Strategies for maintaining dynamic balance in persons with neurological disorders during overground walking

Maintaining a stable gait requires a dynamic balance control, that can be altered in persons with Multiple Sclerosis (MS), Stroke (ST), and Parkinson’s disease (PD). The understanding of the strategy for Center of Mass (CoM) positioning adopted by patients during walking is important to be able to program treatments aimed at improving gait control and preventing falls. Forty-four persons with a mild-to-moderate neurological disorder (20 with MS, 14 with ST, 10 with PD) underwent clinical examination and gait analysis. Ten Healthy Subjects (HS) walking at matched speed provided the normative data. Dynamic balance was assessed using the margin of stability (MoS). It was calculated as the distance between the extrapolated Center of Pressure and the extrapolated CoM at mid-stance. The MoS values for lower limbs were calculated in patients and compared with speed-matched values of HS. Persons with neurological disorder showed increased MoS in the medio-lateral direction with respect to HS. Within-group comparison analysis showed a symmetry between lower limbs in HS (Mean (95%CI) [mm], dominant vs non-dominant limb, 43.3 (31.9–54.6) vs 42.9 (28.8–56.9)) and PD (less affected vs more affected limb, 71.1 (59.8–82.5) vs 72.5 (58.5–86.6)), while a significant asymmetry was found in MS (54.4 (46.4–62.4) vs 81.1 (71.2–91.1)) and ST (52.1 (42.6–61.7) vs 74.7 (62.8–86.6)) participants. The history of falls was comparable among PD, MS, and ST groups, and the MoS in the frontal plane showed a strong correlation with these records. Objective assessment of MoS revealed pathology-specific strategies showing different impacts in MS, ST, and PD on the ability to control CoM information to manage the balance between limbs during gait. MoS evaluation will provide useful information to address a tailored rehabilitation program and to monitor disease progression.

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Sensorimotor Strategies in Individuals With Poststroke Hemiparesis When Standing Up Without Vision

Motor Control ◽

10.1123/mc.2018-0098 ◽

2020 ◽

Vol 24 (1) ◽

pp. 150-167

Author(s):

Yuko Kuramatsu ◽

Yuji Yamamoto ◽

Shin-Ichi Izumi

Keyword(s):

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Center Of Mass ◽

Healthy Controls ◽

Orthogonal Direction ◽

Standing Up ◽

Lift Off ◽

Task Accomplishment ◽

Asymmetrical Balance

This study investigated the sensorimotor strategies for dynamic balance control in individuals with stroke by restricting sensory input that might influence task accomplishment. Sit-to-stand movements were performed with restricted vision by participants with hemiparesis and healthy controls. The authors evaluated the variability in the position of participants’ center of mass and velocity, and the center-of-pressure position, in each orthogonal direction at the lift-off point. When vision was restricted, the variability in the mediolateral center-of-pressure position decreased significantly in individuals with hemiparesis, but not in healthy controls. Participants with hemiparesis adopted strategies that explicitly differed from those used by healthy individuals. Variability may be decreased in the direction that most requires accuracy. Individuals with hemiparesis have been reported to have asymmetrical balance deficits, and that meant they had to prioritize mediolateral motion control to prevent falling. This study suggests that individuals with hemiparesis adopt strategies appropriate to their characteristics.

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Applying the Minimal Detectable Change of a Static and Dynamic Balance Test Using a Portable Stabilometric Platform to Individually Assess Patients with Balance Disorders

Healthcare ◽

10.3390/healthcare8040402 ◽

2020 ◽

Vol 8 (4) ◽

pp. 402 ◽

Cited By ~ 1

Author(s):

Juan De la Torre ◽

Javier Marin ◽

Marco Polo ◽

José J. Marín

Keyword(s):

