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ABSTRACT: An electromyography (EMG)-driven electromechanical robot system integrated with neuromuscular electrical stimulation (NMES) was developed for wrist training after stroke. The performance of the system in assisting wrist flexion/extension tracking was evaluated on five chronic stroke subjects, when the system provided five different schemes with or without NMES and robot assistance. The tracking performances were measured by range of motion (ROM) of the wrist and root mean squared error (RMSE). The performance is better when both NMES and robot assisted in the tracking than those with either NMES or robot only (P<0.05). The muscle co-contractions in the upper limb measured by EMG were reduced when NMES provided assistance (P<0.05). All subjects also attended a 20-session wrist training for evaluating the training effects (3-5 times/week). The results showed improvements on the voluntary motor functions in the hand, wrist and elbow functions after the training, as indicated by the clinical scores of Fugl-Meyer Assessment, Action Research Arm Test, Wolf Motor Function Test; and also showed reduced spasticity in the wrist and the elbow as measured by the Modified Ashworth Score of each subject. After the training, the co-contractions were reduced between the flexor carpi radialis and extensor carpi radialis, and between the biceps brachii and triceps brachii. Assistance from the robot helped improve the movement accuracy; and the NMES helped increase the muscle activation for the wrist joint and suppress the excessive muscular activities from the elbow joint. The NMES-robot assisted wrist training could improve the hand, wrist, and elbow functions.
Journal of electromyography and kinesiology: official journal of the International Society of Electrophysiological Kinesiology 01/2012; 22(3):431-9. · 2.00 Impact Factor
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ABSTRACT: In this work, a novel FES-robot system was developed for wrist rehabilitation training after stroke. The FES-robot system could be continuously controlled by electromyography (EMG) from the residual wrist muscles to facilitate wrist flexion and extension tracking tasks on a horizontal plane by providing assistance from both FES and robot parts. The system performance with five different assistive combinations from the FES and robot parts was evaluated by subjects with chronic stroke (n=5). The results suggested that the assistance from the robot part mainly improved the movement accuracy in the tracking tasks; and the assistance from the FES part mainly suppressed the excessive muscular activities from the elbow joint. The best combination was when the assistances from FES and robot was 1:1, and the results showed better wrist tracking performance with less muscle co-contraction from the elbow joint.
IEEE ... International Conference on Rehabilitation Robotics : [proceedings]. 06/2011; 2011:5975424.
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ABSTRACT: An exoskeleton hand robotic training device is specially designed for persons after stroke to provide training on their impaired hand by using an exoskeleton robotic hand which is actively driven by their own muscle signals. It detects the stroke person's intention using his/her surface electromyography (EMG) signals from the hemiplegic side and assists in hand opening or hand closing functional tasks. The robotic system is made up of an embedded controller and a robotic hand module which can be adjusted to fit for different finger length. Eight chronic stroke subjects had been recruited to evaluate the effects of this device. The preliminary results showed significant improvement in hand functions (ARAT) and upper limb functions (FMA) after 20 sessions of robot-assisted hand functions task training. With the use of this light and portable robotic device, stroke patients can now practice more easily for the opening and closing of their hands at their own will, and handle functional daily living tasks at ease. A video is included together with this paper to give a demonstration of the hand robotic system on chronic stroke subjects and it will be presented in the conference.
IEEE ... International Conference on Rehabilitation Robotics : [proceedings]. 06/2011; 2011:5975340.
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ABSTRACT: A LED was fabricated by first forming a porous region on a cast polycrystalline silicon substrate by anodization and then depositing a Au layer. Under forward bias, the LED was observed to have a stable yellowish white emission. Based on the measured spectra, it is proposed that the origin of the emission is due to microplasma formed in the depletion region of the heterojunction formed between the porous polysilicon layer and the polysilicon bulk. The results suggested that the cast polycrystalline substrate can be used for cheap and largearea applications in porous silicon devices.
