Gait Initiation in Community-Dwelling Adults With Parkinson Disease: Comparison With Older and Younger Adults Without the Disease

Abstract Background and Purpose. Initiation of gait requires transitions from relatively stationary positions to stability with movement and from double- to single-limb stances. These are deliberately destabilizing activities that may be difficult for people with early Parkinson disease (PD), even when they have no problems with level walking. We studied differences in postural stability during gait initiation between participants with early and middle stages of PD (characterized by Hoehn and Yahr as stages 1–3) and 2 other groups of participants without PD—older and younger adults. Subjects. The mean ages of the 3 groups of participants were as follows: subjects with PD, 69.3 years (SD=5.7, range=59–78); older subjects without PD, 69.0 years (SD=3.9, range=65–79); and younger subjects without PD, 27.5 (SD=3.9, range=22–35). Methods. A 3-dimensional motion analysis system was used with 2 force platforms to obtain data for center of mass (COM) and center of pressure (COP). The distance between the vertical projections of the COM and the COP (COM–COP distance) was used to reflect postural control during 5 events in gait initiation. Results. By use of multivariate analysis of variance, differences in COM–COP distance were found among the 3 groups. An analysis of variance indicated differences for 4 of the 5 events in gait initiation. A Scheffe post hoc analysis demonstrated differences in gait initiation between the subjects with PD and both groups of subjects without PD (2 events) and between the subjects with PD and the younger subjects without PD (2 events). Discussion and Conclusion. The COM–COP distance relationship was used to measure postural control during the transition from quiet standing to steady-state gait. Differences between groups indicated that individuals with impaired postural control allow less COM–COP distance than do individuals with no known neurologic problems. The method used could prove useful in the development and assessment of interventions to improve ambulation safety and enhance the independence of people with impaired postural control.

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Inter-Individual Variability in Postural Control During External Center of Mass Stabilization

Frontiers in Physiology ◽

10.3389/fphys.2021.722732 ◽

2022 ◽

Vol 12 ◽

Author(s):

Daša Gorjan ◽

Nejc Šarabon ◽

Jan Babič

Keyword(s):

Postural Control ◽

Center Of Pressure ◽

Center Of Mass ◽

Individual Variability ◽

Quiet Standing ◽

Pendulum System ◽

Velocity Amplitude ◽

Postural Responses ◽

External Stabilization ◽

Underlying Mechanisms

Understanding the relation between the motion of the center of mass (COM) and the center of pressure (COP) is important to understand the underlying mechanisms of maintaining body equilibrium. One way to investigate this is to stabilize COM by fixing the joints of the human and looking at the corresponding COP reactions. However, this approach constrains the natural motion of the human. To avoid this shortcoming, we stabilized COM without constraining the joint movements by using an external stabilization method based on inverted cart-pendulum system. Interestingly, this method only stabilized COM of a subgroup of participants and had a destabilizing effect for others which implies significant variability in inter-individual postural control. The aim of this work was to investigate the underlying causes of inter-individual variability by studying the postural parameters of quiet standing before the external stabilization. Eighteen volunteers took part in the experiment where they were standing on an actuated cart for 335 s. In the middle of this period we stabilized their COM in anteroposterior direction for 105 s. To stabilize the COM, we controlled the position of the cart using a double proportional–integral–derivative controller. We recorded COM position throughout the experiment, calculated its velocity, amplitude, and frequency during the quiet standing before the stabilization, and used these parameters as features in hierarchical clustering method. Clustering solution revealed that postural parameters of quiet standing before the stabilization cannot explain the inter-individual variability of postural responses during the external COM stabilization. COM was successfully stabilized for a group of participants but had a destabilizing effect on the others, showing a variability in individual postural control which cannot be explained by postural parameters of quiet-stance.

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Stiffness Control of Balance During Quiet Standing and Dual Task in Older Adults: The MOBILIZE Boston Study

Journal of Neurophysiology ◽

10.1152/jn.00820.2009 ◽

2010 ◽

Vol 104 (6) ◽

pp. 3510-3517 ◽

Cited By ~ 25

Author(s):

Hyun Gu Kang ◽

Lewis A. Lipsitz

Keyword(s):

