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Laboratory Versus Daily Life Gait Characteristics In Patients With Multiple Sclerosis, Parkinson’S Disease, And Matched Controls, Vrutangkumar V. Shah, James Mcnames, Martina Mancini, Patricia Carlson-Kuhta, Rebecca I. Spain, John G. Nutt, Mahmoud El-Gohary, Carolin Curtze, Fay B. Horak

Journal Articles

Background and purpose

Recent findings suggest that a gait assessment at a discrete moment in a clinic or laboratory setting may not reflect functional, everyday mobility. As a step towards better understanding gait during daily life in neurological populations, we compared gait measures that best discriminated people with multiple sclerosis (MS) and people with Parkinson’s Disease (PD) from their respective, age-matched, healthy control subjects (MS-Ctl, PD-Ctl) in laboratory tests versus a week of daily life monitoring.

Methods

We recruited 15 people with MS (age mean ± SD: 49 ± 10 years), 16 MS-Ctl (45 ± 11 years), 16 people with …

Differences Between Joint-Space And Musculoskeletal Estimations Of Metabolic Rate Time Profiles, Arash Mohammadzadeh Gonabadi, Prokopios Antonellis, Philippe Malcolm

Journal Articles

Motion capture laboratories can measure multiple variables at high frame rates, but we can only measure the average metabolic rate of a stride using respiratory measurements. Biomechanical simulations with equations for calculating metabolic rate can estimate the time profile of metabolic rate within the stride cycle. A variety of methods and metabolic equations have been proposed, including metabolic time profile estimations based on joint parameters. It is unclear whether differences in estimations are due to differences in experimental data or due to methodological differences. This study aimed to compare two methods for estimating the time profile of metabolic rate, within …

Stochastic Resonance Reduces Sway And Gait Variability In Individuals With Unilateral Transtibial Amputation: A Pilot Study, Aaron Likens, Jenny A. Kent, C. Ian Sloan, Shane R. Wurdeman, Nicholas Stergiou

Journal Articles

Sub-threshold (imperceptible) vibration, applied to parts of the body, impacts how people move and perceive our world. Could this idea help someone who has lost part of their limb? Sub-threshold vibration was applied to the thigh of the affected limb of 20 people with unilateral transtibial amputation. Vibration conditions tested included two noise structures: pink and white. Center of pressure (COP) excursion (range and root-mean-square displacements) during quiet standing, and speed and spatial stride measures (mean and standard deviations of step length and width) during walking were assessed. Pink noise vibration decreased COP displacements in standing, and white noise vibration …

Gait Complexity Is Acutely Restored In Older Adults When Walking To A Fractal-Like Visual Stimulus, Joao R. Vaz, Brian Knarr, Nicholas Stergiou

Journal Articles

Typically, gait rehabilitation uses an invariant stimulus paradigm to improve gait related deficiencies. However, this approach may not be optimal as it does not incorporate gait complexity, or in more precise words, the variable fractal-like nature found in the gait fluctuations commonly observed in healthy populations. Aging which also affects gait complexity, resulting in a loss of adaptability to the surrounding environment, could benefit from gait rehabilitation that incorporates a variable fractal-like stimulus paradigm. Therefore, the present study aimed to investigate the effect of a variable fractal-like visual stimulus on the stride-to-stride fluctuations of older adults during overground walking. Additionally, …

Effect Of Bout Length On Gait Measures In People With And Without Parkinson’S Disease During Daily Life, Vrutangkumar V. Shah, James Mcnames, Graham Harker, Martina Mancini, Patricia Carlson-Kuhta, John G. Nutt, Mahmoud El-Gohary, Carolin Curtze, Fay B. Horak

Journal Articles

Although the use of wearable technology to characterize gait disorders in daily life is increasing, there is no consensus on which specific gait bout length should be used to characterize gait. Clinical trialists using daily life gait quality as study outcomes need to understand how gait bout length affects the sensitivity and specificity of measures to discriminate pathological gait as well as the reliability of gait measures across gait bout lengths. We investigated whether Parkinson’s disease (PD) affects how gait characteristics change as bout length changes, and how gait bout length affects the reliability and discriminative ability of gait measures …

Strength Of Plantar- And Dorsiflexors Mediates Step Regularity During A High Cognitive Load Situation In A Cross-Sectional Cohort Of Older And Younger Adults, Farahnaz Fallah Tafti, Kristen Watson, Julie Blaskewicz Boron, Sara A. Myers, Kendra K. Schmid, Jennifer M. Yentes

Journal Articles

Background and Purpose:

Completing simultaneous tasks while standing or walking (ie, a high cognitive load situation [HCLS]) is inevitable in daily activities and can lead to interference in task performances. Age-related physical and cognitive changes may confound performance variability during HCLS in older and younger adults. Identification of these confounding effects may reveal therapy targets to maintain optimal physical function later in life. The aim of this study was to investigate the effect of increasing the difficulty levels of an additional motor task and restricting visual information, on gait parameters in younger and older adults while considering the effect of …

Age Induced Modifications In The Persistency Of Voluntary Sway When Actively Tracking The Complex Motion Of A Visual Target, Haralampos Sotirakis, Nick Stergiou, Dimitrios A. Patikas, Vassilia Hatzitaki

Journal Articles

Movement persistency, reflected in systematic cycle to cycle fluctuations of a rhythmical task such as walking or voluntary sway, is compromised with increasing age, making older adults more susceptible to falls. In the present study, we tested whether it is possible to improve rhythmic voluntary sway persistency in old age by actively tracking the complex (i.e. persistent) motion of a visual target. Twenty healthy young and 20 older adults performed 132 cycles of anterior-posterior sway under two conditions: a) self-paced sway and b) sway while tracking the vertical motion of a complex visual target. The persistency of sway cycle amplitude …

Cytokine Signature Of Inflammation Mediated By Autoreactive Th-Cells, In Calf Muscle Of Claudicating Patients With Fontaine Stage Ii Peripheral Artery Disease, George P. Casale, Johnathan R. Thompson, Lauren C. Carpenter, Julian Kyung-Soo Kim, Timothy J. Lackner, Constance Mietus, Duy M. Ha, Sara A. Myers, Katyarina E. Brunette, Shuai Li, Christina Shields, Gregory Wilcockson, Iraklis Pipinos

Journal Articles

Peripheral artery disease (PAD), a severe atherosclerotic condition primarily of the elderly, afflicts 200 million individuals, worldwide, and is associated with lower extremity myopathy. Circulating markers of inflammation have been linked to risk and severity of PAD but the contribution of local inflammation to myopathy remains unknown. We evaluated, by ELISA, calf muscle of PAD patients (N = 23) and control subjects (N = 18) for local expression of inflammatory cytokines including Granulocyte/Monocyte Colony-Stimulating Factor (GM-CSF), Interleukin 17A (IL-17A), Interferon ϒ (IFN-ϒ), tumor necrosis factor α (TNF-α), and Interleukin 6 (IL-6). One or more of these cytokines were expressed in …

Folk Physics In The Twenty-First Century: Understanding Tooling As Embodied, Dorothy M. Fragaszy, Madhur Mangalam

Journal Articles

Povinelli’s (2000) studies with chimpanzees (Pan troglodytes) reported in “Folk Physics for Apes” were firmly grounded in a Cartesian view of knowledge, which posits that humans use abstract concepts such as force, gravity, and shape to reason causally about events and plan our actions (with tools in the case of Folk Physics for Apes). Povinelli set out to examine if chimpanzees, like humans, used causal concepts to solve mechanical problems, as the Cartesian view predicts. However, Povinelli’s findings uniformly challenged his expectations. Povinelli’s book stimulated research and contributed to the development of alternate understandings of how animals (including humans) use …

To Walk Or To Run – A Question Of Movement Attractor Stability, Peter C. Raffalt, Jenny A. Kent, Shane R. Wurdeman, Nicholas Stergiou

Journal Articles

During locomotion, humans change gait mode between walking and running as locomotion speed is either increased or decreased. Dynamical systems theory predicts that the self-organization of coordinated motor behaviors dictates the transition from one distinct stable attractor behavior to another distinct attractor behavior (e.g. walk to run or vice versa) as the speed is changed. To evaluate this prediction, the present study investigated the attractor stability of walking and running across a range of speeds evoking both self-selected gait mode and non-self-selected gait mode. Eleven subjects completed treadmill walking for 3 min at 0.89, 1.12, 1.34, 1.56, 1.79, 2.01, 2.24 …

Assessing The Temporal Organization Of Walking Variability: A Systematic Review And Consensus Guidelines On Detrended Fluctuation Analysis, Deepak K. Ravi, Vivien Marmelat, William R. Taylor, Karl M. Newell, Nicholas Stergiou, Navrag B. Singh

Journal Articles

Human physiological signals are inherently rhythmic and have a hallmark feature in that even distant intrasignal measurements are related to each other. This relationship is termed long-range correlation and has been recognized as an indicator of the optimal state of the observed physiological systems, among which the locomotor system. Loss of long-range correlations has been found as a result of aging as well as disease, which can be evaluated with detrended fluctuation analysis (DFA). Recently, DFA and the scaling exponent α have been employed for understanding the degeneration of temporal regulation of human walking biorhythms in, for example, Parkinson disease …

