Shoulder abduction loading affects motor coordination in individuals with chronic stroke, informing targeted rehabilitation

Background A comprehensive scale assessing motor coordination of multiple body segments was developed using a 3-phase content validation process. The Comprehensive Coordination Scale (CCS) evaluates motor coordination defined as the ability to produce context-dependent movements of multiple effectors in both spatial and temporal domains. The scale assesses motor coordination in individuals with neurological injuries at 2 levels of movement description: the motor performance level describes end point movements (ie, hand, foot), and the movement quality level describes limb joints/trunk movements contributing to end point movement. Objective To determine measurement properties of the scale in people with chronic stroke. Methods Standardized approaches determined the internal consistency (factor loadings), intrarater and interrater reliability (interclass correlation coefficient), measurement error (SEM; minimal detectable change [MDC]), construct validity, and interpretability (ie, ceiling and floor effects) of the CCS. Results Data from 30 patients with chronic stroke were used for the analysis. The internal consistency of the scale was high (0.94), and the scale consisted of separate factors characterizing end point motor performance and movement quality. Intrarater (intraclass correlation coefficient [ICC] = 0.97-0.97) and interrater (ICC=0.76-0.98) reliability of the whole scale and subscales were good to excellent. The CCS had an SEM of 1.80 points (total score = 69 points) and an MDC95 of 4.98 points. The CCS total score was related to Fugl-Meyer Assessment total and motor scores and had no ceiling or floor effects. Conclusions The CCS scale has strong measurement properties and may be a useful measure of spatial and temporal coordination deficits in chronic stroke survivors.

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Increased shoulder abduction loads decreases volitional finger extension in individuals with chronic stroke: Preliminary findings

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society ◽

10.1109/embc.2014.6944948 ◽

2014 ◽

Cited By ~ 1

Author(s):

Yiyun Lan ◽

Jun Yao ◽

Jules Dewald

Keyword(s):

Chronic Stroke ◽

Shoulder Abduction ◽

Finger Extension

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Coupling of shoulder joint torques in individuals with chronic stroke mirrors controls, with additional non-load-dependent negative effects in a combined-torque task

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-021-00924-1 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Joseph V. Kopke ◽

Levi J. Hargrove ◽

Michael D. Ellis

Keyword(s):

Task Performance ◽

Internal Rotation ◽

Dual Task ◽

External Rotation ◽

Load Level ◽

Chronic Stroke ◽

Shoulder Abduction ◽

Dual Tasks ◽

Joint Torques ◽

Co Activation

Abstract Background After stroke, motor control is often negatively affected, leaving survivors with less muscle strength and coordination, increased tone, and abnormal synergies (coupled joint movements) in their affected upper extremity. Humeral internal and external rotation have been included in definitions of abnormal synergy but have yet to be studied in-depth. Objective Determine the ability to generate internal and external rotation torque under different shoulder abduction and adduction loads in persons with chronic stroke (paretic and non-paretic arm) and uninjured controls. Methods 24 participants, 12 with impairments after stroke and 12 controls, completed this study. A robotic device controlled abduction and adduction loading to 0, 25, and 50% of maximum strength in each direction. Once established against the vertical load, each participant generated maximum internal and external rotation torque in a dual-task paradigm. Four linear mixed-effects models tested the effect of group (control, non-paretic, and paretic), load (0, 25, 50% adduction or abduction), and their interaction on task performance; one model was created for each combination of dual-task directions (external or internal rotation during abduction or adduction). The protocol was then modeled using OpenSim to understand and explain the role of biomechanical (muscle action) constraints on task performance. Results Group was significant in all task combinations. Paretic arms were less able to generate internal and external rotation during abduction and adduction, respectively. There was a significant effect of load in three of four load/task combinations for all groups. Load-level and group interactions were not significant, indicating that abduction and adduction loading affected each group in a similar manner. OpenSim musculoskeletal modeling mirrored the experimental results of control and non-paretic arms and also, when adjusted for weakness, paretic arm performance. Simulations incorporating increased co-activation mirrored the drop in performance observed across all dual-tasks in paretic arms. Conclusion Common biomechanical constraints (muscle actions) explain limitations in external and internal rotation strength during adduction and abduction dual-tasks, respectively. Additional non-load-dependent effects such as increased antagonist co-activation (hypertonia) may cause the observed decreased performance in individuals with stroke. The inclusion of external rotation in flexion synergy and of internal rotation in extension synergy may be over-simplifications.

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

Stroke ◽

10.1161/str.51.suppl_1.tp147 ◽

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.

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