Dissociating Sensorimotor Recovery and Compensation During Exoskeleton Training Following Stroke

Axial load transmission through the elbow during forearm rotation

Three-dimensional reaching tasks: Effect of reaching height and width on upper limb kinematics and muscle activity

IntroductionMore knowledge of the relationships between kinematic measures and clinical assessments is required to guide clinical decision making and future research.ObjectivesTo determine which kinematic variables obtained during a drinking task were associated with clinical assessments of upper extremity functioning in people with spinal cord injury (SCI).MethodsIn total, 25 individuals with chronic cervical (n = 17) or thoracic (n = 8) complete (n = 14) or motor incomplete (n = 11) SCI (mean age 58.4, SD 13.8) were included. Kinematic data, including movement time, smoothness and joint angles was captured with a 5-camera optoelectronic system during a unimanual drinking task. Action Research Arm Test (ARAT), Sollerman Hand Function Test (SHFT) and basic hand classification of the Upper Extremity Data Set (ISCI-Hand) were used as clinical assessments. Multiple regression analysis was used to identify kinematic variables associated with clinical assessments after controlling for potential confounding factors, such as, age, severity of SCI, sensory function, and hand surgery.ResultsMovement time, smoothness and movement pattern kinematics including trunk displacement, elbow and wrist joint angles were correlated (p < 0.05) with all three clinical scales while the velocity-related kinematics and inter-joint coordination showed low correlations. Multiple regression analysis revealed that wrist angle combined with movement time or smoothness explained 82% and 77% of the total variance in ARAT and SHFT, respectively. Wrist angle alone explained 59% of the variance in ISCI-Hand. The proprioception of the hand increased the explanatory power in the models of ARAT and SHFT. Associations between kinematics and clinical assessments in the subgroup with cervical SCI were equivalent to the whole group analyses. The number of participants in the subgroup with thoracic SCI was small and only allowed limited analysis.ConclusionsWrist angle, movement time, movement smoothness are the most important kinematic variables associated with upper extremity clinical assessments in people with SCI. The results are most valid for individuals with cervical SCI. All three assessments are appropriate for SCI. Further research with larger representative sample of thoracic SCI needed.

The rehabilitation process for the upper extremities of individuals with stroke requires therapists to use splints for supportive and corrective purposes. The aim of this study was to assess the effectiveness of spiral strapping in inhibiting spasticity and improving the upper extremity motor functions of individuals with chronic stroke. Forty Saudi individuals aged 50-60 years with chronic stroke participated in this study. Their degrees of spasticity according to the Modified Ashworth Scale ranged across grades 1, 1+, and 2. Participants were randomly assigned to experimental and control groups. Participants in both groups received 1 h of conventional physical therapy for 3 d/wk to improve the motor functions of their upper extremities. In addition, participants in the experimental group wore an upper-limb spiral strapping with a hand splint 10 h/d for 6 d/wk. The treatment program for both groups was delivered for 4 weeks. Changes in the scores of Action Research Arm Test for elbow joint spasticity, active range of motion of the shoulder, elbow, and forearm joints, and hand grip strength were evaluated before and after treatment in both groups. Significant improvements in all measured variables after treatment were reported in both groups, except for elbow joint spasticity in the control group. The experimental group showed significant post-treatment improvement in the scores for all measured variables compared with the control group. Spiral strapping was beneficial in inhibiting mild degrees of spasticity and improving the motor functions of the upper extremities of stroke patients.

Repeatability of upper limb kinematics for children with and without cerebral palsy

Proper scapulothoracic motion is critical for the health and function of the shoulder and represents a principal focus in the rehabilitation setting. Variants of the traditional push-up are used frequently to help restore proper scapular kinematics. To date, substantial research has focused on muscle activation levels of rotator cuff and scapular-stabilizing musculature, whereas a dearth of literature exists regarding scapular kinematics during push-up variants. To examine the effect of shoulder position on scapular kinematics across the range of motion (ROM) of a traditional push-up. Cross-sectional study. University laboratory. Sixteen healthy participants without a history of upper extremity or spine injury requiring rehabilitation or surgery. Participants performed a traditional push-up while kinematic measurements were acquired from multiple upper extremity segments. The 3 shoulder position conditions were (1) self-selected position, (2) shoulder adducted upon ascent (at side), and (3) shoulder elevated to approximately 90°. Scapular posterior tilt, upward rotation, and external rotation were examined across elbow-extension ROM and compared across conditions. Posterior tilt was greater in the self-selected and at-side conditions than in the elevated condition and increased linearly with elbow extension. External rotation was greater in the self-selected and at-side conditions compared with that in the elevated condition. In the at-side condition, upward rotation began lower than in the other conditions at the start of the concentric phase but increased above the others soon after the elbow started to extend. Performing a traditional push-up with the shoulders elevated may place the scapula in a position of impingement. Clinicians should be cognizant of shoulder elevation when prescribing and monitoring exercise progression. The results of this study will provide further direction for clinicians in prescribing rehabilitation exercises for the upper extremity, especially closed chain exercises for shoulder conditions.

