scholarly journals Effects of aging on motor control strategies during bimanual isometric force control

2019 ◽  
Vol 27 (4) ◽  
pp. 267-275
Author(s):  
Yan Jin ◽  
JiWon Seong ◽  
YoungChae Cho ◽  
BumChul Yoon
Keyword(s):  
Older Adults ◽  
Motor Control ◽  
Control Strategy ◽  
Force Control ◽  
Isometric Force ◽  
Control Strategies ◽  
Force Variability ◽  
Dual Tasking ◽  
Effects Of Aging ◽  
Force Accuracy

Aging-induced degeneration of the neuromuscular system would result in deteriorated complex muscle force coordination and difficulty in executing daily activities that require both hands. The aim of this study was to provide a basic description of how aging and dual-task activity would affect the motor control strategy during bimanual isometric force control in healthy adults. In total, 17 young adults (aged 25.1 ± 2.4 years) and 14 older adults (aged 72.6 ± 3.4 years) participated in the study. The subjects were instructed to press both hands simultaneously to match the 1 Hz sine curve force under two conditions (with or without calculation) with continuous visual feedback. Differences in bimanual motor synergy, bimanual coordination, force accuracy, force variability, and calculation speed were compared. This study found that the specific motor control strategy of older adults involved a decreased bimanual force control ability with both increased VUCM and VORT, and was not influenced by dual tasking. These findings might have implications for establishing interventions for aging-induced hand force control deficits.

Motor control strategies during bimanual isometric force control among healthy individuals

2019 ◽  
Vol 27 (2) ◽  
pp. 127-136 ◽  
Author(s):  
Yan Jin ◽  
Minhee Kim ◽  
Sejun Oh ◽  
BumChul Yoon
Keyword(s):  
Young Adults ◽  
Motor Control ◽  
Control Strategy ◽  
Force Control ◽  
Isometric Force ◽  
Control Strategies ◽  
Force Variability ◽  
Force Level ◽  
Target Force ◽  
Motor Synergy

This study aimed to provide a basic description of the motor control strategy during bimanual isometric force control in healthy young adults. Thirty healthy young adults (mean age: 27.4 ± 3.7 years) participated in the study. The subjects were instructed to press both hands simultaneously to match the target force level of 5%, 25%, and 50% bimanual maximum voluntary force using continuous visual feedback. Bimanual motor synergy and bimanual coordination, as well as force asymmetry, force accuracy, and force variability were compared. This study identified the specific motor control strategy of healthy young adults during bimanual isometric force control, indicating that they proportionally increased “good” and “bad” variabilities, resulting in comparable bimanual motor synergy as the target force level increased.

Force Control Strategy of Five-Digit Precision Grasping With Aligned and Unaligned Configurations

2022 ◽  
pp. 001872082110409
Author(s):  
Po-Tsun Chen ◽  
Hsiu-Yun Hsu ◽  
You-Hua Su ◽  
Chien-Ju Lin ◽  
Hsiao-Feng Chieh ◽  
...  
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Task Type ◽  
Applied Force ◽  
Force Variability ◽  
Force Transducers ◽  
Task Requirements ◽  
Power Grasp ◽  
Precision Grasping ◽  
Large Moment

Objective To investigate the digit force control during a five-digit precision grasp in aligned (AG) and unaligned grasping (UG) configurations. Background The effects of various cylindrical handles for tools on power grasp performance have been previously investigated. However, there is little information on force control strategy of precision grasp to fit various grasping configurations. Method Twenty healthy young adults were recruited to perform a lift-hold-lower task. The AG and UG configurations on a cylindrical simulator with force transducers were adjusted for each individual. The applied force and moment, the force variability during holding, and force correlations between thumb and each finger were measured. Result No differences in applied force, force correlation, repeatability, and variability were found between configurations. However, the moments applied in UG were significantly larger than those in AG. Conclusion The force control during precision grasp did not change significantly across AG and UG except for the digit moment. The simulator is controlled efficiently with large moment during UG, which is thus the optimal configuration for precision grasping with a cylindrical handle. Further research should consider the effects of task type and handle design on force control, especially for individuals with hand disorders. Application To design the handle of specific tool, one should consider the appropriate configuration according to the task requirements of precision grasping to reduce the risk of accumulating extra loads on digits with a cylindrical handle.

