenge associated with increased injury frequency and severity in older adults. The current study evaluates younger and older adults' behaviours when overcoming challenges sampling moving walkway and escalator environments. Twelve younger adults (18-40 years, Male = 8) and 15 older adults (60-81 years, Male = 5) were examined using an integration of optoelectronic motion capture and mobile eye-tracking. Participants were investigated approaching and stepping onto a flat conveyor belt (static or moving; with or without surface (demarcation) lines). Specifically, the four conditions were: (i) static surface without demarcation lines; (ii) static surface with demarcation lines; (iii) moving surface without demarcation lines; and (iv) moving surface with demarcation lines. A two (age group) x two (surface-condition) x two (demarcation-condition) linear mixed-model revealed no main or interaction effects (p > .05) for perturbation magnitude, indicating participants maintained successful locomotion. However, different adaptive behaviours were identified between conditions with moving and accuracy demands (e.g., moving surfaces increased step length, demarcations reduced step length). Between subject effects identified differences between age groups. Older adults utilised different behaviours, such as earlier gaze transfer from the final approach walkway step location. Overall, the current study suggests that adaptive behaviours emerge relative to the environment's specific demands and the individual's action capabilities.
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Affiliation(s)
- Rhys Hunt
- School of Sport, Health and Exercise Science, University of Portsmouth, United Kingdom.
| | - Chris Mills
- School of Sport, Health and Exercise Science, University of Portsmouth, United Kingdom
| | - Gillian Frost
- Health and Safety Executive, Science Division, United Kingdom
| | - Tim Blackmore
- School of Sport, Health and Exercise Science, University of Portsmouth, United Kingdom
| | - Matt Miller-Dicks
- School of Sport, Health and Exercise Science, University of Portsmouth, United Kingdom.
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13
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Krajewski KT, Johnson CC, Ahamed NU, Moir GL, Mi Q, Flanagan SD, Anderst WJ, Connaboy C. Recruit-aged adults may preferentially weight task goals over deleterious cost functions during short duration loaded and imposed gait tasks. Sci Rep 2023; 13:4910. [PMID: 36966216 PMCID: PMC10039906 DOI: 10.1038/s41598-023-31972-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/20/2023] [Indexed: 03/27/2023] Open
Abstract
Optimal motor control that is stable and adaptable to perturbation is reflected in the temporal arrangement and regulation of gait variability. Load carriage and forced-marching are common military relevant perturbations to gait that have been implicated in the high incidence of musculoskeletal injuries in military populations. We investigated the interactive effects of load magnitude and locomotion pattern on motor variability, stride regulation and spatiotemporal complexity during gait in recruit-aged adults. We further investigated the influences of sex and task duration. Healthy adults executed trials of running and forced-marching with and without loads at 10% above their gait transition velocity. Spatiotemporal parameters were analyzed using a goal equivalent manifold approach. With load and forced-marching, individuals used a greater array of motor solutions to execute the task goal (maintain velocity). Stride-to-stride regulation became stricter as the task progressed. Participants exhibited optimal spatiotemporal complexity with significant but not meaningful differences between sexes. With the introduction of load carriage and forced-marching, individuals relied on a strategy that maximizes and regulates motor solutions that achieve the task goal of velocity specifically but compete with other task functions. The appended cost penalties may have deleterious effects during prolonged execution, potentially increasing the risk of musculoskeletal injuries.
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Affiliation(s)
- Kellen T Krajewski
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Camille C Johnson
- Biodynamics Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Nizam U Ahamed
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gavin L Moir
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, USA
| | - Qi Mi
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shawn D Flanagan
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - William J Anderst
- Biodynamics Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Chris Connaboy
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Lower Extremity Ambulatory Research, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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14
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Malik RN, Marigold DS, Chow M, Lam T. Probing the deployment of peripheral visual attention during obstacle-crossing planning. Front Hum Neurosci 2022; 16:1039201. [PMID: 36618994 PMCID: PMC9813236 DOI: 10.3389/fnhum.2022.1039201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
Gaze is directed to one location at a time, making peripheral visual input important for planning how to negotiate different terrain during walking. Whether and how the brain attends to this input is unclear. We developed a novel paradigm to probe the deployment of sustained covert visual attention by testing orientation discrimination of a Gabor patch at stepping and non-stepping locations during obstacle-crossing planning. Compared to remaining stationary, obstacle-crossing planning decreased visual performance (percent correct) and sensitivity (d') at only the first of two stepping locations. Given the timing of the first and second steps before obstacle crossing relative to the Gabor patch presentation, the results suggest the brain uses peripheral vision to plan one step at a time during obstacle crossing, in contrast to how it uses central vision to plan two or more steps in advance. We propose that this protocol, along with multiple possible variations, presents a novel behavioral approach to identify the role of covert visual attention during obstacle-crossing planning and other goal-directed walking tasks.
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Affiliation(s)
- Raza N. Malik
- School of Kinesiology, University of British Columbia, Burnaby, BC, Canada,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada,*Correspondence: Raza N. Malik
| | - Daniel S. Marigold
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada,Institute for Neuroscience and Neurotechnology, Simon Fraser University, Burnaby, BC, Canada
| | - Mason Chow
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Tania Lam
- School of Kinesiology, University of British Columbia, Burnaby, BC, Canada,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
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15
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Luo Y, Lu X, Grimaldi NS, Ahrentzen S, Hu B. Salient Targets and Fear of Falling Changed the Gait Pattern and Joint Kinematic of Older Adults. SENSORS (BASEL, SWITZERLAND) 2022; 22:9352. [PMID: 36502056 PMCID: PMC9740332 DOI: 10.3390/s22239352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Fear of falling and environmental barriers in the home are two major factors that cause the incidence of falling. Poor visibility at night is one of the key environmental barriers that contribute to falls among older adult residents. Ensuring their visual perception of the surroundings, therefore, becomes vital to prevent falling injuries. However, there are limited works in the literature investigating the impact of the visibility of the target on older adults' walking destinations and how that impact differs across them with different levels of fear of falling. OBJECTIVE The purpose of the study was to examine the effects of target salience on older adults' walking performance and investigate whether older adults with varying levels of fear of falling behave differently. METHODS The salient target was constructed with LED strips around the destination of walking. Fifteen older adults (aged 75 years old and above), seven with low fear of falling and eight with high fear of falling, volunteered for the study. Participants walked from the designated origin (i.e., near their beds) to the destination (i.e., near the bathroom entrance), with the target turned on or off around the destination of the walking trials. Spatiotemporal gait variables and lower-body kinematics were recorded by inertial sensors and compared by using analysis of variance methods. RESULTS Data from inertial sensors showed that a more salient target at the destination increased older adults' gait speed and improved their walking stability. These changes were accompanied by less hip flexion at heel strikes and toe offs during walking. In addition, older adults with low fear of falling showed more substantial lower-body posture adjustments with the salient target presented in the environment. CONCLUSIONS Older adults with a low fear of falling can potentially benefit from a more salient target at their walking destination, whereas those with a high fear of falling were advised to implement a more straightforward falling intervention in their living areas.
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Affiliation(s)
- Yue Luo
- Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Xiaojie Lu
- Shimberg Center for Housing Studies, University of Florida, Gainesville, FL 32611, USA
- Microelectronics Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511453, China
| | - Nicolas S. Grimaldi
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Sherry Ahrentzen
- Shimberg Center for Housing Studies, University of Florida, Gainesville, FL 32611, USA
| | - Boyi Hu
- Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL 32611, USA
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16
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Abu-Ismail L, Al-Shami K, Al-Shami M, Nashwan AJ. The effect of COVID-19 pandemic and wearing face masks on ophthalmology practice: What is known so far? A narrative review. Front Med (Lausanne) 2022; 9:1019434. [PMID: 36518743 PMCID: PMC9742357 DOI: 10.3389/fmed.2022.1019434] [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: 08/15/2022] [Accepted: 11/07/2022] [Indexed: 08/29/2023] Open
Abstract
Face masks, along with other preventive measures, can help slow the spread of COVID-19. Despite the positive effect of the mask in combating the virus, it has some negative effects on the human body that must be followed up on and reduced. In this study, we discuss the impact of wearing face masks on the eye and the common issues associated with using them. The literature search was conducted using electronic databases such as PubMed and Google Scholar. Only articles published in English were included. A total of 39 relevant articles were deemed eligible. After the duplicate articles were removed, the titles and abstracts of 20 papers underwent full-text screening. The review comprised both prospective and retrospective investigations, case reports, and a series of reporting ocular symptoms following the use of face masks. The COVID-19 pandemic affected ophthalmology practices in managing patients. New factors must be considered, especially when dealing with anti-VEGF injections, such as the risk of endophthalmitis, tests and symptoms of patients with glaucoma, and the emerging symptoms associated with the COVID-19 vaccination. The use of face masks and breathing aids seemed to influence the tear film.