Objective: Movement impairments such as those due to stroke often result in the nervous system adopting atypical movements to compensate for movement deficits. Monitoring these compensatory patterns is critical for improving functional outcomes during rehabilitation. The purpose of this study was to test the feasibility and validity of a wearable sensor system for detecting compensatory trunk kinematics during activities of daily living. Approach: Participants with no history of neurological impairments performed reaching and manipulation tasks with their upper extremity, and their movements were recorded by a wearable sensor system and validated using a motion capture system. Compensatory movements of the trunk were induced using a brace that limited range of motion at the elbow. Main results: Our results showed that the elbow brace elicited compensatory movements of the trunk during reaching tasks but not manipulation tasks, and that a wearable sensor system with two sensors could reliably classify compensatory movements (~90% accuracy). Significance: These results show the potential of the wearable system to assess and monitor compensatory movements outside of a lab setting.

This study, conducted in a group of nine chronic patients with right-side hemiparesis after stroke, investigated the effects of a robotic-assisted rehabilitation training with an upper limb robotic exoskeleton for the restoration of motor function in spatial reaching movements. The robotic assisted rehabilitation training was administered for a period of 6 weeks including reaching and spatial antigravity movements. To assess the carry-over of the observed improvements in movement during training into improved function, a kinesiologic assessment of the effects of the training was performed by means of motion and dynamic electromyographic analysis of reaching movements performed before and after training. The same kinesiologic measurements were performed in a healthy control group of seven volunteers, to determine a benchmark for the experimental observations in the patients’ group. Moreover degree of functional impairment at the enrolment and discharge was measured by clinical evaluation with upper limb Fugl-Meyer Assessment scale (FMA, 0–66 points), Modified Ashworth scale (MA, 0–60 pts) and active ranges of motion. The robot aided training induced, independently by time of stroke, statistical significant improvements of kinesiologic (movement time, smoothness of motion) and clinical (4.6 ± 4.2 increase in FMA, 3.2 ± 2.1 decrease in MA) parameters, as a result of the increased active ranges of motion and improved co-contraction index for shoulder extension/flexion. Kinesiologic parameters correlated significantly with clinical assessment values, and their changes after the training were affected by the direction of motion (inward vs. outward movement) and position of target to be reached (ipsilateral, central and contralateral peripersonal space). These changes can be explained as a result of the motor recovery induced by the robotic training, in terms of regained ability to execute single joint movements and of improved interjoint coordination of elbow and shoulder joints.

BackgroundCompensatory movements are commonly employed by stroke survivors during seated reaching and may have negative effects on their long-term recovery. Detecting compensation is useful for coaching the patient to reduce compensatory trunk movements and improving the motor function of the paretic arm. Sensor-based and camera-based systems have been developed to detect compensatory movements, but they still have some limitations, such as causing object obstructions, requiring complex setups and raising privacy concerns. To overcome these drawbacks, this paper proposes a compensatory movement detection system based on pressure distribution data and is unobtrusive, simple and practical. Machine learning algorithms were applied to classify compensatory movements automatically. Therefore, the purpose of this study was to develop and test a pressure distribution-based system for the automatic detection of compensation movements of stroke survivors using machine learning algorithms.MethodsEight stroke survivors performed three types of reaching tasks (back-and-forth, side-to-side, and up-and-down reaching tasks) with both the healthy side and the affected side. The pressure distribution data were recorded, and five features were extracted for classification. The k-nearest neighbor (k-NN) and support vector machine (SVM) algorithms were applied to detect and categorize the compensatory movements. The surface electromyography (sEMG) signals of nine trunk muscles were acquired to provide a detailed description and explanation of compensatory movements.ResultsCross-validation yielded high classification accuracies (F1-score>0.95) for both the k-NN and SVM classifiers in detecting compensation movements during all the reaching tasks. In detail, an excellent performance was achieved in discriminating between compensation and noncompensation (NC) movements, with an average F1-score of 0.993. For the multiclass classification of compensatory movement patterns, an average F1-score of 0.981 was achieved in recognizing the NC, trunk lean-forward (TLF), trunk rotation (TR) and shoulder elevation (SE) movements.ConclusionsGood classification performance in detecting and categorizing compensatory movements validated the feasibility of the proposed pressure distribution-based system. Reliable classification accuracy achieved by the machine learning algorithms indicated the potential to monitor compensation movements automatically by using the pressure distribution-based system when stroke survivors perform seated reaching tasks.

