Effects of Seat Cushion Material on Center of Pressure and Movement Trajectory during a Reaching Task

Effective telerehabilitation technologies enable patients with certain physiological disabilities to engage in rehabilitative exercises for performing Activities of Daily Living (ADLs). Therefore, training and assessment scenarios for the performance of ADLs are vital for the promotion for telerehabilitation. In this paper we investigate quantitatively and automatically assessing patient’s kinematic ability to perform functional upper extremity reaching tasks. The shape of the movement trajectory and the instantaneous acceleration of kinematically crucial body parts, such as wrists, are used to compute the approximate entropy of the motions to represent stability (smoothness) in addition to the duration of the activity. Computer simulations were conducted to illustrate the consistency, sensitivity and robustness of the proposed method. A preliminary experiment with kinematic data captured from healthy subjects mimicking a reaching task with dyskinesia showed a high degree of correlation (Cohen’s kappa 0.85 withp<0.05) between a human observer and the proposed automatic classification tool in terms of assigning the datasets to various levels to represent the subjects’ kinematic abilities to perform reaching tasks. This study supported the use of Microsoft Kinect to quantitatively evaluate the ability of individuals with involuntary movements to perform an upper extremity reaching task.

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Distinct population code for movement kinematics and changes of ongoing movements in human subthalamic nucleus

10.1101/2020.11.11.378224 ◽

2020 ◽

Author(s):

Dennis London ◽

Arash Fazl ◽

Kalman Katlowitz ◽

Marisol Soula ◽

Michael H Pourfar ◽

...

Keyword(s):

Subthalamic Nucleus ◽

Action Plan ◽

Field Potential ◽

Neural Code ◽

Neuronal Firing ◽

Movement Trajectory ◽

Movement Kinematics ◽

Critical Test ◽

Reaching Task ◽

Basal Ganglia Structures

AbstractThe subthalamic nucleus (STN) is theorized to globally suppress movement through connections with downstream basal ganglia structures. Current theories are supported by increased STN activity when subjects withhold an uninitiated action plan, but a critical test of these theories requires studying STN responses when an ongoing action is replaced with an alternative. Here, we perform this test using an extended reaching task with instructions to switch movement trajectory mid-action. We show that STN activity decreases during action switches, contrary to prevalent theories. Further, beta oscillations in the local field potential in STN, which are associated with movement inhibition do not show increased power or entraining of neuronal firing during switches. We report an inhomogeneous population neural code in STN, with one sub-population encoding movement kinematics and direction and another encoding unexpected action switches. We suggest an elaborate neural code in STN that contributes to planning actions and changing the plans.

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Long-Range Temporal Correlations, Multifractality, and the Causal Relation Between Neural Inputs and Movements

ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, Volume 2 ◽

10.1115/dscc2011-6081 ◽

2011 ◽

Author(s):

Jianbo Gao ◽

Yi Zheng ◽

Jing Hu

Keyword(s):

Factor Analysis ◽

Long Range ◽

Multifractal Analysis ◽

Causal Relation ◽

Fano Factor ◽

Fluctuation Analysis ◽

Movement Trajectory ◽

Multifractal Detrended Fluctuation Analysis ◽

Reaching Task ◽

Temporal Correlations

Understanding the causal relation between neural inputs and movements is very important for the success of brain machine interfaces (BMIs). In this study, we perform systematic statistical and information theoretical analysis of neuronal firings of 104 neurons, and employ three different types of fractal and multifractal techniques (including Fano factor analysis, multifractal detrended fluctuation analysis (MF-DFA), and wavelet multifractal analysis) to examine whether neuronal firings related to movements may have long-range temporal correlations. We find that MF-DFA and wavelet multifractal analysis (but not Fano factor analysis) clearly indicate that when neuronal firings are not well correlated with movement trajectory, they do not have or only have weak temporal correlations. When neuronal firings are well correlated with movements, they are characterized by very strong temporal correlations, up to a time scale comparable to the average time between two successive reaching tasks. This suggests that neurons well correlated with hand trajectory experienced a “re-setting” effect at the start of each reaching task. We further discuss the significance of the coalition of those important neurons in executing cortical control of prostheses.

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Even well-practiced movements benefit from repetition

10.1101/2021.12.21.473484 ◽

2021 ◽

Author(s):

Katrin Sutter ◽

Leonie Oostwoud Wijdenes ◽

Robert J. van Beers ◽

W. Pieter Medendorp

Keyword(s):

Movement Trajectory ◽

Movement Variability ◽

Movement Initiation ◽

Random Sequences ◽

Reaching Task

Professional golf players spend years practicing, but will still perform one or two practice swings without a ball before executing the actual swing. Why do they do this? In this study we tested the hypothesis that repeating a well-practiced movement leads to a reduction of movement variability. To operationalize this hypothesis, participants were tested in a center-out reaching task with four different targets, on four different days. To probe the effect of repetition they performed random sequences from one to six movements to the same target. Our findings show that, with repetition, movements are not only initiated earlier but their variability is reduced across the entire movement trajectory. Furthermore, this effect is present within and across the four sessions. Together, our results suggest that movement repetition changes the tradeoff between movement initiation and movement precision.

