Muscle torques and joint accelerations provide more sensitive measures of post-stroke movement deficits than joint angles.

2021 ◽  
Author(s):  
Ariel B Thomas ◽  
Erienne V Olesh ◽  
Amelia Adcock ◽  
Valeriya Gritsenko
Keyword(s):  
Motor Control ◽  
Motion Capture ◽  
Reaching Movements ◽  
Motor Deficits ◽  
Joint Angles ◽  
Active Joint ◽  
Joint Torques ◽  
Post Stroke ◽  
Muscle Moments ◽  
Muscle Torques

The whole repertoire of complex human motion is enabled by forces applied by our muscles and controlled by the nervous system. The impact of stroke on the complex multi-joint motor control is difficult to quantify in a meaningful way that informs about the underlying deficit in the active motor control and intersegmental coordination. We tested whether post-stroke deficit can be quantified with high sensitivity using motion capture and inverse modeling of a broad range of reaching movements. Our hypothesis is that muscle moments estimated based on active joint torques provide a more sensitive measure of post-stroke motor deficits than joint angles. The motion of twenty-two participants was captured while performing reaching movements in a center-out task, presented in virtual reality. We used inverse dynamics analysis to derive active joint torques that were the result of muscle contractions, termed muscle torques, that caused the recorded multi-joint motion. We then applied a novel analysis to separate the component of muscle torque related to gravity compensation from that related to intersegmental dynamics. Our results show that muscle torques characterize individual reaching movements with higher information content than joint angles do. Moreover, muscle torques enable distinguishing the individual motor deficits caused by aging or stroke from the typical differences in reaching between healthy individuals. Similar results were obtained using metrics derived from joint accelerations. This novel quantitative assessment method may be used in conjunction with home-based gaming motion-capture technology for remote monitoring of motor deficits and inform the development of evidence-based robotic therapy interventions.

scholarly journals Muscle forces comprise a more sensitive measure of post-stroke movement deficits than joint angles

2019 ◽  
Author(s):  
Ariel B. Thomas ◽  
Erienne V. Olesh ◽  
Amelia Adcock ◽  
Valeriya Gritsenko
Keyword(s):  
Nervous System ◽  
Motion Capture ◽  
Neural Control ◽  
Motor Deficits ◽  
Muscle Forces ◽  
Joint Angles ◽  
Sensitive Measure ◽  
Post Stroke ◽  
Age Related ◽  
Muscle Torques

AbstractBackground and PurposeThe whole repertoire of complex human motion is enabled by forces applied by our muscles and controlled by the nervous system. The effect of damage to the nervous system such as stroke on the complex multi-joint motion is difficult to quantify in a meaningful way that informs about the underlying deficit in the neural control of movement. We tested the idea that the disruption in intersegmental coordination after stroke can be quantified with higher sensitivity using metrics based on forces rather than motion. Our study aim was to objectively quantify post-stroke motor deficits using motion capture of stereotypical reaching movements. Our hypothesis is that muscle forces estimated based on active joint torques are a more sensitive measure of post-stroke motor deficits than angular kinematics.MethodsThe motion of twenty-two participants was captured when reaching to virtual targets in a center-out task. We used inverse dynamic analysis to derive muscle torques, which were the result of the neural control signals to muscles to produce the recorded multi-joint movements. We then applied a novel analysis to separate the component of muscle torque related to gravity compensation from that related to motion production. We used the kinematic and dynamic variables derived from motion capture to assess age-related and post-stroke motor deficits.ResultsWe found that reaching with the non-dominant arm was accomplished with shoulder and elbow torques that had larger amplitudes and inter-trial variability compared to reaching with the dominant arm. These dominance effects confounded the assessment of post-stroke motor deficits using amplitude and variability metrics. We then identified the metric based on waveform comparison that was insensitive to dominance effects. We used it to show that muscle torques with gravity-related components subtracted were much more sensitive to post-stroke motor deficits compared to measures based on joint angles. Using this metric, it was possible to quantify the extent of individual deficits caused by stroke independently from age-related deficits and dominance effects.ConclusionsFunctional deficits seen in task performance have biomechanical underpinnings, seen only through force-based analysis. Our study has shown that estimating muscle forces that drive motion can quantify with high sensitivity post-stroke deficits in intersegmental coordination. A force-based assessment developed based on this method could help quantify less “observable” deficits in mildly affected stroke patients, such as those classified as asymptomatic via traditional motion-based assessments, but who may still report difficulty moving, increased fatigue, and/or inactivity. Moreover, identifying deficits in the different components of muscle forces may be a way to personalize and standardize intervention and increase the effectiveness of robotic therapy.

