scholarly journals Using a Module-Based Analysis Framework for Investigating Muscle Coordination during Walking in Individuals Poststroke: A Literature Review and Synthesis

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Bryant A. Seamon ◽  
Richard R. Neptune ◽  
Steven A. Kautz
Keyword(s):  
Motor Control ◽  
Nonnegative Matrix ◽  
Analytical Framework ◽  
Control Individual ◽  
Current Evidence ◽  
Muscle Coordination ◽  
Flexion Extension ◽  
Gait Mechanics ◽  
Walking Performance ◽  
Future Work

Factorization methods quantitatively group electromyographic signals from several muscles during dynamic tasks into multiple modules where each module consists of muscles that are coactive during the movement. Module-based analyses may provide an analytical framework for testing theories of poststroke motor control recovery based on one’s ability to move independently from mass flexion-extension muscle group coactivation. Such a framework may be useful for understanding the causality between underlying neural impairments, biomechanical function, and walking performance in individuals poststroke. Our aim is to synthesize current evidence regarding the relationships between modules, gait mechanics, and rehabilitation in individuals poststroke. We synthesized eleven studies that performed module-based analyses during walking tasks for individuals poststroke. Modules were primarily identified by nonnegative matrix factorization, and fewer modules correlated with poor walking performance on biomechanical and clinical measures. Fewer modules indicated reduced ability to control individual muscle timing during paretic leg stance. There was evidence that rehabilitation can lead to the use of more and/or better-timed modules. While future work will need to establish the ability of modules to identify impairment mechanisms, they appear to offer a promising analytical approach for evaluating motor control.

scholarly journals Merging of Healthy Motor Modules Predicts Reduced Locomotor Performance and Muscle Coordination Complexity Post-Stroke

2010 ◽  
Vol 103 (2) ◽  
pp. 844-857 ◽  
Author(s):  
David J. Clark ◽  
Lena H. Ting ◽  
Felix E. Zajac ◽  
Richard R. Neptune ◽  
Steven A. Kautz
Keyword(s):  
Nervous System ◽  
Neural Control ◽  
Muscle Activation ◽  
Nonnegative Matrix ◽  
Modular Organization ◽  
Coordination Pattern ◽  
Muscle Coordination ◽  
Post Stroke ◽  
Muscle Activation Patterns ◽  
Flexion Extension

Evidence suggests that the nervous system controls motor tasks using a low-dimensional modular organization of muscle activation. However, it is not clear if such an organization applies to coordination of human walking, nor how nervous system injury may alter the organization of motor modules and their biomechanical outputs. We first tested the hypothesis that muscle activation patterns during walking are produced through the variable activation of a small set of motor modules. In 20 healthy control subjects, EMG signals from eight leg muscles were measured across a range of walking speeds. Four motor modules identified through nonnegative matrix factorization were sufficient to account for variability of muscle activation from step to step and across speeds. Next, consistent with the clinical notion of abnormal limb flexion-extension synergies post-stroke, we tested the hypothesis that subjects with post-stroke hemiparesis would have altered motor modules, leading to impaired walking performance. In post-stroke subjects ( n = 55), a less complex coordination pattern was shown. Fewer modules were needed to account for muscle activation during walking at preferred speed compared with controls. Fewer modules resulted from merging of the modules observed in healthy controls, suggesting reduced independence of neural control signals. The number of modules was correlated to preferred walking speed, speed modulation, step length asymmetry, and propulsive asymmetry. Our results suggest a common modular organization of muscle coordination underlying walking in both healthy and post-stroke subjects. Identification of motor modules may lead to new insight into impaired locomotor coordination and the underlying neural systems.

The Role of Social Media in Adolescent Loneliness and Mental Health Problems: Current Evidence and Suggestions for Future Work

2021 ◽  
Author(s):  
Warner Myntti ◽  
Jensen Spicer ◽  
Carol Janney ◽  
Stacey Armstrong ◽  
Sarah Domoff
Keyword(s):  
Mental Health ◽  
Social Media ◽  
Mental Health Problems ◽  
Media Use ◽  
Current Evidence ◽  
Social Media Use ◽  
The Social ◽  
Future Work ◽  
The Relationship

Adolescents are spending more time interacting with peers online than in person, evidencing the need to examine this shift’s implications for adolescent loneliness and mental health. The current review examines research documenting an association between social media use and mental health, and highlights several specific areas that should be further explored as mechanisms within this relationship. Overall, it appears that frequency of social media use, the kind of social media use, the social environment, the platform used, and the potential for adverse events are especially important in understanding the relationship between social media use and adolescent mental health.

