scholarly journals Changes in the Determinism of the Gait Dynamics with the Intervention of a Robotic Walker

2020 ◽  
Vol 10 (14) ◽  
pp. 4939
Author(s):  
Xianglong Wan ◽  
Yoji Yamada
Keyword(s):  
Walking Speed ◽  
Recurrence Plot ◽  
Scaling Exponent ◽  
Normal Walking ◽  
Gait Dynamics ◽  
Local Scaling ◽  
Individual Level ◽  
Robotic Walker ◽  
Posterior Direction ◽  
Anterior Posterior

(1) Robotic walkers have gradually been developed over the last decade, and their use has caused changes in gait. However, detailed gait analyses during robotic walker-assisted walking have not been performed. In this study, we aim to identify the changes in determinism of gait dynamics owing to the intervention of a robotic walker. (2) Eleven healthy subjects participated in walking experiments under normal walking, rollator-assisted walking, and robotic walker-assisted walking conditions. We analyzed the measured trunk acceleration to derive the gait parameters, local scaling exponent (LSE, from correlation sum), and percentage of determinism (%DET, from recurrence plot). (3) The walking speed during rollator-assisted walking was significantly lower than that during robotic walker-assisted walking. Changes in the shape of the LSE along the anterior–posterior direction revealed the influence of the robotic walker at an individual level. The changes in %DET along the anterior–posterior direction were also significantly different between normal walking and robotic walker-assisted walking. (4) The rollator decreased the walking speed in comparison to normal walking. The changed LSE and reduced %DET imply reduced deterministic patterns and disturbance to the gait dynamics. The robotic walker only affects the gait dynamics in the anterior–posterior direction. Furthermore, the burden on the subjects was reduced during robotic walker-assisted walking.

Hip Sway in Patients With Hip Osteoarthritis During One-Leg Standing With a Focus on Time Series Data

Motor Control ◽  
2021 ◽  
pp. 1-17
Author(s):  
Takuya Ibara ◽  
Makoto Takahashi ◽  
Koichi Shinkoda ◽  
Mahito Kawashima ◽  
Masaya Anan
Keyword(s):  
Time Series ◽  
Center Of Pressure ◽  
Hip Osteoarthritis ◽  
Series Data ◽  
Scaling Exponent ◽  
Balance Performance ◽  
Kinematic Parameters ◽  
Lateral Direction ◽  
Posterior Direction ◽  
Anterior Posterior

This study aimed to investigate the hip sway and the relationship between the center of pressure (CoP) and kinematic parameters regarding the time series scaling component α in patients with hip osteoarthritis (OA) during a one-leg standing task. The scaling exponent α, SD, hip sway maximal acceleration change, and balance performance, which was measured using CoP parameters, were compared between hip OA and control groups during a one-leg standing task. The relationships between balance performance with CoP parameters and kinematic parameters were investigated with the regression analysis. In the hip OA group, the scaling exponent α was smaller in the medial–lateral direction, and the SD and maximal amount of change in hip sway acceleration were larger in the anterior–posterior direction in the hip OA group. In this group, the CoP parameters were significantly associated with α in the medial–lateral direction (negatively) and in the anterior–posterior direction (positively). In the hip OA group, hip sway adaptability in the medial–lateral direction was limited, while the anterior–posterior direction showed greater movement.

Effects of assistive devices on postural control following a balance disturbance along the anterior-posterior direction

2021 ◽  
Vol 90 ◽  
pp. 239-244
Author(s):  
Yunju Lee ◽  
Rachel Badr ◽  
Brianna Bove ◽  
Patrick Jewett ◽  
Meri Goehring
Keyword(s):  
Postural Control ◽  
Assistive Devices ◽  
Posterior Direction ◽  
Anterior Posterior

Using mastoid vibration can detect the uni/bilateral vestibular deterioration by aging during standing

2021 ◽  
pp. 1-10
Author(s):  
Yufeng Lin ◽  
Mukul Mukherjee ◽  
Nicholas Stergiou ◽  
Jung Hung Chien
Keyword(s):  
Balance Control ◽  
Short Axis ◽  
Confidence Ellipse ◽  
Old Adults ◽  
Dependent Variables ◽  
Posterior Direction ◽  
Control Patterns ◽  
Main Effects ◽  
Ellipse Area ◽  
Anterior Posterior

BACKGROUND: The mastoid vibration (MV) has been used to investigate unilateral vestibular dysfunction by inducing nystagmus. Additionally, this MV can be used to quantify the effect of deterioration by aging on the vestibular system during walking. Could such MV be used to assess the uni/bilateral vestibular deterioration by aging during standing? OBJECTIVE: This study attempted to determine the feasibility of using MV for identifying the uni/bilateral vestibular deterioration by aging during standing. METHODS: Fifteen young and ten old adults’ balance control patterns were assessed by three random MV conditions: 1) No MV; 2) Unilateral MV; 3) Bilateral MV. The dependent variables were the 95% confidence ellipse areas and the sample entropy values, which were calculated based on the center of gravity displacement within each condition. RESULTS: Significant main effects of MV and aging were found on all outcome variables. A significant interaction between aging and different MV types was observed in the 95% confidence ellipse area (p = 0.002) and the length of the short axis (anterior-posterior direction, p = 0.001). CONCLUSIONS: We concluded that the MV could be used to identify different vestibular dysfunctions, specifically in old adults.

