Movements Of Upper Extremities Research Articles

The complementary dominance hypothesis: a model for remediating the 'good' hand in stroke survivors.

The complementary dominance hypothesis is a novel model of motor lateralization substantiated by decades of research examining interlimb differences in the control of upper extremity movements in neurotypical adults and hemisphere-specific motor deficits in stroke survivors. In contrast to earlier ideas that attribute handedness to the specialization of one hemisphere, our model proposes complementary motor control specializations in each hemisphere. The dominant hemisphere mediates optimal control of limb dynamics as required for smooth and efficient movements, whereas the non-dominant hemisphere mediates impedance control, important for countering unexpected mechanical conditions and achieving steady-state limb positions. Importantly, this model proposes that each hemisphere contributes its specialization to both arms (though with greater influence from either arm's contralateral hemisphere) and thus predicts that lesions to one hemisphere should produce hemisphere-specific motor deficits in not only the contralesional arm, but also the ipsilesional arm of stroke survivors - a powerful prediction now supported by a growing body of evidence. Such ipsilesional arm motor deficits vary with contralesional arm impairment, and thus individuals with little to no functional use of the contralesional arm experience both the greatest impairments in the ipsilesional arm, as well as the greatest reliance on it to serve as the main or sole manipulator for activities of daily living. Accordingly, we have proposed and tested a novel intervention that reduces hemisphere-specific ipsilesional arm deficits and thereby improves functional independence in stroke survivors with severe contralesional impairment.

The assistive potential of functional electrical stimulation to support object manipulation in functional upper extremity movements after stroke: A randomized cross-over study

The assistive potential of functional electrical stimulation to support object manipulation in functional upper extremity movements after stroke: A randomized cross-over study

A case of diabetic striatopathy due to uncontrolled type 2 diabetes.

Hemichorea-hemiballismus (HCHB) syndrome is a syndrome characterized by choreic movements which are irregular, nonrepetitive, and random movements, and ballismus which are spontaneous and violent movements. HCHB syndrome with a metabolic cause is a rare presentation that can be precipitated by uncontrolled diabetes. Presented here is a case of HCHB syndrome with right-sided neuroimaging findings and contralateral chorea due to uncontrolled type 2 diabetes mellitus. This patient was found to be obtunded with a blood glucose of greater than 500 mg/dL by EMS. After the administration of insulin, she was able to answer clarifying questions of noncompliance with her antihyperglycemic medications. She had a computed tomography without contrast of the head which showed hyperdense lesions in the right caudate nucleus and putamen consistent with HCHB syndrome. She was started on treatment for nonketotic hyperglycemia with insulin. As her mentation improved, she was able to cooperate with physical examination, which revealed irregular and violent movements in the left upper and lower extremities. Her hemichorea and hemiballismus improved with strict glycemic control, and she was able to be discharged to a skilled nursing facility for further rehabilitation. She would later have repeated hospitalizations for poor glycemic control, and repeat neuroimaging would reveal the resolution of hyperdensities after 4 months. HCHB syndrome due to uncontrolled diabetes has been termed diabetic striatopathy and is characterized by poor glycemic control, unilateral striatal hyperdensity on CT imaging, and contralateral choreic movements. Diabetic striatopathy remains a poorly understood disease, and the exact pathophysiologic mechanism has not been definitively elucidated. Diabetic striatopathy is a relatively new term for metabolic etiology of hemichorea-hemiballismus syndrome and was coined in 2009. The triad for diabetic striatopathy is poor glycemic control, unilateral striatal hyperdensity on CT imaging, and contralateral choreic movements. Multiple etiologies have been suggested for the cause of diabetic striatopathy including petechial hemorrhage, mineral deposition, myelin destruction, and infarction with reactive astrocytosis; however, the exact mechanism has yet to be determined. Antidopaminergic medications may be used to control the choreic movements of diabetic striatopathy; however, the mainstay of treatment is glycemic control, often with insulin therapy.

A Training Program Using Modified Joystick-Operated Ride-on Toys to Complement Conventional Upper Extremity Rehabilitation in Children with Cerebral Palsy: Results from a Pilot Study.

