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Larivière C, Eskandari AH, Mecheri H, Duclos C. Validation of proprioception measures of the lumbar spine. J Electromyogr Kinesiol 2024; 78:102924. [PMID: 39182462 DOI: 10.1016/j.jelekin.2024.102924] [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: 04/30/2024] [Revised: 08/15/2024] [Accepted: 08/20/2024] [Indexed: 08/27/2024] Open
Abstract
BACKGROUND To better personalize treatment and monitor recovery of individuals with low back pain, objective tests of sensorimotor functions, such as lumbar proprioception, must be selected based on their reliability and validity. The primary objective of this study was to test the concurrent validity of three measures of lumbar proprioception. METHODS Thirty-one participants performed three lumbar proprioception tests (motion perception threshold, active and passive joint positioning sense), a whole-body mobility and balance (time up-and-go) and two trunk-specific postural control (threshold of stability and sensor-based sway measures) tests. RESULTS Only the motion perception threshold proprioception test showed some validity, correlating with the trunk-specific postural control tests [r range (positive values): 0.37 to 0.60]. The three lumbar proprioception measures were not correlated to each other. The threshold of stability measure was correlated with the time up-and-go (r = 0.37) and trunk-specific (sensor-based sway measures) postural control [r range (positive values): 0.48 to 0.77] tests. CONCLUSION The present study generated three original findings. Only the motion perception threshold proprioception test demonstrated its concurrent validity. In fact, the three lumbar proprioception tests performed in the present study were not correlated to each other, thus assessing different constructs. Finally, the threshold of stability protocol was validated against other tests. These findings will help in selecting the most appropriate lumbar proprioception measures to study the effects of exercise treatments in patients with back pain.
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Affiliation(s)
- C Larivière
- Institut de recherche Robert-Sauvé en Santé et en sécurité du travail (IRSST), Montreal, Quebec, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, Quebec, Canada.
| | - A H Eskandari
- Institut de recherche Robert-Sauvé en Santé et en sécurité du travail (IRSST), Montreal, Quebec, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, Quebec, Canada
| | - H Mecheri
- Institut de recherche Robert-Sauvé en Santé et en sécurité du travail (IRSST), Montreal, Quebec, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, Quebec, Canada
| | - C Duclos
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, Quebec, Canada; École de réadaptation, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
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Carey S, Ross JM, Abney D, Balasubramaniam R. Effects of auditory noise intensity and color on the dynamics of upright stance. Sci Rep 2024; 14:10518. [PMID: 38714827 PMCID: PMC11076473 DOI: 10.1038/s41598-024-61186-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 05/02/2024] [Indexed: 05/10/2024] Open
Abstract
Previous work assessing the effect of additive noise on the postural control system has found a positive effect of additive white noise on postural dynamics. This study covers two separate experiments that were run sequentially to better understand how the structure of the additive noise signal affects postural dynamics, while also furthering our knowledge of how the intensity of auditory stimulation of noise may elicit this phenomenon. Across the two experiments, we introduced three auditory noise stimulations of varying structure (white, pink, and brown noise). Experiment 1 presented the stimuli at 35 dB while Experiment 2 was presented at 75 dB. Our findings demonstrate a decrease in variability of the postural control system regardless of the structure of the noise signal presented, but only for high intensity auditory stimulation.
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Affiliation(s)
- Sam Carey
- Cognitive & Information Sciences, University of California, Merced, 5200 N Lake Road, Merced, CA, 95343, USA.
| | - Jessica M Ross
- Veterans Affairs Palo Alto Healthcare System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University Medical School, Stanford, CA, USA
| | - Drew Abney
- Department of Psychology, University of Georgia, Athens, GA, USA
| | - Ramesh Balasubramaniam
- Cognitive & Information Sciences, University of California, Merced, 5200 N Lake Road, Merced, CA, 95343, USA
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Nordbeck PC, Andrade V, Silva PL, Kuznetsov NA. DFA as a window into postural dynamics supporting task performance: does choice of step size matter? FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1233894. [PMID: 37609060 PMCID: PMC10440697 DOI: 10.3389/fnetp.2023.1233894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/28/2023] [Indexed: 08/24/2023]
Abstract
Introduction: Detrended Fluctuation Analysis (DFA) has been used to investigate self-similarity in center of pressure (CoP) time series. For fractional gaussian noise (fGn) signals, the analysis returns a scaling exponent, DFA-α, whose value characterizes the temporal correlations as persistent, random, or anti-persistent. In the study of postural control, DFA has revealed two time scaling regions, one at the short-term and one at the long-term scaling regions in the diffusion plots, suggesting different types of postural dynamics. Much attention has been given to the selection of minimum and maximum scales, but the choice of spacing (step size) between the window sizes at which the fluctuation function is evaluated may also affect the estimates of scaling exponents. The aim of this study is twofold. First, to determine whether DFA can reveal postural adjustments supporting performance of an upper limb task under variable demands. Second, to compare evenly-spaced DFA with two different step sizes, 0.5 and 1.0 in log2 units, applied to CoP time series. Methods: We analyzed time series of anterior-posterior (AP) and medial-lateral (ML) CoP displacement from healthy participants performing a sequential upper limb task under variable demand. Results: DFA diffusion plots revealed two scaling regions in the AP and ML CoP time series. The short-term scaling region generally showed hyper-diffusive dynamics and long-term scaling revealed mildly persistent dynamics in the ML direction and random-like dynamics in the AP direction. There was a systematic tendency for higher estimates of DFA-α and lower estimates for crossover points for the 0.5-unit step size vs. 1.0-unit size. Discussion: Results provide evidence that DFA-α captures task-related differences between postural adjustments in the AP and ML directions. Results also showed that DFA-α estimates and crossover points are sensitive to step size. A step size of 0.5 led to less variable DFA-α for the long-term scaling region, higher estimation for the short-term scaling region, lower estimate for crossover points, and revealed anomalous estimates at the very short range that had implications for choice of minimum window size. We, therefore, recommend the use of 0.5 step size in evenly spaced DFAs for CoP time series similar to ours.
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Affiliation(s)
| | - Valéria Andrade
- Center for Cognition, Action, and Perception, Department of Psychology, University of Cincinnati, Cincinnati, OH, United States
| | - Paula L. Silva
- Center for Cognition, Action, and Perception, Department of Psychology, University of Cincinnati, Cincinnati, OH, United States
| | - Nikita A. Kuznetsov
- Department of Rehabilitation, Exercise, and Nutrition Sciences, College of Allied Health Science, University of Cincinnati, Cincinnati, OH, United States
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Kobel MJ, Wagner AR, Merfeld DM. Recurrence quantification analysis of postural sway in patients with persistent postural perceptual dizziness. FRONTIERS IN REHABILITATION SCIENCES 2023; 4:1142018. [PMID: 37576917 PMCID: PMC10415033 DOI: 10.3389/fresc.2023.1142018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 06/30/2023] [Indexed: 08/15/2023]
Abstract
Background Persistent postural perceptual dizziness (PPPD) is a common cause of chronic dizziness and imbalance. Emerging evidence suggests that changes in quantitative measures of postural control may help identify individuals with PPPD, however, traditional linear metrics of sway have yielded inconsistent results. Methodologies to examine the temporal structure of sway, including recurrent quantification analysis (RQA), have identified unique changes in dynamic structure of postural control in other patient populations. This study aimed to determine if adults with PPPD exhibit changes in the dynamic structure of sway and whether this change is modulated on the basis of available sensory cues. Methods Twelve adults diagnosed with PPPD and twelve age-matched controls, completed a standard battery of quiet stance balance tasks that involved the manipulation of visual and/or proprioceptive feedback. For each group, the regularity and complexity of the CoP signal was assessed using RQA and the magnitude and variability of the CoP signal was quantified using traditional linear measures. Results An overall effect of participant group (i.e., healthy controls vs. PPPD) was seen for non-linear measures of temporal complexity quantified using RQA. Changes in determinism (i.e., regularity) were also modulated on the basis of availability of sensory cues in patients with PPPD. No between-group difference was identified for linear measures assessing amount and variability of sway. Conclusions Participants with PPPD on average exhibited sway that was similar in magnitude to, but significantly more repeatable and less complex than, healthy controls. These data show that non-linear measures provide unique information regarding the effect of PPPD on postural control, and as a result, may serve as potential rehabilitation outcome measures.
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Affiliation(s)
- Megan J. Kobel
- Department of Otolaryngology—Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Andrew R. Wagner
- Department of Otolaryngology—Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Health & Rehabilitation Sciences, Ohio State University, Columbus, OH, United States
| | - Daniel M. Merfeld
- Department of Otolaryngology—Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Health & Rehabilitation Sciences, Ohio State University, Columbus, OH, United States
- Department of Speech and Hearing Science, Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, Ohio State University, Columbus, OH, United States
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Carey S, Ross JM, Balasubramaniam R. Auditory, tactile, and multimodal noise reduce balance variability. Exp Brain Res 2023; 241:1241-1249. [PMID: 36961554 PMCID: PMC10130119 DOI: 10.1007/s00221-023-06598-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/10/2023] [Indexed: 03/25/2023]
Abstract
Auditory and somatosensory white noise can stabilize standing balance. However, the differential effects of auditory and tactile noise stimulation on balance are unknown. Prior work on unimodal noise stimulation showed gains in balance with white noise through the auditory and tactile modalities separately. The current study aims to examine whether multimodal noise elicits similar responses to unimodal noise. We recorded the postural sway of healthy young adults who were presented with continuous white noise through the auditory or tactile modalities and through a combination of both (multimodal condition) using a wearable device. Our results replicate previous work that showed that auditory or tactile noise reduces sway variability with and without vision. Additionally, we show that multimodal noise also reduces the variability of sway. Analysis of different frequency bands of sway is typically used to separate open-loop exploratory (< 0.3 Hz) and feedback-driven (> 0.3 Hz) sway. We performed this analysis and showed that unimodal and multimodal white noise affected postural sway variability similarly in both timescales. These results support that the sensory noise effects on balance are robust across unimodal and multimodal conditions and can affect both mechanisms of sway represented in the frequency spectrum. In future work, the parameters of acoustic/tactile manipulation should be optimized for the most effective balance stabilization, and multimodal therapies should be explored for older adults with typical age-related balance instabilities.