International Journal of Electronics. 11/2010; October 1(1998):419-423.
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ABSTRACT: A functional electrical stimulation (FES)-robot system controlled by subjects' motor intention was developed in our previous study. The effectiveness of the FES-robot on wrist training was investigated in this work. Five hemiplegic subjects with chronic stroke were recruited for an FES-robot assisted wrist training with 20 sessions. After the training, motor improvements were found in the wrist and fingers, represented by significant increase (P<;;0.05) in clinical scores of the Fugl-Meyer Assessment (FMA), the Action Research Arm Test (ARAT), and the Modified Ashworth Score (MAS). Muscle coordination in the upper limb was also improved during the training as assessed by electromyography. The increased ARAT scores suggested improved upper limb motor functions, especially in the hand and fingers, compared to no improvement in previous study with only interactive robot-assisted wrist training without FES.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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ABSTRACT: A novel design of a hand functions task training robotic system was developed for the stroke rehabilitation. It detects the intention of hand opening or hand closing from the stroke person using the electromyography (EMG) signals measured from the hemiplegic side. This training system consists of an embedded controller and a robotic hand module. Each hand robot has 5 individual finger assemblies capable to drive 2 degrees of freedom (DOFs) of each finger at the same time. Powered by the linear actuator, the finger assembly achieves 55 degree range of motion (ROM) at the metacarpophalangeal (MCP) joint and 65 degree range of motion (ROM) at the proximal interphalangeal (PIP) joint. Each finger assembly can also be adjusted to fit for different finger length. With this task training system, stroke subject can open and close their impaired hand using their own intention to carry out some of the daily living tasks.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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ABSTRACT: A novel design of a hand functions task training robotic system was developed for the stroke rehabilitation. It detects the intention of hand opening or hand closing from the stroke person using the electromyography (EMG) signals measured from the hemiplegic side. This training system consists of an embedded controller and a robotic hand module. Each hand robot has 5 individual finger assemblies capable to drive 2 degrees of freedom (DOFs) of each finger at the same time. Powered by the linear actuator, the finger assembly achieves 55 degree range of motion (ROM) at the metacarpophalangeal (MCP) joint and 65 degree range of motion (ROM) at the proximal interphalangeal (PIP) joint. Each finger assembly can also be adjusted to fit for different finger length. With this task training system, stroke subject can open and close their impaired hand using their own intention to carry out some of the daily living tasks.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2010; 2010:3406-9.
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ABSTRACT: Functional electrical stimulation (FES) and rehabilitation robots are techniques used to assist in post-stroke rehabilitation. However, FES and rehabilitation robots are still separate systems currently; and their combined training effects on persons after experiencing a stroke have not been well studied yet. In this work, a new combined FES-robot system driven by user's voluntary intention was developed for wrist joint training after stroke. The performance of the FES-robot assisted wrist tracking was evaluated on five subjects with chronic stroke. With simultaneous assistance from both the FES and robot parts of the system, the motion accuracy was improved and excessive activation in elbow flexor was reduced during wrist tracking.
Studies in health technology and informatics 01/2010; 154:223-8.
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ABSTRACT: A functional electrical stimulation (FES)-robot system controlled by subjects' motor intention was developed in our previous study. The effectiveness of the FES-robot on wrist training was investigated in this work. Five hemiplegic subjects with chronic stroke were recruited for an FES-robot assisted wrist training with 20 sessions. After the training, motor improvements were found in the wrist and fingers, represented by significant increase (P < 0.05) in clinical scores of the Fugl-Meyer Assessment (FMA), the Action Research Arm Test (ARAT), and the Modified Ashworth Score (MAS). Muscle coordination in the upper limb was also improved during the training as assessed by electromyography. The increased ARAT scores suggested improved upper limb motor functions, especially in the hand and fingers, compared to no improvement in previous study with only interactive robot-assisted wrist training without FES.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2010; 2010:5819-22.