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Affiliation(s)
- Luai Abu-Ismail
- Department of Ophthalmology, Islamic Hospital, Amman, Jordan
| | - Khayry Al-Shami
- Department of Clinical Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, Jordan
| | - Manar Al-Shami
- Department of Clinical Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, Jordan
- Princess Basma Hospital, Ministry of Health, Irbid, Jordan
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17
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Desmet DM, Cusumano JP, Dingwell JB. Adaptive multi-objective control explains how humans make lateral maneuvers while walking. PLoS Comput Biol 2022; 18:e1010035. [PMID: 36374914 PMCID: PMC9704766 DOI: 10.1371/journal.pcbi.1010035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 11/28/2022] [Accepted: 10/26/2022] [Indexed: 11/15/2022] Open
Abstract
To successfully traverse their environment, humans often perform maneuvers to achieve desired task goals while simultaneously maintaining balance. Humans accomplish these tasks primarily by modulating their foot placements. As humans are more unstable laterally, we must better understand how humans modulate lateral foot placement. We previously developed a theoretical framework and corresponding computational models to describe how humans regulate lateral stepping during straight-ahead continuous walking. We identified goal functions for step width and lateral body position that define the walking task and determine the set of all possible task solutions as Goal Equivalent Manifolds (GEMs). Here, we used this framework to determine if humans can regulate lateral stepping during non-steady-state lateral maneuvers by minimizing errors consistent with these goal functions. Twenty young healthy adults each performed four lateral lane-change maneuvers in a virtual reality environment. Extending our general lateral stepping regulation framework, we first re-examined the requirements of such transient walking tasks. Doing so yielded new theoretical predictions regarding how steps during any such maneuver should be regulated to minimize error costs, consistent with the goals required at each step and with how these costs are adapted at each step during the maneuver. Humans performed the experimental lateral maneuvers in a manner consistent with our theoretical predictions. Furthermore, their stepping behavior was well modeled by allowing the parameters of our previous lateral stepping models to adapt from step to step. To our knowledge, our results are the first to demonstrate humans might use evolving cost landscapes in real time to perform such an adaptive motor task and, furthermore, that such adaptation can occur quickly-over only one step. Thus, the predictive capabilities of our general stepping regulation framework extend to a much greater range of walking tasks beyond just normal, straight-ahead walking.
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Affiliation(s)
- David M. Desmet
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Joseph P. Cusumano
- Department of Engineering Science & Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jonathan B. Dingwell
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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18
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Kreter N, Lybbert C, Gordon KE, Fino PC. The effects of physical and temporal certainty on human locomotion with discrete underfoot perturbations. J Exp Biol 2022; 225:jeb244509. [PMID: 36124619 PMCID: PMC9659331 DOI: 10.1242/jeb.244509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/05/2022] [Indexed: 11/20/2022]
Abstract
Foot placement can be selected to anticipate upcoming perturbations, but it is unclear how this anticipatory strategy is influenced by available response time or precise knowledge of the perturbation's characteristics. This study investigates anticipatory and reactive locomotor strategies for repeated underfoot perturbations with varying levels of temporal certainty, physical certainty, and available response time. Thirteen healthy adults walked with random underfoot perturbations from a mechanized shoe. Temporal certainty was challenged by presenting the perturbations with or without warning. Available response time was challenged by adjusting the timing of the warning before the perturbation. Physical certainty was challenged by making perturbation direction (inversion or eversion) unpredictable for certain conditions. Linear-mixed effects models assessed the effect of each condition on the percentage change of margin of stability and step width. For perturbations with one stride or less of response time, we observed few changes to step width or margin of stability. As response time increased to two strides, participants adopted wider steps in anticipation of the perturbation (P=0.001). Physical certainty had little effect on gait for the step of the perturbation, but participants recovered normal gait sooner when the physical nature of the perturbation was predictable (P<0.001). Despite having information about the timing and direction of upcoming perturbations, individuals do not develop perturbation-specific feedforward strategies. Instead, they use feedback control to recover normal gait after a perturbation. However, physical certainty appears to make the feedback controller more efficient and allows individuals to recover normal gait sooner.
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Affiliation(s)
- Nicholas Kreter
- Department of Health and Kinesiology, University of Utah, 250 South 1850 East, Salt Lake City, UT 84112, USA
| | - Carter Lybbert
- Department of Health and Kinesiology, University of Utah, 250 South 1850 East, Salt Lake City, UT 84112, USA
| | - Keith E. Gordon
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N Michigan Ave, Suite. 1100, Chicago, IL 60611, USA
| | - Peter C. Fino
- Department of Health and Kinesiology, University of Utah, 250 South 1850 East, Salt Lake City, UT 84112, USA
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19
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Zipser-Mohammadzada F, Conway BA, Halliday DM, Zipser CM, Easthope CA, Curt A, Schubert M. Intramuscular coherence during challenging walking in incomplete spinal cord injury: Reduced high-frequency coherence reflects impaired supra-spinal control. Front Hum Neurosci 2022; 16:927704. [PMID: 35992941 PMCID: PMC9387543 DOI: 10.3389/fnhum.2022.927704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022] Open
Abstract
Individuals regaining reliable day-to-day walking function after incomplete spinal cord injury (iSCI) report persisting unsteadiness when confronted with walking challenges. However, quantifiable measures of walking capacity lack the sensitivity to reveal underlying impairments of supra-spinal locomotor control. This study investigates the relationship between intramuscular coherence and corticospinal dynamic balance control during a visually guided Target walking treadmill task. In thirteen individuals with iSCI and 24 controls, intramuscular coherence and cumulant densities were estimated from pairs of Tibialis anterior surface EMG recordings during normal treadmill walking and a Target walking task. The approximate center of mass was calculated from pelvis markers. Spearman rank correlations were performed to evaluate the relationship between intramuscular coherence, clinical parameters, and center of mass parameters. In controls, we found that the Target walking task results in increased high-frequency (21–44 Hz) intramuscular coherence, which negatively related to changes in the center of mass movement, whereas this modulation was largely reduced in individuals with iSCI. The impaired modulation of high-frequency intramuscular coherence during the Target walking task correlated with neurophysiological and functional readouts, such as motor-evoked potential amplitude and outdoor mobility score, as well as center of mass trajectory length. The Target walking effect, the difference between Target and Normal walking intramuscular coherence, was significantly higher in controls than in individuals with iSCI [F(1.0,35.0) = 13.042, p < 0.001]. Intramuscular coherence obtained during challenging walking in individuals with iSCI may provide information on corticospinal gait control. The relationships between biomechanics, clinical scores, and neurophysiology suggest that intramuscular coherence assessed during challenging tasks may be meaningful for understanding impaired supra-spinal control in individuals with iSCI.
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Affiliation(s)
- Freschta Zipser-Mohammadzada
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
- *Correspondence: Freschta Zipser-Mohammadzada,
| | - Bernard A. Conway
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - David M. Halliday
- Department of Electronic Engineering, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
| | - Carl Moritz Zipser
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Chris A. Easthope
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
- Cereneo Foundation, Center for Interdisciplinary Research, Vitznau, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
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20
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Visual Demands of Walking Are Reflected in Eye-Blink-Evoked EEG-Activity. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12136614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Blinking is a natural user-induced response which paces visual information processing. This study investigates whether blinks are viable for segmenting continuous electroencephalography (EEG) activity, for inferring cognitive demands in ecologically valid work environments. We report the blink-related EEG measures of participants who performed auditory tasks either standing, walking on grass, or whilst completing an obstacle course. Blink-related EEG activity discriminated between different levels of cognitive demand during walking. Both behavioral parameters (e.g., blink duration or head motion) and blink-related EEG activity varied with walking conditions. Larger occipital N1 was observed during walking, relative to standing and traversing an obstacle course, which reflects differences in bottom-up visual perception. In contrast, the amplitudes of top-down components (N2, P3) significantly decreased with increasing walking demands, which reflected narrowing attention. This is consistent with blink-related EEG, specifically in Theta and Alpha power that, respectively, increased and decreased with increasing demands of the walking task. This work presents a novel and robust analytical approach to evaluate the cognitive demands experienced in natural work settings, which precludes the use of artificial task manipulations for data segmentation.
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21
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Visual control during climbing: Variability in practice fosters a proactive gaze pattern. PLoS One 2022; 17:e0269794. [PMID: 35687600 PMCID: PMC9187105 DOI: 10.1371/journal.pone.0269794] [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: 01/19/2022] [Accepted: 05/30/2022] [Indexed: 11/19/2022] Open
Abstract
In climbing, the visual system is confronted with a dual demand: controlling ongoing movement and searching for upcoming movement possibilities. The aims of the present research were: (i) to investigate the effect of different modes of practice on how learners deal with this dual demand; and (ii) to analyze the extent this effect may facilitate transfer of learning to a new climbing route. The effect of a constant practice, an imposed schedule of variations and a self-controlled schedule of variations on the gaze behaviors and the climbing fluency of novices were compared. Results showed that the constant practice group outperformed the imposed variability group on the training route and the three groups climbing fluency on the transfer route did not differ. Analyses of the gaze behaviors showed that the constant practice group used more online gaze control during the last session whereas the imposed variability group relied on a more proactive gaze control. This last gaze pattern was also used on the transfer route by the imposed variability group. Self-controlled variability group displayed more interindividual differences in gaze behaviors. These findings reflect that learning protocols induce different timing for gaze patterns that may differently facilitate adaptation to new climbing routes.
