Design of Myocontrolled Neuroprosthesis

2014 ◽  
pp. 275-303 ◽  
Author(s):  
Emilia Ambrosini ◽  
Simona Ferrante ◽  
Alessandro Pedrocchi
Keyword(s):  
Electrical Stimulation ◽  
Muscle Activity ◽  
Voluntary Movement ◽  
Control Strategies ◽  
Point Of View ◽  
Therapeutic Effects ◽  
Emg Signal ◽  
Stimulation Parameters ◽  
Neurological Patients ◽  
Clinical Environments

Recent studies suggest that the therapeutic effects of Functional Electrical Stimulation (FES) are maximized when the patterned electrical stimulation is delivered in close synchrony with the attempted voluntary movement. FES systems that modulate stimulation parameters based on the residual volitional muscle activity would assure this combination. However, the development of such a system might be not trivial, both from a hardware and a software point of view. This chapter provides an extensive overview of devices and filtering solutions proposed in the literature to estimate the residual volitional EMG signal in the presence of electrical stimulation. Different control strategies to modulate FES parameters as well as the results of the first studies involving neurological patients are also presented. This chapter provides some guidelines to help people who want to design innovative myocontrolled neuroprostheses and might favor the spread of these solutions in clinical environments.

scholarly journals A foot drop compensation device based on surface multi-field functional electrical stimulation—Usability study in a clinical environment

2019 ◽  
Vol 6 ◽  
pp. 205566831986214
Author(s):  
Eukene Imatz-Ojanguren ◽  
Gema Sánchez-Márquez ◽  
Jose Ramón Asiain-Aristu ◽  
Joxean Cueto-Mendo ◽  
Edurne Jaunarena-Goicoechea ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Brain Injury ◽  
Functional Electrical Stimulation ◽  
Foot Drop ◽  
Average Score ◽  
Therapeutic Effects ◽  
Usability Study ◽  
Clinical Environment ◽  
System Usability Scale ◽  
Clinical Environments

Introduction Functional electrical stimulation applies electrical pulses to the peripheral nerves to artificially achieve a sensory/motor function. When applied for the compensation of foot drop it provides both assistive and therapeutic effects. Multi-field electrodes have shown great potential but may increase the complexity of these systems. Usability aspects should be checked to ensure their success in clinical environments. Methods We developed the Fesia Walk device, based on a surface multi-field electrode and an automatic calibration algorithm, and carried out a usability study to check the feasibility of integrating this device in therapeutic programs in clinical environments. The study included 4 therapists and 10 acquired brain injury subjects (8 stroke and 2 traumatic brain injury). Results Therapists and users were “very satisfied” with the device according to the Quebec User Evaluation of Satisfaction with Assistive Technology scale, with average scores of 4.1 and 4.2 out of 5, respectively. Therapists considered the Fesia Walk device as “excellent” according to the System Usability Scale with an average score of 85.6 out of 100. Conclusions This study showed us that it is feasible to include surface multi-field technology while keeping a device simple and intuitive for successful integration in common neurorehabilitation programs.

scholarly journals Extracting synergies in gait: using EMG variability to evaluate control strategies

2012 ◽  
Vol 108 (5) ◽  
pp. 1537-1544 ◽  
Author(s):  
Rajiv Ranganathan ◽  
Chandramouli Krishnan
Keyword(s):  
Muscle Activity ◽  
Control Strategies ◽  
Muscle Synergies ◽  
Neural Activation ◽  
Neural Basis ◽  
Neural Organization ◽  
Lower Limb Muscles ◽  
Emg Signal ◽  
Neural Coupling ◽  
Muscle Groups

There has been extensive debate as to whether muscle synergies in motor tasks reflect underlying neural organization or simply correlations in muscle activity that are imposed by the task. One possible means of distinguishing these two alternatives is through the analysis of variability in the electromyogram (EMG). Here, we simulated EMG in eight lower-limb muscles and introduced hypothetical neural coupling between specific muscle groups. Neural coupling was simulated by introducing correlations in the neural activation commands to different muscles (positive, negative, or zero coupling). When the entire EMG signal was used for analysis, the extracted synergies reflected only simultaneous muscle activity, regardless of the neural coupling between the muscles. On the other hand, examining the variability in the EMG after subtracting the ensemble average was successful in identifying the simulated neural coupling. The extracted synergies from these two methods were also different when we analyzed data from participants during treadmill walking. The results emphasize the importance of examining EMG variability to understand the neural basis of muscle synergies.