The pilot study assessed the utility of a training program using modified, commercially available dual-joystick-operated ride-on toys to promote unimanual and bimanual upper extremity (UE) function in children with cerebral palsy (CP). The ride-on-toy training was integrated within a 3-week, intensive, task-oriented training camp for children with CP. Eleven children with hemiplegia between 4 and 10 years received the ride-on-toy training program 20-30 min/day, 5 days/week for 3 weeks. Unimanual motor function was assessed using the Quality of Upper Extremity Skills Test (QUEST) before and after the camp. During ride-on-toy training sessions, children wore activity monitors on both wrists to assess the duration and intensity of bimanual UE activity. Video data from early and late sessions were coded for bimanual UE use, independent navigation, and movement bouts. Children improved their total and subscale QUEST scores from pretest to post-test while increasing moderate activity in their affected UE from early to late sessions, demonstrating more equal use of both UEs across sessions. There were no significant changes in the rates of movement bouts from early to late sessions. We can conclude that joystick-operated ride-on toys function as child-friendly, intrinsically rewarding tools that can complement conventional therapy and promote bimanual motor functions in children with CP.

Clinical Reasoning: A 38-Year-Old Woman Presenting With Acute Hyperkinetic Movements of Her Right Arm

We present a case report of a 38-year-old woman who presented to the hospital with acute onset high amplitude, non-rhythmic, hyperkinetic movements of the right upper extremity, abnormal sensation of the right upper extremity from the elbow to the hand, and the inability to recognize her hand without visual input. This case discusses the differential diagnoses of acute hyperkinetic movement disorders and concurrent alien-limb in a patient presenting within the time window for vascular intervention. Readers are led through the reasoning behind acute interventional decision-making in a patient with a rare presentation. Workup reveals the eventual diagnosis.

The Effect of Two-Handed Overhead Medicine Ball Throwing Exercises on Upper Extreme Muscle Strength and Kinematic Movement in Soccer Throw-ins

This study aims to analyze the effect of two-handed overhead medicine ball (THOMBT) training on upper extremity muscle strength and kinematic movement. This research utilized an experimental method with a pre-test and post-test design. Sample collection used a random sampling technique. The sampling results were then divided into a control group (CTRL) and an experimental group (THOMBT). The Shapiro-Wilk test and Levene's test were used as prerequisite tests. Paired t-tests and independent sample t-tests were used to compare improvements within and between groups. Statistical significance was set at p < 0.05. Cohen's effect size (ES) was used to measure group differences. A total of 15 players were in the experimental group with an average age of 16.20 ± 0.77 years, while 15 other players were in the control group with an average age of 16.13 ± 0.83. Before and after the four-week trial period, upper extremity muscle strength testing was conducted using push-ups, sit-ups, and kinematic movement tests, which included throwing distance, arm angular speed, and release angle tests. The result is the THOMBT group showed significant improvements in push-ups (p = .000, Δ% = 22.44), sit-ups (p = .000, Δ% = 9.33), distance throws (p = .000, Δ% = 8.20), and arm angular velocity (p = .000, Δ% = 14.98). Meanwhile, the CTRL group did not have a significant increase. The conclusion is that THOMBT training for four weeks is effective in increasing upper extremity strength ability and movement kinematics, but not variable angle of release. Keywords: throws, medicine ball, muscle strength, kinematics movement.

Association between core strength and dynamic balance of throwing hand in professional healthy cricket fast bowlers: A cross sectional study