scholarly journals Derivation of a finite-element model of lingual deformation during swallowing from the mechanics of mesoscale myofiber tracts obtained by MRI

2010 ◽  
Vol 109 (5) ◽  
pp. 1500-1514 ◽  
Author(s):  
Srboljub M. Mijailovich ◽  
Boban Stojanovic ◽  
Milos Kojic ◽  
Alvin Liang ◽  
Van J. Wedeen ◽  
...  
Keyword(s):  
Finite Element ◽  
Connective Tissue ◽  
Diffusion Tensor ◽  
Element Model ◽  
Out Of Plane ◽  
Posterior Direction ◽  
Elastic Constraints ◽  
The Relationship ◽  
Passive Muscle ◽  
Anterior Posterior

To demonstrate the relationship between lingual myoarchitecture and mechanics during swallowing, we performed a finite-element (FE) simulation of lingual deformation employing mesh aligned with the vector coordinates of myofiber tracts obtained by diffusion tensor imaging with tractography in humans. Material properties of individual elements were depicted in terms of Hill's three-component phenomenological model, assuming that the FE mesh was composed of anisotropic muscle and isotropic connective tissue. Moreover, the mechanical model accounted for elastic constraints by passive and active elements from the superior and inferior directions and the effect of out-of-plane muscles and connective tissue. Passive bolus effects were negligible. Myofiber tract activation was simulated over 500 ms in 1-ms steps following lingual tip association with the hard palate and incorporated specifically the accommodative and propulsive phases of the swallow. Examining the displacement field, active and passive muscle stress, elemental stretch, and strain rate relative to changes of global shape, we demonstrate that lingual reconfiguration during these swallow phases is characterized by (in sequence) the following: 1) lingual tip elevation and shortening in the anterior-posterior direction; 2) inferior displacement related to hyoglossus contraction at its inferior-most position; and 3) dominant clockwise rotation related to regional contraction of the genioglossus and contraction of the hyoglossus following anterior displacement. These simulations demonstrate that lingual deformation during the indicated phases of swallowing requires temporally patterned activation of intrinsic and extrinsic muscles and delineate a method to ascertain the mechanics of normal and pathological swallowing.

scholarly journals The CAT-CAM socket and quadrilateral socket: A comparison of energy cost during ambulation

1993 ◽  
Vol 17 (2) ◽  
pp. 95-100 ◽  
Author(s):  
R. S. Gailey ◽  
D. Lawrence ◽  
C. Burditt ◽  
P. Spyropoulos ◽  
C. Newell ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Randomized Trials ◽  
Walking Speed ◽  
Vascular Pathology ◽  
Control Group ◽  
Alignment Method ◽  
Normal Walking ◽  
Post Hoc ◽  
Healthy Males

Twenty unilateral trans-femoral amputees fitted with either the Contoured Adducted Trochanteric-Controlled Alignment Method (CAT-CAM) socket (n=10) or the quadrilateral (QUAD) socket (n=10), and a “non-amputee” control group (n=10) participated in the study. Subjects meeting the following criteria were studied: healthy males between the ages of 18 and 55 years, amputation due to non-vascular pathology, an unaffected sound limb, at least six months use of the test prosthesis, and a minimal stump length of 15 cm. Subjects ambulated in two randomized trials separated by 20 minutes of rest at 2 assigned speeds: a pace reflecting normal walking speed (97 m/min=2.5 mph) or a slower speed (48.5 m/min=1.25 mph). Heart rate (HR) and Oxygen uptake (VO2) measured during steady state walking were analyzed via two-way ANOVA. Differences among means were further analyzed using Tukey post hoc and simple effects tests. Significant differences were observed between the control group and CAT-CAM subjects with respect to VO2 (p < 0.05) and HR (p < 0.01) at the slower speed. The control group and subjects using the QUAD socket also differed with respect to VO2 (p < 0.01) and HR (p < 0.01) at the slower pace. Faster pace required more energy expenditure (p < 0.01) and produced higher HR (p < 0.01) than slower speeds. At faster pace, a significantly higher energy expenditure in the QUAD than the CAT-CAM group was observed (p<0.01). It is concluded that ambulating at normal pace using the CAT-CAM socket design uses less energy than when using a QUAD socket design.

scholarly journals Maximum isometric tongue force in patients with obstructive sleep apnoea