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Affiliation(s)
- Sam Carey
- Sensorimotor Neuroscience Laboratory, Cognitive & Information Sciences, University of California, 5200 N Lake Road, Merced, CA, 95343, USA.
| | - Jessica M Ross
- Veterans Affairs Palo Alto Healthcare System and the Sierra Pacific Mental Illness, Research, Education, and Clinical Center, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Stanford, CA, USA
| | - Ramesh Balasubramaniam
- Sensorimotor Neuroscience Laboratory, Cognitive & Information Sciences, University of California, 5200 N Lake Road, Merced, CA, 95343, USA.
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Sex differences in the association of postural control with indirect measures of body representations. Sci Rep 2022; 12:4556. [PMID: 35296686 PMCID: PMC8927351 DOI: 10.1038/s41598-022-07738-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/01/2022] [Indexed: 12/21/2022] Open
Abstract
Besides anthropometric variables, high-order body representations have been hypothesised to influence postural control. However, this has not been directly tested before. Moreover, some studies indicate that sex moderates the relationship of anthropometry and postural control. Therefore, as a proof of concept we investigated the association of body representations with postural control as well as the influence of participants’ sex/gender. Body image measures were assessed with a figural drawing task. Body schema was tested by a covert and an overt task. Body sway was measured during normal bipedal quiet standing with eyes closed (with/without neck extended). Statistical analysis consisted of hierarchical multiple linear regressions with the following regression steps: (1) sensory condition, (2) sex/gender, (3) age, (4) anthropometry, (5) body schema, (6) body image, (7) sex/gender-interactions. Across 36 subjects (19 females), body schema was significantly associated with body sway variability and open-loop control, in addition to commonly known influencing factors, such as sensory condition, gender, age and anthropometry. While in females, also body image dissatisfaction substantially was associated with postural control, this was not the case in males. Sex differences and possible causes why high-order body representations may influence concurrent sensorimotor control of body sway are discussed.
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Liang V, Henderson G, Wu J. Neuromuscular response to a single session of whole-body vibration in children with cerebral palsy: A pilot study. Clin Biomech (Bristol, Avon) 2020; 80:105170. [PMID: 32920250 DOI: 10.1016/j.clinbiomech.2020.105170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/25/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Whole-body vibration (WBV) is a relative new intervention paradigm that could reduce spasticity and improve motor function in children with cerebral palsy (CP). We investigated neuromuscular response to a single session of side-alternating WBV with different amplitudes in children with CP. METHODS Ten children with spastic CP aged 7-17 years at GMFCS level I-III participated in this pilot study. Participants received two sessions of side-alternating WBV with the same frequency (20 Hz) but different amplitudes (low-amplitude: 1 mm and high-amplitude: 2 mm). Each session included six sets of 90 s of WBV and 90 s of rest. Before and after each WBV session, we used (a) the modified Ashworth scale to evaluate the spasticity of the participants' leg muscles, (b) a quiet standing task to analyze center-of-pressure (CoP) pattern and postural control, and (c) overground walking trials to assess spatiotemporal gait parameters and joint range-of-motion (RoM). RESULTS Both WBV sessions similarly reduced the spasticity of the ankle plantarflexors, improved long-range correlation of CoP profile during standing, and reduced muscle activity of tibialis anterior during walking. The high-amplitude WBV further increased ankle RoM during walking. CONCLUSIONS This study demonstrates that a single session of WBV with either a low or a high amplitude can reduce spasticity, enhance standing posture, and improve gait patterns in children with CP. It suggests that low-amplitude WBV may induce similar neuromuscular response as high-amplitude WBV in children with spastic CP and can provide positive outcomes for those who are not able to tolerate stronger vibration.
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Affiliation(s)
- Virginia Liang
- Department of Physical Therapy, University of Illinois, Chicago, IL, USA
| | - Gena Henderson
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA, USA
| | - Jianhua Wu
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA, USA; Center for Movement & Rehabilitation Research, Georgia State University, Atlanta, GA, USA.
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Alviar C, Dale R, Dewitt A, Kello C. Multimodal Coordination of Sound and Movement in Music and Speech. DISCOURSE PROCESSES 2020. [DOI: 10.1080/0163853x.2020.1768500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Camila Alviar
- Cognitive and Information Sciences, University of California, Merced
| | - Rick Dale
- Department of Communication, University of California, Los Angeles
| | - Akeiylah Dewitt
- Cognitive and Information Sciences, University of California, Merced
| | - Christopher Kello
- Cognitive and Information Sciences, University of California, Merced
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Semak MR, Schwartz J, Heise G. Examining Human Unipedal Quiet Stance: Characterizing Control through Jerk. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2020; 2020:5658321. [PMID: 32377224 PMCID: PMC7199553 DOI: 10.1155/2020/5658321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/07/2019] [Indexed: 11/18/2022]
Abstract
We investigated the quality of smoothness during human unipedal quiet stance. Smoothness is quantified by the time rate of change of the accelerations, or jerks, associated with the motion of the foot and can be seen as an indicative of how controlled the balance process is. To become more acquainted with this as a quantity, we wanted to establish whether or not it can be modeled as a (stationary) stochastic process and, if so, explore its temporal scaling behavior. Specifically, our study focused on the jerk concerning the center-of-pressure (COP) for each foot. Data were collected via a force plate for individuals attempting to maintain upright posture using one leg (with eyes open). Positive tests for stochasticity allowed us to treat the time series as a stochastic process and, given this, we took the jerk to be proportional to the increment of the force realizations. Detrended fluctuation analysis was the primary tool used to explore the scaling behavior. Results suggest that both the medial-lateral and anterior-posterior components of the jerk display persistent and antipersistent correlations which can be modeled by fractional Gaussian noise over three different temporal scaling regions. Finally, we discussed certain possible implications of these features such as a jerk-based control over the force on the foot's COP.
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Affiliation(s)
- Matthew R. Semak
- Department of Physics and Astronomy, University of Northern Colorado, Greeley, CO 80639, USA
| | - Jeremiah Schwartz
- Department of Physics and Astronomy, University of Northern Colorado, Greeley, CO 80639, USA
| | - Gary Heise
- School of Sport and Exercise Science, University of Northern Colorado, Greeley, CO 80639, USA
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Shahvarpour A, Preuss R, Larivière C. The effect of extensible and non-extensible lumbar belts on trunk postural balance in subjects with low back pain and healthy controls. Gait Posture 2019; 72:211-216. [PMID: 31255888 DOI: 10.1016/j.gaitpost.2019.06.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 05/23/2019] [Accepted: 06/19/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND Previous findings suggest that wearing a lumbar belt may benefit some patients with low back pain; however, the mechanisms of action are not yet fully understood. RESEARCH QUESTION The effect of wearing two flexible (extensible and non-extensible) lumbar belts on trunk postural control was investigated during an unstable sitting task. METHODS Healthy subjects and subjects with LBP sat on a wobbling chair, with and without the lumbar belts. Chair rotation was measured in the sagittal and frontal planes, and 10 linear and nonlinear measures of balance were computed to assess the quantity (3 measures) and quality (7 measures) of the movements. RESULTS Both lumbar belts induced similar changes in specific measures of trunk postural control, for both subject groups, generally indicative of more instability and less controllability, but with low effect sizes (0.14 and 0.40). Subjects with LBP also showed lower entropy (complexity; effect size 0.93) and higher determinism (predictability; effect size 0.56) than healthy controls, under all test conditions. These findings indicate that the subjects with LBP used a less complex, more predictable trunk postural control strategy, suggestive of impaired adaptability and responsiveness to dynamic trunk postural control demands. The findings also suggest other factors related to dynamic adaptability may be impaired by lumbar belt use. SIGNIFICANCE The effects of the lumbar belts on trunk postural control were small, however, their practical implications for the management of LBP remain to be determined in relation to other effects of lumbar belts (e.g. increased mechanical stiffness).
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Affiliation(s)
- Ali Shahvarpour
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505 Boul. de Maisonneuve O, Montreal, QC, H3A 3C2, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada.
| | - Richard Preuss
- School of Physical and Occupational Therapy, McGill University, 3654 prom Sir-William-Osler, Montreal, QC, H3G 1Y5, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada.
| | - Christian Larivière
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505 Boul. de Maisonneuve O, Montreal, QC, H3A 3C2, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada.
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Martínez-Martí F, Martínez-García MS, Carvajal MÁ, Palma AJ, Anguiano M, Lallena AM. Fractal behavior of the trajectories of the foot centers of pressure during pregnancy. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/aaf0f3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Imaizumi S, Asai T, Hiromitsu K, Imamizu H. Voluntarily controlled but not merely observed visual feedback affects postural sway. PeerJ 2018; 6:e4643. [PMID: 29682421 PMCID: PMC5909687 DOI: 10.7717/peerj.4643] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/29/2018] [Indexed: 12/04/2022] Open
Abstract
Online stabilization of human standing posture utilizes multisensory afferences (e.g., vision). Whereas visual feedback of spontaneous postural sway can stabilize postural control especially when observers concentrate on their body and intend to minimize postural sway, the effect of intentional control of visual feedback on postural sway itself remains unclear. This study assessed quiet standing posture in healthy adults voluntarily controlling or merely observing visual feedback. The visual feedback (moving square) had either low or high gain and was either horizontally flipped or not. Participants in the voluntary-control group were instructed to minimize their postural sway while voluntarily controlling visual feedback, whereas those in the observation group were instructed to minimize their postural sway while merely observing visual feedback. As a result, magnified and flipped visual feedback increased postural sway only in the voluntary-control group. Furthermore, regardless of the instructions and feedback manipulations, the experienced sense of control over visual feedback positively correlated with the magnitude of postural sway. We suggest that voluntarily controlled, but not merely observed, visual feedback is incorporated into the feedback control system for posture and begins to affect postural sway.