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ABSTRACT: Restoring hand functions may greatly improve the post-stroke life quality. In this work, we developed a new interactive rehabilitation robot for hand function training after stroke. The robotic system can provide three modes of training: (1) continuous passive motion; (2) electromyography (EMG)-triggered motion; and (3) continuous EMG-driven motion to simulate the hand opening, grip and pinch tasks. The system also can quantitatively record finger force, finger positions, and EMG during training tasks.
Rehabilitation Robotics, 2009. ICORR 2009. IEEE International Conference on; 07/2009
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ABSTRACT: The effect of using robots to improve motor recovery has received increased attention, while the treatment effectiveness remains a topic of study. We compared the training effects by treatments on the wrist joint of chronic stroke patients with an electromyography (EMG)-driven robot (interactive group, n = 15) and a robot with continuous passive motion (passive group, n = 12) by a randomized controlled trial. The interactive treatment with the EMG-driven robot improved the motor function for both the wrist and elbow joints in muscle coordination and spasticity reduction after the training, which could be kept for 3 months. The passive mode training mainly reduced the spasticity in the wrist flexor, but did not contribute to the muscle coordination improvement.
Rehabilitation Robotics, 2009. ICORR 2009. IEEE International Conference on; 07/2009
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ABSTRACT: This study was to extend previous neuromusculoskeletal modeling efforts through combining the in vivo ultrasound-measured musculotendon parameters on persons after stroke.
A subject-specific neuromusculoskeletal model of the elbow was developed to predict the individual muscle force during dynamic movement and then validated by joint trajectory. The model combined a geometrical model and a Hill-type musculotendon model, and used subject-specific musculotendon parameters as inputs. EMG signals and joint angle were recorded from healthy control subjects (n=4) and persons after stroke (n=4) during voluntary elbow flexion in a vertical plane. Ultrasonography was employed to measure the muscle optimal length and pennation angle of each prime elbow flexor (biceps brachii, brachialis, brachioradialis) and extensor (three heads of triceps brachii). Maximum isometric muscle stresses of the flexor and extensor muscle group were calibrated by minimizing the root mean square difference between the predicted and measured maximum isometric torque-angle curves. These parameters were then inputted into the neuromusculoskeletal model to predict the individual muscle force using the input of EMG signals directly without any trajectory fitting procedure involved.
The results showed that the prediction of voluntary flexion in the hemiparetic group using subject-specific parameters data was better than that using cadaveric data extracted from the literature.
The results demonstrated the feasibility of using EMG-driven neuromusculoskeletal modeling with direct ultrasound measurement for the prediction of voluntary elbow movement for both subjects without impairment and persons after stroke.
Clinical biomechanics (Bristol, Avon) 12/2008; 24(1):101-9. · 1.76 Impact Factor
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ABSTRACT: The motor recovery procedure during robot-assisted wrist rehabilitation for persons after stroke has not been well studied previously. In this work, we carried out a comparative study on the training effects on 10 hemiplegic persons with chronic stroke between a wrist treatment assisted by an electromyography (EMG)-driven robotic system (interactive treatment, n=5, EMG group) and a wrist treatment assisted by a clinical robot system with continuous passive motion (n=5, passive group). Significant decreases (P < 0.05) in muscle spasticity were observed at the wrist joint in both the EMG and passive groups; and reduced muscle spasticity at the elbow joint were also obtained in the EMG group (P < 0.05). These spasticity decreases were associated with the reduction of EMG activation levels during the training. The EMG-driven robot-assisted training also improved the muscle coordination capability of the persons after stroke.