2020 ◽  
Author(s):  
Richard Birk ◽  
Boris A. Stuck ◽  
Joachim T. Maurer ◽  
Angela Schell ◽  
C. Emika Müller ◽  
...  
Keyword(s):  
Isometric Force ◽  
Upper Airway ◽  
Sleep Apnoea ◽  
Matched Pair ◽  
Healthy Individuals ◽  
New Device ◽  
Obstructive Sleep ◽  
Posterior Direction ◽  
Maximum Isometric Force ◽  
Anterior Posterior

Abstract Background Obstructive sleep apnea (OSA) is a sleep disorder with a prevalence of 9–38%. The underlying pathology in OSA is a collapse of the upper airway. Especially in more severely affected patients, this collapse is often located at the level of the tongue base. Therefore, various implantable systems (anchors and ligament techniques) were developed to prevent or overcome this collapse. These systems are exposed to various forces. Different models have been developed to measure these forces and data comparing forces in healthy individuals with OSA patients are rare. Purpose Purpose of the study was to evaluate possible differences in tongue forces between healthy individuals and patients with OSA. Method To evaluate maximum isometric tongue forces, we conducted a matched pair design study including 20 healthy individuals and 20 patients suffering from OSA. Maximum isometric tongue forces were measured in an anterior/posterior direction with the help of self-designed new device that clamps the tongue. Results We could show that the maximum isometric force does not differ significantly in healthy individuals (10.7 ± 5.2N) from patients with OSA (14.4 ± 6.3N). Conclusion Currently there are no indications that maximum isometric tongue force does differ in healthy individuals and patients with OSA. Higher, as well as lower, tongue forces in patients with OSA seem not to differ from healthy subjects and therefore may not be needed to consider, in the development of tongue management devices, for OSA patients.

scholarly journals Tomography of scaling

2019 ◽  
Vol 16 (160) ◽  
pp. 20190602
Author(s):  
Marc Barthelemy
Keyword(s):  
Complex Systems ◽  
Real World ◽  
Threshold Effects ◽  
Scaling Exponent ◽  
Nonlinear Behaviour ◽  
Standard Analysis ◽  
Local Scaling ◽  
Regression Methods ◽  
Real World Datasets ◽  
Tomography Scan

Scaling describes how a given quantity Y that characterizes a system varies with its size P . For most complex systems, it is of the form Y ∼ P β with a non-trivial value of the exponent β , usually determined by regression methods. The presence of noise can make it difficult to conclude about the existence of a nonlinear behaviour with β ≠ 1 and we propose here to circumvent fitting problems by investigating how two different systems of sizes P 1 and P 2 are related to each other. This leads us to define a local scaling exponent β loc that we study versus the ratio P 2 / P 1 and provides some sort of ‘tomography scan’ of scaling across different values of the size ratio, allowing us to assess the relevance of nonlinearity in the system and to identify an effective exponent that minimizes the error for predicting the value of Y . We illustrate this method on various real-world datasets for cities and show that our method reinforces in some cases the standard analysis, but is also able to provide new insights in inconclusive cases and to detect problems in the scaling form such as the absence of a single scaling exponent or the presence of threshold effects.

Manometric Studies of the Upper Esophageal Sphincter

1977 ◽  
Vol 86 (5) ◽  
pp. 598-602 ◽  
Author(s):  
Barry P. Berlin ◽  
Francis Tedesco ◽  
Jeffrey T. Fierstein ◽  
Joseph H. Ogura
Keyword(s):  
Clinical Evidence ◽  
Marked Decrease ◽  
Upper Esophageal Sphincter ◽  
Intraluminal Pressure ◽  
Laryngeal Surgery ◽  
Pressure Profiles ◽  
Posterior Direction ◽  
Manometric Studies ◽  
Esophageal Sphincter ◽  
Anterior Posterior

The pharyngoesophageal sphincter (PES) has been studied extensively using the standard three lumen esophageal catheter. Studies using this catheter are nonreproduciible because intraluminal pressure in the PES is dependent on the orientation of the catheter. This difficulty was overcome when a multiluminal catheter was developed by Winans. In this work we used a modification of this multiluminal catheter to study the PES in 6 normal patients and in 13 patients who had undergone partial laryngeal surgery. Pressure profiles in the six normal patients revealed a marked increase in intraluminal pressure in the anterior-posterior direction. This is explained by the anatomy of the cricopharyngeal muscle which does not insert in a median raphe. These readings were reliable and reproducible. The operative patients included nine subtotal supraglottic laryngectomies and four partial laryngopharyngectomies. Eight patients had a cricopharyngeal myotomy and five did not. Pre- and postoperative measurements in this series revealed a marked decrease in PES pressure in those patients who had a myotomy; however, all patients were decannulated and swallowed postoperatively without clinical evidence of aspiration. All future manometric studies of the PES should employ a multilumined catheter in order that the differential pressures in the upper esophagus are recorded.

Pedestrians' Normal Walking Speed and Speed When Crossing a Street

2007 ◽  
Vol 2002 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Jeannette Montufar ◽  
Jorge Arango ◽  
Michelle Porter ◽  
Satoru Nakagawa
Keyword(s):  
Walking Speed ◽  
Normal Walking
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