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Affiliation(s)
- Shu Imaizumi
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
| | - Tomohisa Asai
- Cognitive Mechanisms Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | | | - Hiroshi Imamizu
- Cognitive Mechanisms Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan.,Graduate School of Humanities and Sociology, The University of Tokyo, Tokyo, Japan
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van den Hoorn W, Kerr GK, van Dieën JH, Hodges PW. Center of Pressure Motion After Calf Vibration Is More Random in Fallers Than Non-fallers: Prospective Study of Older Individuals. Front Physiol 2018; 9:273. [PMID: 29632494 PMCID: PMC5879095 DOI: 10.3389/fphys.2018.00273] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/08/2018] [Indexed: 11/25/2022] Open
Abstract
Aging is associated with changes in balance control and elderly take longer to adapt to changing sensory conditions, which may increase falls risk. Low amplitude calf muscle vibration stimulates local sensory afferents/receptors and affects sense of upright when applied in stance. It has been used to assess the extent the nervous system relies on calf muscle somatosensory information and to rapidly change/perturb part of the somatosensory information causing balance unsteadiness by addition and removal of the vibratory stimulus. This study assessed the effect of addition and removal of calf vibration on balance control (in the absence of vision) in elderly individuals (>65 years, n = 99) who did (n = 41) or did not prospectively report falls (n = 58), and in a group of young individuals (18-25 years, n = 23). Participants stood barefoot and blindfolded on a force plate for 135 s. Vibrators (60 Hz, 1 mm) attached bilaterally over the triceps surae muscles were activated twice for 15 s; after 15 and 75 s (45 s for recovery). Balance measures were applied in a windowed (15 s epoch) manner to compare center-of-pressure (CoP) motion before, during and after removal of calf vibration between groups. In each epoch, CoP motion was quantified using linear measures, and non-linear measures to assess temporal structure of CoP motion [using recurrence quantification analysis (RQA) and detrended fluctuation analysis]. Mean CoP displacement during and after vibration did not differ between groups, which suggests that calf proprioception and/or weighting assigned by the nervous system to calf proprioception was similar for the young and both groups of older individuals. Overall, compared to the elderly, CoP motion of young was more predictable and persistent. Balance measures were not different between fallers and non-fallers before and during vibration. However, non-linear aspects of CoP motion of fallers and non-fallers differed after removal of vibration, when dynamic re-weighting is required. During this period fallers exhibited more random CoP motion, which could result from a reduced ability to control balance and/or a reduced ability to dynamically reweight proprioceptive information. These results show that non-linear measures of balance provide evidence for deficits in balance control in people who go on to fall in the following 12 months.
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Affiliation(s)
- Wolbert van den Hoorn
- Centre for Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health & Rehabilitation Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Graham K. Kerr
- Movement Neuroscience Program, Institute of Health and Biomechanical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jaap H. van Dieën
- Amsterdam Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Paul W. Hodges
- Centre for Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health & Rehabilitation Sciences, The University of Queensland, Brisbane, QLD, Australia
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14
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Transitions in persistence of postural dynamics depend on the velocity and structure of postural perturbations. Exp Brain Res 2018; 236:1491-1500. [PMID: 29564503 DOI: 10.1007/s00221-018-5235-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 03/12/2018] [Indexed: 10/17/2022]
Abstract
The sensorimotor system prefers sway velocity information when maintaining upright posture. Sway velocity has a unique characteristic of being persistent on a short time-scale and anti-persistent on a longer time-scale. The time where the transition from persistence to anti-persistence occurs provides information about how sway velocity is controlled. It is, however, not clear what factors affect shifts in this transition point. This research investigated postural responses to support surface movements of different temporal correlations and movement velocities. Participants stood on a force platform that was translated according to three different levels of temporal correlation. White noise had no correlation, pink noise had moderate correlation, and sine wave movements had very strong correlation. Each correlation structure was analyzed at five different average movement velocities (0.5, 1.0, 2.0, 3.0, and 4.0 cm·s-1), as well as one trial of quiet stance. Center of pressure velocity was analyzed using fractal analysis to determine the transition from persistent to anti-persistent behavior, as well as the strength of persistence. As movement velocity increased, the time to transition became longer for the sine wave and shorter for the white and pink noise movements. Likewise, during the persistent time-scale, the sine wave resulted in the strongest correlation, while white and pink noise had weaker correlations. At the highest three movement velocities, the strength of persistence was lower for the white noise compared to pink noise movements. These results demonstrate that the predictability and velocity of support surface oscillations affect the time-scale threshold between persistent and anti-persistent postural responses. Consequently, whether a feedforward or feedback control is utilized for appropriate postural responses may also be determined by the predictability and velocity of environmental stimuli. The study provides new insight into flexibility and adaptability in postural control. This information has implications for the design of rehabilitative protocols in neuromuscular control.
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Shahvarpour A, Gagnon D, Preuss R, Henry SM, Larivière C. Trunk postural balance and low back pain: Reliability and relationship with clinical changes following a lumbar stabilization exercise program. Gait Posture 2018; 61:375-381. [PMID: 29448220 DOI: 10.1016/j.gaitpost.2018.02.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 01/05/2018] [Accepted: 02/06/2018] [Indexed: 02/02/2023]
Abstract
Lumbar stabilization programs reduce pain and disability, but the mechanisms of action underlying this treatment are unknown. Trunk postural control during unstable sitting represents a surrogate measure of motor control mechanisms involved to maintain the dynamic stability of the spine. This exploratory study aimed to determine the reliability of trunk postural control measures over an 8-week interval, their sensitivity to low back pain status and treatment and their relationship with clinical outcomes. Trunk postural control measures were determined in patients with low back pain before and after an 8-week lumbar stabilization exercise program. Healthy controls were assessed over the same interval, but without any treatment, to determine the reliability of the measures and act as a control group at baseline. The kinematics of a wobble chair during unstable sitting was summarized using different linear and nonlinear measures quantifying the quantity and quality of movement, respectively. The reliability of the measures was moderate to excellent. The results showed significant reduction in pain and disability following the intervention. While no impairment at baseline scores was found, some linear and nonlinear measures changed over the intervention period among the patient group. However, for nonlinear measures only, significant correlations were detected with the change scores of pain and disability. The change of measures over the intervention period was likely due to learning rather than the intervention as similar alteration was detected in the healthy subjects. The results suggest that only the quality (not the quantity) of movement may have relationship with pain and disability.
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Affiliation(s)
- Ali Shahvarpour
- School of Rehabilitation, Faculty of Medicine, Université de Montréal, 2900 Boul, Edouard-Montpetit, Montreal, Quebec , H3T 1J4 Canada; Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505 Boul, de Maisonneuve O. Montreal, Quebec, H3A 3C2, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal Rehabilitation Institute, Montreal, Quebec, Canada.
| | - Dany Gagnon
- School of Rehabilitation, Faculty of Medicine, Université de Montréal, 2900 Boul, Edouard-Montpetit, Montreal, Quebec , H3T 1J4 Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal Rehabilitation Institute, Montreal, Quebec, Canada.
| | - Richard Preuss
- School of Physical and Occupational Therapy, McGill University, 3654 prom Sir-William-Osler, Montreal, Quebec, H3G 1Y5, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal Rehabilitation Institute, Montreal, Quebec, Canada.
| | - Sharon M Henry
- Department of Rehabilitation and Movement Science, The University of Vermont, 305 Rowell Building, Burlington, VT, United States.
| | - Christian Larivière
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505 Boul, de Maisonneuve O. Montreal, Quebec, H3A 3C2, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal Rehabilitation Institute, Montreal, Quebec, Canada.
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16
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Hilbun AL, Karsai I. The effect of age on balancing behavior: complexity analysis of mediolateral force trajectories. Physiol Meas 2017; 39:015002. [PMID: 29176038 DOI: 10.1088/1361-6579/aa9d0b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE We quantified, via complexity analysis, the postural stability of healthy people from a wide age range. APPROACH Thirty-five healthy people aged 18-72 performed three tasks while balancing on one foot on a force plate: standard balancing task, mental task (balancing while answering basic arithmetic questions), and knot-tying task (balancing while tying two knots in a piece of ribbon). Mediolateral force trajectories were analyzed to determine control strategy via Hurst exponents, Lyapunov exponents, Kolmogorov complexity, root mean square, and phase-space plots. MAIN RESULTS We found increased pattern repetition in balancing with increased age, as evidenced by the emergence of a double attractor pattern in phase-space plots and the increase of Hurst exponents with age from approximately 0.3 to 0.8. SIGNIFICANCE As people age, they tend to develop strong feed-forward control strategies for balancing, and lose the complexity of micro movements intrinsic to young age. There is an open-loop control strategy for balancing that emerges in older adulthood, and there are attractors inherent to balancing which begin to develop in middle age.
