Decrease in force control among older adults under unpredictable conditions

AbstractThe control of ankle muscle force is an integral component of walking and postural control. Aging impairs the ability to produce force steadily and accurately, which can compromise functional capacity and quality of life. Here, we hypothesized that reduced force control in older adults would be associated with altered cortico-cortical communication within a network comprising the primary motor area (M1), the premotor cortex (PMC), parietal, and prefrontal regions. We examined electroencephalographic (EEG) responses from fifteen younger (20-26 yr) and fifteen older (65-73 yr) participants during a unilateral dorsiflexion force-tracing task. Dynamic Causal Modelling (DCM) and Parametric Empirical Bayes (PEB) were used to investigate how directed connectivity between contralateral M1, PMC, parietal, and prefrontal regions was related to age group and precision in force production. DCM and PEB analyses revealed that the strength of connections between PMC and M1 were related to ankle force precision and differed by age group. For young adults, bidirectional PMC-M1 coupling was negatively related to task performance: stronger backward M1-PMC and forward PMC-M1 coupling was associated with worse force precision. The older group exhibited deviations from this pattern. For the PMC to M1 coupling, there were no age-group differences in coupling strength; however, within the older group, stronger coupling was associated with better performance. For the M1 to PMC coupling, older adults followed the same pattern as young adults - with stronger coupling accompanied by worse performance - but coupling strength was lower than in the young group. Our results suggest that bidirectional M1-PMC communication is related to precision in ankle force production and that this relationship changes with aging. We argue that the observed age-related differences reflect compensatory mechanisms whereby older adults maintain performance in the face of declines in the sensorimotor system.

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

Adaptive Behavior ◽

10.1177/1059712319849896 ◽

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.

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Digit Force Controls and Corresponding Brain Activities in Finger Pressing Performance: A Comparison Between Older Adults and Young Individuals

Journal of Aging and Physical Activity ◽

10.1123/japa.2018-0252 ◽

2020 ◽

Vol 28 (1) ◽

pp. 94-103

Author(s):

Pai-Yun Cheng ◽

Hsiao-Feng Chieh ◽

Chien-Ju Lin ◽

Hsiu-Yun Hsu ◽

Jia-Jin J. Chen ◽

...

Keyword(s):

Older Adults ◽

Infrared Spectroscopy ◽

Force Control ◽

Near Infrared ◽

Brain Activity ◽

Hand Function ◽

Young Group ◽

Primary Motor Area ◽

Group Response ◽

The Brain

This study aims toward an investigation and comparison of the digital force control and the brain activities of older adults and young groups during digital pressing tasks. A total of 15 young and 15 older adults were asked to perform force ramp tasks at different force levels with a custom pressing system. Near-infrared spectroscopy was used to collect the brain activities in the prefrontal cortex and primary motor area. The results showed that the force independence and hand function of the older adults were worse than that of the young adults. The cortical activations in the older adults were higher than those in the young group during the tasks. A significant hemodynamic between-group response and mild negative correlations between brain activation and force independence ability were found. Older adults showed poor force independence ability and manual dexterity and required additional brain activity to compensate for the degeneration.

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

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2020.594810 ◽

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.

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