Older Adults ◽

Postural Control ◽

Dual Task ◽

Postural Sway ◽

Center Of Pressure ◽

Muscle Tone ◽

Community Dwelling ◽

Quiet Standing ◽

Study Cohort ◽

Boston Study

Distractions affect postural control, but this mechanism is not well understood. Diversion of resources during cognitive stress may lead to decreased motor drive and postural muscle tone. This may appear as decreased postural stiffness and increased postural sway amplitude. We hypothesized that dual tasking leads to decreased stiffness and increased sway amplitude. Postural sway (center of pressure; COP) data were used from 724 participants aged 77.9 ± 5.3 yr, a representative sample of community-dwelling older adults, the MOBILIZE Boston Study cohort. Subjects stood barefoot with eyes open for 30 s per trial on a force plate. Five trials were performed each with and without a serial subtractions-by-3 task. Sway data were fit to a damped oscillator inverted pendulum model. Amplitudes (COP and center of mass), mechanical stiffness, and damping of the sway behavior were determined. Sway amplitudes and damping increased with the dual task ( P < 0.001); stiffness decreased only mediolaterally ( P < 0.001). Those with difficulty doing the dual task exhibited larger sway and less damping mediolaterally ( P ≤ 0.001) and an increased stiffness with dual task anteroposteriorly (interaction P = 0.004). Dual task could still independently explain increases in sway ( P < 0.001) after accounting for stiffness changes. Thus the hypothesis was supported only in mediolateral sway. The simple model helped to explain the dual task related increase of sway only mediolaterally. It also elucidated the differential influence of cognitive function on the mechanics of anteroposterior and mediolateral sway behaviors. Dual task may divert the resources necessary for mediolateral postural control, thus leading to falls.

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Tai Chi Intervention Improves Dynamic Postural Control During Gait Initiation in Older Adults: A Pilot Study

Journal of Applied Biomechanics ◽

10.1123/jab.2013-0256 ◽

2014 ◽

Vol 30 (6) ◽

pp. 697-706 ◽

Cited By ~ 10

Author(s):

Srikant Vallabhajosula ◽

Beverly L. Roberts ◽

Chris J. Hass

Keyword(s):

Older Adults ◽

Postural Control ◽

Tai Chi ◽

Center Of Pressure ◽

Center Of Mass ◽

Separation Distance ◽

Gait Initiation ◽

Mobility Disability ◽

Post Intervention ◽

Movement Characteristics

Tai Chi intervention has been shown to be beneficial for balance improvement. The current study examined the effectiveness of Tai Chi to improve the dynamic postural control among older adults with mobility disability. Six sedentary older adults with mobility disability participated in a 16-week Tai Chi intervention consisting of one hour sessions three times a week. Dynamic postural control was assessed pre- and post intervention as participants initiated gait in four stepping conditions: forward; 45° medially, with the stepping leg crossing over the other leg; 45° and 90° laterally. The center of pressure (CoP) displacement, velocity, and its maximum separation distance from the center of mass in the anteroposterior, mediolateral, and resultant directions were analyzed. Results showed that in the postural phase, Tai Chi increased the CoP mediolateral excursions in the medial (13%) and forward (28%) conditions, and resultant CoP center of mass distance in the medial (9%) and forward (19%) conditions. In the locomotion phase, the CoP mediolateral displacement and velocity significantly increased after the Tai Chi intervention (both by > 100% in the two lateral conditions). These results suggest that through alteration in CoP movement characteristics, Tai Chi intervention might improve the dynamic postural control during gait initiation among older adults.

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“Going Backward”: Effects of age and fatigue on posterior-directed falls in Parkinson disease

Neurorehabilitation ◽

10.3233/nre-210040 ◽

2021 ◽

pp. 1-9

Author(s):

Evan V. Papa ◽

Rita M. Patterson ◽

Nicoleta Bugnariu

Keyword(s):

Postural Control ◽

Parkinson Disease ◽

Repeated Measures ◽

Center Of Pressure ◽

Angular Displacement ◽

Reaction Times ◽

Older Individuals ◽

Peak Knee ◽

Significant Difference ◽

Fatiguing Exercise

BACKGROUND: Nearly half of persons with Parkinson disease (PD) report fatigue as a factor in their fall history. However, it is unknown whether these self-reported falls are caused by a sensation of fatigue or performance fatigue. OBJECTIVE: We sought to investigate the influences of performance fatigue and age on postural control in persons with PD. METHODS: Individuals with PD (n = 14) underwent postural control assessments before (T0) and immediately after (T1) fatiguing exercise. Biomechanical data were gathered on participants completing a treadmill-induced, posterior-directed fall. Performance fatigue was produced using lower extremity resistance exercise on an isokinetic ergometer. Repeated measures ANCOVAs were used with age as a covariate to determine the effects of performance fatigue on biomechanical variables. RESULTS: After adjustment for age, there was a statistically significant difference in peak center of pressure (COP) latency during the support phase of recovery. Pairwise comparisons demonstrated a decrease in peak ankle displacement from T0 to T1. Age was also found to be significantly related to reaction time and peak knee displacement while participants were fatigued. CONCLUSIONS: The decreased peak COP latency, along with decreased ankle angular displacement, suggest that persons with PD adopt a stiffening strategy in response to backward directed falls. Postural stiffening is not uncommon in persons with PD and could be a risk factor for falls. Older individuals with PD demonstrate slower mobility scores and decreased reaction times in the setting of fatigue, suggesting a combined effect of the aging and fatigue processes.