Effect of gravity and kinematic constraints on muscle synergies in arm cycling.

2021 ◽  
Author(s):  
Lilla Botzheim ◽  
Jozsef Laczko ◽  
Diego Torricelli ◽  
Mariann Mravcsik ◽  
José L. Pons ◽  
...  
Keyword(s):  
Motor Control ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Body Position ◽  
Medical Rehabilitation ◽  
Muscle Synergies ◽  
Muscle Coordination ◽  
Arm Cycling ◽  
Custom Made ◽  
Crank Length

Arm cycling is a bi-manual motor task used in medical rehabilitation and in sports training. Understanding how muscle coordination changes across different biomechanical constraints in arm cycling is a step towards improved rehabilitation approaches. This exploratory study aims to get new insights on motor control during arm cycling. To achieve our main goal, we used the muscle synergies analysis to test three hypotheses: 1) body position with respect to gravity (sitting and supine) has an effect on muscle synergies; 2) the movement size (crank length) has an effect on the synergistic behavior; 3) the bimanual cranking mode (asynchronous and synchronous) requires different synergistic control. Thirteen able-bodied volunteers performed arm cranking on a custom-made device with unconnected cranks, which allowed testing three different conditions: body position (sitting versus supine), crank length (10cm versus 15cm) and cranking mode (synchronous versus asynchronous). For each of the eight possible combinations, subjects cycled for 30 seconds while electromyography of 8 muscles (4 from each arm) were recorded: biceps brachii, triceps brachii, anterior deltoid and posterior deltoid. Muscle synergies in this 8-dimensional muscle space were extracted by non-negative matrix factorization. Four synergies accounted for over 90% of muscle activation variances in all conditions. Results showed that synergies were affected by body position and cranking mode but practically unaffected by movement size. These results suggest that the central nervous system may employ different motor control strategies in response to external constraints such as cranking mode and body position during arm cycling.

scholarly journals Watching over or Working with? Understanding Social Work Innovation in Response to Extra-Familial Harm

2020 ◽  
Vol 9 (4) ◽  
pp. 37 ◽  
Author(s):  
Lauren Elizabeth Wroe ◽  
Jenny Lloyd
Keyword(s):  
Social Work ◽  
Case Studies ◽  
Analytical Framework ◽  
Analytic Framework ◽  
England And Wales ◽  
Critical Issues ◽  
And Control ◽  
Future Work ◽  
Public Bodies

This paper critically reflects on the role of surveillance and trusted relationships in social work in England and Wales. It explores the characteristics of relationships of trust and relationships of surveillance and asks how these approaches apply to emerging policy and practices responses to extra-familial forms of harm (EFH). Five bodies of research that explore safeguarding responses across a range of public bodies are drawn on to present an analytical framework that explores elements of safeguarding responses, constituting relationships of trust or relationships of surveillance and control. This analytic framework is applied to two case studies, each of which detail a recent practice innovation in response to EFH studied by the authors, as part of a larger body of work under the Contextual Safeguarding programme. The application of this framework signals a number of critical issues related to the focus/rationale, methods and impact of interventions into EFH that should be considered in future work to address EFH, to ensure young people’s rights to privacy and participation are upheld.

scholarly journals Muscle Synergies Reliability in the Power Clean Exercise

2020 ◽  
Vol 5 (4) ◽  
pp. 75
Author(s):  
Paulo D. G. Santos ◽  
João R. Vaz ◽  
Paulo F. Correia ◽  
Maria J. Valamatos ◽  
António P. Veloso ◽  
...  
Keyword(s):  
Nonnegative Matrix Factorization ◽  
Nonnegative Matrix ◽  
Human Movement ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Complex Task ◽  
Muscle Coordination ◽  
High Similarity ◽  
Strength Tests ◽  
Power Clean

Muscle synergy extraction has been utilized to investigate muscle coordination in human movement, namely in sports. The reliability of the method has been proposed, although it has not been assessed previously during a complex sportive task. Therefore, the aim of the study was to evaluate intra- and inter-day reliability of a strength training complex task, the power clean, assessing participants’ variability in the task across sets and days. Twelve unexperienced participants performed four sets of power cleans in two test days after strength tests, and muscle synergies were extracted from electromyography (EMG) data of 16 muscles. Three muscle synergies accounted for almost 90% of variance accounted for (VAF) across sets and days. Intra-day VAF, muscle synergy vectors, synergy activation coefficients and individual EMG profiles showed high similarity values. Inter-day muscle synergy vectors had moderate similarity, while the variables regarding temporal activation were still strongly related. The present findings revealed that the muscle synergies extracted during the power clean remained stable across sets and days in unexperienced participants. Thus, the mathematical procedure for the extraction of muscle synergies through nonnegative matrix factorization (NMF) may be considered a reliable method to study muscle coordination adaptations from muscle strength programs.