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Distinct population code for movement kinematics and changes of ongoing movements in human subthalamic nucleus

eLife ◽

10.7554/elife.64893 ◽

2021 ◽

Vol 10 ◽

Author(s):

Dennis London ◽

Arash Fazl ◽

Kalman Katlowitz ◽

Marisol Soula ◽

Michael Pourfar ◽

...

Keyword(s):

Subthalamic Nucleus ◽

Action Plan ◽

Field Potential ◽

Neural Code ◽

Movement Trajectory ◽

Population Code ◽

Movement Kinematics ◽

Critical Test ◽

Reaching Task ◽

Basal Ganglia Structures

The subthalamic nucleus (STN) is theorized to globally suppress movement through connections with downstream basal ganglia structures. Current theories are supported by increased STN activity when subjects withhold an uninitiated action plan, but a critical test of these theories requires studying STN responses when an ongoing action is replaced with an alternative. We perform this test in subjects with Parkinson's disease using an extended reaching task where the movement trajectory changes mid-action. We show that STN activity decreases during action switches, contrary to prevalent theories. Further, beta oscillations in the STN local field potential, which are associated with movement inhibition, do not show increased power or spiking entrainment during switches. We report an inhomogeneous population neural code in STN, with one sub-population encoding movement kinematics and direction and another encoding unexpected action switches. We suggest an elaborate neural code in STN that contributes to planning actions and changing the plans.

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Effect of seat cushion on dynamic stability in sitting during a reaching task in wheelchair users with paraplegia

Archives of Physical Medicine and Rehabilitation ◽

10.1053/apmr.2001.19473 ◽

2001 ◽

Vol 82 (2) ◽

pp. 274-281 ◽

Cited By ~ 31

Author(s):

Rachid Aissaoui ◽

Chantal Boucher ◽

Daniel Bourbonnais ◽

Michèle Lacoste ◽

Jean Dansereau

Keyword(s):

Dynamic Stability ◽

Wheelchair Users ◽

Reaching Task ◽

Seat Cushion

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Mindful Exercise (Baduanjin) as an Adjuvant Treatment for Older Adults (60 Years Old and Over) of Knee Osteoarthritis: A Randomized Controlled Trial

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/9869161 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

JiaJia Ye ◽

Qikai Zheng ◽

Liye Zou ◽

Qian Yu ◽

Nicola Veronese ◽

...

Keyword(s):

Older Adults ◽

Postural Control ◽

Knee Osteoarthritis ◽

Physical Function ◽

Center Of Pressure ◽

Control Group ◽

Movement Trajectory ◽

Womac Function ◽

Ellipse Area ◽

Experimental Group

Background. The postural stability is a major factor that helps prevent developing knee osteoarthritis with aging. The aim of this study was to investigate the effects of Baduanjin qigong on postural control and physical function in older adults with knee osteoarthritis. Methods. Fifty-six individuals over 60 years of age with knee osteoarthritis were randomly assigned to either an experimental group (n = 28) or a control group (n = 28). Participants in the experimental group received a 12-week Baduanjin training, while those in the control group did not receive any additional physical exercise during the study period. The postural control was quantified by perimeter and ellipse area of center of pressure movement trajectory. The assessments were conducted three times (baseline, week 8, and week 12). Results. The perimeter and ellipse area with both open- and closed-eyes conditions and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function were significantly improved at week eight in the experimental group (p<0.005). The ellipse area with open-eyes condition, WOMAC index, and stiffness and physical function domains were significantly decreased after the 12 weeks of Baduanjin training compared to the control group (p<0.005). Only the perimeter area with both open- and closed-eyes conditions was not statistically significant at week 12 in the intervention group (p>0.005). Conclusions. Baduanjin is an effective and adjuvant therapy for older adults with knee osteoarthritis. Regular Baduanjin training can improve postural control and WOMAC function of old individuals with knee osteoarthritis. More advanced techniques and biopsychological measurements are required for further understanding of Baduanjin exercise in this population. The trial was registered in Chinese Clinical Trial Registry (ChiCTR-IOR-16010042).

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Optimality of Upper-Arm Reaching Trajectories Based on the Expected Value of the Metabolic Energy Cost

Neural Computation ◽

10.1162/neco_a_00757 ◽

2015 ◽

Vol 27 (8) ◽

pp. 1721-1737 ◽

Cited By ~ 3

Author(s):

Yoshiaki Taniai ◽

Jun Nishii

Keyword(s):

Energy Cost ◽

Cost Model ◽

Expected Value ◽

Metabolic Energy ◽

Stride Frequency ◽

Movement Trajectory ◽

Potential Candidate ◽

Upper Arm ◽

Reaching Task ◽

Arm Reaching

When we move our body to perform a movement task, our central nervous system selects a movement trajectory from an infinite number of possible trajectories under constraints that have been acquired through evolution and learning. Minimization of the energy cost has been suggested as a potential candidate for a constraint determining locomotor parameters, such as stride frequency and stride length; however, other constraints have been proposed for a human upper-arm reaching task. In this study, we examined whether the minimum metabolic energy cost model can also explain the characteristics of the upper-arm reaching trajectories. Our results show that the optimal trajectory that minimizes the expected value of energy cost under the effect of signal-dependent noise on motor commands expresses not only the characteristics of reaching movements of typical speed but also those of slower movements. These results suggest that minimization of the energy cost would be a basic constraint not only in locomotion but also in upper-arm reaching.

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