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22
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Mohammadzada F, Zipser CM, Easthope CA, Halliday DM, Conway BA, Curt A, Schubert M. Mind your step: Target walking task reveals gait disturbance in individuals with incomplete spinal cord injury. J Neuroeng Rehabil 2022; 19:36. [PMID: 35337335 PMCID: PMC8957135 DOI: 10.1186/s12984-022-01013-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 03/15/2022] [Indexed: 11/23/2022] Open
Abstract
Background Walking over obstacles requires precise foot placement while maintaining balance control of the center of mass (CoM) and the flexibility to adapt the gait patterns. Most individuals with incomplete spinal cord injury (iSCI) are capable of overground walking on level ground; however, gait stability and adaptation may be compromised. CoM control was investigated during a challenging target walking (TW) task in individuals with iSCI compared to healthy controls. The hypothesis was that individuals with iSCI, when challenged with TW, show a lack of gait pattern adaptability which is reflected by an impaired adaptation of CoM movement compared to healthy controls. Methods A single-center controlled diagnostic clinical trial with thirteen participants with iSCI (0.3–24 years post injury; one subacute and twelve chronic) and twelve healthy controls was conducted where foot and pelvis kinematics were acquired during two conditions: normal treadmill walking (NW) and visually guided target walking (TW) with handrail support, during which participants stepped onto projected virtual targets synchronized with the moving treadmill surface. Approximated CoM was calculated from pelvis markers and used to calculate CoM trajectory length and mean CoM Euclidean distance TW-NW (primary outcome). Nonparametric statistics, including spearman rank correlations, were performed to evaluate the relationship between clinical parameter, outdoor mobility score, performance, and CoM parameters (secondary outcome). Results Healthy controls adapted to TW by decreasing anterior–posterior and vertical CoM trajectory length (p < 0.001), whereas participants with iSCI reduced CoM trajectory length only in the vertical direction (p = 0.002). Mean CoM Euclidean distance TW-NW correlated with participants’ neurological level of injury (R = 0.76, p = 0.002) and CoM trajectory length (during TW) correlated with outdoor mobility score (R = − 0.64, p = 0.026). Conclusions This study demonstrated that reduction of CoM movement is a common strategy to cope with TW challenge in controls, but it is impaired in individuals with iSCI. In the iSCI group, the ability to cope with gait challenges worsened the more rostral the level of injury. Thus, the TW task could be used as a gait challenge paradigm in ambulatory iSCI individuals. Trial registration Registry number/ ClinicalTrials.gov Identifier: NCT03343132, date of registration 2017/11/17. Supplementary Information The online version contains supplementary material available at 10.1186/s12984-022-01013-7.
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Affiliation(s)
- Freschta Mohammadzada
- Spinal Cord Injury Center, Neurophysiology, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland.
| | - Carl Moritz Zipser
- Spinal Cord Injury Center, Neurophysiology, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Chris A Easthope
- Spinal Cord Injury Center, Neurophysiology, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland.,Cereneo Foundation, Center for Interdisciplinary Research, 6354, Vitznau, Switzerland
| | - David M Halliday
- Department of Electronic Engineering, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, UK
| | - Bernard A Conway
- Biomedical Engineering, University of Strathclyde, Glasgow, G4 0NW, UK
| | - Armin Curt
- Spinal Cord Injury Center, Neurophysiology, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Martin Schubert
- Spinal Cord Injury Center, Neurophysiology, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland
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23
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Spedden ME, Beck MM, West TO, Farmer SF, Nielsen JB, Lundbye-Jensen J. Dynamics of cortical and corticomuscular connectivity during planning and execution of visually guided steps in humans. Cereb Cortex 2022; 33:258-277. [PMID: 35238339 PMCID: PMC7614067 DOI: 10.1093/cercor/bhac066] [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: 10/21/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 01/17/2023] Open
Abstract
The cortical mechanisms underlying the act of taking a step-including planning, execution, and modification-are not well understood. We hypothesized that oscillatory communication in a parieto-frontal and corticomuscular network is involved in the neural control of visually guided steps. We addressed this hypothesis using source reconstruction and lagged coherence analysis of electroencephalographic and electromyographic recordings during visually guided stepping and 2 control tasks that aimed to investigate processes involved in (i) preparing and taking a step and (ii) adjusting a step based on visual information. Steps were divided into planning, initiation, and execution phases. Taking a step was characterized by an upregulation of beta/gamma coherence within the parieto-frontal network during planning followed by a downregulation of alpha and beta/gamma coherence during initiation and execution. Step modification was characterized by bidirectional modulations of alpha and beta/gamma coherence in the parieto-frontal network during the phases leading up to step execution. Corticomuscular coherence did not exhibit task-related effects. We suggest that these task-related modulations indicate that the brain makes use of communication through coherence in the context of large-scale, whole-body movements, reflecting a process of flexibly fine-tuning inter-regional communication to achieve precision control during human stepping.
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Affiliation(s)
| | - Mikkel Mailing Beck
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Timothy O. West
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London WC1N 3AR, UK,Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK
| | - Simon F. Farmer
- Department of Clinical Neurology, The National Hospital for Neurology and Neurosurgery, Queen Square London WC1N 3BG, UK,Department of Clinical and Movement Neurosciences, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Jens Bo Nielsen
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark,Elsass Foundation, Charlottenlund, Denmark
| | - Jesper Lundbye-Jensen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Matthis JS, Muller KS, Bonnen KL, Hayhoe MM. Retinal optic flow during natural locomotion. PLoS Comput Biol 2022; 18:e1009575. [PMID: 35192614 PMCID: PMC8896712 DOI: 10.1371/journal.pcbi.1009575] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/04/2022] [Accepted: 10/14/2021] [Indexed: 11/18/2022] Open
Abstract
We examine the structure of the visual motion projected on the retina during natural locomotion in real world environments. Bipedal gait generates a complex, rhythmic pattern of head translation and rotation in space, so without gaze stabilization mechanisms such as the vestibular-ocular-reflex (VOR) a walker's visually specified heading would vary dramatically throughout the gait cycle. The act of fixation on stable points in the environment nulls image motion at the fovea, resulting in stable patterns of outflow on the retinae centered on the point of fixation. These outflowing patterns retain a higher order structure that is informative about the stabilized trajectory of the eye through space. We measure this structure by applying the curl and divergence operations on the retinal flow velocity vector fields and found features that may be valuable for the control of locomotion. In particular, the sign and magnitude of foveal curl in retinal flow specifies the body's trajectory relative to the gaze point, while the point of maximum divergence in the retinal flow field specifies the walker's instantaneous overground velocity/momentum vector in retinotopic coordinates. Assuming that walkers can determine the body position relative to gaze direction, these time-varying retinotopic cues for the body's momentum could provide a visual control signal for locomotion over complex terrain. In contrast, the temporal variation of the eye-movement-free, head-centered flow fields is large enough to be problematic for use in steering towards a goal. Consideration of optic flow in the context of real-world locomotion therefore suggests a re-evaluation of the role of optic flow in the control of action during natural behavior.
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Affiliation(s)
- Jonathan Samir Matthis
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Karl S. Muller
- Center for Perceptual Systems, University of Texas at Austin, Austin, Texas, United States of America
| | - Kathryn L. Bonnen
- School of Optometry, Indiana University Bloomington, Bloomington, Indiana, United States of America
| | - Mary M. Hayhoe
- Center for Perceptual Systems, University of Texas at Austin, Austin, Texas, United States of America
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25
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Volgushev M, Nguyen CT, Iyer GS, Beloozerova IN. When cats need to see to step accurately? J Physiol 2022; 600:75-94. [PMID: 34761816 PMCID: PMC9241584 DOI: 10.1113/jp282255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/29/2021] [Indexed: 01/03/2023] Open
Abstract
Locomotion on complex terrains often requires vision. However, how vision serves locomotion is not well understood. Here, we asked when visual information necessary for accurate stepping is collected and how its acquisition relates to the step cycle. In cats of both sexes, we showed that a brief (200-400 ms) interruption of visual input can rapidly influence cat's walking along a horizontal ladder. Depending on the phase within the step cycle, a 200 ms period of darkness could be tolerated fully without any changes to the strides or could lead to minor increases of stride duration. The effects of 300-400 ms of visual input denial, which typically prolonged stances and/or swings, also depended on the phase of the darkness onset. The increase of the duration of strides was always shorter than the duration of darkness. We conclude that visual information for planning a swing is collected starting from the middle of the preceding stance until the beginning of the current swing. For a stance (and/or a swing of the other paw), visual information is collected starting from the end of the previous stance and until the middle of the current stance. Acquisition of visual information during these windows is not uniform but depends on the phase of the step cycle. Notably, both the extension of these windows and their non-homogeneity are closely related to the pattern of gaze behaviour in cats, described previously. This new knowledge will help to guide research and understanding of neuronal mechanisms of visuomotor integration and modulation of visual function by strides during locomotion. KEY POINTS: Cats, like humans, rely on vision to navigate in complex environments. In cats walking along a horizontally placed ladder, we show that visual information required for accurate stepping is collected in a non-uniform manner throughout the stride cycle. Brief denial of visual input during a swing prolongs the next stance of that forelimb. Denial of visual input during a stance prolongs this stance, as well as the next swing and stance. Denial during the first half of a stance has a greater effect than during the second half. The phase dependence of the use of vision for accurate stepping and the pattern of affected swings and stances are closely related to the previously described pattern of gaze behaviour in cats. This new knowledge opens new perspectives for research into neuronal mechanisms of visuomotor coordination and visual function during walking and for understanding related disorders.