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Affiliation(s)
- A L Hilbun
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, United States of America
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Effect of whole-body vibration on center-of-mass movement during standing in children and young adults. Gait Posture 2017; 54:148-153. [PMID: 28292716 DOI: 10.1016/j.gaitpost.2017.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/19/2016] [Accepted: 03/03/2017] [Indexed: 02/02/2023]
Abstract
Whole body vibration (WBV) can affect postural control and muscular activation. The purpose of this study was to investigate the center-of-mass (COM) movement of children and young adults before, during, immediately after, and 5min after 40-s WBV in quiet standing. Fourteen young adults (mean age 24.5 years) and fourteen children (mean age 8.1 years) participated in the study. A full-body 35-marker set was placed on the participants and used to calculate COM. Forty-second standing trials were collected before, during, immediately after, and 5min after WBV with an frequency of 28Hz and an amplitude of <1mm. Two visual conditions were provided: eyes-open (EO) and eyes-closed (EC). COM variables included time-domain measures (average velocity, range, sway area and fractal dimension), frequency-domain measures (total power and median frequency), and detrended fluctuation analysis (DFA) scaling exponent in both anterior-posterior (AP) and medial-lateral (ML) directions. Results show that during WBV both children and adults increased average velocity and median frequency, but decreased range and the DFA scaling exponent. Immediately after WBV both groups increased the range, but showed pre-vibration values for most of the COM variables. Comparing to adults, children displayed a higher COM velocity, range, fractal dimension, and total power, but a lower DFA scaling exponent at all phases. The results suggest that both children and adults can quickly adapt their postural control system to WBV and maintain balance during and after vibration. Children display some adult-like postural control during and after WBV; however, their postural development continues into adolescence.
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Ross J, Will O, McGann Z, Balasubramaniam R. Auditory white noise reduces age-related fluctuations in balance. Neurosci Lett 2016; 630:216-221. [DOI: 10.1016/j.neulet.2016.07.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/21/2016] [Accepted: 07/29/2016] [Indexed: 11/15/2022]
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Learning dynamic control of body roll orientation. Exp Brain Res 2015; 234:483-92. [PMID: 26525709 DOI: 10.1007/s00221-015-4469-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Our objective was to examine how the control of orientation is learned in a task involving dynamically balancing about an unstable equilibrium point, the gravitational vertical, in the absence of leg reflexes and muscle stiffness. Subjects (n = 10) used a joystick to set themselves to the gravitational vertical while seated in a multi-axis rotation system (MARS) device programmed with inverted pendulum dynamics. The MARS is driven by powerful servomotors and can faithfully follow joystick commands up to 2.5 Hz with a 30-ms latency. To make the task extremely difficult, the pendulum constant was set to 600°/s(2). Each subject participated in five blocks of four trials, with a trial ending after a cumulative 100 s of balancing, excluding reset times when a subject lost control. To characterize performance and learning, we used metrics derived from joystick movements, phase portraits (joystick deflections vs MARS position and MARS velocity vs angular position), and stabilogram diffusion functions. We found that as subjects improved their balancing performance, they did so by making fewer destabilizing joystick movements and reducing the number and duration of joystick commands. The control strategy they acquired involved making more persistent short-term joystick movements, waiting longer before making changes to ongoing motion, and only intervening intermittently.
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Trunk postural control in unstable sitting: Effect of sex and low back pain status. Clin Biomech (Bristol, Avon) 2015; 30:933-9. [PMID: 26253690 DOI: 10.1016/j.clinbiomech.2015.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Adequate neuromuscular control of the lumbar spine is required to prevent lumbar injuries. A trunk postural control test protocol, controlling for the influence of body size on performance, was implemented to carry out between-subject comparisons. The aim of this study was to assess the effect of sex and low back pain status with the use of two measures of trunk postural control, the first based on chair motion, and the second based on trunk motion. METHODS Thirty-six subjects (with and without low back pain) performed three 60-s trunk postural control trials with their eyes closed while seated on an instrumented wobble chair, following a calibration procedure. Chair and trunk angular kinematics were measured with an optoelectronic system. A chair-based stabilogram and a trunk-based (lumbar spine) stabilogram were created using the angular motions produced in the sagittal and frontal planes. Twenty body-sway measures were computed for each stabilogram. FINDINGS The calibration task efficiently controlled for the influence of body size. Several sex effects were detected, with most of them originating from the trunk-based measures. Subjects with low back pain and healthy controls showed comparable trunk postural control. INTERPRETATION Sex differences were substantiated for the first time, but almost only with the trunk-based stabilogram, showing that the kinematic information captured on the trunk segments is quite different from what is captured on the wobble chair. Contrary to previous studies, pain status was not related to lowered trunk postural control, which can be attributed to the patients recruited or measurement reliability issues.
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Hernandez ME, Snider J, Stevenson C, Cauwenberghs G, Poizner H. A Correlation-Based Framework for Evaluating Postural Control Stochastic Dynamics. IEEE Trans Neural Syst Rehabil Eng 2015; 24:551-561. [PMID: 26011886 DOI: 10.1109/tnsre.2015.2436344] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The inability to maintain balance during varying postural control conditions can lead to falls, a significant cause of mortality and serious injury among older adults. However, our understanding of the underlying dynamical and stochastic processes in human postural control have not been fully explored. To further our understanding of the underlying dynamical processes, we examine a novel conceptual framework for studying human postural control using the center of pressure (COP) velocity autocorrelation function (COP-VAF) and compare its results to Stabilogram Diffusion Analysis (SDA). Eleven healthy young participants were studied under quiet unipedal or bipedal standing conditions with eyes either opened or closed. COP trajectories were analyzed using both the traditional posturographic measure SDA and the proposed COP-VAF. It is shown that the COP-VAF leads to repeatable, physiologically meaningful measures that distinguish postural control differences in unipedal versus bipedal stance trials with and without vision in healthy individuals. More specifically, both a unipedal stance and lack of visual feedback increased initial values of the COP-VAF, magnitude of the first minimum, and diffusion coefficient, particularly in contrast to bipedal stance trials with open eyes. Use of a stochastic postural control model, based on an Ornstein-Uhlenbeck process that accounts for natural weight-shifts, suggests an increase in spring constant and decreased damping coefficient when fitted to experimental data. This work suggests that we can further extend our understanding of the underlying mechanisms behind postural control in quiet stance under varying stance conditions using the COP-VAF and provides a tool for quantifying future neurorehabilitative interventions.
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22
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Ross JM, Balasubramaniam R. Auditory white noise reduces postural fluctuations even in the absence of vision. Exp Brain Res 2015; 233:2357-63. [DOI: 10.1007/s00221-015-4304-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/25/2015] [Indexed: 10/23/2022]
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Degache F, Van Zaen J, Oehen L, Guex K, Trabucchi P, Millet G. Alterations in postural control during the world's most challenging mountain ultra-marathon. PLoS One 2014; 9:e84554. [PMID: 24465417 PMCID: PMC3897373 DOI: 10.1371/journal.pone.0084554] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/15/2013] [Indexed: 11/18/2022] Open
Abstract
We investigated postural control (PC) effects of a mountain ultra-marathon (MUM): a 330-km trail run with 24000 m of positive and negative change in elevation. PC was assessed prior to (PRE), during (MID) and after (POST) the MUM in experienced ultra-marathon runners (n = 18; finish time = 126 ± 16 h) and in a control group (n = 8) with a similar level of sleep deprivation. Subjects were instructed to stand upright on a posturographic platform over a period of 51.2 seconds using a double-leg stance under two test conditions: eyes open (EO) and eyes closed (EC). Traditional measures of postural stability (center of pressure trajectory analysis) and stabilogram-diffusion analysis (SDA) parameters were analysed. For the SDA, a significantly greater short-term effective diffusion was found at POST compared with PRE in the medio-lateral (ML; Dxs) and antero-posterior (AP) directions (Dys) in runners (p<0.05) The critical time interval (Ctx) in the ML direction was significantly higher at MID (p<0.001) and POST (p<0.05) than at PRE in runners. At MID (p<0.001) and POST (p<0.05), there was a significant difference between the two groups. The critical displacement (Cdx) in the ML was significantly higher at MID and at POST (p<0.001) compared with PRE for runners. A significant difference in Cdx was observed between groups in EO at MID (p<0.05) and POST (p<0.005) in the ML direction and in EC at POST in the ML and AP directions (p<0.05). Our findings revealed significant effects of fatigue on PC in runners, including, a significant increase in Ctx (critical time in ML plan) in EO and EC conditions. Thus, runners take longer to stabilise their body at POST than at MID. It is likely that the mountainous characteristics of MUM (unstable ground, primarily uphill/downhill running, and altitude) increase this fatigue, leading to difficulty in maintaining balance.
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Affiliation(s)
- Francis Degache
- School of Health Sciences, Health Research Unit, University of Applied Sciences Western Switzerland, Lausanne, Switzerland
| | - Jérôme Van Zaen
- Applied Signal Processing Group, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lukas Oehen
- Institute of Sports Sciences, Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Kenny Guex
- School of Health Sciences, Department of Physiotherapy, University of Applied Sciences Western Switzerland, Lausanne, Switzerland
| | | | - Gégoire Millet
- Institute of Sports Sciences, Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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24
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van den Heuvel MRC, van Wegen EEH, de Goede CJT, Burgers-Bots IAL, Beek PJ, Daffertshofer A, Kwakkel G. The effects of augmented visual feedback during balance training in Parkinson's disease: study design of a randomized clinical trial. BMC Neurol 2013; 13:137. [PMID: 24093506 PMCID: PMC3852133 DOI: 10.1186/1471-2377-13-137] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 09/30/2013] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Patients with Parkinson's disease often suffer from reduced mobility due to impaired postural control. Balance exercises form an integral part of rehabilitative therapy but the effectiveness of existing interventions is limited. Recent technological advances allow for providing enhanced visual feedback in the context of computer games, which provide an attractive alternative to conventional therapy. The objective of this randomized clinical trial is to investigate whether a training program capitalizing on virtual-reality-based visual feedback is more effective than an equally-dosed conventional training in improving standing balance performance in patients with Parkinson's disease. METHODS/DESIGN Patients with idiopathic Parkinson's disease will participate in a five-week balance training program comprising ten treatment sessions of 60 minutes each. Participants will be randomly allocated to (1) an experimental group that will receive balance training using augmented visual feedback, or (2) a control group that will receive balance training in accordance with current physical therapy guidelines for Parkinson's disease patients. Training sessions consist of task-specific exercises that are organized as a series of workstations. Assessments will take place before training, at six weeks, and at twelve weeks follow-up. The functional reach test will serve as the primary outcome measure supplemented by comprehensive assessments of functional balance, posturography, and electroencephalography. DISCUSSION We hypothesize that balance training based on visual feedback will show greater improvements on standing balance performance than conventional balance training. In addition, we expect that learning new control strategies will be visible in the co-registered posturographic recordings but also through changes in functional connectivity.