Postural Control Is Altered In Females With Excessive Medial Knee Displacement, Joao R. Vaz, Nikolaos Stergiou, Ana Diniz, Ricardo Dinis, Pedro Pezarat-Correia

Journal Articles

Knee valgus motion observed during landing tasks has been proposed as a predictor of future knee injury. It mainly involves excess motion in the frontal plane and is known to be greater in individuals with excessive medial knee displacement (MKD). This affects postural control during sports manoeuvres. Previous sports medicine-related research suggests that the nature of these fluctuations provide rich and more sensitive information to identify risk of (re)injury. We aimed to investigate the fluctuations of the centre of pressure (CoP) in individuals with and without excessive MKD. Twenty females (12 controls; 8 excessive MKD) were instructed to perform single-leg …

Filtering Affects The Calculation Of The Largest Lyapunov Exponent, Peter C. Raffalt, Ben Senderling, Nicholas Stergiou

Journal Articles

The calculation of the largest Lyapunov exponent (LyE) requires the reconstruction of the time series in an N-dimensional state space. For this, the time delay (Tau) and embedding dimension (EmD) are estimated using the Average Mutual Information and False Nearest Neighbor algorithms. However, the estimation of these variables (LyE, Tau, EmD) could be compromised by prior filtering of the time series evaluated. Therefore, we investigated the effect of filtering kinematic marker data on the calculation of Tau, EmD and LyE using several different computational codes. Kinematic marker data were recorded from 37 subjects during treadmill walking and filtered using a …

Lessons Learned: How To Organize Your Laboratory Meetings, Nicholas Stergiou

Journal Articles

In this issue, JAB continues a series of editorials from highlyimpactful faculty and researchers on“lessons learned”through-out their careers or lives. The hope is that the rest of us can benefitfrom their experiences. I would like to thank these individuals forsharing their thoughts with us.—Michael Madigan, Editor-in-ChiefNicholas Stergiou(nstergiou@unomaha.edu)is with the Divisionof Biomechanics and Research Development, University of Ne-braska Omaha, Omaha, NE; and the College of Public Health,University of Nebraska Medical Center, Omaha, NE.

Aromatic L-Amino Acid Decarboxylase Gene Therapy Enhanceslevodopa Response In Parkinson’S Disease, John G. Nutt, Carolin Curtze, Amie Hiller, Shannon Anderson, Paul S. Larson, Amber D. Van Laar, R. Mark Richardson, Marin E. Thompson, Alexander Sedkov, Mika Leinonen, Bernard Ravina, Krystof Bankiewicz, Chadwick W. Christine

Journal Articles

Background: As Parkinson’s disease progresses, levodopa treatment loses efficacy, partly through the loss of the endogenous dopamine-synthesizing enzyme L-amino acid decarboxylase (AADC). In the phase I PD-1101 study, putaminal administration of VY-AADC01, an investigational adeno-associated virus serotype-2 vector for delivery of the AADC gene in patients with advanced Parkinson’s disease, was well tolerated, improved motor function, and reduced antiparkinsonian medication requirements.

Objectives: This substudy aimed to determine whether the timing and magnitude of motor response to intravenous levodopa changed in PD-1101 patients after VY-AADC01administration.

Methods: Participants received 2-hour threshold (0.6 mg/kg/h) and suprathreshold (1.2 mg/kg/h) levodopa infusions …

Step Width Variability As A Discriminator Of Age-Related Gait Changes, Andreas Skiadopoulos, Emily E. Moore, Harlan Sayles, Kendra K. Schmid, Nicholas Stergiou

Journal Articles

Background

There is scientific evidence that older adults aged 65 and over walk with increased step width variability which has been associated with risk of falling. However, there are presently no threshold levels that define the optimal reference range of step width variability. Thus, the purpose of our study was to estimate the optimal reference range for identifying older adults with normative and excessive step width variability.