BackgroundThe core musculature gets activated by feed forward fashion during the movement of upper extremity, as in kinetic chain of throwing, shoulder muscle contributes larger dynamic balance and also in reversed manner. Aim of the current study was to associate the strength of core and the dynamic balance of throwing hand in cricket fast bowlers. Methods72 subjects were initially screened for eligibility, and ultimately, 55 male participants from various cricket coaching academies, aged 19.1 ± 2.6 on average, were included. The mean BMI of the participants was 20.9. The assessments included the Modified Upper Quarter Y Balance Test (mUQYBT)- Medial (M), Supero-Lateral reach (SL), Infero-Lateral reach(IL) along with Core measures- 600 Abdominal flexion test (600 AFT), right side plank test (RSP), Left side plank test (LSP), Beiring Sorenson test (BST), all of which were successfully completed. ResultsBased on our findings, we observed a mild positive correlation between the values of mUQYBT and core measures. We employed Pearson's coefficient to evaluate the association, and the R2 values were utilized to quantify the amount of variability. The resulting scores were RSP to SL (r = 0.38, R2 = 0.14), LSP to SL (r = 0.43, R2 = 0.19), LSP to RSP (r = 0.790, R2 = 0.62), BSP to Composite score (r = 0.29, R2 = 0.08), SL to 600 AFT* (r = 0.231, R2 = 0.05) and BMI to IL* (r = −0.107, R2 = 0.01). ConclusionIn conclusion, a positive correlation was exhibited between dynamic balance and core strength in healthy cricket fast bowlers. Educating bowlers on proper movement techniques and prescribing targeted exercises can enhance dynamic balance, reducing the risk of injuries.

Combined repetitive facilitative exercise under continuous neuromuscular electrical stimulation and task-oriented training for hemiplegic upper extremity during convalescent phase after stroke: before-and-after feasibility trial.

Whereas repetitive facilitative exercise (RFE) affects primarily recovery of motor impairment after stroke, task-oriented training (TOT) focuses on facilitating daily use of the affected upper extremity. However, feasibility of combined RFE and TOT has not been reported. We originated "task-oriented RFE," as a new combination therapy for patients with hemiplegic upper extremity after subacute stroke, to examine its feasibility in convalescent rehabilitation wards. This is a before-and-after pilot study. Eight patients with hemiplegic upper extremity after subacute stroke received the task-oriented RFE program for 6 weeks at 80 min per day (20-60 min of TOT applied after 60-20 min of RFE under continuous neuromuscular electrical stimulation) in a convalescent rehabilitation ward. In the current program, we introduced the Aid for Decision-making in Occupation Choice (ADOC) iPad application as a goal-setting method for determining tasks. Feasibility was assessed with adherence to the protocol, adverse events in response to the intervention, and preliminary efficacy. Motor functions, amount of use and quality of movement in the hemiparetic upper extremity, and satisfaction of the patients were evaluated with Fugl-Meyer Assessment (FMA), the Action Research Arm Test (ARAT), the motor activity log (MAL) for the amount of use (AOU) and quality of movement (QOM) of the paralyzed hand, and ADOC. All participants accomplished the program, which was implemented as originally planned; neither nonattendance nor an adverse event occurred during the study. Favorable outcomes were obtained with all measures; mean changes in FMA, ARAT in the dominant hand, MAL-AOU, and MAL-QOM were greater than minimal clinically important differences. Mean changes in ADOC were greater than the minimal detectable change. The task-oriented RFE program was safe, well-tolerated, beneficial, and feasible within 80 min a day of occupational therapy, which means also within the procedural constraints of the Japanese health insurance system during the convalescent phase. Future studies are warranted to examine whether combined RFE and TOT enhances the efficacies of each program alone.

Review of outcomes measures used to evaluate upper extremity surgical treatment of cervical spinal cord injury with recommendations for the future

Cervical spinal cord injury is a life-altering event that profoundly affects an individual’s upper extremity function. Nerve transfer surgeries have been shown to restore more natural movement and fine motor control in this population. At present, there is no consensus on how to evaluate the efficacy of these restorative surgeries. The purpose of this work was to perform a comprehensive review of the existing literature and describe the outcome measures used. We hypothesized that the assessments will be heterogeneous across studies and will incompletely capture the effect of nerve transfers on upper extremity motion in cervical spinal cord injury. A search strategy was designed and a review of multiple databases (Embase.com, Ovid-Medline All, and Scopus) yielded 481 articles; 26 unique studies met inclusion criteria and underwent analysis. Both manual muscle strength testing and video content were presented in the majority of studies. Outcome assessments including myometry, functional outcomes measures (such as the grasp and release test), patient-reported outcomes (including generic, extremity, and disease-specific types), and custom de novo questionnaires were used variably across studies. Future work should focus on standardizing outcomes measures in the field and developing and incorporating kinematic analysis to quantify the intricate, coordinated, and precise movement attained after nerve transfer surgery in the setting of cervical spinal cord injury.