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Static Balance ◽

Minimal Detectable Change ◽

Detectable Change ◽

Balance Test ◽

Balance Disorders ◽

Eyes Closed ◽

Specialist Physician

Balance disorders have a high prevalence among elderly people in developed countries, and falls resulting from balance disorders involve high healthcare costs. Therefore, tools and indicators are necessary to assess the response to treatments. Therefore, the aim of this study is to detect relevant changes through minimal detectable change (MDC) values in patients with balance disorders, specifically with vertigo. A test-retest of a static and dynamic balance test was conducted on 34 healthy young volunteer subjects using a portable stabilometric platform. Afterwards, in order to show the MDC applicability, eight patients diagnosed with balance disorders characterized by vertigo of vestibular origin performed the balance test before and after a treatment, contrasting the results with the assessment by a specialist physician. The balance test consisted of four tasks from the Romberg test for static balance control, assessing dynamic postural balance through the limits of stability (LOS). The results obtained in the test-retest show the reproducibility of the system as being similar to or better than those found in the literature. Regarding the static balance variables with the lowest MDC value, we highlight the average velocity of the center of pressure (COP) in all tasks and the root mean square (RMS), the area, and the mediolateral displacement in soft surface, with eyes closed. In LOS, all COP limits and the average speed of the COP and RMS were highlighted. Of the eight patients assessed, an agreement between the specialist physician and the balance test results exists in six of them, and for two of the patients, the specialist physician reported no progression, whereas the balance test showed worsening. Patients showed changes that exceeded the MDC values, and these changes were correlated with the results reported by the specialist physician. We conclude that (at least for these eight patients) certain variables were sufficiently sensitive to detect changes linked to balance progression. This is intended to improve decision making and individualized patient monitoring.

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Age-related neuromuscular function and dynamic balance control during slow and fast balance perturbations

Journal of Neurophysiology ◽

10.1152/jn.00476.2013 ◽

2013 ◽

Vol 110 (11) ◽

pp. 2557-2562 ◽

Cited By ~ 3

Author(s):

Jarmo M. Piirainen ◽

Vesa Linnamo ◽

Neil J. Cronin ◽

Janne Avela

Keyword(s):

Sensory Feedback ◽

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Neuromuscular Function ◽

Plantar Flexor ◽

Fast Recovery ◽

M Wave ◽

Age Related ◽

Wave Latency

This study investigated age-related differences in dynamic balance control and its connection to reflexes and explosive isometric plantar flexor torque in 19 males (9 Young aged 20–33 yr, 10 Elderly aged 61–72 yr). Dynamic balance was measured during Slow (15 cm/s) and Fast (25 cm/s) anterior and posterior perturbations. H/M-ratio was measured at 20% of maximal M-wave (H/M20%) 10, 30, and 90 ms after perturbations. Stretch reflexes were measured from tibialis anterior and soleus during anterior and posterior perturbations, respectively. In Slow, Elderly exhibited larger peak center-of-pressure (COP) displacement (15%; P < 0.05) during anterior perturbations. In Fast, Young showed a trend for faster recovery (37%; P = 0.086) after anterior perturbations. M-wave latency was similar between groups (6.2 ± 0.7 vs. 6.9 ± 1.2 ms), whereas Elderly showed a longer H-reflex latency (33.7 ± 2.3 vs. 36.4 ± 1.7 ms; P < 0.01). H/M20% was higher in Young 30 ms after Fast anterior (50%; P < 0.05) and posterior (51%; P < 0.05) perturbations. Plantar flexor rapid torque was also higher in Young (26%; P < 0.05). After combining both groups' data, H/M20% correlated negatively with Slow peak COP displacement ( r = −0.510, P < 0.05) and positively with Fast recovery time ( r = 0.580, P < 0.05) for anterior perturbations. Age-related differences in balance control seem to be more evident in anterior than posterior perturbations, and rapid sensory feedback is generally important for balance perturbation recovery.