scholarly journals Design, Validity, and Reliability of a New Test, Based on an Inertial Measurement Unit System, for Measuring Cervical Posture and Motor Control in Children with Cerebral Palsy

Diagnostics ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 661
Author(s):  
Cristina Carmona-Pérez ◽  
Alberto Pérez-Ruiz ◽  
Juan L. Garrido-Castro ◽  
Francisco Torres Vidal ◽  
Sandra Alcaraz-Clariana ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Motor Control ◽  
Inertial Measurement Unit ◽  
Measurement Unit ◽  
Validity And Reliability ◽  
Inertial Measurement ◽  
Functional Measures ◽  
Flexion Extension ◽  
Children With Cerebral Palsy ◽  
Cervical Posture

Objective: The aim of this study was to design and propose a new test based on inertial measurement unit (IMU) technology, for measuring cervical posture and motor control in children with cerebral palsy (CP) and to evaluate its validity and reliability. Methods: Twenty-four individuals with CP (4–14 years) and 24 gender- and age-matched controls were evaluated with a new test based on IMU technology to identify and measure any movement in the three spatial planes while the individual is seated watching a two-minute video. An ellipse was obtained encompassing 95% of the flexion/extension and rotation movements in the sagittal and transversal planes. The protocol was repeated on two occasions separated by 3 to 5 days. Construct and concurrent validity were assessed by determining the discriminant capacity of the new test and by identifying associations between functional measures and the new test outcomes. Relative reliability was determined using the intraclass correlation coefficient (ICC) for test–retest data. Absolute reliability was obtained by the standard error of measurement (SEM) and the Minimum Detectable Change at a 90% confidence level (MDC90). Results: The discriminant capacity of the area and both dimensions of the new test was high (Area Under the Curve ≈ 0.8), and consistent multiple regression models were identified to explain functional measures with new test results and sociodemographic data. A consistent trend of ICCs higher than 0.8 was identified for CP individuals. Finally, the SEM can be considered low in both groups, although the high variability among individuals determined some high MDC90 values, mainly in the CP group. Conclusions: The new test, based on IMU data, is valid and reliable for evaluating posture and motor control in children with CP.

scholarly journals Biomechanical demands of percussive techniques in the context of early stone toolmaking

2021 ◽  
Vol 18 (178) ◽  
pp. 20201044
Author(s):  
R. Macchi ◽  
G. Daver ◽  
M. Brenet ◽  
S. Prat ◽  
L. Hugheville ◽  
...  
Keyword(s):  
Motor Control ◽  
Muscle Activity ◽  
Joint Angle ◽  
Biceps Brachii ◽  
Stone Tool ◽  
Muscle Coordination ◽  
Physical Demands ◽  
Kinematic Pattern ◽  
Evolutionary Advantage ◽  
Behavioural Repertoire

Recent discoveries in archaeology and palaeoanthropology highlight that stone tool knapping could have emerged first within the genera Australopithecus or Kenyanthropus rather than Homo . To explore the implications of this hypothesis determining the physical demands and motor control needed for performing the percussive movements during the oldest stone toolmaking technology (i.e. Lomekwian) would help. We analysed the joint angle patterns and muscle activity of a knapping expert using three stone tool replication techniques: unipolar flaking on the passive hammer (PH), bipolar (BP) flaking on the anvil, and multidirectional and multifacial flaking with free hand (FH). PH presents high levels of activity for Biceps brachii and wrist extensors and flexors. By contrast, BP and FH are characterized by high solicitation of forearm pronation. The synergy analyses depict a high muscular and kinematic coordination. Whereas the muscle pattern is very close between the techniques, the kinematic pattern is more variable, especially for PH. FH displays better muscle coordination and conversely lesser joint angle coordination. These observations suggest that the transition from anvil and hammer to freehand knapping techniques in early hominins would have been made possible by the acquisition of a behavioural repertoire producing an evolutionary advantage that gradually would have been beneficial for stone tool production.

scholarly journals Voice Onset Time in Individuals With Hyperfunctional Voice Disorders: Evidence for Disordered Vocal Motor Control