Biomedical Robotics and Biomechatronics, 2008. BioRob 2008. 2nd IEEE RAS & EMBS International Conference on; 11/2008
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ABSTRACT: Robot and functional electrical stimulation (FES) techniques have been used for improving motor functions after stroke respectively. In this work, we aimed to examine the combined effects from Robot and FES in post-stroke wrist rehabilitation. We developed a new electromyography (EMG)-driven FES-robot system with a control algorithm, which was interactive to the voluntary motor inputs from persons after stroke. Two hemiplegic subjects with chronic stroke were recruited to test the EMG-driven FES-robot system. The results demonstrated that the integrated system was effective in improving the tracking performance represented by root mean squared error (RMSE) and root mean squared jerk (RMSJ) of tracking trajectories in programmed wrist tracking tasks assisted with different proportions of the interactive supports from the FES and robot parts respectively. This combined system may have the potential to be applied in stroke rehabilitation.
Biomedical Robotics and Biomechatronics, 2008. BioRob 2008. 2nd IEEE RAS & EMBS International Conference on; 11/2008
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ABSTRACT: This study was to investigate the motor functional recovery process in chronic stroke during robot-assisted wrist training. Fifteen subjects with chronic upper extremity paresis after stroke attended a 20-session wrist tracking training using an interactive rehabilitation robot. Electromyographic (EMG) parameters, i.e., EMG activation levels of four muscles: biceps brachii (BIC), triceps brachii (TRI, lateral head), flexor carpiradialis (FCR), and extensor carpiradialis (ECR) and their co-contraction indexes (CI) were used to monitor the neuromuscular changes during the training course. The EMG activation levels of the FCR (11.1% of decrease from the initial), BIC (17.1% of decrease from the initial), and ECR (29.4% of decrease from the initial) muscles decreased significantly during the training (P<0.05). Such decrease was associated with decreased Modified Ashworth Scores for both the wrist and elbow joints (P<0.05). Significant decrease (P<0.05) was also found in CIs of muscle pairs, BIC&TRI (21% of decrease from the initial), FCR&BIC (11.3% of decrease from the initial), ECR&BIC (49.3% of decrease from the initial). The decreased CIs related to the BIC muscle were mainly caused by the reduction in the BIC EMG activation level, suggesting a better isolation of the wrist movements from the elbow motions. The decreased CI of ECR& FCR in the later training sessions (P<0.05) was due to the reduced co-contraction phase of the antagonist muscle pair in the tracking tasks. Significant improvements (P<0.05) were also found in motor outcomes related to the shoulder/elbow and wrist/hand scores assessed by the Fugl-Meyer assessment before and after the training. According to the evolution of the EMG parameters along the training course, further motor improvements could be obtained by providing more training sessions, since the decreases of the EMG parameters did not reach a steady state before the end of the training. The results in this study provided an objective and quantitative EMG measure to describe the motor recovery process during poststroke robot-assisted wrist for the further understanding on the neuromuscular mechanism associated with the recovery.
Journal of electromyography and kinesiology: official journal of the International Society of Electrophysiological Kinesiology 05/2008; 19(4):639-50. · 2.00 Impact Factor
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ABSTRACT: This study was to investigate the properties of mechanomyography (MMG), or muscle sound, of the paretic muscle in the affected side of hemiplegic subjects after stroke during isometric voluntary contractions, in comparison with those from the muscle in the unaffected side of the hemiplegic subjects and from the healthy muscle of unimpaired subjects. MMG and electromyography (EMG) signals were recorded simultaneously from the biceps brachii muscles of the dominant arm of unimpaired subjects (n=5) and the unaffected and affected arms of subjects after stroke (n=8), when performing a fatiguing maximal voluntary contraction (MVC) associated with the decrease in elbow flexion torque, and then submaximal elbow flexions at 20%, 40%, 60% and 80% MVCs. The root mean squared (RMS) values, the mean power frequencies (MPF, in the power density spectrum, PDS) of the EMG and MMG, and the high frequency rate (HF-rate, the ratio of the power above 15Hz in the MMG PDS) were used for the analysis. The MMG RMS decreased more slowly during the MVC in the affected muscle compared to the healthy and unaffected muscles. A transient increase could be observed in the MMG MPFs from the unaffected and healthy muscles during the MVC, associated with the decrease in their simultaneous EMG MPFs due to the muscular fatigue. No significant variation could be seen in the EMG and MMG MPFs in the affected muscles during the MVC. The values in the MPF and HF-rate of MMG from the affected muscles were significantly lower than those from the healthy and unaffected muscles (P<0.05) at the high contraction level (80% MVC). Both the MMG and EMG RMS values in the healthy and unaffected groups were found to be significantly higher than the affected group (P<0.05) at 60% and 80% MVCs. These observations were related to an atrophy of the fast-twitch fibers and a reduction of the neural input in the affected muscles of the hemiplegic subjects. The results in this study suggested MMG could be used as a complementary to EMG for the analysis on muscular characteristics in subjects after stroke.