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Affiliation(s)
- Maxim Volgushev
- Department of Psychological Sciences, University of
Connecticut, Storrs, CT, USA
| | - Celina T. Nguyen
- Barrow Neurological Institute, St Joseph’s Hospital
and Medical Center, Phoenix, AZ, USA
- Neurosciences Graduate Program, University of California
San Diego, La Jolla, CA, USA
| | - Gautam S. Iyer
- Barrow Neurological Institute, St Joseph’s Hospital
and Medical Center, Phoenix, AZ, USA
| | - Irina N. Beloozerova
- Barrow Neurological Institute, St Joseph’s Hospital
and Medical Center, Phoenix, AZ, USA
- School of Biological Sciences, Georgia Institute of
Technology, Atlanta, GA, USA
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26
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Beloozerova IN. Neuronal activity reorganization in motor cortex for successful locomotion after a lesion in the ventrolateral thalamus. J Neurophysiol 2022; 127:56-85. [PMID: 34731070 PMCID: PMC8742732 DOI: 10.1152/jn.00191.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Thalamic stroke leads to ataxia if the cerebellum-receiving ventrolateral thalamus (VL) is affected. The compensation mechanisms for this deficit are not well understood, particularly the roles that single neurons and specific neuronal subpopulations outside the thalamus play in recovery. The goal of this study was to clarify neuronal mechanisms of the motor cortex involved in mitigation of ataxia during locomotion when part of the VL is inactivated or lesioned. In freely ambulating cats, we recorded the activity of neurons in layer V of the motor cortex as the cats walked on a flat surface and horizontally placed ladder. We first reversibly inactivated ∼10% of the VL unilaterally using glutamatergic transmission antagonist CNQX and analyzed how the activity of motor cortex reorganized to support successful locomotion. We next lesioned 50%-75% of the VL bilaterally using kainic acid and analyzed how the activity of motor cortex reorganized when locomotion recovered. When a small part of the VL was inactivated, the discharge rates of motor cortex neurons decreased, but otherwise the activity was near normal, and the cats walked fairly well. Individual neurons retained their ability to respond to the demand for accuracy during ladder locomotion; however, most changed their response. When the VL was lesioned, the cat walked normally on the flat surface but was ataxic on the ladder for several days after lesion. When ladder locomotion normalized, neuronal discharge rates on the ladder were normal, and the shoulder-related group was preferentially active during the stride's swing phase.NEW & NOTEWORTHY This is the first analysis of reorganization of the activity of single neurons and subpopulations of neurons related to the shoulder, elbow, or wrist, as well as fast- and slow-conducting pyramidal tract neurons in the motor cortex of animals walking before and after inactivation or lesion in the thalamus. The results offer unique insights into the mechanisms of spontaneous recovery after thalamic stroke, potentially providing guidance for new strategies to alleviate locomotor deficits after stroke.
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Affiliation(s)
- Irina N. Beloozerova
- 1School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia,2Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona
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27
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The Role of Muscle Spindle Feedback in the Guidance of Hindlimb Movement by the Ipsilateral Forelimb during Locomotion in Mice. eNeuro 2021; 8:ENEURO.0432-21.2021. [PMID: 34764190 PMCID: PMC8641919 DOI: 10.1523/eneuro.0432-21.2021] [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: 10/13/2021] [Revised: 10/14/2021] [Accepted: 11/02/2021] [Indexed: 11/21/2022] Open
Abstract
Safe and efficient locomotion relies on placing the foot on a reliable surface at the end of each leg swing movement. Visual information has been shown to be important for determining the location of foot placement in humans during walking when precision is required. Yet in quadrupedal animals where the hindlimbs are outside of the visual field, such as in mice, the mechanisms by which precise foot placement is achieved remain unclear. Here we show that the placement of the hindlimb paw is determined by the position of the forelimb paw during normal locomotion and in the presence of perturbations. When a perturbation elicits a stumbling corrective reaction, we found that the forelimb paw shifts posteriorly relative to body at the end of stance, and this spatial shift is echoed in hindlimb paw placement at the end of the swing movement. Using a mutant mouse line in which muscle spindle feedback is selectively removed, we show that this posterior shift of paw placement is dependent on muscle spindle feedback in the hindlimb but not in the forelimb. These findings uncover a neuronal mechanism that is independent of vision to ensure safe locomotion during perturbation. This mechanism adds to our general knowledge of how the nervous system controls targeted limb movements and could inform the development of autonomous walking machines.
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28
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van Leeuwen AM, van Dieën JH, Daffertshofer A, Bruijn SM. Ankle muscles drive mediolateral center of pressure control to ensure stable steady state gait. Sci Rep 2021; 11:21481. [PMID: 34728667 PMCID: PMC8563802 DOI: 10.1038/s41598-021-00463-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/07/2021] [Indexed: 11/08/2022] Open
Abstract
During steady-state walking, mediolateral gait stability can be maintained by controlling the center of pressure (CoP). The CoP modulates the moment of the ground reaction force, which brakes and reverses movement of the center of mass (CoM) towards the lateral border of the base of support. In addition to foot placement, ankle moments serve to control the CoP. We hypothesized that, during steady-state walking, single stance ankle moments establish a CoP shift to correct for errors in foot placement. We expected ankle muscle activity to be associated with this complementary CoP shift. During treadmill walking, full-body kinematics, ground reaction forces and electromyography were recorded in thirty healthy participants. We found a negative relationship between preceding foot placement error and CoP displacement during single stance; steps that were too medial were compensated for by a lateral CoP shift and vice versa, steps that were too lateral were compensated for by a medial CoP shift. Peroneus longus, soleus and tibialis anterior activity correlated with these CoP shifts. As such, we identified an (active) ankle strategy during steady-state walking. As expected, absolute explained CoP variance by foot placement error decreased when walking with shoes constraining ankle moments. Yet, contrary to our expectations that ankle moment control would compensate for constrained foot placement, the absolute explained CoP variance by foot placement error did not increase when foot placement was constrained. We argue that this lack of compensation reflects the interdependent nature of ankle moment and foot placement control. We suggest that single stance ankle moments do not only compensate for preceding foot placement errors, but also assist control of the subsequent foot placement. Foot placement and ankle moment control are 'caught' in a circular relationship, in which constraints imposed on one will also influence the other.
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Affiliation(s)
- A M van Leeuwen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Institute of Brain and Behavior Amsterdam, Amsterdam, The Netherlands
| | - J H van Dieën
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - A Daffertshofer
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Institute of Brain and Behavior Amsterdam, Amsterdam, The Netherlands
| | - S M Bruijn
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands.
- Institute of Brain and Behavior Amsterdam, Amsterdam, The Netherlands.
- Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, People's Republic of China.
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29
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Binocular vision and the control of foot placement during walking in natural terrain. Sci Rep 2021; 11:20881. [PMID: 34686759 PMCID: PMC8536664 DOI: 10.1038/s41598-021-99846-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 09/27/2021] [Indexed: 11/19/2022] Open
Abstract
Coordination between visual and motor processes is critical for the selection of stable footholds when walking in uneven terrains. While recent work (Matthis et al. in Curr Biol 8(28):1224–1233, 2018) demonstrates a tight link between gaze (visual) and gait (motor), it remains unclear which aspects of visual information play a role in this visuomotor control loop, and how the loss of this information affects that relationship. Here we examine the role of binocular information in the visuomotor control of walking over complex terrain. We recorded eye and body movements while normally-sighted participants walked over terrains of varying difficulty, with intact vision or with vision in one eye blurred to disrupt binocular vision. Gaze strategy was highly sensitive to the complexity of the terrain, with more fixations dedicated to foothold selection as the terrain became more difficult. The primary effect of increased sensory uncertainty due to disrupted binocular vision was a small bias in gaze towards closer footholds, indicating greater pressure on the visuomotor control process. Participants with binocular vision losses due to developmental disorders (i.e., amblyopia, strabismus), who have had the opportunity to develop alternative strategies, also biased their gaze towards closer footholds. Across all participants, we observed a relationship between an individual’s typical level of binocular visual function and the degree to which gaze is shifted toward the body. Thus the gaze–gait relationship is sensitive to the level of sensory uncertainty, and deficits in binocular visual function (whether transient or long-standing) have systematic effects on gaze strategy in complex terrains. We conclude that binocular vision provides useful information for locating footholds during locomotion. Furthermore, we have demonstrated that combined eye/body tracking in natural environments can be used to provide a more detailed understanding of the impact of a type of vision loss on the visuomotor control process of walking, a vital everyday task.
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30
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Hu B, Li S, Chen Y, Kavi R, Coppola S. Applying deep neural networks and inertial measurement unit in recognizing irregular walking differences in the real world. APPLIED ERGONOMICS 2021; 96:103414. [PMID: 34087702 DOI: 10.1016/j.apergo.2021.103414] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 01/13/2021] [Accepted: 03/05/2021] [Indexed: 05/10/2023]
Abstract
Falling injuries pose serious health risks to people of all ages, and knowing the extent of exposure to irregular surfaces will increase the ability to measure fall risk. Current gait analysis methods require overly complicated instrumentation and have not been tested for external factors such as walking surfaces that are encountered in the real-world, thus the results are difficult to extrapolate to real-world situations. Artificial intelligence approaches (in particular deep learning networks of varied architectures) to analyze data collected from wearable sensors were used to identify irregular surface exposure in a real-world setting. Thirty young adults wore six Inertial Measurement Unit (IMU) sensors placed on their body (right wrist, trunks at the L5/S1 level, left and right thigh, left and right shank) while walking over eight different surfaces commonly encountered in the living community as well as occupational settings. Three variations of deep learning models were trained to solve this walking surface recognition problem: 1) convolution neural network (CNN); 2) long short term memory (LSTM) network and 3) LSTM structure with an extra global pooling layer (Global-LSTM) which learns the coordination between different data streams (e.g. different channels of the same sensor as well as different sensors). Results indicated that all three deep learning models can recognize walking surfaces with above 0.90 accuracy, with the Global-LSTM yielding the best performance at 0.92 accuracy. In terms of individual sensors, the right thigh based Global-LSTM model reported the highest accuracy (0.90 accuracy). Results from this study provide further evidence that deep learning and wearable sensors can be utilized to recognize irregular walking surfaces induced motion alteration and applied to prevent falling injuries.
