Abstract TP147: Quantitative Measures of Strength and Synergy Differentiate Individuals With Chronic Stroke With and Without Clinically Detectable Elbow Contracture

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Grace C Bellinger ◽  
Michael D Ellis
Keyword(s):  
Quantitative Measure ◽  
Chronic Stroke ◽  
Future Research ◽  
Emg Activity ◽  
Shoulder Abduction ◽  
Joint Control ◽  
Elbow Extension ◽  
Unaffected Side ◽  
Elbow Contracture ◽  
Flexion Synergy

Many individuals with chronic stroke demonstrate contracture of the elbow flexors. The development of contracture may be attributable to underlying impairments such as weakness, flexion synergy, and hyperactive reflexes. This study explored differences in motor impairment and function between 17 individuals with clinically detectable elbow flexor contracture and 17 individuals with full passive range of motion. The groups did not differ in age (61.61 ± 7.99, 55.06 ± 12.48, p = 0.078), years post-stroke (12.92 ± 9.34, 10.60 ± 7.16, p = 0.423), or Fugl-Meyer Motor Assessment score (FMA, 26.35 ± 5.86, 26.47 ± 8.70, p = 0.963). The passive range limitation in the contracture group was 3 to 36° (11.65 ± 8.30°). Kinetics, kinematics, and EMG were used to quantify four motor impairments and reaching function. Shoulder abduction and elbow extension strength were measured isometrically and normalized to the unaffected side. Flexion synergy was quantified as a force-based measure assessing independent joint control. Flexor spasticity was quantified while reaching at 50% of maximum shoulder abduction as the change in biceps EMG from reach onset to peak angular velocity, normalized by maximal EMG activity. Reaching function was defined as maximum reaching distance against gravity and normalized by target distance (-10° of full extension). The groups differed in elbow extension strength (Contracture, 0.315 ± 0.129; No contracture, 0.559 ± 0.153; p < 0.001) and flexion synergy (0.146 ± 0.186, 0.397 ± 0.229, p = 0.009). The groups did not differ in shoulder abduction strength (0.500 ± 0.174, 0.615 ± 0.199, p = 0.080), flexor spasticity (0.079 ± 0.090, 0.056 ± 0.115, p = 0.523), or reaching function (0.501 ± 0.391, 0.714 ± 0.296, p = 0.082). The findings of this study suggest a relationship between elbow contracture and the concurrent presence of elbow extension weakness and flexion synergy. The quantitative measure of reaching function will likely differentiate individuals with and without contracture if the assessment is modified so that the standardized reaching target is located at 0° of elbow extension (normal range). Future research should use quantitative metrics to further explore the temporal recovery of impairments in order to prevent the development of contracture.

scholarly journals Neck rotation modulates flexion synergy torques, indicating an ipsilateral reticulospinal source for impairment in stroke

2012 ◽  
Vol 108 (11) ◽  
pp. 3096-3104 ◽  
Author(s):  
Michael D. Ellis ◽  
Justin Drogos ◽  
Carolina Carmona ◽  
Thierry Keller ◽  
Julius P. A. Dewald
Keyword(s):  
Reticular Formation ◽  
Muscle Activation ◽  
External Rotation ◽  
Statistical Design ◽  
Head Rotation ◽  
Elbow Flexion ◽  
Shoulder Abduction ◽  
Joint Control ◽  
Age Range ◽  
Flexion Synergy

The effect of reticular formation excitability on maximum voluntary torque (MVT) generation and associated muscle activation at the shoulder and elbow was investigated through natural elicitation (active head rotation) of the asymmetric tonic neck reflex (ATNR) in 26 individuals with stroke and 9 age-range-matched controls. Isometric MVT generation at the shoulder and elbow was quantified with the head rotated (face pointing) contralateral and ipsilateral to the paretic (stroke) and dominant (control) arm. Given the dominance of abnormal torque coupling of elbow flexion with shoulder abduction (flexion synergy) in stroke and well-developed animal models demonstrating a linkage between reticular formation and ipsilateral elbow flexors and shoulder abductors, we hypothesized that constituent torques of flexion synergy, specifically elbow flexion and shoulder abduction, would increase with contralateral head rotation. The findings of this investigation support this hypothesis. Increases in MVT for three of four flexion synergy constituents (elbow flexion, shoulder abduction, and shoulder external rotation) were observed during contralateral head rotation only in individuals with stroke. Electromyographic data of the associated muscle coactivations were nonsignificant but are presented for consideration in light of a likely underpowered statistical design for this specific variable. This study not only provides evidence for the reemergence of ATNR following stroke but also indicates a common neuroanatomical link, namely, an increased reliance on ipsilateral reticulospinal pathways, as the likely mechanism underlying the expression of both ATNR and flexion synergy that results in the loss of independent joint control.