scholarly journals A Novel Biomechanical Analysis of Horticultural Digging

2017 ◽  
Vol 27 (6) ◽  
pp. 746-753 ◽  
Author(s):  
James Shippen ◽  
Paul Alexander ◽  
Barbara May
Keyword(s):  
Motion Capture ◽  
The Body ◽  
Contact Forces ◽  
Biomechanical Analysis ◽  
Motion Capture Data ◽  
Joint Angles ◽  
Joint Torques ◽  
Risk Of Injury ◽  
Joint Contact ◽  
Good Technique

Musculoskeletal injuries are commonly reported in workers employed in labor-intensive agricultural-type tasks. A novel method of determining joint angles, joint torques, and contact forces, using three-dimensional motion capture and musculoskeletal modeling, was applied to the movements of a sample of workers, engaged in the horticultural task of digging, to determine if objective biomechanical data could be correlated with a subjective visual assessment to predict risk of injury. The joint angle time histories of horticulturists were calculated from the motion capture data, and this was used to articulate a musculoskeletal model of the subjects. The joint torques were calculated using inverse dynamics methods from which the individual muscle loads were established using a cost function minimization approach. Finally, the joint contact forces were calculated including the muscle forces. The motion capture data of digging trials were observed by a team of horticulturists and physiotherapists who categorized each of the observed trials according to form, efficiency, and risk of injury. Trials demonstrating techniques which were more likely to yield injuries were identified as “examples of bad technique”; those judged to be less likely to yield injuries were categorized as “examples of good technique.” It was found that the joint torques and contact forces and their variability were lower in the trial which was identified as good technique, and consistently higher in the examples of bad technique. The results of the study suggest that measurement of joint angles, joint torques, joint contact forces, and forces in the muscles could serve as a valuable tool to develop training programs for horticultural workers engaged in certain high intensity tasks, such as digging, to effectively improve efficiency and reduce incidence of injury. It may also be possible to modify horticulture-related equipment to minimize the internal loads within the body to reduce the risk to health and, therefore, extend active participation in horticulture.

scholarly journals Stroke promotes the development of brain atrophy and delayed cell death in hypertensive rats

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammed A. Sayed ◽  
Wael Eldahshan ◽  
Mahmoud Abdelbary ◽  
Bindu Pillai ◽  
Waleed Althomali ◽  
...  
Keyword(s):  
Cell Death ◽  
Fold Increase ◽  
Magnetic Resonance Images ◽  
Protein Quantification ◽  
Motor Deficits ◽  
Long Term Memory ◽  
Delayed Presentation ◽  
Hypertensive Rats ◽  
Post Stroke ◽  
Delayed Cell Death

AbstractPost-stroke cognitive impairment (PSCI) is a major source of disability, affecting up to two thirds of stroke survivors with no available therapeutic options. The condition remains understudied in preclinical models due to its delayed presentation. Although hypertension is a leading risk factor for dementia, how ischemic stroke contributes to this neurodegenerative condition is unknown. In this study, we used a model of hypertension to study the development of PSCI and its mechanisms. Spontaneously hypertensive rats (SHR) were compared to normotensive rats and were subjected to 1-h middle cerebral artery occlusion or sham surgery. Novel object recognition, passive avoidance test and Morris water maze were used to assess cognition. In addition, brain magnetic resonance images were obtained 12-weeks post-stroke and tissue was collected for immunohistochemistry and protein quantification. Stroked animals developed impairment in long-term memory at 4-weeks post-stroke despite recovery from motor deficits, with hypertensive animals showing some symptoms of anhedonia. Stroked SHRs displayed grey matter atrophy and had a two-fold increase in apoptosis in the ischemic borderzone and increased markers of inflammatory cell death and DNA damage at 12 weeks post-stroke. This indicates that preexisting hypertension exacerbates the development of secondary neurodegeneration after stroke beyond its acute effects on neurovascular injury.