This paper presents the results of a preliminary assessment study to investigate baseline performance measures and differences between control and stroke participants during reaching tasks in three directions. H-Man, planar robot is, used for this purpose. Thirteen healthy and two chronic stroke patients with upper limb motor impairment participated in the study. Assessment of performance was made through three task parameters (smoothness of movement, peak velocity, and time to peak velocity). The results from healthy subjects indicate no significant difference between different directions, however significant differences are observed in stroke participants across different directions for smoothness measure (Spectral Arc Length). All the three measures show significant differences between control and Stroke participants for corresponding directions.

Clinical evaluation of valgus elbow laxity is difficult. The optimum position of elbow flexion and forearm rotation with which to identify valgus laxity in a patient with an injury of the ulnar collateral ligament of the elbow has not been determined. The purpose of the present study was to determine the effect of forearm rotation and elbow flexion on valgus elbow laxity. Twelve intact cadaveric upper extremities were studied with a custom elbow-testing device. Laxity was measured with the forearm in pronation, supination, and neutral rotation at 30 degrees, 50 degrees, and 70 degrees of elbow flexion with use of 2 Nm of valgus torque. Testing was conducted with the ulnar collateral ligament intact, with the joint vented, after cutting of the anterior half (six specimens) or posterior half (six specimens) of the anterior oblique ligament of the ulnar collateral ligament, and after complete sectioning of the anterior oblique ligament. Laxity was measured in degrees of valgus angulation in different positions of elbow flexion and forearm rotation. There were no significant differences in valgus laxity with respect to elbow flexion within each condition. Overall, for both groups of specimens (i.e., specimens in which the anterior or posterior half of the anterior oblique ligament was cut), neutral forearm rotation resulted in greater valgus laxity than pronation or supination did (p < 0.05). Transection of the anterior half of the anterior oblique ligament did not significantly increase valgus laxity; however, transection of the posterior half resulted in increased valgus laxity in some positions. Full transection of the anterior oblique ligament significantly increased valgus laxity in all positions (p < 0.05). The results of this in vitro cadaveric study demonstrated that forearm rotation had a significant effect on varus-valgus laxity. Laxity was always greatest in neutral forearm rotation throughout the ranges of elbow flexion and the various surgical conditions. The information obtained from the present study suggests that forearm rotation affects varus-valgus elbow laxity. Additional investigation is warranted to determine if forearm rotation should be considered in the evaluation and treatment of ulnar collateral ligament injuries of the elbow joint.

An intact distal radioulnar joint (DRUJ) is essential for normal functioning of the upper limb. Osteoarthritis of the DRUJ often leads to ulnar wrist pain, limitation of forearm rotation and reduced grip strength, all of which limit activities of daily living. Once the joint is damaged, salvage procedures are recommended. Between 1986 and 1996 a modified Sauvé-Kapandji procedure was performed in 117 patients with painfully limited forearm rotation and osteoarthritis of the distal radioulnar joint (DRUJ). Of the 117 patients, 73 women and 32 men, whose ages at operation ranged from 22 to 74 years (average 58 years), were retrospectively reviewed clinically and radiologically 8 years (range 5-12 years) after the operation. The DASH questionnaire was used with 53 patients, 43 patients were accepted for the study, and 10 were excluded. Forearm rotation improved in all patients, ulnar wrist pain was reduced in 97% of the patients, and 9% had mild pain at the proximal ulnar stump. Grip strength improved from a preoperative mean of 38% to a postoperative mean of 55% compared with the contralateral side. The mean DASH score was 28 points (range 0-53 points). In all cases the arthrodesis fused within 8 weeks. The radiographs showed approximation between the proximal ulna stump and the radius compared with the preoperative situation in 74% of the patients. Our clinical and radiological findings suggest that the Sauvé-Kapandji procedure is indicated in symptomatic, non-reconstructable disorders of the DRUJ. The DASH questionnaire provides a general view of the functional outcome after the Sauvé-Kapandji procedure. The DASH questionnaire is very helpful in evaluating the effect of the Sauvé-Kapandji procedure on the entire upper limb.