Methods

We searched systematically the BMC, Cochrane Library, EBSCO, Frontiers, IEEE, PubMed, Scopus, SpringerLink, Web of Science, Wiley, and PROQUEST databases until September 2018, and included the studies that measured step width variability …

Reply, Matthew A. Fuglestad, Hernan Hernandez Md, Yue Gao, Henamari Ybay, Molly Schieber, Katyarina E. Brunette, Sara A. Myers, George P. Casale, Iraklis Pipinos

Journal Articles

Letter to the editor response

Auditory And Visual External Cues Have Different Effects On Spatial But Similar Effects On Temporal Measures Of Gait Variability, Joao R. Vaz, Troy Rand, Jessica Fujan-Hansen, Mukul Mukherjee, Nicholas Stergiou

Journal Articles

Walking synchronized to external cues is a common practice in clinical settings. Several research studies showed that this popular gait rehabilitation tool alters gait variability. There is also recent evidence which suggests that alterations in the temporal structure of the external cues could restore gait variability at healthy levels. It is unknown, however, if such alterations produce similar effects if the cueing modalities used are different; visual or auditory. The modality could affect gait variability differentially, since there is evidence that auditory cues mostly act in the temporal domain of gait, while visual cues act in the spatial domain of …

Swaying To The Complex Motion Of A Visual Target Affects Postural Sway Variability, Haralampos Sotirakis, Dimitrios A. Patikas, Nicholas Stergiou, Vassilia Hatzitaki

Journal Articles

Background

Voluntary shifting body weight in the anteroposterior direction is an important element of daily life activities, such as rising from a chair or initiating a step. In order to accommodate the daily-life challenges of such tasks, voluntary postural sway needs to be flexible and variable.

Research question

In this study we asked how whole-body tracking of a complex visual target motion with the concurrent provision of feedback modulates the variability of voluntary sway.

Methods

Twenty young adults (age: 27.10 ± 9.15years, height: 170.73 ± 9.40 cm, mass: 62.84 ± 11.48 kg) performed 132 cycles of voluntary antero-posterior sway, on …

Acl Injury And Reconstruction Affect Control Of Ground Reaction Forces Produced During A Novel Task That Simulates Cutting Movements, Amelia Lanier, Brian Knarr, Nicholas Stergiou, Lynn Snyder-Mackler, Thomas S. Buchanan

Journal Articles

After anterior cruciate ligament (ACL) injury and reconstruction, biomechanical and neuromuscular control deficits persist and 25% of those who have experienced an ACL injury will experience a second ACL rupture in the first year after returning to sports. There remains a need for improved rehabilitation and the ability to detect an individual's risk of secondary ACL rupture. Nonlinear analysis metrics, such as the largest Lyapunov exponent (LyE) can provide new biomechanical insight in this population by identifying how movement patterns evolve over time. The purpose of this study was to determine how ACL injury, ACL reconstruction (ACLR), and participation in …

Linear And Nonlinear Measures Of Postural Control In A Toddler With Cerebral Palsy: Brief Report, Samuel R. Pierce, Athylia C. Paremski, Julie Skorup, Nicholas Stergiou, Ben Senderling, Laura A. Prosser

Journal Articles

Purpose:

The purpose of this study was to describe changes in linear and nonlinear measures of postural control along with motor outcomes in a young child with cerebral palsy.

Summary of Key Points:

Posturography in sitting and standing, the Gross Motor Function Measure-66 (GMFM-66), and the Early Clinical Assessment of Balance (ECAB) were performed prior to, during, and after physical therapy. The child demonstrated independent sitting throughout the study and developed independent standing during the study. He made improvements in the GMFM-66 and ECAB throughout the study. Higher average values were found in all linear and nonlinear measures in standing …

Modular Footwear That Partially Offsets Downhill Or Uphill Grades Minimizes The Metabolic Cost Of Human Walking, Prokopios Antonellis, Cory M. Frederick, Arash Mohammadzadeh Gonabadi, Philippe Malcolm

Journal Articles

Walking on different grades becomes challenging on energetic and muscular levels compared to level walking. While it is not possible to eliminate the cost of raising or lowering the centre of mass (COM), it could be possible to minimize the cost of distal joints with shoes that offset downhill or uphill grades. We investigated the effects of shoe outsole geometry in 10 participants walking at 1 m s−1 on downhill, level and uphill grades. Level shoes minimized metabolic rate during level walking (Psecond-order effect < 0.001). However, shoes that entirely offset the (overall) treadmill grade did not minimize the metabolic rate of walking on grades: shoes with a +3° (upward) inclination minimized metabolic rate during downhill walking on a −6° grade, and shoes with a −3° (downward) inclination minimized metabolic rate during uphill walking on a +6° grade (P interaction effect = 0.023). Shoe inclination influenced (distal) ankle joint parameters, including soleus muscle activity, ankle moment and work rate, whereas treadmill grade influenced (whole-body) ground reaction force and COM work rate as well as (distal) ankle joint parameters including tibialis anterior and plantarflexor muscle activity, ankle moment and work rate. Similar modular footwear could be used to minimize joint loads or assist with walking on rolling terrain.