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Affiliation(s)
- Maarten RC van den Heuvel
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, Amsterdam, 1081 BT, The Netherlands
| | - Erwin EH van Wegen
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, Amsterdam, 1081 BT, The Netherlands
- Department of Rehabilitation Medicine, MOVE Research Institute Amsterdam, VU University Medical Center, De Boelelaan 1118, Amsterdam, 1007 MB, The Netherlands
| | - Cees JT de Goede
- Department of Rehabilitation Medicine, MOVE Research Institute Amsterdam, VU University Medical Center, De Boelelaan 1118, Amsterdam, 1007 MB, The Netherlands
| | - Ingrid AL Burgers-Bots
- Department of Rehabilitation Medicine, MOVE Research Institute Amsterdam, VU University Medical Center, De Boelelaan 1118, Amsterdam, 1007 MB, The Netherlands
| | - Peter J Beek
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, Amsterdam, 1081 BT, The Netherlands
| | - Andreas Daffertshofer
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, Amsterdam, 1081 BT, The Netherlands
| | - Gert Kwakkel
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, van der Boechorststraat 9, Amsterdam, 1081 BT, The Netherlands
- Department of Rehabilitation Medicine, MOVE Research Institute Amsterdam, VU University Medical Center, De Boelelaan 1118, Amsterdam, 1007 MB, The Netherlands
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25
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Criterion validity and between-day reliability of an inertial-sensor-based trunk postural stability test during unstable sitting. J Electromyogr Kinesiol 2013; 23:899-907. [PMID: 23582401 DOI: 10.1016/j.jelekin.2013.03.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 03/01/2013] [Indexed: 11/20/2022] Open
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Hendershot BD, Nussbaum MA. Persons with lower-limb amputation have impaired trunk postural control while maintaining seated balance. Gait Posture 2013; 38:438-42. [PMID: 23391751 DOI: 10.1016/j.gaitpost.2013.01.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 02/02/2023]
Abstract
Abnormal mechanics of movement resulting from lower-limb amputation (LLA) may increase stability demands on the spinal column and/or alter existing postural control mechanisms and neuromuscular responses. A seated balance task was used to investigate the effects of LLA on trunk postural control and stability, among eight males with unilateral LLA (4 transtibial, 4 transfemoral), and eight healthy, non-amputation controls (matched by age, stature, and body mass). Traditional measures derived from center of pressure (COP) time series, and measures obtained from non-linear stabilogram diffusion analyses, were used to characterize trunk postural control. All traditional measures of postural control (95% ellipse area, RMS distance, and mean velocity) were significantly larger among participants with LLA. Non-linear stabilogram diffusion analyses also revealed significant differences in postural control among persons with LLA, but only in the antero-posterior direction. Normalized trunk muscle activity was also larger among participants with LLA. Larger COP-based sway measures among participants with LLA during seated balance suggest an association between LLA and reduced trunk postural control. Reductions in postural control and spinal stability may be a result of adaptations in functional tissue properties and/or neuromuscular responses, and may potentially be caused by repetitive exposure to abnormal gait and movement. Such alterations could then lead to an increased risk for spinal instability, intervertebral motions beyond physiological limits, and pain.
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Affiliation(s)
- Brad D Hendershot
- Virginia Tech - Wake Forest School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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27
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Zhou J, Manor B, Liu D, Hu K, Zhang J, Fang J. The complexity of standing postural control in older adults: a modified detrended fluctuation analysis based upon the empirical mode decomposition algorithm. PLoS One 2013; 8:e62585. [PMID: 23650518 PMCID: PMC3641070 DOI: 10.1371/journal.pone.0062585] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 03/23/2013] [Indexed: 11/18/2022] Open
Abstract
Human aging into senescence diminishes the capacity of the postural control system to adapt to the stressors of everyday life. Diminished adaptive capacity may be reflected by a loss of the fractal-like, multiscale complexity within the dynamics of standing postural sway (i.e., center-of-pressure, COP). We therefore studied the relationship between COP complexity and adaptive capacity in 22 older and 22 younger healthy adults. COP magnitude dynamics were assessed from raw data during quiet standing with eyes open and closed, and complexity was quantified with a new technique termed empirical mode decomposition embedded detrended fluctuation analysis (EMD-DFA). Adaptive capacity of the postural control system was assessed with the sharpened Romberg test. As compared to traditional DFA, EMD-DFA more accurately identified trends in COP data with intrinsic scales and produced short and long-term scaling exponents (i.e., α(Short), α(Long)) with greater reliability. The fractal-like properties of COP fluctuations were time-scale dependent and highly complex (i.e., α(Short) values were close to one) over relatively short time scales. As compared to younger adults, older adults demonstrated lower short-term COP complexity (i.e., greater α(Short) values) in both visual conditions (p>0.001). Closing the eyes decreased short-term COP complexity, yet this decrease was greater in older compared to younger adults (p<0.001). In older adults, those with higher short-term COP complexity exhibited better adaptive capacity as quantified by Romberg test performance (r(2) = 0.38, p<0.001). These results indicate that an age-related loss of COP complexity of magnitude series may reflect a clinically important reduction in postural control system functionality as a new biomarker.
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Affiliation(s)
- Junhong Zhou
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Brad Manor
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Divisions of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Dongdong Liu
- College of Engineering, Peking University, Beijing, China
| | - Kun Hu
- Medical Biodynamics Program, Division of Sleep Medicine, Brigham and Women’s Hospital/Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
| | - Jue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- College of Engineering, Peking University, Beijing, China
| | - Jing Fang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- College of Engineering, Peking University, Beijing, China
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28
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Ihlen EAF, Skjæret N, Vereijken B. The influence of center-of-mass movements on the variation in the structure of human postural sway. J Biomech 2012; 46:484-90. [PMID: 23149080 DOI: 10.1016/j.jbiomech.2012.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 10/18/2012] [Accepted: 10/21/2012] [Indexed: 11/25/2022]
Abstract
The present article investigates the influence of center-of-mass movements on the variation of the structure in human postural sway. Twelve healthy younger persons performed 60s quiet standing, 60s relaxed standing, and 10 min relaxed standing on two force plates. Center-of-pressure (CoP) and gravitational line (GL) profiles were calculated from the ground reaction forces and moments. The temporal variation of CoP structure was calculated by the local scaling exponent h(t) and a Monte Carlo surrogate test was used to identify phase couplings between temporal scales. The range of variation of h(t) was significantly larger in relaxed standing compared to quiet standing (p<0.00001) and highly correlated with the range of GL movements (r>0.76, p<0.001). However, the variation in h(t) was not generated by the GL movements because the CoP-GL traces was close to identical variation in h(t) (r>0.95, p<0.00001). The Monte Carlo surrogate test indicated the presence of intermittent phase couplings between the temporal scales of both CoP traces and the CoP-GL residuals in the periods with GL movements. The present results suggest that human posture is controlled by intermittent phase coupling of the CoP and GL movements. Furthermore, the investigation of the variation in CoP structure might extend existing theories of changes in postural control for example older persons and patients with a neurodegenerative disease.
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Affiliation(s)
- Espen A F Ihlen
- Department of Neuroscience, Norwegian University of Science and Technology, N-7489 Trondheim, Norway.
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Riley MA, Bonnette S, Kuznetsov N, Wallot S, Gao J. A tutorial introduction to adaptive fractal analysis. Front Physiol 2012; 3:371. [PMID: 23060804 PMCID: PMC3460370 DOI: 10.3389/fphys.2012.00371] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 08/29/2012] [Indexed: 11/30/2022] Open
Abstract
The authors present a tutorial description of adaptive fractal analysis (AFA). AFA utilizes an adaptive detrending algorithm to extract globally smooth trend signals from the data and then analyzes the scaling of the residuals to the fit as a function of the time scale at which the fit is computed. The authors present applications to synthetic mathematical signals to verify the accuracy of AFA and demonstrate the basic steps of the analysis. The authors then present results from applying AFA to time series from a cognitive psychology experiment on repeated estimation of durations of time to illustrate some of the complexities of real-world data. AFA shows promise in dealing with many types of signals, but like any fractal analysis method there are special challenges and considerations to take into account, such as determining the presence of linear scaling regions.
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Affiliation(s)
- Michael A Riley
- Department of Psychology, Center for Cognition, Action, and Perception, University of Cincinnati Cincinnati, OH, USA
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Adaptive Fractal Analysis Reveals Limits to Fractal Scaling in Center of Pressure Trajectories. Ann Biomed Eng 2012; 41:1646-60. [DOI: 10.1007/s10439-012-0646-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 08/22/2012] [Indexed: 10/27/2022]
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Lin D, Nussbaum MA, Madigan ML. Efficacy of three interventions at mitigating the adverse effects of muscle fatigue on postural control. ERGONOMICS 2012; 55:103-113. [PMID: 22176488 DOI: 10.1080/00140139.2011.636454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
UNLABELLED This study evaluated the efficacy of three interventions at reducing the adverse effects of muscle fatigue on postural control. The first provided rest breaks according to perceived decrements in postural stability, while the other two involved auditory stimulations (static pure tone and moving conversation). Sixteen participants performed repetitive box handling (lifting + lowering) over 1.5 h to induce muscle fatigue mainly in the lumbar extensors. Trials of quiet upright stance were completed at 10-min intervals, during which the interventions (or a control condition) were applied. Postural control was assessed using perceived stability (PS) and several measures derived from centre-of-pressure (COP) time series. Allowance of rest breaks did not significantly affect any of the objective measures, though a trend indicated an offset to fatigue-induced decreases in PS. Both the static pure tone and moving conversation led to significant changes in the dependent measures indicating a mitigation of fatigue-induced postural instability. PRACTITIONER SUMMARY We examined the effects of three control strategies on postural control in the presence of muscle fatigue induced by a simulated occupational task. The findings can facilitate the development of future strategies or practical interventions to reduce falling risk and prevent falls.