An Algorithm for Activity Recognition and Assessment of Adults Poststroke.

Stroke is the leading cause of long-term disability in the United States. Providers have no robust tools to objectively and accurately measure the activity of people with stroke living at home. To explore the integration of validated upper extremity assessments poststroke within an activity recognition system. Exploratory descriptive study using data previously collected over 3 mo to report on algorithm testing and assessment integration. Data were collected in the homes of community-dwelling participants. Participants were at least 6 mo poststroke, were able to ambulate with or without an assistive device, and self-reported some difficulty using their arm in everyday activities. The activity detection algorithm's accuracy was determined by comparing its activity labels with manual labels. The algorithm integrated assessment by describing the quality of upper extremity movement, which was determined by reporting extent of reach, mean and maximum speed during movement, and smoothness of movement. Sixteen participants (9 women, 7 men) took part in this study, with an average age of 63.38 yr (SD = 12.84). The algorithm was highly accurate in correctly identifying activities, with 87% to 95% accuracy depending on the movement. The algorithm was also able to detect the quality of movement for upper extremity movements. The algorithm was able to accurately identify in-kitchen activities performed by adults poststroke. Information about the quality of these movements was also successfully calculated. This algorithm has the potential to supplement clinical assessments in treatment planning and outcomes reporting. Plain-Language Summary: This study shows that clinical algorithms have the potential to inform occupational therapy practice by providing clinically relevant data about the in-home activities of adults poststroke. The algorithm accurately identified activities that were performed in the kitchen by adults poststroke. The algorithm also identified the quality of upper extremity movements of people poststroke who were living at home.

Optimizing RNNs for EMG Signal Classification: A Novel Strategy Using Grey Wolf Optimization.

Accurate classification of electromyographic (EMG) signals is vital in biomedical applications. This study evaluates different architectures of recurrent neural networks for the classification of EMG signals associated with five movements of the right upper extremity. A Butterworth filter was implemented for signal preprocessing, followed by segmentation into 250 ms windows, with an overlap of 190 ms. The resulting dataset was divided into training, validation, and testing subsets. The Grey Wolf Optimization algorithm was applied to the gated recurrent unit (GRU), long short-term memory (LSTM) architectures, and bidirectional recurrent neural networks. In parallel, a performance comparison with support vector machines (SVMs) was performed. The results obtained in the first experimental phase revealed that all the RNN networks evaluated reached a 100% accuracy, standing above the 93% achieved by the SVM. Regarding classification speed, LSTM ranked as the fastest architecture, recording a time of 0.12 ms, followed by GRU with 0.134 ms. Bidirectional recurrent neural networks showed a response time of 0.2 ms, while SVM had the longest time at 2.7 ms. In the second experimental phase, a slight decrease in the accuracy of the RNN models was observed, standing at 98.46% for LSTM, 96.38% for GRU, and 97.63% for the bidirectional network. The findings of this study highlight the effectiveness and speed of recurrent neural networks in the EMG signal classification task.

A clinical study on different surgical options for management of post-burn axillary contractures