Abstract W P140: Post-stroke Oculomotor Abnormalities evident during Objective Eye Tracking but Not under Clinical Assessment

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
John-Ross Rizzo ◽  
Todd Hudson ◽  
Briana Kowal ◽  
Michal Wiseman ◽  
Preeti Raghavan
Keyword(s):  
Motor Control ◽  
Eye Movements ◽  
Eye Movement ◽  
Oculomotor Control ◽  
Healthy Controls ◽  
Visually Guided ◽  
Stroke Patients ◽  
Movement Execution ◽  
Post Stroke ◽  
Control Post

Introduction: Visual abnormalities and manual motor control have been studied extensively after stroke, but an understanding of oculomotor control post-stroke has not. Recent studies have revealed that in visually guided reaches arm movements are planned during eye movement execution, which may contribute to increased task complexity. In fact, in healthy controls during visually guided reaches, the onset of eye movement is delayed, its velocity reduced, and endpoint errors are larger relative to isolated eye movements. Our objective in this experiment was to examine the temporal properties of eye movement execution for stroke patients with no diagnosed visual impairment. The goal is to improve understanding of oculomotor control in stroke relative to normal function, and ultimately further understand its coordination with manual motor control during joint eye and hand movements. We hypothesized that stroke patients would show abnormal initiation or onset latency for saccades made in an eye movement task, as compared to healthy controls. Methods: We measured the kinematics of eye movements during point-to-point saccades; there was an initial static, fixation point and the stimulus was a flashed target on a computer monitor. We used a video-based eye tracker for objective recording of the eye at a sampling frequency of 2000 Hz (SR Research, Eyelink). 10 stroke subjects, over 4 months from injury and with no diagnosed visual impairment, and 10 healthy controls completed 432 saccades in a serial fashion. Results: Stroke patients had significantly faster onset latencies as compared to healthy controls during saccades (99.5ms vs. 245.2ms, p=0.00058). Conclusion: A better understanding of the variations in oculomotor control post-stroke, which may go unnoticed during clinical assessment, may improve understanding of how eye control synchronizes with arm or manual motor control. This knowledge could assist in tailoring rehabilitative strategies to amplify motor recovery. For next steps, we will perform objective eye and hand recordings during visually guided reaches post-stroke to better understand the harmonization or lack thereof after neurologic insult.

scholarly journals Abnormal Speech Motor Control in Individuals with 16p11.2 Deletions

2017 ◽  
Author(s):  
Carly Demopoulos ◽  
Hardik Kothare ◽  
Danielle Mizuiri ◽  
Jennifer Henderson-Sabes ◽  
Brieana Fregeau ◽  
...  
Keyword(s):  
Motor Control ◽  
Auditory Feedback ◽  
Spectral Peak ◽  
Motor Deficits ◽  
Speech Motor Control ◽  
Sensorimotor Adaptation ◽  
Speech And Language ◽  
Vowel Production ◽  
Identity Changes ◽  
Speech Motor

AbstractSpeech and motor deficits are highly prevalent (>70%) in individuals with the 600 kb BP4-BP5 16p11.2 deletion; however, the mechanisms that drive these deficits are unclear, limiting our ability to target interventions and advance treatment. This study examined fundamental aspects of speech motor control in participants with the 16p11.2 deletion. To assess capacity for control of voice, we examined how accurately and quickly subjects changed the pitch of their voice within a trial to correct for a transient perturbation of the pitch of their auditory feedback. When compared to sibling controls, 16p11.2 deletion carriers show an over-exaggerated pitch compensation response to unpredictable mid-vocalization pitch perturbations. We also examined sensorimotor adaptation of speech by assessing how subjects learned to adapt their sustained productions of formants (speech spectral peak frequencies important for vowel identity), in response to consistent changes in their auditory feedback during vowel production. Deletion carriers show reduced sensorimotor adaptation to sustained vowel identity changes in auditory feedback. These results together suggest that 16p11.2 deletion carriers have fundamental impairments in the basic mechanisms of speech motor control and these impairments may partially explain the deficits in speech and language in these individuals.

scholarly journals The efficacy of interactive, motion capture-based rehabilitation on functional outcomes in an inpatient stroke population: a randomized controlled trial

2017 ◽  
Vol 32 (2) ◽  
pp. 191-200 ◽  
Author(s):  
John Cannell ◽  
Emelyn Jovic ◽  
Amy Rathjen ◽  
Kylie Lane ◽  
Anna M Tyson ◽  
...  
Keyword(s):  
Usual Care ◽  
Motion Capture ◽  
Stroke Rehabilitation ◽  
Primary Outcome ◽  
Intervention Group ◽  
Step Test ◽  
Controlled Clinical Trial ◽  
Post Stroke ◽  
Randomized Controlled ◽  
Functional Reach