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Affiliation(s)
- B Hu
- Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
| | - S Li
- Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL, USA
| | - Y Chen
- Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL, USA
| | - R Kavi
- West Virginia University, Morgantown, WV, 26505, USA.
| | - S Coppola
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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31
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Kopiske K, Koska D, Baumann T, Maiwald C, Einhäuser W. Icy road ahead-rapid adjustments of gaze-gait interactions during perturbed naturalistic walking. J Vis 2021; 21:11. [PMID: 34351396 PMCID: PMC8354071 DOI: 10.1167/jov.21.8.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Most humans can walk effortlessly across uniform terrain even when they do not pay much attention to it. However, most natural terrain is far from uniform, and we need visual information to maintain stable gait. Recent advances in mobile eye-tracking technology have made it possible to study, in natural environments, how terrain affects gaze and thus the sampling of visual information. However, natural environments provide only limited experimental control, and some conditions cannot safely be tested. Typical laboratory setups, in contrast, are far from natural settings for walking. We used a setup consisting of a dual-belt treadmill, 240∘ projection screen, floor projection, three-dimensional optical motion tracking, and mobile eye tracking to investigate eye, head, and body movements during perturbed and unperturbed walking in a controlled yet naturalistic environment. In two experiments (N = 22 each), we simulated terrain difficulty by repeatedly inducing slipping through accelerating either of the two belts rapidly and unpredictably (Experiment 1) or sometimes following visual cues (Experiment 2). We quantified the distinct roles of eye and head movements for adjusting gaze on different time scales. While motor perturbations mainly influenced head movements, eye movements were primarily affected by the presence of visual cues. This was true both immediately following slips and—to a lesser extent—over the course of entire 5-min blocks. We find adapted gaze parameters already after the first perturbation in each block, with little transfer between blocks. In conclusion, gaze–gait interactions in experimentally perturbed yet naturalistic walking are adaptive, flexible, and effector specific.
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Affiliation(s)
- Karl Kopiske
- Cognitive Systems Lab, Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany.,
| | - Daniel Koska
- Group "Research Methodology and Data Analysis in Biomechanics," Institute of Human Movement Science and Health, Chemnitz University of Technology, Chemnitz, Germany.,
| | - Thomas Baumann
- Cognitive Systems Lab, Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany.,
| | - Christian Maiwald
- Group "Research Methodology and Data Analysis in Biomechanics," Institute of Human Movement Science and Health, Chemnitz University of Technology, Chemnitz, Germany.,
| | - Wolfgang Einhäuser
- Physics of Cognition Group, Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany.,
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32
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Sombric CJ, Torres-Oviedo G. Cognitive and Motor Perseveration Are Associated in Older Adults. Front Aging Neurosci 2021; 13:610359. [PMID: 33986654 PMCID: PMC8110726 DOI: 10.3389/fnagi.2021.610359] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Aging causes perseveration (difficulty to switch between actions) in motor and cognitive tasks, suggesting that the same neural processes could govern these abilities in older adults. To test this, we evaluated the relation between independently measured motor and cognitive perseveration in young (21.4 ± 3.7 y/o) and older participants (76.5 ± 2.9 y/o). Motor perseveration was measured with a locomotor task in which participants had to transition between distinct walking patterns. Cognitive perseveration was measured with a card matching task in which participants had to switch between distinct matching rules. We found that perseveration in the cognitive and motor domains were positively related in older, but not younger individuals, such that participants exhibiting greater perseveration in the motor task also perseverated more in the cognitive task. Additionally, exposure reduces motor perseveration: older adults who had practiced the motor task could transition between walking patterns as proficiently as naïve, young individuals. Our results suggest an overlap in neural processes governing cognitive and motor perseveration with aging and that exposure can counteract the age-related motor perseveration.
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Affiliation(s)
| | - Gelsy Torres-Oviedo
- Sensorimotor Learning Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
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33
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Abstract
We rely on gaze to guide subsequent steps during walking, more so when the terrain ahead is more uncertain. New research shows that the increased visual exploration during walking as the terrain becomes more uncertain reflects our preference for accuracy over effort in step choice.
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Affiliation(s)
- Shruthi Sukumar
- Department of Computer Science, University of Colorado Boulder, 1111 Engineering Drive, Boulder, CO 80309, USA.
| | - Alaa A Ahmed
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, CO 80309, USA
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34
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Ellmers TJ, Cocks AJ, Kal EC, Young WR. Conscious Movement Processing, Fall-Related Anxiety, and the Visuomotor Control of Locomotion in Older Adults. J Gerontol B Psychol Sci Soc Sci 2021; 75:1911-1920. [PMID: 32761087 PMCID: PMC7566972 DOI: 10.1093/geronb/gbaa081] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Indexed: 12/25/2022] Open
Abstract
Objectives Older adults anxious about falling will often consciously process walking movements in an attempt to avoid falling. They also fixate their gaze on the present step rather than looking ahead to plan future actions. The present work examined whether conscious movement strategies result in such restricted visual planning. Methods A total of 18 community-dwelling older adults (agemean = 71.22; SD = 5.75) walked along a path and stepped into two raised targets. Repeated-measures analyses of variance were used to compare gaze behavior and movement kinematics when participants walked: (a) at baseline (ground level); (b) under conditions designed to induce fall-related anxiety (walkway elevated 0.6 m); and (c) in the absence of anxiety (ground level), but with explicit instructions to consciously process movements. Results Participants reported increased conscious movement processing when walking both on the elevated walkway (fall-related anxiety condition) and at ground level when instructed to consciously process gait. During both conditions, participants altered their gaze behavior, visually prioritizing the immediate walkway 1–2 steps ahead (areas needed for the on-line visual control of individual steps) at the expense of previewing distal areas of the walking path required to plan future steps. These alterations were accompanied by significantly slower gait and increased stance durations prior to target steps. Conclusions Consciously processing movement (in the relative absence of anxiety) resulted in gaze behavior comparable to that observed during conditions of fall-related anxiety. As anxious participants also self-reported directing greater attention toward movement, this suggests that fall-related anxiety may disrupt the visual control of gait through increased conscious movement processing.
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Affiliation(s)
- Toby J Ellmers
- College of Health and Life Sciences, Brunel University London, UK.,Centre for Cognitive Neuroscience, Brunel University London, UK
| | - Adam J Cocks
- College of Health and Life Sciences, Brunel University London, UK.,Centre for Cognitive Neuroscience, Brunel University London, UK
| | - Elmar C Kal
- College of Health and Life Sciences, Brunel University London, UK.,Centre for Cognitive Neuroscience, Brunel University London, UK
| | - William R Young
- College of Health and Life Sciences, Brunel University London, UK.,School of Sport and Health Sciences, University of Exeter, UK
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35
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Koren Y, Mairon R, Sofer I, Parmet Y, Ben-Shahar O, Bar-Haim S. Gazing down increases standing and walking postural steadiness. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201556. [PMID: 33959324 PMCID: PMC8074885 DOI: 10.1098/rsos.201556] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 02/23/2021] [Indexed: 05/30/2023]
Abstract
When walking on an uneven surface or complex terrain, humans tend to gaze downward. This behaviour is usually interpreted as an attempt to acquire useful information to guide locomotion. Visual information, however, is not used exclusively for guiding locomotion; it is also useful for postural control. Both locomotive and postural control have been shown to be sensitive to the visual flow arising from the respective motion of the individual and the three-dimensional environment. This flow changes when a person gazes downward and may present information that is more appropriate for postural control. To investigate whether downward gazing can be used for postural control, rather than exclusively for guiding locomotion, we quantified the dynamics of standing and walking posture in healthy adults, under several visual conditions. Through these experiments we were able to demonstrate that gazing downward, just a few steps ahead, resulted in a steadier standing and walking posture. These experiments indicate that gazing downward may serve more than one purpose and provide sufficient evidence of the possible interplay between the visual information used for guiding locomotion and that used for postural control. These findings contribute to our understanding of the control mechanism/s underlying gait and posture and have possible clinical implications.
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Affiliation(s)
- Yogev Koren
- Physical Therapy Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Rotem Mairon
- Computer Science Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ilay Sofer
- Physical Therapy Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yisrael Parmet
- Industrial Engineering and Management Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ohad Ben-Shahar
- Computer Science Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Simona Bar-Haim
- Physical Therapy Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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36
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Restoration of bilateral motor coordination from preserved agonist-antagonist coupling in amputation musculature. J Neuroeng Rehabil 2021; 18:38. [PMID: 33596960 PMCID: PMC7891024 DOI: 10.1186/s12984-021-00829-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/26/2021] [Indexed: 11/26/2022] Open
Abstract
Background Neuroprosthetic devices controlled by persons with standard limb amputation often lack the dexterity of the physiological limb due to limitations of both the user’s ability to output accurate control signals and the control system’s ability to formulate dynamic trajectories from those signals. To restore full limb functionality to persons with amputation, it is necessary to first deduce and quantify the motor performance of the missing limbs, then meet these performance requirements through direct, volitional control of neuroprosthetic devices. Methods We develop a neuromuscular modeling and optimization paradigm for the agonist-antagonist myoneural interface, a novel tissue architecture and neural interface for the control of myoelectric prostheses, that enables it to generate virtual joint trajectories coordinated with an intact biological joint at full physiologically-relevant movement bandwidth. In this investigation, a baseline of performance is first established in a population of non-amputee control subjects (\documentclass[12pt]{minimal}
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\begin{document}$$n = 4$$\end{document}n=4) to generate virtual subtalar prosthetic joint kinematics using measured surface electromyography (sEMG) signals generated by musculature within the affected leg residuum. Results Using their optimized neuromuscular subtalar models under blindfolded conditions with only proprioceptive feedback, AMI amputation subjects demonstrate bilateral subtalar coordination accuracy not significantly different from that of the non-amputee control group (Kolmogorov-Smirnov test, \documentclass[12pt]{minimal}
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\begin{document}$$P \ge 0.052$$\end{document}P≥0.052) while standard amputation subjects demonstrate significantly poorer performance (Kolmogorov-Smirnov test, \documentclass[12pt]{minimal}
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\begin{document}$$P < 0.001$$\end{document}P<0.001). Conclusions These results suggest that the absence of an intact biological joint does not necessarily remove the ability to produce neurophysical signals with sufficient information to reconstruct physiological movements. Further, the seamless manner in which virtual and intact biological joints are shown to coordinate reinforces the theory that desired movement trajectories are mentally formulated in an abstract task space which does not depend on physical limb configurations. Supplementary Information The online version contains supplementary material available at 10.1186/s12984-021-00829-z.