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Muscle Contributions to Balance Control During Amputee and Nonamputee Stair Ascent

Journal of Biomechanical Engineering ◽

10.1115/1.4047387 ◽

2020 ◽

Vol 142 (12) ◽

Author(s):

Nicole G. Harper ◽

Jason M. Wilken ◽

Richard R. Neptune

Keyword(s):

Angular Momentum ◽

Lower Limb ◽

Sagittal Plane ◽

Balance Control ◽

Dynamic Balance ◽

Frontal Plane ◽

Rate Of Change ◽

Prosthetic Devices ◽

Stair Ascent

Abstract Dynamic balance is controlled by lower-limb muscles and is more difficult to maintain during stair ascent compared to level walking. As a result, individuals with lower-limb amputations often have difficulty ascending stairs and are more susceptible to falls. The purpose of this study was to identify the biomechanical mechanisms used by individuals with and without amputation to control dynamic balance during stair ascent. Three-dimensional muscle-actuated forward dynamics simulations of amputee and nonamputee stair ascent were developed and contributions of individual muscles, the passive prosthesis, and gravity to the time rate of change of angular momentum were determined. The prosthesis replicated the role of nonamputee plantarflexors in the sagittal plane by contributing to forward angular momentum. The prosthesis largely replicated the role of nonamputee plantarflexors in the transverse plane but resulted in a greater change of angular momentum. In the frontal plane, the prosthesis and nonamputee plantarflexors contributed oppositely during the first half of stance while during the second half of stance, the prosthesis contributed to a much smaller extent. This resulted in altered contributions from the intact leg plantarflexors, vastii and hamstrings, and the intact and residual leg hip abductors. Therefore, prosthetic devices with altered contributions to frontal-plane angular momentum could improve balance control during amputee stair ascent and minimize necessary muscle compensations. In addition, targeted training could improve the force production magnitude and timing of muscles that regulate angular momentum to improve balance control.

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Auditory feedback alters postural control and functional ability in patients with chronic stroke

10.21203/rs.2.23937/v1 ◽

2020 ◽

Author(s):

Hee Sung Lim ◽

Jiseon Ryu ◽

Sihyun Ryu

Keyword(s):

White Noise ◽

Inclination Angle ◽

Auditory Feedback ◽

Exercise Intervention ◽

Center Of Pressure ◽

Dynamic Balance ◽

Effective Means ◽

Center Of Mass ◽

Chronic Stroke ◽

Post Intervention

Abstract Background: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke and the pre- and post-intervention changes in dynamic balance during walking by analyzing the anterior-posterior (A-P) and medial-lateral (M-L) center of pressure (CoP) range and velocity, center of mass (CoM), and A-P/M-L inclination angle using CoM-CoP and to establish the basis for using auditory feedback as an effective means of exercise intervention by bringing changes in dynamic balance abilities of patients with chronic stroke and retain the necessary abilities for maintaining independent and functional daily living.Methods: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory feedback used white noise, and all participants listened for 20 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated during the walking, and the variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle.Results: There is a significant increase in the A-P CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). In addition, the changes in CoP velocity on the paretic and non-paretic sides increased in both the A-P and M-L directions but not significantly.Conclusion: Our findings confirmed the positive effect of using white noise as auditory feedback through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

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Rethinking Margin of Stability: Incorporating Step-To-Step Regulation to Resolve the Paradox

10.1101/2021.12.01.470263 ◽

2021 ◽

Author(s):

Meghan Kazanski ◽

Joseph P. Cusumano ◽

Jonathan B. Dingwell

Keyword(s):