Journal of Electromyography and Kinesiology 08/2007; 17(4):473-83. · 1.97 Impact Factor
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ABSTRACT: This study described the operation of the myoelectrically controlled robotic system designed to assist wrist movement in a horizontal plane for patients after stroke. Electromyographic (EMG) signals from flexor carpi radialis (FCR), extensor carpi radialis (ECR) detecting subject's intention are used to control the mechanical assistance from the robotic system either to assist wrist flexion and wrist extension. This study had recruited five subjects after stroke. The results revealed that the range of motion (ROM) in the five subjects increased with the assistance of the myoelectrically controlled robotic system. The amplitude of agonist EMG signal decreased with the increase of assistance, which might reflect less effort was needed for the subject to perform the movement. This study demonstrates that it is feasible to apply myoelectrically controlled robotic system to provide substantial external torque to the affected wrist joint for subjects after stroke. Its therapeutic effect will be further investigated during stroke rehabilitation.
Rehabilitation Robotics, 2007. ICORR 2007. IEEE 10th International Conference on; 07/2007
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ABSTRACT: The motor recovery procedure during robot-assisted wrist rehabilitation for persons after stroke has not been well studied previously. In this work, we analyzed the variations in the muscular co-activation patterns related to the wrist and elbow motions in hemiplegic persons with chronic stroke (n=4) during a 20-session's interactive robot-assisted training. Significant decreases in muscle cocontractions (P<0.05) for all muscle pairs were observed, which was mainly due to the reduction in the muscle activation levels. Improvements were also found in motor functions assessed by clinical scales before and after the training. The results suggested an increased selective control on individual muscles for both wrist and elbow joints in a designed task after the robot-assisted training.
Rehabilitation Robotics, 2007. ICORR 2007. IEEE 10th International Conference on; 07/2007
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ABSTRACT: An analytical model has been proposed for multilayer stacked on-chip transformers, including the effects of the eddy current losses in the metal layers and Si substrate. The model gives good agreement with S-parameter measurements on structures fabricated using a four-metal-layer 0.35 mum CMOS process. It is shown that proper account of the eddy current losses is necessary to predict accurately the S-parameter characteristics of on-chip transformers at higher frequencies
IEE Proceedings - Microwaves Antennas and Propagation 11/2006; · 0.49 Impact Factor
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ABSTRACT: The motor recovery procedure of chronic stroke during robot-assisted training has not been well studied previously. In this work, we analyzed the variations in the coactivating patterns of elbow and shoulder muscles (biceps, triceps lateral, anterior deltoid, and posterior deltoid) in hemiplegic persons with chronic stroke (n=4) during a 20-session's interactive robot-assisted treatment. Significant decreases in muscle cocontractions (P<0.05) for all muscle pairs started from the 8<sup>th</sup> session of the training. Improvements were also observed in motor scores of Fugl-Meyer and modified Ashworth scale after the treatment. The results suggested an increased dexterity and selective control on individual muscles for both elbow and shoulder joints in a designed task after the robot-assisted training
Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE; 10/2006