Objective: To compare the efficacy of novel interactive, motion capture-rehabilitation software to usual care stroke rehabilitation on physical function. Design: Randomized controlled clinical trial. Setting: Two subacute hospital rehabilitation units in Australia. Participants: In all, 73 people less than six months after stroke with reduced mobility and clinician determined capacity to improve. Interventions: Both groups received functional retraining and individualized programs for up to an hour, on weekdays for 8–40 sessions (dose matched). For the intervention group, this individualized program used motivating virtual reality rehabilitation and novel gesture controlled interactive motion capture software. For usual care, the individualized program was delivered in a group class on one unit and by rehabilitation assistant 1:1 on the other. Main measures: Primary outcome was standing balance (functional reach). Secondary outcomes were lateral reach, step test, sitting balance, arm function, and walking. Results: Participants (mean 22 days post-stroke) attended mean 14 sessions. Both groups improved (mean (95% confidence interval)) on primary outcome functional reach (usual care 3.3 (0.6 to 5.9), intervention 4.1 (−3.0 to 5.0) cm) with no difference between groups ( P = 0.69) on this or any secondary measures. No differences between the rehabilitation units were seen except in lateral reach (less affected side) ( P = 0.04). No adverse events were recorded during therapy. Conclusion: Interactive, motion capture rehabilitation for inpatients post stroke produced functional improvements that were similar to those achieved by usual care stroke rehabilitation, safely delivered by either a physical therapist or a rehabilitation assistant.

Do Arm Postures Vary With the Speed of Reaching?

1999 ◽  
Vol 81 (5) ◽  
pp. 2582-2586 ◽  
Author(s):  
Kiisa C. Nishikawa ◽  
Sara T. Murray ◽  
Martha Flanders
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Reaching Movements ◽  
Total Force ◽  
Joint Torques ◽  
Dynamic Factors ◽  
Human Arm ◽  
Wide Range ◽  
Dynamic Forces

Do arm postures vary with the speed of reaching? For reaching movements in one plane, the hand has been observed to follow a similar path regardless of speed. Recent work on the control of more complex reaching movements raises the question of whether a similar “speed invariance” also holds for the additional degrees of freedom. Therefore we examined human arm movements involving initial and final hand locations distributed throughout the three-dimensional (3D) workspace of the arm. Despite this added complexity, arm kinematics (summarized by the spatial orientation of the “plane of the arm” and the 3D curvature of the hand path) changed very little for movements performed over a wide range of speeds. If the total force (dynamic + quasistatic) had been optimized by the control system (e.g., as in a minimization of the change in joint torques or the change in muscular forces), the optimal solution would change with speed; slow movements would reflect the minimal antigravity torques, whereas fast movements would be more strongly influenced by dynamic factors. The speed-invariant postures observed in this study are instead consistent with a hypothesized optimization of only the dynamic forces.

scholarly journals Diabetes Mellitus-Related Dysfunction of the Motor System

2020 ◽  
Vol 21 (20) ◽  
pp. 7485
Author(s):  
Ken Muramatsu
Keyword(s):  
Motor Control ◽  
Motor Neurons ◽  
Motor System ◽  
Corticospinal Tract ◽  
Experimental Studies ◽  
Sensory System ◽  
Treatment Strategies ◽  
Motor Deficits ◽  
New Perspective ◽  
The Brain

Although motor deficits in humans with diabetic neuropathy have been extensively researched, its effect on the motor system is thought to be lesser than that on the sensory system. Therefore, motor deficits are considered to be only due to sensory and muscle impairment. However, recent clinical and experimental studies have revealed that the brain and spinal cord, which are involved in the motor control of voluntary movement, are also affected by diabetes. This review focuses on the most important systems for voluntary motor control, mainly the cortico-muscular pathways, such as corticospinal tract and spinal motor neuron abnormalities. Specifically, axonal damage characterized by the proximodistal phenotype occurs in the corticospinal tract and motor neurons with long axons, and the transmission of motor commands from the brain to the muscles is impaired. These findings provide a new perspective to explain motor deficits in humans with diabetes. Finally, pharmacological and non-pharmacological treatment strategies for these disorders are presented.

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