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Domínguez-Zamora FJ, Marigold DS. Motives driving gaze and walking decisions. Curr Biol 2021; 31:1632-1642.e4. [PMID: 33600769 DOI: 10.1016/j.cub.2021.01.069] [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] [Received: 07/13/2020] [Revised: 10/01/2020] [Accepted: 01/20/2021] [Indexed: 01/23/2023]
Abstract
To navigate complex environments, people must decide how to direct gaze to acquire relevant information and decide where, when, and how to move the body. Recent work supports the idea that gaze may be directed to reduce task-relevant environmental uncertainty and to ensure movement accuracy based on the cost (or effort) to move the body and maintain balance. During walking, these two factors may compete for gaze allocation and explain how we make decisions about where to step. Using a forced-choice walking paradigm, where we manipulated the visual uncertainty (simulating uncertain terrain characteristics) and motor cost associated with specific step-target choices, we examined the motives driving gaze and step decisions. We characterized each individual's distinct gaze behavior based on their sensitivity to changes in visual uncertainty, which predicted step-choice behavior when foot-placement accuracy was important to the task. We show that individuals who tended to look at both target choices as visual uncertainty increased prioritized stepping onto the more certain location after looking at it longer, even at the expense of increased motor cost. In contrast, individuals who tended to look at only one of the target choices as visual uncertainty increased preferred to step on the target that minimized motor cost. Overall, we demonstrate that how a person explores the environment with their eyes dictates where they step. These gaze and step decisions may relate to the value a person assigns to information gain, being certain of their actions, and conserving energy.
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Affiliation(s)
- F Javier Domínguez-Zamora
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Daniel S Marigold
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
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Render AC, Kazanski ME, Cusumano JP, Dingwell JB. Walking humans trade off different task goals to regulate lateral stepping. J Biomech 2021; 119:110314. [PMID: 33667882 DOI: 10.1016/j.jbiomech.2021.110314] [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] [Received: 09/07/2020] [Revised: 01/26/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
People walk in complex environments where they must adapt their steps to maintain balance and satisfy changing task goals. How people do this is not well understood. We recently developed computational models of lateral stepping, based on Goal Equivalent Manifolds that serve as motor regulation templates, to identify how people regulate walking movements from step-to-step. In normal walking, healthy adults strongly maintain step width, but also lateral position on their path. Here, we used this framework to pose empirically-testable hypotheses about how humans might adapt their lateral stepping dynamics when asked to prioritize different stepping goals. Participants walked on a treadmill in a virtual-reality environment under 4 conditions: normal walking and, while given direct feedback at each step, walking while trying to maintain constant step width, constant absolute lateral position, or constant heading (direction). Time series of lateral stepping variables were extracted, and variability and statistical persistence (reflecting step-to-step regulation) quantified. Participants exhibited less variability of the prescribed stepping variable compared to normal walking during each feedback condition. Stepping regulation results supported our models' predictions: to maintain constant step width or position, people either maintained or increased regulation of the prescribed variable, but also decreased regulation of its complement. Thus, people regulated lateral foot placements in predictable and systematic ways determined by specific task goals. Humans regulate stepping movements to not only "just walk" (step without falling), but also to achieve specific goal-directed tasks within a specific environment. The framework and motor regulation templates presented here capture these important interactions.
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Affiliation(s)
- Anna C Render
- Department of Kinesiology, Pennsylvania State University, University Park, PA 16802 USA
| | - Meghan E Kazanski
- Department of Kinesiology, Pennsylvania State University, University Park, PA 16802 USA
| | - Joseph P Cusumano
- Department of Engineering Science & Mechanics, Pennsylvania State University, University Park, PA 16802 USA
| | - Jonathan B Dingwell
- Department of Kinesiology, Pennsylvania State University, University Park, PA 16802 USA.
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Cao L, Chen X, Haendel BF. Overground Walking Decreases Alpha Activity and Entrains Eye Movements in Humans. Front Hum Neurosci 2021; 14:561755. [PMID: 33414709 PMCID: PMC7782973 DOI: 10.3389/fnhum.2020.561755] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/02/2020] [Indexed: 01/25/2023] Open
Abstract
Experiments in animal models have shown that running increases neuronal activity in early visual areas in light as well as in darkness. This suggests that visual processing is influenced by locomotion independent of visual input. Combining mobile electroencephalography, motion- and eye-tracking, we investigated the influence of overground free walking on cortical alpha activity (~10 Hz) and eye movements in healthy humans. Alpha activity has been considered a valuable marker of inhibition of sensory processing and shown to negatively correlate with neuronal firing rates. We found that walking led to a decrease in alpha activity over occipital cortex compared to standing. This decrease was present during walking in darkness as well as during light. Importantly, eye movements could not explain the change in alpha activity. Nevertheless, we found that walking and eye related movements were linked. While the blink rate increased with increasing walking speed independent of light or darkness, saccade rate was only significantly linked to walking speed in the light. Pupil size, on the other hand, was larger during darkness than during light, but only showed a modulation by walking in darkness. Analyzing the effect of walking with respect to the stride cycle, we further found that blinks and saccades preferentially occurred during the double support phase of walking. Alpha power, as shown previously, was lower during the swing phase than during the double support phase. We however could exclude the possibility that the alpha modulation was introduced by a walking movement induced change in electrode impedance. Overall, our work indicates that the human visual system is influenced by the current locomotion state of the body. This influence affects eye movement pattern as well as neuronal activity in sensory areas and might form part of an implicit strategy to optimally extract sensory information during locomotion.
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Affiliation(s)
- Liyu Cao
- Department of Psychology (III), Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Xinyu Chen
- Department of Psychology (III), Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Barbara F Haendel
- Department of Psychology (III), Julius-Maximilians-Universität Würzburg, Würzburg, Germany
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van Leeuwen AM, van Dieën JH, Daffertshofer A, Bruijn SM. Active foot placement control ensures stable gait: Effect of constraints on foot placement and ankle moments. PLoS One 2020; 15:e0242215. [PMID: 33332421 PMCID: PMC7746185 DOI: 10.1371/journal.pone.0242215] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/28/2020] [Indexed: 12/25/2022] Open
Abstract
Step-by-step foot placement control, relative to the center of mass (CoM) kinematic state, is generally considered a dominant mechanism for maintenance of gait stability. By adequate (mediolateral) positioning of the center of pressure with respect to the CoM, the ground reaction force generates a moment that prevents falling. In healthy individuals, foot placement is complemented mainly by ankle moment control ensuring stability. To evaluate possible compensatory relationships between step-by-step foot placement and complementary ankle moments, we investigated the degree of (active) foot placement control during steady-state walking, and under either foot placement-, or ankle moment constraints. Thirty healthy participants walked on a treadmill, while full-body kinematics, ground reaction forces and EMG activities were recorded. As a replication of earlier findings, we first showed step-by-step foot placement is associated with preceding CoM state and hip ab-/adductor activity during steady-state walking. Tight control of foot placement appears to be important at normal walking speed because there was a limited change in the degree of foot placement control despite the presence of a foot placement constraint. At slow speed, the degree of foot placement control decreased substantially, suggesting that tight control of foot placement is less essential when walking slowly. Step-by-step foot placement control was not tightened to compensate for constrained ankle moments. Instead compensation was achieved through increases in step width and stride frequency.
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Affiliation(s)
- A. M. van Leeuwen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Institute of Brain and Behavior Amsterdam, Amsterdam, The Netherlands
| | - J. H. van Dieën
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - A. Daffertshofer
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Institute of Brain and Behavior Amsterdam, Amsterdam, The Netherlands
| | - S. M. Bruijn
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Institute of Brain and Behavior Amsterdam, Amsterdam, The Netherlands
- Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, PR China
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Penkava J, Bardins S, Brandt T, Wuehr M, Huppert D. Spontaneous visual exploration during locomotion in patients with phobic postural vertigo. J Neurol 2020; 267:223-230. [PMID: 32852578 PMCID: PMC7718196 DOI: 10.1007/s00415-020-10151-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/23/2020] [Accepted: 08/07/2020] [Indexed: 11/29/2022]
Abstract
Background Earlier studies on stance and gait with posturographic and EMG-recordings and automatic gait analysis in patients with phobic postural vertigo (PPV) or visual height intolerance (vHI) revealed similar patterns of body stiffening with muscle co-contraction and a slow, cautious gait. Visual exploration in vHI patients was characterized by a freezing of gaze-in-space when standing and reduced horizontal eye and head movements during locomotion. Objective Based on the findings in vHI patients, the current study was performed with a focus on visual control of locomotion in patients with PPV while walking along a crowded hospital hallway. Methods Twelve patients with PPV and eleven controls were recruited. Participants wore a mobile infrared video eye-tracking system that continuously measured eye-in-head movements in the horizontal and vertical planes and head orientation and motion in the yaw, pitch, and roll planes. Visual exploration behavior of participants was recorded at the individually preferred speed for a total walking distance of 200 m. Gaze-in-space directions were determined by combining eye-in-head and head-in-space orientation. Walking speeds were calculated based on the trial duration and the total distance traversed. Participants were asked to rate their feelings of discomfort during the walk on a 4-point numeric rating scale. The examiners rated the crowdedness of the hospital hallway on a 4-point numeric rating scale. Results The major results of visual exploration behavior in patients with PPV in comparison to healthy controls were: eye and head positions were directed more downward in the vertical plane towards the ground ahead with increased frequency of large amplitude vertical orientation movements towards the destination, the end of the ground straight ahead. The self-adjusted speed of locomotion was significantly lower in PPV. Particularly those patients that reported high levels of discomfort exhibited a specific visual exploration of their horizontal surroundings. The durations of fixating targets in the visual surroundings were significantly shorter as compared to controls. Conclusion Gaze control of locomotion in patients with PPV is characterized by a preferred deviation of gaze more downward and by horizontal explorations for suitable auxiliary means for potential postural support in order to prevent impending falls. These eye movements have shorter durations of fixation as compared to healthy controls and patients with vHI. Finally, the pathological alterations in eye–head coordination during locomotion correlate with a higher level of discomfort and anxiety about falling.