Inverted Pendulum ◽

Balance Control ◽

Center Of Mass ◽

Frontal Plane ◽

Lateral Instability ◽

Foot Placement ◽

Margin Of Stability ◽

Increased Risk ◽

Mediolateral Stability ◽

Balance Dynamics

ABSTRACTMaintaining frontal-plane stability is a major objective of human walking. Derived from inverted pendulum dynamics, the mediolateral Margin of Stability (MoSML) is frequently used to measure people’s frontal-plane stability on average. However, typical MoSML-based analyses deliver paradoxical interpretations of stability status. To address mediolateral stability using MoSML, we must first resolve this paradox. Here, we developed a novel framework that unifies the well-established inverted pendulum model with Goal-Equivalent Manifold (GEM)-based analyses to assess how humans regulate step-to-step balance dynamics to maintain mediolateral stability. We quantified the extent to which people corrected fluctuations in mediolateral center-of-mass state relative to a MoSML-defined candidate stability GEM in the inverted pendulum phase plane. Participants’ variability and step-to-step correction of tangent and perpendicular deviations from the candidate stability GEM demonstrate that regulation of balance dynamics involves more than simply trying to execute a constant-MoSML balance control strategy. Participants adapted these step-to-step corrections to mediolateral sensory and mechanical perturbations. How participants regulated mediolateral foot placement strongly predicted how they regulated center-of-mass state fluctuations, suggesting that regulation of center-of-mass state occurs as a biomechanical consequence of foot placement regulation. We introduce the Probability of Instability (PoI), a convenient statistic that accounts for step-to-step variance to properly predict instability likelihood on any given future step. Participants increased lateral PoI when destabilized, as expected. These lateral PoI indicated an increased risk of lateral instability, despite larger (i.e., more stable) average MoSML. PoI thereby explicitly predicts instability risk to decisively resolve the existing paradox that arises from conventional MoSML implementations.

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DUAL-TASK BALANCE CONTROL IN ADOLESCENT ATHLETES FOLLOWING CONCUSSION

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00152 ◽

2020 ◽

Vol 8 (4_suppl3) ◽

pp. 2325967120S0015

Author(s):

Tracy Zaslow ◽

Camille Burton ◽

Nicole M. Mueske ◽

Adriana Conrad-Forrest ◽

Bianca Edison ◽

...

Keyword(s):

Dual Task ◽

Verbal Fluency ◽

Walking Speed ◽

Balance Control ◽

Dynamic Balance ◽

Center Of Mass ◽

Quiet Standing ◽

Return To Play ◽

Treatment Protocols ◽

Single Task

Background: Previous research has identified deficient dual-task balance control at the time of return to play (RTP) and possible worsening after RTP in older adolescents/young adults with concussion. These findings have not been investigated in younger patients with concussion. Hypothesis/Purpose: We hypothesized that concussed adolescents would have slower walking speed and increased medial-lateral (ML) center of mass (COM) movement, which would normalize by the time of RTP but worsen after resuming activity. Methods: 13 adolescent concussion patients (7 male; age 10-17 years) were prospectively evaluated at their initial visit (IV) (mean 18, range 4-43 days post-concussion), at RTP clearance (mean 46, range 12-173 days post-concussion), and one month later (mean 26, range 20-41 days post-RTP) along with 11 controls (3 male) seen for similarly timed visits. Standing balance was assessed using range and root mean squared (RMS) COM motion in the anterior-posterior (AP) and ML directions during standing on both legs with eyes open while performing quiet standing, dual-task audio Stroop, side-to-side head turns, and side-to-side thumb tracking tasks. Dynamic balance was assessed using walking speed and COM ML range and velocity during walking alone and with side-to-side head turns and verbal fluency (reciting words starting with “F”) dual tasks. Patients were compared against controls using t-tests, and changes over time were evaluated using linear mixed-effects regression. Results: During standing, patients had higher COM ML RMS than controls at IV during head turns and higher COM AP range during thumb tracking. COM ML motion decreased from IV to RTP (head turns range -6.5mm, p=0.058; head turns RMS -16.8mm, p=0.002; thumb range 9.2mm, p=0.012) and increased from RTP to 1 month follow-up (head turns RMS +10.0mm, p=0.040; Stroop RMS +8.4mm, p=0.086). Patients walked slower than controls at IV during all tasks, and COM ML range was higher in patients vs. controls during verbal fluency at IV and RTP. Walking speed increased from IV to RTP during verbal fluency (+7.8cm/s, p=0.044), from RTP to post-RTP in single task walking (+6.1cm/s, p=0.041), and at each successive visit during head turns (+6.0cm/s and +6.5cm/s, p<0.07). COM ML range also decreased in patients from IV to RTP with verbal fluency (-14.7mm, p=0.011) and from RTP to post-RTP in single task walking ( 4.0mm, p=0.061). Conclusion: Adolescent concussion patients had deficits in static and dynamic balance control at initial presentation. This tended to improve by RTP and only worsened post-RTP for dual-task ML control during standing, suggesting that current conservative treatment protocols are appropriate.