Background: Post-burn contracture is a common sequele occurring after burn. Upper limb contracture like axilla is also occurring more commonly because it is most mobile part of body and likely to involve in burn. Post-burn contracture of axilla leads to functional deficit as it limits the movement of upper extremity mainly abduction and extension. Patients with axillary contracture are unable to utilize his upper limb because he is unable to take the hand at required site. Aims and Objectives: The objective of this study was to study various operative strategies for patients presenting with post-burn axillary contracture. Materials and Methods: Twenty patients presenting with post-burn axillary contractures were taken in our study. Results: In our study of 20 patients of post-burn axillary contracture, five patients had Grade I (25%), Grade II 05 (25%), Grade III 01 (5%), and Grade IV 09 (45%) contractures. Regarding surgical procedure, Z-plasty was done in 8 patients (40%), release with skin grafting 10 patients (50%), and local flap done in 2 patients (10%). In our study, the mean degree of range of motion achieved after release of axillary contracture was 120°. In our study, 2 patients (10%) developed re-contracture, 1 patient (5%) had a graft failure while 85% of the patients had no complications. Conclusion: In the present study of 20 cases of management of post-burn axillary contracture, it is reasonable to conclude that the prevention of contracture is of utmost importance. The choice of surgical procedure for reconstruction of post-burn axillary contractures can be made according to the pattern of scar contracture and the state of the surrounding skin. The choice of a flap should have priority over the skin graft due to the superior functional and esthetic results of flaps. The results were satisfactory in our study in most cases with regard to quality of life, coverage, and range of motion.

A Comparison of Approaches for Segmenting the Reaching and Targeting Motion Primitives in Functional Upper Extremity Reaching Tasks.

There is growing interest in the kinematic analysis of human functional upper extremity movement (FUEM) for applications such as health monitoring and rehabilitation. Deconstructing functional movements into activities, actions, and primitives is a necessary procedure for many of these kinematic analyses. Advances in machine learning have led to progress in human activity and action recognition. However, their utility for analyzing the FUEM primitives of reaching and targeting during reach-to-grasp and reach-to-point tasks remains limited. Domain experts use a variety of methods for segmenting the reaching and targeting motion primitives, such as kinematic thresholds, with no consensus on what methods are best to use. Additionally, current studies are small enough that segmentation results can be manually inspected for correctness. As interest in FUEM kinematic analysis expands, such as in the clinic, the amount of data needing segmentation will likely exceed the capacity of existing segmentation workflows used in research laboratories, requiring new methods and workflows for making segmentation less cumbersome. This paper investigates five reaching and targeting motion primitive segmentation methods in two different domains (haptics simulation and real world) and how to evaluate these methods. This work finds that most of the segmentation methods evaluated perform reasonably well given current limitations in our ability to evaluate segmentation results. Furthermore, we propose a method to automatically identify potentially incorrect segmentation results for further review by the human evaluator. Clinical impact: This work supports efforts to automate aspects of processing upper extremity kinematic data used to evaluate reaching and grasping, which will be necessary for more widespread usage in clinical settings.

Patient-Specific Movement Regime: Investigating the Potential of Upper-Extremity Motions for Intelligent Myoelectric Prosthetic Control

Patient-Specific Movement Regime: Investigating the Potential of Upper-Extremity Motions for Intelligent Myoelectric Prosthetic Control

Characterization of Upper Extremity Kinematics Using Virtual Reality Movement Tasks and Wearable IMU Technology.

Task-specific training has been shown to be an effective neuromotor rehabilitation intervention, however, this repetitive approach is not always very engaging. Virtual reality (VR) systems are becoming increasingly popular in therapy due to their ability to encourage movement through customizable and immersive environments. Additionally, VR can allow for a standardization of tasks that is often lacking in upper extremity research. Here, 16 healthy participants performed upper extremity movement tasks synced to music, using a commercially available VR game known as Beat Saber. VR tasks were customized to characterize participants' joint angles with respect to each task's specified cardinal direction (inward, outward, upward, or downward) and relative task location (medial, lateral, high, and/or low). Movement levels were designed using three common therapeutic approaches: (1) one arm moving only (unilateral), (2) two arms moving in mirrored directions about the participant's midline (mirrored), or (3) two arms moving in opposing directions about the participant's midline (opposing). Movement was quantified using an XSens System, a wearable inertial measurement unit (IMU) technology. Results reveal a highly engaging and effective approach to quantifying movement strategies. Inward and outward (horizontal) tasks resulted in decreased wrist extension. Upward and downward (vertical) tasks resulted in increased shoulder flexion, wrist radial deviation, wrist ulnar deviation, and elbow flexion. Lastly, compared to opposing, mirrored, and unilateral movement levels often exaggerated joint angles. Virtual reality games, like Beat Saber, offer a repeatable and customizable upper extremity intervention that has the potential to increase motivation in therapeutic applications.