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Affiliation(s)
- J Penkava
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany.
| | - S Bardins
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany
| | - T Brandt
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany
- Institute for Clinical Neurosciences, Ludwig-Maximilians-University, Munich, Germany
| | - M Wuehr
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany
| | - D Huppert
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig-Maximilians-University, Marchioninistr. 15, 81377, Munich, Germany
- Institute for Clinical Neurosciences, Ludwig-Maximilians-University, Munich, Germany
- Department of Neurology, University Hospital, Ludwig-Maximilians-University, Munich, Germany
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Affiliation(s)
- Elmar C Kal
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
| | - William R Young
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
- School of Sport and Health Sciences, University of Exeter, Exeter, UK
| | - Toby J Ellmers
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
- School of Sport and Health Sciences, University of Exeter, Exeter, UK
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Thomas NDA, Gardiner JD, Crompton RH, Lawson R. Keep your head down: Maintaining gait stability in challenging conditions. Hum Mov Sci 2020; 73:102676. [PMID: 32956985 DOI: 10.1016/j.humov.2020.102676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Peripheral vision often deteriorates with age, disrupting our ability to maintain normal locomotion. Laboratory based studies have shown that lower visual field loss, in particular, is associated with changes in gaze and gait behaviour whilst walking and this, in turn, increases the risk of falling in the elderly. Separately, gaze and gait behaviours change and fall risk increases when walking over complex surfaces. It seems probable, but has not yet been established, that these challenges to stability interact. RESEARCH QUESTION How does loss of the lower visual field affect gaze and gait behaviour whilst walking on a variety of complex surfaces outside of the laboratory? Specifically, is there a synergistic interaction between the effects on behaviour of blocking the lower visual field and increased surface complexity? METHODS We compared how full vision versus simulated lower visual field loss affected a diverse range of behavioural measures (head pitch angle, eye angle, muscle coactivation, gait speed and walking smoothness as measured by harmonic ratios) in young participants. Participants walked over a range of surfaces of different complexity, including pavements, grass, steps and pebbles. RESULTS In both full vision and blocked lower visual field conditions, surface complexity influenced gaze and gait behaviour. For example, more complex surfaces were shown to be associated with lowered head pitch angles, increased leg muscle coactivation, reduced gait speed and decreased walking smoothness. Relative to full vision, blocking the lower visual field caused a lowering of head pitch, especially for more complex surfaces. However, crucially, muscle coactivation, gait speed and walking smoothness did not show a significant change between full vision and blocked lower visual field conditions. Finally, head pitch angle, muscle coactivation, gait speed and walking smoothness were all correlated highly with each other. SIGNIFICANCE Our study showed that blocking the lower visual field did not significantly change muscle coactivation, gait speed or walking smoothness. This suggests that young people cope well when walking with a blocked lower visual field, making minimal behavioural changes. Surface complexity had a greater effect on gaze and gait behaviour than blocking the lower visual field. Finally, head pitch angle was the only measure that showed a significant synergistic interaction between surface complexity and blocking the lower visual field. Together our results indicate that, first, a range of changes occur across the body when people walk over more complex surfaces and, second, that a relatively simple behavioural change (to gaze) suffices to maintain normal gait when the lower visual field is blocked, even in more challenging environments. Future research should assess whether young people cope as effectively when several impairments are simulated, representative of the comorbidities found with age.
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Affiliation(s)
- Nicholas D A Thomas
- Institute of Population Health, University of Liverpool, Liverpool L69 7ZA, UK; Institute of Life Course & Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK.
| | - James D Gardiner
- Institute of Life Course & Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Robin H Crompton
- Institute of Life Course & Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Rebecca Lawson
- Institute of Population Health, University of Liverpool, Liverpool L69 7ZA, UK
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Krajewski KT, Dever DE, Johnson CC, Mi Q, Simpson RJ, Graham SM, Moir GL, Ahamed NU, Flanagan SD, Anderst WJ, Connaboy C. Load Magnitude and Locomotion Pattern Alter Locomotor System Function in Healthy Young Adult Women. Front Bioeng Biotechnol 2020; 8:582219. [PMID: 33042981 PMCID: PMC7525027 DOI: 10.3389/fbioe.2020.582219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/19/2020] [Indexed: 11/24/2022] Open
Abstract
Introduction During cyclical steady state ambulation, such as walking, variability in stride intervals can indicate the state of the system. In order to define locomotor system function, observed variability in motor patterns, stride regulation and gait complexity must be assessed in the presence of a perturbation. Common perturbations, especially for military populations, are load carriage and an imposed locomotion pattern known as forced marching (FM). We examined the interactive effects of load magnitude and locomotion pattern on motor variability, stride regulation and gait complexity during bipedal ambulation in recruit-aged females. Methods Eleven healthy physically active females (18–30 years) completed 1-min trials of running and FM at three load conditions: no additional weight/bodyweight (BW), an additional 25% of BW (BW + 25%), and an additional 45% of BW (BW + 45%). A goal equivalent manifold (GEM) approach was used to assess motor variability yielding relative variability (RV; ratio of “good” to “bad” variability) and detrended fluctuation analysis (DFA) to determine gait complexity on stride length (SL) and stride time (ST) parameters. DFA was also used on GEM outcomes to calculate stride regulation. Results There was a main effect of load (p = 0.01) on RV; as load increased, RV decreased. There was a main effect of locomotion (p = 0.01), with FM exhibiting greater RV than running. Strides were regulated more tightly and corrected quicker at BW + 45% compared (p < 0.05) to BW. Stride regulation was greater for FM compared to running. There was a main effect of load for gait complexity (p = 0.002); as load increased gait complexity decreased, likewise FM had less (p = 0.02) gait complexity than running. Discussion This study is the first to employ a GEM approach and a complexity analysis to gait tasks under load carriage. Reduction in “good” variability as load increases potentially exposes anatomical structures to repetitive site-specific loading. Furthermore, load carriage magnitudes of BW + 45% potentially destabilize the system making individuals less adaptable to additional perturbations. This is further evidenced by the decrease in gait complexity, which all participants demonstrated values similarly observed in neurologically impaired populations during the BW + 45% load condition.
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Affiliation(s)
- Kellen T Krajewski
- Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Dennis E Dever
- Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Camille C Johnson
- Biodynamics Laboratory, Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Qi Mi
- Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Richard J Simpson
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, United States
| | - Scott M Graham
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom
| | - Gavin L Moir
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, United States
| | - Nizam U Ahamed
- Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Shawn D Flanagan
- Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - William J Anderst
- Biodynamics Laboratory, Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Chris Connaboy
- Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
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Hardeman LES, Kal EC, Young WR, van der Kamp J, Ellmers TJ. Visuomotor control of walking in Parkinson's disease: Exploring possible links between conscious movement processing and freezing of gait. Behav Brain Res 2020; 395:112837. [PMID: 32739286 DOI: 10.1016/j.bbr.2020.112837] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/10/2020] [Accepted: 07/24/2020] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Changes in visual attention have been argued to influence freezing of gait (FOG) in people with Parkinson's Disease (PD). However, the specific visual search patterns of people with FOG pathology (PD + FOG) and potential underlying mechanisms are not well understood. The current study explored visual search behavior in PD + FOG while walking on a pathway featuring environmental features known to exacerbate FOG (e.g., narrow doorway and tripping hazards). Potential underpinning attentional mechanisms were also assessed, such as conscious movement processing. METHODS Visual search behavior of twelve people with PD + FOG tested in ON-state (Mage = 74.3) and twelve age-matched healthy controls (Mage = 72.5) were analyzed during a complex walking task. The task required participants to step over an obstacle and navigate through a narrow doorway, surrounded by clutter. RESULTS People with PD + FOG more frequently directed visual attention to ongoing and imminent steps compared to healthy controls (Mdn = 26% vs Mdn = 14%, respectively; p = 0.042). Self-reported conscious movement processing was also significantly higher in people with PD + FOG. The one participant who froze during the walking task fixated the future trip hazard (obstacle, approximately 6 steps ahead) almost exclusively during freezing trials (i.e., 60-100% of the trial). In contrast, during 'non-freeze' trials, this participant increased the duration of fixations towards ongoing and imminent steps. CONCLUSION Results suggest that people with PD + FOG strongly monitor/control ongoing and immediately upcoming stepping movements. However, prolonged fixations towards threats to future movements might prevent people with PD + FOG from processing the visual information needed to do this, thereby provoke freezing episodes.
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Affiliation(s)
- L E S Hardeman
- Faculty of Behavioral and Movement Sciences, VU University Amsterdam, Netherlands; College of Health, Medicine and Life Sciences, Brunel University London, UK
| | - E C Kal
- College of Health, Medicine and Life Sciences, Brunel University London, UK; Centre for Cognitive Neuroscience, Brunel University London, UK
| | - W R Young
- College of Health, Medicine and Life Sciences, Brunel University London, UK; School of Sport and Health Sciences, University of Exeter, UK
| | - J van der Kamp
- Faculty of Behavioral and Movement Sciences, VU University Amsterdam, Netherlands
| | - T J Ellmers
- College of Health, Medicine and Life Sciences, Brunel University London, UK; Centre for Cognitive Neuroscience, Brunel University London, UK.