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Affiliation(s)
- Dingding Lin
- Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA, USA
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Stylianou AP, McVey MA, Lyons KE, Pahwa R, Luchies CW. Postural sway in patients with mild to moderate Parkinson's disease. Int J Neurosci 2011; 121:614-21. [PMID: 21740307 DOI: 10.3109/00207454.2011.602807] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Clinical assessment of postural instability in persons with Parkinson's disease (PD) is done with the retropulsive pull test, but since this test does not assess the underlying causes of postural instability, there is a need for additional assessment tools. The aim of this study was to identify postural sway parameters for use in a multifactorial approach to quantify postural instability. Nineteen adults diagnosed with idiopathic PD, 14 healthy age-matched controls (EH), and 10 healthy young adults (YH) completed the study. Postural parameters were extracted during quiet standing in eyes open (EO) and eyes closed (EC) conditions. Removing visual feedback affected the groups in a similar way. Significant differences between the PD and the two control groups were found in sway path length, area, and ranges in the anterior-posterior (AP) and medial-lateral (ML) directions and the Hurst exponents. PD significantly increased AP sway path length compared with YH and ML sway path length compared with EH. The Hurst exponents in PD were significantly different than in EH. The results suggest that the ML direction is a successful discriminator between PD and age-matched controls and that the interaction between ML and AP directions should be considered in the method used to quantify postural instability.
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Affiliation(s)
- Antonis P Stylianou
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
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Human movement variability, nonlinear dynamics, and pathology: is there a connection? Hum Mov Sci 2011; 30:869-88. [PMID: 21802756 DOI: 10.1016/j.humov.2011.06.002] [Citation(s) in RCA: 596] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Revised: 06/05/2011] [Accepted: 06/06/2011] [Indexed: 12/12/2022]
Abstract
Fields studying movement generation, including robotics, psychology, cognitive science, and neuroscience utilize concepts and tools related to the pervasiveness of variability in biological systems. The concept of variability and the measures for nonlinear dynamics used to evaluate this concept open new vistas for research in movement dysfunction of many types. This review describes innovations in the exploration of variability and their potential importance in understanding human movement. Far from being a source of error, evidence supports the presence of an optimal state of variability for healthy and functional movement. This variability has a particular organization and is characterized by a chaotic structure. Deviations from this state can lead to biological systems that are either overly rigid and robotic or noisy and unstable. Both situations result in systems that are less adaptable to perturbations, such as those associated with unhealthy pathological states or absence of skillfulness.
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Stambolieva K. Fractal properties of postural sway during quiet stance with changed visual and proprioceptive inputs. J Physiol Sci 2011; 61:123-30. [PMID: 21246316 PMCID: PMC10717211 DOI: 10.1007/s12576-010-0129-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 12/26/2010] [Indexed: 10/18/2022]
Abstract
We studied the fractal dynamics of postural sway during quiet stance with changed visual and/or proprioceptive information. Radius-vector length and angle of rotation of center of foot pressure (COP) displacements were used as parameters of postural sway. The experiments were performed on 24 healthy volunteers of both sexes aged 20-30 years. Using a battery of nonlinearity tests, differences in the degree of fractality of both parameters during stance were found. We found that the behavior of radius-vector was similar to fractional Brownian motion, while that of angle of rotation was similar to flicker noise. Quantitative parameters that can be used to characterize the changes in radius-vector length and angle of rotation include self-similarity intervals and fractal dimension. In healthy subjects, the process of postural control maintains its fractal structure independently of altered sensory information. We believe that this analysis provides information about new methods for evaluating postural sway behavior during quiet stance.
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Affiliation(s)
- Katerina Stambolieva
- Laboratory of Sensorimotor and Cognitive Processes, Institute of Neurobiology, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 23, 1113, Sofia, Bulgaria.
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Delignières D, Torre K, Bernard PL. Transition from persistent to anti-persistent correlations in postural sway indicates velocity-based control. PLoS Comput Biol 2011; 7:e1001089. [PMID: 21390333 PMCID: PMC3044760 DOI: 10.1371/journal.pcbi.1001089] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 01/20/2011] [Indexed: 02/07/2023] Open
Abstract
The displacement of the center-of-pressure (COP) during quiet stance has often been accounted for by the control of COP position dynamics. In this paper, we discuss the conclusions drawn from previous analyses of COP dynamics using fractal-related methods. On the basis of some methodological clarification and the analysis of experimental data using stabilogram diffusion analysis, detrended fluctuation analysis, and an improved version of spectral analysis, we show that COP velocity is typically bounded between upper and lower limits. We argue that the hypothesis of an intermittent velocity-based control of posture is more relevant than position-based control. A simple model for COP velocity dynamics, based on a bounded correlated random walk, reproduces the main statistical signatures evidenced in the experimental series. The implications of these results are discussed. Postural control during quiet standing is usually conceived of as the control of position: when position goes beyond a given threshold, corrective mechanisms are engaged to restore equilibrium. In this paper, we question this conception and show that postural control is based on an intermittent control of velocity, with a reversal in its dynamics when the absolute value of velocity reaches a given threshold. This hypothesis presents some counterintuitive implications. Notably, it means that the active control or correction processes do not intervene at the periphery of postural sways, as generally assumed. According to our findings, control occurs in the central region of the posturogram, where velocity reaches its maximal absolute values. The present study suggests new variables of interest in the study of postural control, especially the maximal absolute velocity of the center-of-pressure, which could describe and predict postural disorders.
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Affiliation(s)
- Didier Delignières
- EA 2991 Movement To Health, Montpellier-1 University, Euromov, Montpellier, France.
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Bigelow KE, Berme N. Development of a protocol for improving the clinical utility of posturography as a fall-risk screening tool. J Gerontol A Biol Sci Med Sci 2010; 66:228-33. [PMID: 21127191 DOI: 10.1093/gerona/glq202] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The usefulness of posturography in the clinical screening of older adults for fall risk has been limited by a lack of standardization in testing methodology and data reporting. This study determines which testing condition and postural sway measures best differentiate recurrent fallers and nonrecurrent fallers. METHODS One hundred and fifty older adults were categorized based on their fall status in the past year. Participants performed four quiet-standing tasks, eyes open and eyes closed in both comfortable and narrow stance, for 60 seconds while standing on a force-measuring platform. Traditional and fractal measures were calculated from the center of pressure data. Logistic regression was performed to determine the model for each condition that best discriminated between recurrent fallers and nonrecurrent fallers. RESULTS The eyes closed comfortable stance condition, with its associated model, best differentiated recurrent fallers and nonrecurrent fallers. Medial-lateral sway velocity, anterior-posterior short-term α-scaling exponent, medial-lateral short-term α-scaling exponent, mean frequency, body mass index, and age were included in this model. Sensitivity of the model was 75%, and specificity was 94%. CONCLUSIONS This resulting model demonstrates potential to differentiate recurrent fallers and nonrecurrent fallers in an eyes closed comfortable stance condition. The inclusion of traditional sway parameters, fractal measures, and personal characteristics in this model demonstrates the importance of considering multiple descriptions of postural stability together rather than using only a single measure to establish fall risk.
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Affiliation(s)
- Kimberly Edginton Bigelow
- Department of Mechanical and Aerospace Engineering, University of Dayton, 300 College Park, Dayton, Ohio 45469-0238, USA.
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Almeida MFS, Cavalheiro GL, Pereira AA, Andrade AO. Investigation of age-related changes in physiological kinetic tremor. Ann Biomed Eng 2010; 38:3423-39. [PMID: 20571851 DOI: 10.1007/s10439-010-0098-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 06/07/2010] [Indexed: 10/19/2022]
Abstract
Tremor is the most common movement disorder characterized by repetitive and stereotyped movements. Most investigations on tremor attempt to understand its relation to neuromuscular dysfunctions. Therefore, there is a lack of studies that aim to investigate the complex relation between the physiological tremor and aging, especially in kinetic conditions. In this context, the main motivation of this research was to quantify age-related changes in the kinetic tremor of clinically healthy individuals. For this, a number of features extracted from tremor activity, obtained from digitized drawings of Archimedes' spirals, were analyzed. In total, 59 subjects participated in the experiments. These individuals were divided into seven groups according to their ages and two types of analysis were carried out. First, the tremor activity of young and elderly adults was investigated by means of traditional features commonly used in tremor analysis, and secondly, linear discriminant analysis (LDA) was employed for the study of the correlation between age and tremor. The results showed significant statistical differences between the kinetic tremor activity of the young and elderly groups. Furthermore, it was found that LDA allowed for the estimate of a unique feature, so-called LDA-value, which showed to be linearly correlated with age.
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Affiliation(s)
- Maria Fernanda S Almeida
- Biomedical Engineering Laboratory, Faculty of Electrical Engineering, Federal University of Uberlândia, Campus Santa Mônica, Bloco 1E, Av. João Naves de Ávila, 2121, Uberlândia, Minas Gerais 38.408-100, Brazil.