2020 ◽  
Vol 63 (2) ◽  
pp. 405-420 ◽  
Author(s):  
Victoria S. McKenna ◽  
Jennifer A. Hylkema ◽  
Monique C. Tardif ◽  
Cara E. Stepp
Keyword(s):  
Motor Control ◽  
Coefficient Of Variation ◽  
Voice Onset Time ◽  
American English ◽  
Onset Time ◽  
Adult Women ◽  
Vocal Hyperfunction ◽  
The Mean ◽  
Future Work ◽  
Age And Sex

Purpose This study examined vocal hyperfunction (VH) using voice onset time (VOT). We hypothesized that speakers with VH would produce shorter VOTs, indicating increased laryngeal tension, and more variable VOTs, indicating disordered vocal motor control. Method We enrolled 32 adult women with VH (aged 20–74 years) and 32 age- and sex-matched controls. All were speakers of American English. Participants produced vowel–consonant–vowel combinations that varied by vowel (ɑ/u) and plosive (p/b, t/d, k/g). VOT—measured at the release of the plosive to the initiation of voicing—was averaged over three repetitions of each vowel–consonant–vowel combination. The coefficient of variation (CoV), a measure of VOT variability, was also computed for each combination. Results The mean VOTs were not significantly different between the two groups; however, the CoVs were significantly greater in speakers with VH compared to controls. Voiceless CoV values were moderately correlated with clinical ratings of dysphonia ( r = .58) in speakers with VH. Conclusion Speakers with VH exhibited greater variability in phonemic voicing targets compared to vocally healthy speakers, supporting the hypothesis for disordered vocal motor control in VH. We suggest future work incorporate VOT measures when assessing auditory discrimination and auditory–motor integration deficits in VH.

Effects of Multiple Concussions

2014 ◽  
Author(s):  
Michael A. McCrea ◽  
Lindsay D. Nelson
Keyword(s):  
Psychiatric Symptoms ◽  
Current Evidence ◽  
Individual Risk ◽  
Neuropsychological Performance ◽  
Number Of Factors ◽  
Scientific Principles ◽  
General Scientific ◽  
Multiple Levels ◽  
Injury Recovery ◽  
Future Work

There is growing concern that suffering multiple sport-related concussions may increase an athlete’s risk of cumulative neurocognitive and neurobehavioral impairment. Many concerns have not been well-validated, however, owing to limited samples of repeatedly concussed players. In this article, we review the theoretical risks and current evidence regarding the extent to which repeat concussions impact players’ experience of and recovery following successive injuries. Concussion effects are considered at multiple levels (e.g., self-reported physical and psychiatric symptoms, neuropsychological performance, and neurophysiological measures) across both the acute and chronic phases of recovery. Recommendations for applying findings to injury management decisions are provided. Although repeat concussions appear to have the potential for cumulative neurophysiological burden, a number of factors (e.g., individual risk for experiencing or responding poorly to injury, recovery time between injuries) appear important to explain discrepant findings among studies and to translate general scientific principles into clinical decisions for individual players. Future work that accumulates larger, prospective samples will allow for clearer delineation of the factors that appear important for predicting how recurrent concussions impact individual athletes.

scholarly journals Physical Therapy Adjuvants to Promote Optimization of Walking Recovery after Stroke

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Mark G. Bowden ◽  
Aaron E. Embry ◽  
Chris M. Gregory
Keyword(s):  
Motor Control ◽  
Muscle Strength ◽  
Dynamic Balance ◽  
Limiting Factor ◽  
Locomotor Function ◽  
Future Studies ◽  
Walking Performance ◽  
Walking Recovery ◽  
The Individual ◽  
Recent Attention

Stroke commonly results in substantial and persistent deficits in locomotor function. The majority of scientific inquiries have focused on singular intervention approaches, with recent attention given to task specific therapies. We propose that measurement should indicate the most critical limiting factor(s) to be addressed and that a combination of adjuvant treatments individualized to target accompanying impairment(s) will result in the greatest improvements in locomotor function. We explore training to improve walking performance by addressing a combination of: (1) walking specific motor control; (2) dynamic balance; (3) cardiorespiratory fitness and (4) muscle strength and put forward a theoretical framework to maximize the functional benefits of these strategies as physical adjuvants. The extent to which any of these impairments contribute to locomotor dysfunction is dependent on the individual and will undoubtedly change throughout the rehabilitation intervention. Thus, the ability to identify and measure the relative contributions of these elements will allow for identification of a primary intervention as well as prescription of additional adjuvant approaches. Importantly, we highlight the need for future studies as appropriate dosing of each of these elements is contingent on improving the capacity to measure each element and to titrate the contribution of each to optimal walking performance.

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