scholarly journals Neural Correlates of Age-Related Changes in Precise Grip Force Regulation: A Combined EEG-fNIRS Study

2020 ◽  
Vol 12 ◽  
Author(s):  
Alisa Berger ◽  
Fabian Steinberg ◽  
Fabian Thomas ◽  
Michael Doppelmayr
Keyword(s):  
Older Adults ◽  
Motor Control ◽  
Force Control ◽  
Grip Force ◽  
Task Complexity ◽  
Brain Activity ◽  
Dominant Hand ◽  
Grip Force Control ◽  
Age Related ◽  
Age Related Changes

Motor control is associated with suppression of oscillatory activity in alpha (8–12 Hz) and beta (12–30 Hz) ranges and elevation of oxygenated hemoglobin levels in motor-cortical areas. Aging leads to changes in oscillatory and hemodynamic brain activity and impairments in motor control. However, the relationship between age-related changes in motor control and brain activity is not yet fully understood. Therefore, this study aimed to investigate age-related and task-complexity-related changes in grip force control and the underlying oscillatory and hemodynamic activity. Sixteen younger [age (mean ± SD) = 25.4 ± 1.9, 20–30 years] and 16 older (age = 56.7 ± 4.7, 50–70 years) healthy men were asked to use a power grip to perform six trials each of easy and complex force tracking tasks (FTTs) with their right dominant hand in a randomized within-subject design. Grip force control was assessed using a sensor-based device. Brain activity in premotor and primary motor areas of both hemispheres was assessed by electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Older adults showed significantly higher inaccuracies and higher hemodynamic activity in both FTTs than did young adults. Correlations between grip force control owing to task complexity and beta activity were different in the contralateral premotor cortex (PMC) between younger and older adults. Collectively, these findings suggest that aging leads to impairment of grip force control and an increase in hemodynamic activity independent of task complexity. EEG beta oscillations may represent a task-specific neurophysiological marker for age-related decline in complex grip force control and its underlying compensation strategies. Further EEG-fNIRS studies are necessary to determine neurophysiological markers of dysfunctions underlying age-related motor disabilities for the improvement of individual diagnosis and therapeutic approaches.

The accuracy of perception of a pinch grip force in older adults

2004 ◽  
Vol 82 (8-9) ◽  
pp. 693-701 ◽  
Author(s):  
Sophie J De Serres ◽  
Nathan Z Fang
Keyword(s):  
Older Adults ◽  
Visual Feedback ◽  
Isometric Force ◽  
Hand Function ◽  
The Elderly ◽  
Tactile Feedback ◽  
Elderly Subjects ◽  
Pinch Force ◽  
Pinch Grip ◽  
Effects Of Aging

The fact that humans can execute accurate movements and generate precise muscle forces is very important for hand function. Target-tracking tasks or target-matching tasks are often executed under combined visual and somatosensory feedback. When visual feedback is removed, subjects have to depend on their perception of force. The objective of the present study was to estimate the effects of aging on the perception of a pinch force produced by the thumb and index finger. In a first set of trials, young (n = 12, age = 25.3 ± 2.4 years) and elderly (n = 12, age = 71.5 ± 3.3 years) healthy individuals were asked to reproduce pinch forces which were equivalent to 5%, 20%, and 40% of their maximal pinch force (MPF). Prior to the execution of these trials, the subjects were familiarized with the force levels by matching targets displayed on a screen. They were then asked to reproduce each of these forces without any visual or verbal feedback. The results showed a larger error in the reproduced force for the elderly subjects when compared with the young adults. However, this larger error was mainly due to an initial overshoot in the force to be reproduced, followed by a gradual decrease towards the appropriate force. This transient overshoot was rarely seen in the performance of the younger subjects. In a second set of trials, the same subjects were asked to produce a pinch force of 5%, 20%, and 40% of MPF with 1 hand using visual feedback. They were also instructed to simultaneously apply a comparable pinch force with the other hand (without any feedback). For both young and older adults, the pinch forces produced by the 2 hands were the same. In addition, in both blocks of trials, hand dominance had no effects on the performance for all subjects. These results suggest that normal aging affects the production of force based on sensorimotor memory rather more than it affects comparative outputs from central descending commands.Key words: prehension, isometric force, aging, tactile feedback.