Many stroke survivors experience persistent upper extremity impairment that limits performance in activities of daily living. Upper limb recovery requires high repetitions of task-specific practice. Stroke survivors are often prescribed task practices at home to supplement rehabilitation therapy. A poor quality of task practices, such as the use of compensatory movement patterns, results in maladaptive neuroplasticity and suboptimal motor recovery. There currently lacks a tool for the remote monitoring of movement quality of stroke survivors' task practices at home. The objective of this study was to evaluate the feasibility of classifying movement quality at home using a wearable IMU. Nineteen stroke survivors wore an IMU sensor on the paretic wrist and performed four functional upper limb tasks in the lab and later at home while videorecording themselves. The lab data served as reference data to classify home movement quality using dynamic time warping. Incorrect and correct movement quality was labeled by a therapist. The home task practice movement quality was classified with an accuracy of 92% and F1 score of 0.95 for all tasks combined. Movement types contributing to misclassification were further investigated. The results support the feasibility of a home movement quality monitoring system to assist with upper limb rehabilitation post stroke.

We studied coordination of central motor commands (СMCs) coming to muscles of the shoulder and shoulder belt in the course of single-joint and two-joint movements including flexion and extension of the elbow and shoulder joints. Characteristics of rectified and averaged EMGs recorded from a few muscles of the upper limb were considered correlates of the CMC parameters. Special attention was paid to coordination of CMCs coming to two-joint muscles that are able to function as common flexors (m. biceps brachii, caput breve, BBcb) and common extensors (m. triceps brachii, caput longum, TBcl) of the elbow and shoulder joints. Upper limb movements used in the tests included planar shifts of the arm from one spatial point to another resulting from either simultaneous changes in the angles of the shoulder and elbow joints or isolated sequential (two-stage) changes in these joint angles. As was found, shoulder muscles providing movements of the elbow with changes in the angle of the elbow joint, i.e., BBcb and TBcl, were also intensely involved in the performance of single-joint movements in the shoulder joint. The CMCs coming to two-joint muscles in the course of two-joint movements appeared, in the first approximation, as sums of the commands received by these muscles in the course of corresponding single-joint movements in the elbow and shoulder joints. Therefore, if we interpret the isolated forearm movement performed due to a change in the angle of the elbow joint as the main motor event, while the shoulder movement is considered the accessory one, we can conclude that realization of a two-joint movement of the upper-limb distal part is based on superposition of CMCs related to basic movements (main and accessory).

Objective To systematically compare the efficacy of perpendicular plating versus parallel plating in the treatment of intercondylar humeral fractures. Methods Such databases as PubMed, EMbase, Cochrane Library, Chinese Biomedical Literature Database, WANFANG database and China National Knowledge Infrastructure were searched from their establishment to September 2014 for the randomized controlled trials (RCTs) investigating perpendicular plating versus parallel plating in the treatment of intercondylar humeral fractures. The references of the RCTs included were also searched by hand. The retrieved RCTs were screened by inclusion and exclusion criteria before data extraction and quality assessment. The meta-analyses were performed using the software RevMan5.1. The level of evidence was assessed by the GRADE system. Results Eight RCTs involving 389 patients were included. The meta-analyses showed no statistically significant differences between perpendicular plating and parallel plating in operation time, fracture healing time, postoperative complications, elbow flexion and extension, forearm rotation, postoperative Mayo Elbow Performance Score or Cassebaum score (P > 0.05). According to the GRADE system, all the evidence was at intermediate level and for moderate recommendation. Conclusions Both perpendicular plating and parallel plating can lead to similarly effective treatment of intercondylar humeral fractures. Both of them can achieve stable fixation. Key words: Humeral fractures; Elbow joint; Fracture fixation, internal; Meta-analysis