scholarly journals Assessing the usage of indirect motor pathways following a hemiparetic stroke

2020 ◽  
Author(s):  
Runfeng Tian ◽  
Julius P.A. Dewald ◽  
Yuan Yang
Keyword(s):  
Model Simulation ◽  
Brain Activity ◽  
Shoulder Abduction ◽  
Joint Control ◽  
Motor Pathways ◽  
Co Activation ◽  
Shoulder Abductor ◽  
Hemiparetic Stroke ◽  
Muscle Connectivity ◽  
Flexion Synergy

AbstractA hallmark impairment in a hemiparetic stroke is a loss of independent joint control resulting in abnormal co-activation of shoulder abductor and elbow flexor muscles in their paretic arm, clinically known as the flexion synergy. The flexion synergy appears while generating shoulder abduction (SABD) torques as lifting the paretic arm. This likely be caused by an increased reliance on contralesional indirect motor pathways following damage to direct corticospinal projections. The assessment of functional connectivity between brain and muscle signals, i.e., brain-muscle connectivity (BMC), may provide insight into such changes to the usage of motor pathways. Our previous model simulation shows that multi-synaptic connections along the indirect motor pathway can generate nonlinear connectivity. We hypothesize that increased usage of indirect motor pathways (as increasing SABD load) will lead to an increase of nonlinear BMC. To test this hypothesis, we measured brain activity, muscle activity from shoulder abductors when stroke participants generate 20% and 40% of maximum SABD torque with their paretic arm. We computed both linear and nonlinear BMC between EEG and EMG. We found dominant nonlinear BMC at contralesional/ipsilateral hemisphere for stroke, whose magnitude increased with the SABD load. These results supported our hypothesis and indicated that nonlinear BMC could provide a quantitative indicator for determining the usage of indirect motor pathways following a hemiparetic stroke.

scholarly journals Participants' Perspectives on the Feasibility of a Novel, Intensive, Task-Specific Intervention for Individuals With Chronic Stroke: A Qualitative Analysis

2013 ◽  
Vol 93 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Angela R. Merlo ◽  
Ashley Goodman ◽  
Bruce A. McClenaghan ◽  
Stacy L. Fritz
Keyword(s):  
Qualitative Analysis ◽  
Muscle Soreness ◽  
Therapeutic Option ◽  
Phenomenological Approach ◽  
Chronic Stroke ◽  
Qualitative Inquiry ◽  
Feasibility Trial ◽  
Future Research ◽  
Valuable Insight ◽  
Specific Intervention

BackgroundEvidence-based practice promotes patient-centered care, yet the majority of rehabilitative research fails to take patient perspectives into consideration. Qualitative research provides a unique opportunity for patients to express opinions and provide valuable insight on intervention processes.ObjectiveThe purpose of this study was to assess the feasibility of a novel, intensive, task-specific intervention from the patient's perspective.DesignA phenomenological approach to qualitative inquiry was used.MethodsEight individuals with chronic stroke participated in an intensive intervention, 3 hours per day for 10 consecutive days. Participants were interviewed twice regarding their impressions of the therapy, and a focus group was conducted with participants and family members. Data analysis included an analytical thematic approach.ResultsFive major themes arose related to the feasibility of the intervention: (1) a manageable amount of fatigue; (2) a difficult, yet doable, level of intensity; (3) a disappointingly short therapy duration; (4) enjoyment of the intervention; and (5) muscle soreness.ConclusionsThe findings suggest that participants perceived this novel and intensive, task-specific intervention as a feasible therapeutic option for individuals with chronic stroke. Despite the fatigue and muscle soreness associated with intensive rehabilitation, participants frequently reported enjoying the therapy and stated disappointment with the short duration (10 days). Future research should include a feasibility trial of longer duration, as well as a qualitative analysis of the benefits associated with the intervention.