Paired DBS and TMS Reveals Dentato-Cortical Facilitation Underlying Upper Extremity Movement in Chronic Stroke Survivors

Background Cerebellum shares robust di-synaptic dentato-thalamo-cortical (DTC) connections with the contralateral motor cortex. Preclinical studies have shown that DTC are excitatory in nature. Structural integrity of DTC is associated with better upper extremity (UE) motor function in people with stroke, indicating DTC are important for cerebellar influences on movement. However, there is a lack of understanding of physiologic influence of DTC in humans, largely due to difficulty in accessing the dentate nucleus. Objective Characterize DTC physiology using dentate nucleus deep brain stimulation (DBS) combined with transcranial magnetic stimulation (TMS) in stroke. Methods Nine chronic stroke survivors with moderate-to-severe UE impairment (Fugl-Meyer 13-38) underwent a paired DBS–TMS experiment before receiving experimental dentate nucleus DBS in our first-in-human phase I trial (Baker et al., 2023, Nature Medicine). Conditioning DBS pulses were given to dentate nucleus 1 to 10 ms prior to supra-threshold TMS pulses given to ipsilesional motor cortex. Effects were assessed on motor evoked potentials (MEPs). Size of DBS-conditioned MEPs was expressed relative to TMS MEPs, where values >1 indicate facilitation. Results Dentate nucleus DBS led to facilitation of MEPs at short-latency intervals (3.5 and 5 ms, P = .049 and .021, respectively), a phenomenon we have termed dentato-cortical facilitation (DCF). Higher DCF was observed among patients with more severe UE impairment. Diffusion tensor imaging revealed microstructure of thalamo-cortical portion of DTC was related to higher corticomotor excitability. Conclusions Our in vivo investigation reveals for the first time in humans the intrinsic excitatory properties of DTC, which can serve as a novel therapeutic target for post-stroke motor recovery.

Overactivity of the Less Affected Side as a Possible Pattern of Asymmetry in Sitting in Patients Suffering from First-Time Ischemic Stroke-An Observational Study.

It has been observed that in some people in the acute phase of ischemic stroke (IS) there is a tendency to shift the body weight towards the side more affected by the disease and a tendency to spontaneous movements of the upper and/or lower limbs (not covered by the neurological syndrome). The purposes of this study were: to define the kind of behavior observed, and to select symptoms which can predict its occurrence. Participants (n = 222) hospitalized due to first-time IS were assigned to three groups. A: 78 patients with no lateralization of the neurological syndrome (lateralization of the neurological syndrome-LoNS); B: 109 patients with LoNS; O+ group: 35 patients, who at the beginning of hospitalization presented, apart from LoNS, characteristic motor symptoms performed by the less affected side. Patients underwent therapy depending on the neurological symptoms. If the patient showed potential symptoms of a new phenomenon, overactivity of the less affected side (OLAS), a trial therapy (focused on this behavior) was used to confirm it. The predictive symptoms, selected among these from the index day, for the occurrence of OLAS in sitting were distinguished: asymmetry in supine posture and simple, repetitive movements of the nonparetic upper extremity.

Upper extremity kinematics: development of a quantitative measure of impairment severity and dissimilarity after stroke