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Nagano A, Noritake H, Luo ZW. An analysis of directional changes in the center of pressure trajectory during stance. Gait Posture 2010; 31:400-2. [PMID: 20138766 DOI: 10.1016/j.gaitpost.2010.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 12/01/2009] [Accepted: 01/08/2010] [Indexed: 02/02/2023]
Abstract
This study proposes a new approach of posturography analysis, which enables the evaluation of directional changes in the center of pressure trajectory. The concept is similar to that of so-called "stabilogram diffusion analysis". Instead of calculating the distance traveled by the center of pressure in a certain time interval, this new method calculates the cosine of the instantaneous velocity vectors of the center of pressure, which corresponds to the amount of change in the sway direction (cosine=1 corresponds to the identical direction; cosine=-1 corresponds to the opposite direction). This method was applied to the analysis of the experimental data in which postural sway was collected under four conditions: open eyes, closed eyes, and two auditory biofeedback conditions. In the biofeedback conditions, auditory signal was given to the subjects when the center of pressure swayed out of a certain area. As results, the differences in the postural reaction under these conditions were clearly shown using the new method. The results indicated that the subjects reacted to the auditory signals by swaying in the opposite direction with biofeedback. It was also found that the eyes open condition exhibited a more random-like profile. As this method analyzes the directional change in the postural sway, this method can be utilized cooperatively together with such a method as stabilogram diffusion analysis, which analyzes the magnitude of sway.
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Affiliation(s)
- Akinori Nagano
- Department of Computer Science and Systems Engineering, Graduate School of Engineering, Kobe University, Kobe, Hyogo, Japan.
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Cavalheiro GL, Almeida MFS, Pereira AA, Andrade AO. Study of age-related changes in postural control during quiet standing through linear discriminant analysis. Biomed Eng Online 2009; 8:35. [PMID: 19922638 PMCID: PMC2785821 DOI: 10.1186/1475-925x-8-35] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 11/18/2009] [Indexed: 11/10/2022] Open
Abstract
Background The human body adopts a number of strategies to maintain an upright position. The analysis of the human balance allows for the understanding and identification of such strategies. The displacement of the centre of pressure (COP) is a measure that has been successfully employed in studies regarding the postural control. Most of these investigations are related to the analysis of individuals suffering from neuromuscular disorders. Recent studies have shown that the elderly population is growing very fast in many countries all over the world, and therefore, researches that try to understand changes in this group are required. In this context, this study proposes the analysis of the postural control, measured by the displacement of the COP, in groups of young and elderly adults. Methods In total 59 subjects participated of this study. They were divided into seven groups according to their age. The displacement of the COP was collected for each subject standing on a force plate. Two experimental conditions, of 30 seconds each, were investigated: opened eyes and closed eyes. Traditional and recent digital signal processing tools were employed for feature computation from the displacement of the COP. Statistical analyses were carried out in order to identify significant differences between the features computed from the distinct groups that could allow for their discrimination. Results Our results showed that Linear Discrimination Analysis (LDA), which is one of the most popular feature extraction and classifier design techniques, could be successfully employed as a linear transformation, based on the linear combination of standard features for COP analysis, capable of estimating a unique feature, so-called LDA-value, from which it was possible to discriminate the investigated groups and show a high correlation between this feature and age. Conclusion These results show that the analysis of features computed from the displacement of the COP are of great importance in studies trying to understand the ageing process. In particular, the LDA-value showed to be an adequate feature for assessment of changes in the postural control which can be related to functional changes that occur over the ageing.
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Affiliation(s)
- Guilherme L Cavalheiro
- Biomedical Engineering Laboratory, Faculty of Electrical Engineering, Federal University of Uberlândia, Campus Santa Mônica, Bloco 1E, Av, João Naves de Avila, 2121, Uberlândia, Minas Gerais, 38,408-100, Brazil.
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Kyvelidou A, Harbourne RT, Stuberg WA, Sun J, Stergiou N. Reliability of center of pressure measures for assessing the development of sitting postural control. Arch Phys Med Rehabil 2009; 90:1176-84. [PMID: 19577031 DOI: 10.1016/j.apmr.2009.01.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 01/27/2009] [Accepted: 01/30/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To determine the reliability of linear and nonlinear tools, including intrasession and intersession reliability, when used to analyze the center of pressure (COP) time series during the development of infant sitting postural control. DESIGN Longitudinal study. SETTING University hospital laboratory. PARTICIPANTS Typically developing infants (N=33; mean +/- SD age at entry in the study, 152.4+/-17.6d). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Infants were tested twice in 1 week at each of the 4 months of the study. Sitting COP data were recorded for 3 trials at each session (2 each month within 1 week). The linear COP parameters of root mean square and range of sway for both the anterior-posterior and the medial-lateral directions, and the sway path, were calculated. The nonlinear parameters of approximate entropy, Lyapunov exponent, and correlation dimension for both directions were also calculated. Intrasession and intersession reliability was quantified by the intraclass correlation coefficient (ICC). RESULTS The nonlinear tool of approximate entropy presented high intrasession and intersession ICC values compared with all other parameters evaluated. Generally, intrasession and intersession reliability increased in the last 2 months of the data collection and as sitting posture matured. CONCLUSIONS Our results showed that the evaluation of COP data is a reliable method of investigating the development of sitting postural control. The present study emphasizes the need for establishing COP reliability before using it as a method of examining intervention progress directed at improving the sitting postural abilities in infants with motor developmental delays.
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Affiliation(s)
- Anastasia Kyvelidou
- Department of Health Physical Education and Recreation, University of Nebraska at Omaha, Omaha, NE 68182-0216, USA
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Tanaka ML, Nussbaum MA, Ross SD. Evaluation of the threshold of stability for the human spine. J Biomech 2009; 42:1017-22. [PMID: 19345355 DOI: 10.1016/j.jbiomech.2009.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 01/30/2009] [Accepted: 02/23/2009] [Indexed: 10/20/2022]
Abstract
The threshold of stability (ToS) is introduced as a new tool for evaluating spinal stability. Current methods have evaluated the magnitude of spinal kinematic variability, stability diffusion, or Lyapunov exponents. This present method differs by modifying task difficulty to obtain a critical value delineating regions of stability and instability. Conceptually, as task difficulty increases, kinematic variability of the system increases and the basin of stability decreases. When kinematic variability exceeds the basin of stability, stability cannot be maintained over time. This concept is first illustrated using a mathematical model, from which an effective potential function was calculated to show the relationships among kinematic variability, the basin of stability, and task difficulty. In addition, an experiment was performed to evaluate the sensitivity of the ToS to changes in postural control using visual feedback as a control variable. The ToS was found to be more sensitive than the Lyapunov exponent to removal of visual feedback, suggesting it may have use as a diagnostic indicator (e.g. for low back pain). Furthermore, this new method has an additional advantage in which minimal instrumentation is needed. Its simplicity, sensitivity, and low cost suggest that the ToS has potential as a diagnostic or prognostic tool in a clinical setting.
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Affiliation(s)
- Martin L Tanaka
- Department of Orthopaedic Surgery, Wake Forest University, Winston-Salem, NC 27157, USA.
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Lin D, Nussbaum MA, Seol H, Singh NB, Madigan ML, Wojcik LA. Acute effects of localized muscle fatigue on postural control and patterns of recovery during upright stance: influence of fatigue location and age. Eur J Appl Physiol 2009; 106:425-34. [DOI: 10.1007/s00421-009-1026-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2009] [Indexed: 10/21/2022]
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Qu X, Nussbaum MA. Effects of external loads on balance control during upright stance: experimental results and model-based predictions. Gait Posture 2009; 29:23-30. [PMID: 18632273 DOI: 10.1016/j.gaitpost.2008.05.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 05/19/2008] [Accepted: 05/26/2008] [Indexed: 02/07/2023]
Abstract
The purpose of this study was to identify the effects of external loads on balance control during upright stance, and to examine the ability of a new balance control model to predict these effects. External loads were applied to 12 young, healthy participants, and effects on balance control were characterized by center-of-pressure (COP) based measures. Several loading conditions were studied, involving combinations of load mass (10% and 20% of individual body mass) and height (at or 15% of stature above the whole-body COM). A balance control model based on an optimal control strategy was used to predict COP time series. It was assumed that a given individual would adopt the same neural optimal control mechanisms, identified in a no-load condition, under diverse external loading conditions. With the application of external loads, COP mean velocity in the anterior-posterior direction and RMS distance in the medial-lateral direction increased 8.1% and 10.4%, respectively. Predicted COP mean velocity and RMS distance in the anterior-posterior direction also increased with external loading, by 11.1% and 2.9%, respectively. Both experimental COP data and model-based predictions provided the same general conclusion, that application of larger external loads and loads more superior to the whole body center of mass lead to less effective postural control and perhaps a greater risk of loss of balance or falls. Thus, it can be concluded that the assumption about consistency in control mechanisms was partially supported, and it is the mechanical changes induced by external loads that primarily affect balance control.
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Affiliation(s)
- Xingda Qu
- Department of Industrial and Systems Engineering, School of Biomedical Engineering and Sciences, Virginia Tech, 250 Durham Hall (0118), Blacksburg, VA 24061, USA
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Rougier PR. What insights can be gained when analysing the resultant centre of pressure trajectory? Neurophysiol Clin 2008; 38:363-73. [DOI: 10.1016/j.neucli.2008.09.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 09/21/2008] [Indexed: 01/18/2023] Open
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Lin D, Seol H, Nussbaum MA, Madigan ML. Reliability of COP-based postural sway measures and age-related differences. Gait Posture 2008; 28:337-42. [PMID: 18316191 DOI: 10.1016/j.gaitpost.2008.01.005] [Citation(s) in RCA: 237] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 01/17/2008] [Accepted: 01/19/2008] [Indexed: 02/02/2023]
Abstract
The objectives of this study were to assess the within-day and between-day reliability of several center of pressure (COP)-based measures of postural sway and identify whether there were age-related differences in reliability. Thirty-two healthy individuals (16 younger and 16 older) participated. COP was recorded during quiet upright stance on 4 different days, and a variety of measures determined: mean velocity, median power frequency, RMS distance, sway area, and two fractal measures derived from Hurst rescaled range analysis (HR/S) and detrended fluctuation analysis (DFA). Intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were used to quantify reliability. Mean velocity was the most reliable measure. DFA exponents had relatively better reliability than HR/S exponents. In general, within-day reliability was better than between-day. In comparison with younger participants, older participants exhibited better relative reliability (ICC) for all COP measures and comparable absolute reliability (SEM) except for mean velocity and sway area. These results may be useful in guiding the future selection and interpretation of COP-based measures.