Transfer of a Motor Fascicle From the Ulnar Nerve to the Branch of the Radial Nerve Destined to the Long Head of the Triceps for Restoration of Elbow Extension in Brachial Plexus Surgery

Neurosurgery ◽  
2011 ◽  
Vol 70 (2) ◽  
pp. E516-E520 ◽  
Author(s):  
Leandro Pretto Flores
Keyword(s):  
Computed Tomography ◽  
Brachial Plexus ◽  
Ulnar Nerve ◽  
Radial Nerve ◽  
Nerve Transfer ◽  
Elbow Flexion ◽  
Shoulder Abduction ◽  
Elbow Extension ◽  
Long Head ◽  
Brachial Plexus Surgery

Abstract BACKGROUND AND IMPORTANCE: Restoration of elbow extension has not been considered of much importance regarding functional outcomes in brachial plexus surgery; however, the flexion of the elbow joint is only fully effective if the motion can be stabilized, what can be achieved solely if the triceps brachii is coactivated. To present a novel nerve transfer of a healthy motor fascicle from the ulnar nerve to the nerve of the long head of the triceps to restore the elbow extension function in brachial plexus injuries involving the upper and middle trunks. CLINICAL PRESENTATION: Case 1 is a 32-year-old man sustaining a right brachial extended upper plexus injury in a motorcycle accident 5 months before admission. The computed tomography myelogram demonstrated avulsion of the C5 and C6 roots. Case 2 is a 24-year-old man who sustained a C5-C7 injury to the left brachial plexus in a traffic accident 4 months before admission. Computed tomography myelogram demonstrated signs of C6 and C7 root avulsion. The technique included an incision at the medial border of the biceps, in the proximal third of the involved arm, followed by identification of the ulnar nerve, the radial nerve, and the branch to the long head of the triceps. The proximal stump of a motor fascicle from the ulnar nerve was sutured directly to the distal stump of the nerve of the long head of the triceps. Techniques to restore elbow flexion and shoulder abduction were applied in both cases. Triceps strength Medical Research Council M4 grade was obtained in both cases. CONCLUSION: The attempted nerve transfer was effective for restoration of elbow extension in primary brachial plexus surgery; however, it should be selected only for cases in which other reliable donor nerves were used to restore elbow flexion.

scholarly journals Control Strategies for the Transition From Multijoint to Single-Joint Arm Movements Studied Using a Simple Mechanical Constraint

2000 ◽  
Vol 83 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Robert A. Scheidt ◽  
W. Zev Rymer
Keyword(s):  
Control Strategies ◽  
Human Subjects ◽  
Dynamic Performance ◽  
Activity Patterns ◽  
Adaptive Controller ◽  
Emg Activity ◽  
Joint Control ◽  
Primary Role ◽  
Joint Task ◽  
Normal Human

Changes were studied in neuromotor control that were evoked by constraining the motion of the elbow joint during planar, supported movements of the dominant arm in eight normal human subjects. Electromyograph (EMG) recordings from shoulder and arm muscles were used to determine whether the normal multijoint muscle activity patterns associated with reaching to a visual target were modified when the movement was reduced to a single-joint task, by pinning the elbow to a particular location in the planar work space. Three blocks of 150 movements each were used in the experiments. Subjects were presented with the unconstrained task in the first and third blocks with an intervening block of constrained trials. Kinematic, dynamic, and EMG measures of performance were compared across blocks. The imposition of the pin constraint caused predictable changes in kinematic performance, in that near-linear motions of the hand became curved. This was followed by changes in limb dynamic performance at the elbow. However, changes in EMG activity at the shoulder lagged the kinematic changes substantially (by about 15 trials). The gradual character of the changes in EMG timing does not support a primary role for segmental reflex action in mediating the transition between multijoint and single-joint control strategies. Furthermore, the scope and magnitude of these changes argues against the notion that human motor performance is driven by the optimization of muscle- or joint-related criteria alone. The findings are best described as reflecting the actions of a feedforward adaptive controller that has properties that are modified progressively according to the environmental state.

Research Status and Development Trends of Hazardous Materials Transportation

2011 ◽  
Vol 361-363 ◽  
pp. 1230-1239
Author(s):  
Zong Feng Zou ◽  
Bao Quan Zhang
Keyword(s):  
Hazardous Materials ◽  
Future Research ◽  
Joint Control ◽  
Large Area ◽  
Role Of Government ◽  
Hazardous Materials Transportation ◽  
Transportation Risk ◽  
Hazmat Transportation ◽  
Research Situation

The related issues of hazardous materials transportation in recent years are summarized and reviewed from the following aspects: hazardous materials transportation risk evaluation models, road routing models, the application of related technology, early warning for emergency response and joint action mechanism and platform construction, the research situation and development pattern of unified monitoring platform, etc. Analysis shows that it is essential to establish more in-depth and scientific quantitative models based on the attainment of more comprehensive and continuous data as well as the consideration of various constraints. It is a direction for future research to develop comprehensive application of technology and to establish HAZMAT transportation joint control platform in large area, and the leading and facilitating role of government should be paid more attention on joint control platform construction in large area.

Sign in / Sign up

Export Citation Format

Share Document