scholarly journals Visual feedback improves bimanual force control performances at planning and execution levels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hyun Joon Kim ◽  
Joon Ho Lee ◽  
Nyeonju Kang ◽  
James H. Cauraugh
Keyword(s):  
Visual Feedback ◽  
Force Control ◽  
Maximum Voluntary Contraction ◽  
Correlation Coefficients ◽  
Uncontrolled Manifold ◽  
Force Variability ◽  
Motor Synergies ◽  
Multiple Trials ◽  
Motor Synergy ◽  
Force Accuracy

AbstractThe purpose of this study was to determine the effect of different visual conditions and targeted force levels on bilateral motor synergies and bimanual force control performances. Fourteen healthy young participants performed bimanual isometric force control tasks by extending their wrists and fingers under two visual feedback conditions (i.e., vision and no-vision) and three targeted force levels (i.e., 5%, 25%, and 50% of maximum voluntary contraction: MVC). To estimate bilateral motor synergies across multiple trials, we calculated the proportion of good variability relative to bad variability using an uncontrolled manifold analysis. To assess bimanual force control performances within a trial, we used the accuracy, variability, and regularity of total forces produced by two hands. Further, analysis included correlation coefficients between forces from the left and right hands. In addition, we examined the correlations between altered bilateral motor synergies and force control performances from no-vision to vision conditions for each targeted force level. Importantly, our findings revealed that the presence of visual feedback increased bilateral motor synergies across multiple trials significantly with a reduction of bad variability as well as improved bimanual force control performances within a trial based on higher force accuracy, lower force variability, less force regularity, and decreased correlation coefficients between hands. Further, we found two significant correlations in (a) increased bilateral motor synergy versus higher force accuracy at 5% of MVC and (b) increased bilateral motor synergy versus lower force variability at 50% of MVC. Together, these results suggested that visual feedback effectively improved both synergetic coordination behaviors across multiple trials and stability of task performance within a trial across various submaximal force levels.

scholarly journals Identifying Motor Control Strategies and Their Role in Low Back Pain: A Cross-Disciplinary Approach Bridging Neurosciences With Movement Biomechanics

2021 ◽  
Vol 2 ◽  
Author(s):  
Stefan Schmid ◽  
Christian Bangerter ◽  
Petra Schweinhardt ◽  
Michael L. Meier
Keyword(s):  
Low Back Pain ◽  
Motor Control ◽  
Back Pain ◽  
Control Strategy ◽  
Control Strategies ◽  
Treatment Options ◽  
Movement Behavior ◽  
Low Back ◽  
Novel Approach ◽  
Optical Motion

Persistent low back pain (LBP) is a major health issue, and its treatment remains challenging due to a lack of pathophysiological understanding. A better understanding of LBP pathophysiology has been recognized as a research priority, however research on contributing mechanisms to LBP is often limited by siloed research within different disciplines. Novel cross-disciplinary approaches are necessary to fill important knowledge gaps in LBP research. This becomes particularly apparent when considering new theories about a potential role of changes in movement behavior (motor control) in the development and persistence of LBP. First evidence points toward the existence of different motor control strategy phenotypes, which are suggested to have pain-provoking effects in some individuals driven by interactions between neuroplastic, psychological and biomechanical factors. Yet, these phenotypes and their role in LBP need further validation, which can be systematically tested using an appropriate cross-disciplinary approach. Therefore, we propose a novel approach, connecting methods from neuroscience and biomechanics research including state-of-the-art optical motion capture, musculoskeletal modeling, functional magnetic resonance imaging and assessments of psychological factors. Ultimately, this cross-disciplinary approach might lead to the identification of different motor control strategy phenotypes with the potential to translate into clinical research for better treatment options.

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