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Surface height effects on postural control: A hypothesis for a stiffness strategy for stance*

Journal of Vestibular Research ◽

10.3233/ves-1999-9405 ◽

1999 ◽

Vol 9 (4) ◽

pp. 277-286 ◽

Cited By ~ 8

Author(s):

Mark G. Carpenter ◽

James S. Frank ◽

Cathy P. Silcher

Keyword(s):

Postural Control ◽

Center Of Pressure ◽

High Surface ◽

Quiet Standing ◽

Vestibular Input ◽

Mean Power ◽

Mean Power Frequency ◽

Balance Confidence ◽

Eyes Closed ◽

Ankle Stiffness

One possible factor influencing the control of upright stance is the perceived threat to one's personal safety, i.e. balance confidence. We explored this factor by examining the control of stationary stance when standing on an elevated platform under various conditions of reduced visual and vestibular inputs. Twenty-eight adults (14 male and 14 female, mean age = 23.5 years) participated in the experiment. Postural control was examined by recording the amplitude variability (RMS) and mean power frequency (MPF) of center of pressure excursions (COP) over a 2-minute interval while participants stood in a normal stance on a low (0.19 m) and a high (0.81 m) platform with toes positioned either at or away from the edge of the platform. Vision was manipulated through eyes open and eyes closed trials. Vestibular input was reduced by tilting the head into extension [1]. Anterior-posterior RMS and MPF of COP were significantly influenced by an interaction between surface height and vision. When vision was available, a significant decrease in RMS was observed during quiet standing on a high surface compared to a low surface independent of step restriction. When vision was available MPF increased when subjects were raised from a low to a high surface. The mean position of the COP was significantly influenced by an interaction between height and step restriction. Differences in RMS and MPF responses to height manipulation were observed between genders in eyes closed conditions. Vestibular input influenced postural control at both low and high levels with significant increases in RMS when vestibular input was reduced. The reciprocal changes observed in RMS and MPF suggest modifications to postural control through changes in ankle stiffness. Vision appears to play a role in increasing ankle stiffness when balance confidence is compromised.

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Effects of additional load at different heights on gait initiation: A statistical parametric mapping of center of pressure and center of mass behavior

PLoS ONE ◽

10.1371/journal.pone.0242892 ◽

2021 ◽

Vol 16 (6) ◽

pp. e0242892

Author(s):

Marcus Fraga Vieira ◽

Fábio Barbosa Rodrigues ◽

Alfredo de Oliveira Assis ◽

Eduardo de Mendonça Mesquita ◽

Thiago Santana Lemes ◽

...

Keyword(s):

Time Series ◽

Center Of Pressure ◽

Center Of Mass ◽

Statistical Parametric Mapping ◽

Gait Initiation ◽

Experimental Conditions ◽

Distributed Load ◽

Uniformly Distributed Load ◽

Reaction Forces ◽

Controlled Object

The purpose of this study was to investigate the effects of different vertical positions of an asymmetrical load on the anticipatory postural adjustments phase of gait initiation. Sixty-eight college students (32 males, 36 females; age: 23.65 ± 3.21 years old; weight: 69.98 ± 8.15 kg; height: 1.74 ± 0.08 m) were enrolled in the study. Ground reaction forces and moments were collected using two force platforms. The participants completed three trials under each of the following random conditions: no-load (NL), waist uniformly distributed load (WUD), shoulder uniformly distributed load (SUD), waist stance foot load (WST), shoulder stance foot load (SST), waist swing foot load (WSW), and shoulder swing foot load (SSW). The paired Hotelling’s T-square test was used to compare the experimental conditions. The center of pressure (COP) time series were significantly different for the SUD vs. NL, SST vs. NL, WST vs. NL, and WSW vs. NL comparisons. Significant differences in COP time series were observed for all comparisons between waist vs. shoulder conditions. Overall, these differences were greater when the load was positioned at the shoulders. For the center of mass (COM) time series, significant differences were found for the WUD vs. NL and WSW vs. NL conditions. However, no differences were observed with the load positioned at the shoulders. In conclusion, only asymmetrical loading at the waist produced significant differences, and the higher the extra load, the greater the effects on COP behavior. By contrast, only minor changes were observed in COM behavior, suggesting that the changes in COP (the controller) behavior are adjustments to maintain the COM (controlled object) unaltered.