BackgroundStrokes are a leading cause of disability worldwide, with many survivors experiencing difficulty in recovering upper extremity movement, particularly hand function and grasping ability. There is currently no objective measure of movement quality, and without it, rehabilitative interventions remain at best informed estimations of the underlying neural structures’ response to produce movement. In this article, we utilize a novel modification to Procrustean distance to quantify curve dissimilarity and propose the Reach Severity and Dissimilarity Index (RSDI) as an objective measure of motor deficits.MethodsAll experiments took place at the Medstar National Rehabilitation Hospital; persons with stroke were recruited from the hospital patient population. Using Fugl-Meyer (FM) scores and reach capacities, stroke survivors were placed in either mild or severe impairment groups. Individuals completed sets of reach-to-target tasks to extrapolate kinematic metrics describing motor performance. The Procrustes method of statistical shape analysis was modified to identify reaching sub-movements that were congruous to able-bodied sub-movements.FindingsMovement initiation proceeds comparably to the reference curve in both two- and three-dimensional representations of mild impairment movement. There were significant effects of the location of congruent segments between subject and reference curves, mean velocities, peak roll angle, and target error. These metrics were used to calculate a preliminary RSDI score with severity and dissimilarity sub-scores, and subjects were reclassified in terms of rehabilitation goals as Speed Emphasis, Strength Emphasis, and Combined Emphasis.InterpretationThe modified Procrustes method shows promise in identifying disruptions in movement and monitoring recovery without adding to patient or clinician burden. The proposed RSDI score can be adapted and expanded to other functional movements and used as an objective clinical tool. By reducing the impact of stroke on disability, there is a significant potential to improve quality of life through individualized rehabilitation.

Spatial mapping of posture-dependent resistance to passive displacement of the hypertonic arm post-stroke

BackgroundMuscles in the post-stroke arm commonly demonstrate abnormal reflexes that result in increased position- and velocity-dependent resistance to movement. We sought to develop a reliable way to quantify mechanical consequences of abnormal neuromuscular mechanisms throughout the reachable workspace in the hemiparetic arm post-stroke.MethodsSurvivors of hemiparetic stroke (HS) and neurologically intact (NI) control subjects were instructed to relax as a robotic device repositioned the hand of their hemiparetic arm between several testing locations that sampled the arm's passive range of motion. During transitions, the robot induced motions at either the shoulder or elbow joint at three speeds: very slow (6°/s), medium (30°/s), and fast (90°/s). The robot held the hand at the testing location for at least 20 s after each transition. We recorded and analyzed hand force and electromyographic activations from selected muscles spanning the shoulder and elbow joints during and after transitions.ResultsHand forces and electromyographic activations were invariantly small at all speeds and all sample times in NI control subjects but varied systematically by transport speed during and shortly after movement in the HS subjects. Velocity-dependent resistance to stretch diminished within 2 s after movement ceased in the hemiparetic arms. Hand forces and EMGs changed very little from 2 s after the movement ended onward, exhibiting dependence on limb posture but no systematic dependence on movement speed or direction. Although each HS subject displayed a unique field of hand forces and EMG responses across the workspace after movement ceased, the magnitude of steady-state hand forces was generally greater near the outer boundaries of the workspace than in the center of the workspace for the HS group but not the NI group.ConclusionsIn the HS group, electromyographic activations exhibited abnormalities consistent with stroke-related decreases in the stretch reflex thresholds. These observations were consistent across repeated testing days. We expect that the approach described here will enable future studies to elucidate stroke's impact on the interaction between the neural mechanisms mediating control of upper extremity posture and movement during goal-directed actions such as reaching and pointing with the arm and hand.

Wrist Motion Assessment in Tennis Players using Three-Dimensional Motion Capture and Dynamic Electromyography

Abstract Background Tennis players often present with ulnar-sided wrist pain, which may reflect repetitive stress and/or faulty mechanics. There is a role for investigating the biomechanics of tennis strokes and how they may relate to wrist pathology. The purpose of this study was to investigate whether three-dimensional motion capture technology and dynamic electromyography (EMG), when used to study groundstrokes in elite junior tennis players, reveals patterns of upper extremity motion that may correlate with the development of clinically relevant pathology. Case Description Three-dimensional kinematic and EMG data were collected from two United States Tennis Association-ranked adolescent tennis players during groundstrokes. There were several observed differences in the two players' degree and timing of pronation/supination, ulnar/radial deviation, and flexion/extension during their strokes. Clinical Significance Advanced motion capture technology facilitates a nuanced understanding of complex movements involved in groundstroke production. This methodology may be useful for identifying athletes who are at risk for injury and guiding rehabilitation for players experiencing pain. Level of Evidence IV