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Cullen MM, Schmitt D, Granatosky MC, Wall CE, Platt M, Larsen R. Gaze-behaviors of runners in a natural, urban running environment. PLoS One 2020; 15:e0233158. [PMID: 32428016 PMCID: PMC7237013 DOI: 10.1371/journal.pone.0233158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/29/2020] [Indexed: 11/18/2022] Open
Abstract
Gaze-tracking techniques have advanced our understanding of visual attention and decision making during walking and athletic events, but little is known about how vision influences behavior during running over common, natural obstacles. This study tested hypotheses about whether runners regularly collect visual information and pre-plan obstacle clearance (feedforward control), make improvisational adjustments (online control), or some combination of both. In this study, the gaze profiles of 5 male and 5 female runners, fitted with a telemetric gaze-tracking device, were used to identify the frequency of fixations on an obstacle during a run. Overall, participants fixated on the obstacle 2.4 times during the run, with the last fixation occurring on average between 40% and 80% of the run, suggesting runners potentially shifted from a feedforward planning strategy to an online control strategy during the late portions of the running trial. A negative association was observed between runner velocity and average number of fixations. Consistent with previous studies on visual strategies used during walking, our results indicate that visual attentiveness is part of an important feedforward strategy for runners allowing them to safely approach an obstacle. Thus, visual obstacle attention is a key factor in the navigation of complex, natural landscapes while running.
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Affiliation(s)
- Mark M. Cullen
- Duke University School of Medicine, Durham, NC, United States of America
| | - Daniel Schmitt
- Department of Evolutionary Anthropology, Duke University, Durham, NC, United States of America
| | - Michael C. Granatosky
- Department of Anatomy, New York Institute of Technology, Old Westbury, NY, United States of America
| | - Christine E. Wall
- Department of Evolutionary Anthropology, Duke University, Durham, NC, United States of America
| | - Michael Platt
- Departments of Neuroscience, Psychology, and Marketing, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Roxanne Larsen
- Duke University School of Medicine, Durham, NC, United States of America
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, United States of America
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Mowbray R, Cowie D. Mind your step: learning to walk in complex environments. Exp Brain Res 2020; 238:1455-1465. [PMID: 32405684 PMCID: PMC7286854 DOI: 10.1007/s00221-020-05821-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/23/2020] [Indexed: 11/26/2022]
Abstract
In everyday contexts, children must respond to both self-related constraints (their own skills and abilities) and environmental constraints (external obstacles and goals). How do young children simultaneously accommodate these to support skilled and flexible behaviour? We used walking in a complex environment as a testbed for two hypotheses. Hypothesis 1: children will accommodate the self-related constraint of high foot placement variability via dynamic scaling. Hypothesis 2: children will plan ahead, even in complex environments. In our task, 3- to 5-year-olds and adults walked over obstacle sequences of varying complexity. We measured foot placement around the first obstacle in the sequence. Hypothesis 1 was partially supported. In simple, single obstacle environments, children engaged in dynamic scaling like adults. Those with more variable foot placement left greater margins of error between the feet and the obstacle. However, in complex, multiple obstacle settings, children employed large, un-tailored margins of error. This parallels other multisensory tasks in which children do not rely on the relative variability of sensory inputs. Hypothesis 2 was supported. Like adults, children planned ahead for environmental constraints. Children adjusted foot placement around the first obstacle depending on the upcoming obstacle sequence. In doing so, they demonstrate surprisingly sophisticated planning. We, therefore, show that in the motor domain, even very young children simultaneously control both self-related and environmental constraints. This allows flexible, safe and efficient behaviour.
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Affiliation(s)
- Rachel Mowbray
- Department of Psychology, University of Durham, Durham, DH1 3LE, UK.
| | - Dorothy Cowie
- Department of Psychology, University of Durham, Durham, DH1 3LE, UK
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Thomas NDA, Gardiner JD, Crompton RH, Lawson R. Look out: an exploratory study assessing how gaze (eye angle and head angle) and gait speed are influenced by surface complexity. PeerJ 2020; 8:e8838. [PMID: 32280566 PMCID: PMC7134013 DOI: 10.7717/peerj.8838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 03/02/2020] [Indexed: 11/20/2022] Open
Abstract
Background Most research investigating the connection between walking and visual behaviour has assessed only eye movements (not head orientation) in respect to locomotion over smooth surfaces in a laboratory. This is unlikely to reflect gaze changes found over the complex surfaces experienced in the real world, especially given that eye and head movements have rarely been assessed simultaneously. Research question How does gaze (eye and head) angle and gait speed change when walking over surfaces of different complexity? Methods In this exploratory study, we used a mobile eye tracker to monitor eye movements and inertia measurement unit sensors (IMUs) to measure head angle whilst subjects (n = 11) walked over surfaces with different complexities both indoors and outdoors. Gait speed was recorded from ankle IMUs. Results Overall, mean gaze angle was lowest over the most complex surface and this surface also elicited the slowest mean gait speed. The head contributed increasingly to the lowering of gaze with increased surface complexity. Less complex surfaces showed no significant difference between gaze and gait behaviour. Significance This study supports previous research showing that increased surface complexity is an important factor in determining gaze and gait behaviour. Moreover, it provides the novel finding that head movements provide important contributions to gaze location. Our future research aims are to further assess the role of the head in determining gaze location during locomotion across a greater range of complex surfaces to determine the key surface characteristics that influence gaze during gait.
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Affiliation(s)
- Nicholas D A Thomas
- Institute of Population Health Sciences, University of Liverpool, Liverpool, United Kingdom.,Institute of Ageing & Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - James D Gardiner
- Institute of Ageing & Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Robin H Crompton
- Institute of Ageing & Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Rebecca Lawson
- Institute of Population Health Sciences, University of Liverpool, Liverpool, United Kingdom
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Mariscal DM, Iturralde PA, Torres-Oviedo G. Altering attention to split-belt walking increases the generalization of motor memories across walking contexts. J Neurophysiol 2020; 123:1838-1848. [PMID: 32233897 DOI: 10.1152/jn.00509.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Little is known about the impact of attention during motor adaptation tasks on how movements adapted in one context generalize to another. We investigated this by manipulating subjects' attention to their movements while exposing them to split-belt walking (i.e., legs moving at different speeds), which is known to induce locomotor adaptation. We hypothesized that reducing subjects' attention to their movements by distracting them as they adapted their walking pattern would facilitate the generalization of recalibrated movements beyond the training environment. We reasoned that awareness of the novel split-belt condition could be used to consciously contextualize movements to that particular situation. To test this hypothesis, young adults adapted their gait on a split-belt treadmill while they observed visual information that either distracted them or made them aware of the belt's speed difference. We assessed adaptation and aftereffects of spatial and temporal gait features known to adapt and generalize differently in different environments. We found that all groups adapted similarly by reaching the same steady-state values for all gait parameters at the end of the adaptation period. In contrast, both groups with altered attention to the split-belts environment (distraction and awareness groups) generalized their movements from the treadmill to overground more than controls, who walked without altered attention. This was specifically observed in the generalization of step time (temporal gait feature), which might be less susceptible to online corrections during walking overground. These results suggest that altering attention to one's movements during sensorimotor adaptation facilitates the generalization of movement recalibration.NEW & NOTEWORTHY Little is known about how attention affects the generalization of motor recalibration induced by sensorimotor adaptation paradigms. We showed that altering attention to movements on a split-belt treadmill led to greater adaptation effects in subjects walking overground. Thus our results suggest that altering patients' attention to their actions during sensorimotor adaptation protocols could lead to greater generalization of corrected movements when moving without the training device.
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Affiliation(s)
- Dulce M Mariscal
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Pablo A Iturralde
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gelsy Torres-Oviedo
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
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A Quality of Experience assessment of haptic and augmented reality feedback modalities in a gait analysis system. PLoS One 2020; 15:e0230570. [PMID: 32203533 PMCID: PMC7089541 DOI: 10.1371/journal.pone.0230570] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 03/03/2020] [Indexed: 11/19/2022] Open
Abstract
Gait analysis is a technique that is used to understand movement patterns and, in some cases, to inform the development of rehabilitation protocols. Traditional rehabilitation approaches have relied on expert guided feedback in clinical settings. Such efforts require the presence of an expert to inform the re-training (to evaluate any improvement) and the patient to travel to the clinic. Nowadays, potential opportunities exist to employ the use of digitized “feedback” modalities to help a user to “understand” improved gait technique. This is important as clear and concise feedback can enhance the quality of rehabilitation and recovery. A critical requirement emerges to consider the quality of feedback from the user perspective i.e. how they process, understand and react to the feedback. In this context, this paper reports the results of a Quality of Experience (QoE) evaluation of two feedback modalities: Augmented Reality (AR) and Haptic, employed as part of an overall gait analysis system. The aim of the feedback is to reduce varus/valgus misalignments, which can cause serious orthopedics problems. The QoE analysis considers objective (improvement in knee alignment) and subjective (questionnaire responses) user metrics in 26 participants, as part of a within subject design. Participants answered 12 questions on QoE aspects such as utility, usability, interaction and immersion of the feedback modalities via post-test reporting. In addition, objective metrics of participant performance (angles and alignment) were also considered as indicators of the utility of each feedback modality. The findings show statistically significant higher QoE ratings for AR feedback. Also, the number of knee misalignments was reduced after users experienced AR feedback (35% improvement with AR feedback relative to baseline when compared to haptic). Gender analysis showed significant differences in performance for number of misalignments and time to correct valgus misalignment (for males when they experienced AR feedback). The female group self-reported higher utility and QoE ratings for AR when compared to male group.
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