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Characteristics of Functional Stability in Young Adolescent Female Artistic Gymnasts

Journal of Human Kinetics ◽

10.2478/hukin-2021-0051 ◽

2021 ◽

Vol 77 (1) ◽

pp. 51-59

Author(s):

Agnieszka Opala-Berdzik ◽

Magdalena Głowacka ◽

Kajetan J. Słomka

Keyword(s):

Postural Control ◽

Center Of Pressure ◽

National Level ◽

Stability Limit ◽

Young Adolescent ◽

Quiet Standing ◽

Adolescent Female ◽

Functional Stability ◽

Postural Control System ◽

Stability Limits

Abstract The aim of this study was to determine whether young adolescent female artistic gymnasts demonstrate better functional stability than age- and sex-matched non-athletes. Different characteristics of the gymnasts’ postural control were expected to be observed. Twenty-two 10- to 13-year-old healthy females (ten national-level artistic gymnasts and twelve non-athletes) participated in the study. To assess their forward functional stability, the 30-s limit of stability test was performed on a force plate. The test consisted of three phases: quiet standing, transition to maximal forward leaning, and standing in the maximal forward leaning position. Between-group comparisons of the directional subcomponents of the root mean squares and mean velocities of the center of pressure and rambling-trembling displacements in two phases (quiet standing and standing in maximal leaning) were conducted. Moreover, anterior stability limits were compared. During standing in maximal forward leaning, there were no differences in the center of pressure and rambling measures between gymnasts and non-athletes (p > 0.05). The values of trembling measures in both anterior-posterior and medial-lateral directions were significantly lower in gymnasts (p < 0.05). Both groups presented similar values for anterior stability limits (p > 0.05). The comparisons of rambling components may suggest a similar supraspinal control of standing in the maximal leaning position between gymnasts and healthy non-athletes. However, decreased trembling in gymnasts may indicate reduced noise in their postural control system possibly due to superior control processes at the spinal level. The anterior stability limit was not influenced by gymnastics training in female adolescents.

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Characteristics of the distance between the center of pressure and the center of mass during quiet standing in patients with knee osteoarthritis

Osteoarthritis and Cartilage ◽

10.1016/j.joca.2019.02.191 ◽

2019 ◽

Vol 27 ◽

pp. S129-S130

Author(s):

K. Sabashi ◽

M. Yamanaka ◽

T. Chiba ◽

T. Ishida ◽

H. Tohyama

Keyword(s):

Knee Osteoarthritis ◽

Center Of Pressure ◽

Center Of Mass ◽

Quiet Standing

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The Effects of Active Self-Correction on Postural Control in Girls with Adolescent Idiopathic Scoliosis: The Role of an Additional Mental Task

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17051640 ◽

2020 ◽

Vol 17 (5) ◽

pp. 1640 ◽

Cited By ~ 1

Author(s):

Elżbieta Piątek ◽

Michał Kuczyński ◽

Bożena Ostrowska

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Postural Control ◽

Repeated Measures ◽

Postural Sway ◽

Center Of Pressure ◽

Force Plate ◽

Stroop Test ◽

Quiet Standing ◽

Mental Task

Due to balance deficits that accompany adolescent idiopathic scoliosis (AIS), the potential interaction between activities of daily living and active self-correction movements (ASC) on postural control deserves particular attention. Our purpose was to assess the effects of ASC movements with or without a secondary mental task on postural control in twenty-five girls with AIS. It is a quasi-experimental within-subject design with repeated measures ANOVA. They were measured in four 20-s quiet standing trials on a force plate: no task, ASC, Stroop test, and both. Based on the center-of-pressure (COP) recordings, the COP parameters were computed. The ASC alone had no effect on any of the postural sway measures. Stroop test alone decreased COP speed and increased COP entropy. Performing the ASC movements and Stroop test together increased the COP speed and decreased COP entropy as compared to the baseline data. In conclusion, our results indicate that AIS did not interfere with postural control. The effects of the Stroop test accounted for good capacity of subjects with AIS to take advantage of distracting attentional resources from the posture. However, performing both tasks together exhibited some deficits in postural control, which may suggest the need for therapeutic consultation while engaging in more demanding activities.

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