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Greater exposure to repetitive subconcussive head impacts is associated with vestibular dysfunction and balance impairments during walking

Neurology ◽

10.1212/01.wnl.0000550640.72136.29 ◽

2018 ◽

Vol 91 (23 Supplement 1) ◽

pp. S27.2-S27

Author(s):

Fernando Santos ◽

Jaclyn B Caccese ◽

Mariana Gongora ◽

Ian Sotnek ◽

Elizabeth Kaye ◽

...

Keyword(s):

Center Of Pressure ◽

Balance Control ◽

Center Of Mass ◽

Vestibular Stimulation ◽

Vestibular Dysfunction ◽

Foot Placement ◽

Head Impacts ◽

Eyes Closed ◽

Balance Deficits ◽

Soccer Heading

Exposure to repetitive subconcussive head impacts (RSHI), specifically soccer heading, is associated with white matter microstructural changes and cognitive performance impairments. However, the effect of soccer heading exposure on vestibular processing and balance control during walking has not been studied. Galvanic vestibular stimulation (GVS) is a tool that can be used to probe the vestibular system during standing and walking. The purpose of this study was to investigate the association of soccer heading with subclinical balance deficits during walking. Twenty adult amateur soccer players (10 males and 10 females, 22.3 ± 4.5 years, 170.5 ± 9.8 cm, 70.0 ± 10.5 kg) walked along a foam walkway with the eyes closed under 2 conditions: with GVS (∼40 trials) and without GVS (∼40 trials). Outcome measures included mediolateral center-of-mass (COM), center-of-pressure (COP) separation, foot placement, mediolateral ankle modulation, hip adduction, and ankle push off. For each balance mechanism, a GVS response was calculated (GVS, mean [without GVS]). In addition, participants completed a questionnaire, reporting soccer heading exposure over the past year. A linear regression model was used to determine if vestibular processing and balance during walking were related to RSHI exposure. Both foot placement (R2 = 0.324, p = 0.009) and hip adduction (R2 = 0.183, p = 0.50) were predicted by RSHI; whereby, greater exposure to RSHI was associated with greater foot placement and hip adduction responses. However, COM-COP separation (R2 < 0.001, p = 0.927), ankle modulation (R2 = 0.037, p = 0.417), and push off (R2 < 0.001, p = 0.968) were not related to RSHI exposure. Individuals who were exposed to greater RSHI were more perturbed by vestibular stimulation during walking, suggesting that there may be vestibular dysfunction and balance impairments with frequent heading; specifically, individuals with greater exposure to RSHI responded with larger foot placement and hip adduction responses to GVS.

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Effect of Milwaukee brace on static and dynamic balance of female hyperkyphotic adolescents

Prosthetics and Orthotics International ◽

10.1177/0309364612448805 ◽

2012 ◽

Vol 37 (1) ◽

pp. 76-84 ◽

Cited By ~ 4

Author(s):

Arezoo Eshraghi ◽

Nader Maroufi ◽

Mohammad Ali Sanjari ◽

Hassan Saeedi ◽

Mohammad Reza Keyhani ◽

...