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Affiliation(s)
- Dingding Lin
- Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA, USA
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Lee H, Granata KP. Process stationarity and reliability of trunk postural stability. Clin Biomech (Bristol, Avon) 2008; 23:735-42. [PMID: 18304711 PMCID: PMC2832481 DOI: 10.1016/j.clinbiomech.2008.01.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 01/09/2008] [Accepted: 01/14/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND Empirical assessments of torso stability can be estimated from postural variability and nonlinear analyses of seated balance tasks. However, processing methods require sufficient signal duration and test-retest experiments require the assessment must be reliable. Our goal was to characterize the reliability and establish the trial duration for torso stability assessment. METHODS Kinetic and kinematic data were recorded while subjects maintained a seated posture on a wobbly seat pan. Stability was evaluated from dynamic variability and nonlinear stability analyses. Process stationarity of the measured signals characterized the minimum necessary trial duration. Intra-class correlations measured within-session and between-session reliability. FINDINGS Trial duration necessary to achieve process stationarity was 30.2 s. Shorter time to stationarity was observed with measures that included multi-dimensional movement behavior. Summary statistics of movement variability demonstrated moderate intra-session reliability, intra-class correlation=0.64 (range 0.38-0.87). Inter-session reliability for movement variance was moderate, intra-class correlation=0.42 (range 0.22-0.64). Nonlinear stability measures typically performed better than estimates of variability with inter-session reliability as high as intra-class correlation=0.83. Process stationarity and reliability were improved in more difficult balance conditions. INTERPRETATION To adequately capture torso dynamics during the stability assessment the trial duration should be at least 30 s. Moderate to excellent test-retest reliability can be achieved in intra-session analyses, but more repeated measurements are required for inter-session comparisons. Stability diffusion exponents, H(S), and the Lyapunov exponents provide excellent measures for intra-session analyses, while H(S) provides excellent inter-session comparisons of torso stability.
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Affiliation(s)
- HyunWook Lee
- Musculoskeletal Biomechanics Laboratories, Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, 219 Norris Hall (0219), Blacksburg, VA 24061, USA
| | - Kevin P. Granata
- Musculoskeletal Biomechanics Laboratories, Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, 219 Norris Hall (0219), Blacksburg, VA 24061, USA,Musculoskeletal Biomechanics Laboratories, School of Biomedical Engineering and Science, Virginia Polytechnic Institute and State University, 219 Norris Hall (0219), Blacksburg, VA 24061, USA
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Slota GP, Granata KP, Madigan ML. Effects of seated whole-body vibration on postural control of the trunk during unstable seated balance. Clin Biomech (Bristol, Avon) 2008; 23:381-6. [PMID: 18093708 DOI: 10.1016/j.clinbiomech.2007.11.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 10/25/2007] [Accepted: 11/07/2007] [Indexed: 02/07/2023]
Abstract
BACKGROUND Low back disorders and their prevention is of great importance for companies and their employees. Whole-body vibration is thought to be a risk factor for low back disorders, but the neuromuscular, biomechanical, and/or physiological mechanisms responsible for this increased risk are unclear. The purpose of this study was to measure the acute effect of seated whole-body vibration on the postural control of the trunk during unstable seated balance. METHODS Twenty-one healthy subjects (age: 23 years (SD 4 years)) were tested on a wobble chair designed to measure trunk postural control. Measurements of kinematic variance and non-linear stability control were based on seat angle before and after 30 min of seated whole-body vibration (bandwidth=2-20 Hz, root-mean-squared amplitude=1.15m/s(2)). FINDINGS All measures of kinematic variance of unstable seated balance increased (P<0.05) after vibration including: ellipse area (35.5%), root-mean-squared radial lean angle (17.9%), and path length (12.2%). Measures of non-linear stability control also increased (P<0.05) including Lyapunov exponent (8.78%), stability diffusion analysis (1.95%), and Hurst rescaled range analysis (5.2%). INTERPRETATION Whole-body vibration impaired postural control of the trunk as evidenced by the increase in kinematic variance and non-linear stability control measures during unstable sitting. These findings imply an impairment in spinal stability and a mechanism by which vibration may increase low back injury risk. Future work should investigate the effects of whole-body vibration on the anatomical and neuromuscular components that contribute to spinal stability.
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Affiliation(s)
- Gregory P Slota
- The Kevin P. Granata Musculoskeletal Biomechanics Laboratory, Virginia Polytechnic Institute and State University, 219 Norris Hall (0219), Blacksburg, VA 24061, USA.
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Kim S, Nussbaum MA, Madigan ML. Direct parameterization of postural stability during quiet upright stance: Effects of age and altered sensory conditions. J Biomech 2008; 41:406-11. [PMID: 17915226 DOI: 10.1016/j.jbiomech.2007.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 08/22/2007] [Accepted: 08/22/2007] [Indexed: 01/09/2023]
Abstract
The purpose of this study was to determine the relationship between measures of local dynamic stability (LDS) during upright stance and both descriptive measures of postural sway and a scaling index (alpha) derived from detrended fluctuation analysis. Center of pressure (COP) time series were obtained from healthy participants (16 young and 16 older) during upright quiet stance. Vision and somatosensation were altered by eye closure and standing on a compliant surface, respectively. A non-linear time-series analysis method was used to compute three LDS parameters from the COP data: A which was defined as the COP excursion range in state space, and tau(S) and tau(L) which were defined as the divergence rates over short- and long-term timescales, respectively. LDS parameters, descriptive COP measures, and alpha had generally consistent sensitivities to age and/or altered sensory conditions. Age x sensory condition interactions, however, had distinct effects on LDS parameters compared to the other COP-based measures. Older individuals exhibited faster divergence rates while having similar magnitudes of A, compared to young individuals. These results suggest that older individuals stiffen the musculoskeletal system via increased muscle activity, perhaps as an age-related postural adaptation. In addition, correlations between LDS parameters and other COP measures were relatively small (r2<<0.29). Hence, LDS parameters (A, tau(S) and tau(L)) provide distinct information on postural control and stability, supplementing other COP-based measures.
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Affiliation(s)
- Sunwook Kim
- Department of Industrial and Systems Engineering, Virginia Tech 250, Durham Hall (0118), Blacksburg, VA 24061, USA
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Kurz MJ, Stergiou N. Hip actuations can be used to control bifurcations and chaos in a passive dynamic walking model. J Biomech Eng 2007; 129:216-22. [PMID: 17408326 DOI: 10.1115/1.2486008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We explored how hip joint actuation can be used to control locomotive bifurcations and chaos in a passive dynamic walking model that negotiated a slightly sloped surface (gamma<0.019 rad). With no hip actuation, our passive dynamic walking model was capable of producing a chaotic locomotive pattern when the ramp angle was 0.01839 rad<gamma<0.0190 rad. Systematic alterations in hip actuation resulted in rapid transition to any locomotive pattern available in the chaotic attractor and induced stability at ramp angles that were previously considered unstable. Our results detail how chaos can be used as a control scheme for locomotion.
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Affiliation(s)
- Max J Kurz
- Integrative Physiology Laboratory, Department of Health and Human Performance, University of Houston, 3855 Holman St., 104S Garrison, Houston, TX 77204-6015, USA.
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Amoud H, Abadi M, Hewson DJ, Michel-Pellegrino V, Doussot M, Duchêne J. Fractal time series analysis of postural stability in elderly and control subjects. J Neuroeng Rehabil 2007; 4:12. [PMID: 17470303 PMCID: PMC1885443 DOI: 10.1186/1743-0003-4-12] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 05/01/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The study of balance using stabilogram analysis is of particular interest in the study of falls. Although simple statistical parameters derived from the stabilogram have been shown to predict risk of falls, such measures offer little insight into the underlying control mechanisms responsible for degradation in balance. In contrast, fractal and non-linear time-series analysis of stabilograms, such as estimations of the Hurst exponent (H), may provide information related to the underlying motor control strategies governing postural stability. In order to be adapted for a home-based follow-up of balance, such methods need to be robust, regardless of the experimental protocol, while producing time-series that are as short as possible. The present study compares two methods of calculating H: Detrended Fluctuation Analysis (DFA) and Stabilogram Diffusion Analysis (SDA) for elderly and control subjects, as well as evaluating the effect of recording duration. METHODS Centre of pressure signals were obtained from 90 young adult subjects and 10 elderly subjects. Data were sampled at 100 Hz for 30 s, including stepping onto and off the force plate. Estimations of H were made using sliding windows of 10, 5, and 2.5 s durations, with windows slid forward in 1-s increments. Multivariate analysis of variance was used to test for the effect of time, age and estimation method on the Hurst exponent, while the intra-class correlation coefficient (ICC) was used as a measure of reliability. RESULTS Both SDA and DFA methods were able to identify differences in postural stability between control and elderly subjects for time series as short as 5 s, with ICC values as high as 0.75 for DFA. CONCLUSION Both methods would be well-suited to non-invasive longitudinal assessment of balance. In addition, reliable estimations of H were obtained from time series as short as 5 s.
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Affiliation(s)
- Hassan Amoud
- Institut Charles Delaunay, FRE CNRS 2848, Université de technologie de Troyes, 10000 Troyes, France
| | - Mohamed Abadi
- Institut Charles Delaunay, FRE CNRS 2848, Université de technologie de Troyes, 10000 Troyes, France
| | - David J Hewson
- Institut Charles Delaunay, FRE CNRS 2848, Université de technologie de Troyes, 10000 Troyes, France
| | | | - Michel Doussot
- Institut Charles Delaunay, FRE CNRS 2848, Université de technologie de Troyes, 10000 Troyes, France
| | - Jacques Duchêne
- Institut Charles Delaunay, FRE CNRS 2848, Université de technologie de Troyes, 10000 Troyes, France
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