Keyword(s):

Sagittal Plane ◽

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Normal Subjects ◽

Balance Performance ◽

Functional Reach ◽

Significant Difference ◽

The Right ◽

Milwaukee Brace

Background: Biomechanical factors, such as spinal deformities can result in balance control disorders. Objectives: The purpose of this study was to examine the effect of bracing on static and dynamic balance control of hyperkyphotic female adolescents. Study Design: Clinical trial. Methods: A force platform was employed to record center of pressure (COP) parameters. Ten adolescents undergoing Milwaukee brace for hyperkyphosis and 14 normal subjects participated in the study. The COP data were collected with and without brace immediately on first day and after 120 days of continuous brace wear. Results: No significant difference was found in dynamic and static balance tests with and without brace on the first day ( P > 0.05). After 120 days, the values of COP displacement in functional reach to the right and left for the hyperkyphotic adolescents when performing without brace enhanced significantly compared to the first day. The forward reach distance was not significantly different between the normal and hyperkyphotic subjects ( P = 0.361); however, hyperkyphotic participants had significantly smaller reach distance in the functional reach to the right (21.88 vs. 25.56cm) and left (17.04 vs. 21.25cm). Conclusion: It might be concluded that bracing had a possible effect on improvement of dynamic balance performance, because the subjects could reach the target in dynamic reach tests with higher displacement in sagittal plane without losing their balance control. Clinical relevance Little is known about the biomechanical aspects of brace wear in individuals with hyperkyphosis. This study investigated balance differences between the healthy and hyperkyphotic individuals, and outcomes of Milwaukee brace wear. It might provide some new insight into the conservative treatment of hyperkyphosis for clinicians and researchers.

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Single-Legged Hop and Single-Legged Squat Balance Performance in Recreational Athletes With a History of Concussion

Journal of Athletic Training ◽

10.4085/1062-6050-185-19 ◽

2020 ◽

Vol 55 (5) ◽

pp. 488-493 ◽

Cited By ~ 4

Author(s):

Robert C. Lynall ◽

Kody R. Campbell ◽

Timothy C. Mauntel ◽

J. Troy Blackburn ◽

Jason P. Mihalik

Keyword(s):

Injury Risk ◽

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Reaction Force ◽

Force Plate ◽

Analysis Of Covariance ◽

Control Group ◽

Time To Stabilization ◽

History Of

Context Researchers have suggested that balance deficiencies may linger during functional activities after concussion recovery. Objective To determine whether participants with a history of concussion demonstrated dynamic balance deficits as compared with control participants during single-legged hops and single-legged squats. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants A total of 15 previously concussed participants (6 men, 9 women; age = 19.7 ± 0.9 years, height = 169.2 ± 9.4 cm, mass = 66.0 ± 12.8 kg, median time since concussion = 126 days [range = 28–432 days]) were matched with 15 control participants (6 men, 9 women; age = 19.7 ± 1.6 years, height = 172.3 ± 10.8 cm, mass = 71.0 ± 10.4 kg). Intervention(s) During single-legged hops, participants jumped off a 30-cm box placed at 50% of their height behind a force plate, landed on a single limb, and attempted to achieve a stable position as quickly as possible. Participants performed single-legged squats while standing on a force plate. Main Outcome Measure(s) Time to stabilization (TTS; time for the normalized ground reaction force to stabilize after landing) was calculated during the single-legged hop, and center-of-pressure path and speed were calculated during single-legged squats. Groups were compared using analysis of covariance, controlling for average days since concussion. Results The concussion group demonstrated a longer TTS than the control group during the single-legged hop on the nondominant leg (mean difference = 0.35 seconds [95% confidence interval = 0.04, 0.64]; F2,27 = 5.69, P = .02). No TTS differences were observed for the dominant leg (F2,27 = 0.64, P = .43). No group differences were present for the single-legged squat on either leg (P ≥ .11). Conclusions Dynamic balance-control deficits after concussion may contribute to an increased musculoskeletal injury risk. Given our findings, we suggest that neuromuscular deficits currently not assessed after concussion may linger. Time to stabilization is a clinically applicable measure that has been used to distinguish patients with various pathologic conditions, such as chronic ankle instability and anterior cruciate ligament reconstruction, from healthy control participants. Whereas the single-legged squat may not sufficiently challenge balance control, future study of the more dynamic single-legged hop is needed to determine its potential diagnostic and prognostic value after concussion.

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