scholarly journals Surface electrical stimulation for foot drop: Control aspects and walking performance

2008 ◽  
Vol 18 (2) ◽  
pp. 47-52 ◽  
Author(s):  
Richard Stein ◽  
Robert Rolf ◽  
Dirk Everaert ◽  
Jacques Bobet ◽  
Suling Chong
Keyword(s):  
Electrical Stimulation ◽  
Walking Speed ◽  
Control Strategies ◽  
Gait Pattern ◽  
Foot Drop ◽  
Therapeutic Effects ◽  
Ankle Foot Orthosis ◽  
The Central Nervous System ◽  
Walking Performance ◽  
Over 40 Years

Use of electrical stimulation to correct foot drop in hemiplegia was proposed over 40 years ago. Recently, improved control strategies have been developed and implemented in commercially available devices. In this article we review the control methods that have been used and present some results from a multi-center clinical trial. A foot-drop stimulator improves the gait pattern and results in an immediate increase in walking speed. In this sense it acts like an ankle-foot orthosis and this immediate increase will be referred to as an orthotic effect. Prolonged use of a foot drop stimulator over a period of months results in further, large increases in walking speed both with the stimulator on and off. Evidence indicates that a part of this increase results from daily use that strengthens residual cortico-spinal connections. Therefore the improvement over time will be referred to as a therapeutic effect. We found that people with non-progressive and progressive conditions of the central nervous system have an orthotic benefit, as well as a therapeutic up to 3 months of use. In generally non-progressive conditions such as stroke, further therapeutic increases are seen up to at least 11 months of use. In disorders such as multiple sclerosis, the progression of the disease eventually overcomes the early therapeutic effects. In conclusion, many individuals can benefit from commercially available foot-drop stimulators with improved control strategies and cosmetic design.

scholarly journals Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2702
Author(s):  
Xiaojun Zhao ◽  
Xiuhui Chai ◽  
Xiaoqiang Guo ◽  
Ahmad Waseem ◽  
Xiaohuan Wang ◽  
...  
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Impedance Matching ◽  
Flow Analysis ◽  
Point Of View ◽  
Impedance Model ◽  
Power Flow Analysis ◽  
Three Phase ◽  
System Node ◽  
Power Quality Conditioner

Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

scholarly journals Assessment of muscle activity using electrical stimulation and mechanomyography: a systematic review

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Raphael Uwamahoro ◽  
Kenneth Sundaraj ◽  
Indra Devi Subramaniam
Keyword(s):  
Electrical Stimulation ◽  
Processing Speed ◽  
Muscle Activity ◽  
Neuromuscular Electrical Stimulation ◽  
Voluntary Contraction ◽  
Electrical Signal ◽  
Muscle Performance ◽  
Inclusion Criteria ◽  
Activity Assessment ◽  
Experimental Protocols

AbstractThis research has proved that mechanomyographic (MMG) signals can be used for evaluating muscle performance. Stimulation of the lost physiological functions of a muscle using an electrical signal has been determined crucial in clinical and experimental settings in which voluntary contraction fails in stimulating specific muscles. Previous studies have already indicated that characterizing contractile properties of muscles using MMG through neuromuscular electrical stimulation (NMES) showed excellent reliability. Thus, this review highlights the use of MMG signals on evaluating skeletal muscles under electrical stimulation. In total, 336 original articles were identified from the Scopus and SpringerLink electronic databases using search keywords for studies published between 2000 and 2020, and their eligibility for inclusion in this review has been screened using various inclusion criteria. After screening, 62 studies remained for analysis, with two additional articles from the bibliography, were categorized into the following: (1) fatigue, (2) torque, (3) force, (4) stiffness, (5) electrode development, (6) reliability of MMG and NMES approaches, and (7) validation of these techniques in clinical monitoring. This review has found that MMG through NMES provides feature factors for muscle activity assessment, highlighting standardized electromyostimulation and MMG parameters from different experimental protocols. Despite the evidence of mathematical computations in quantifying MMG along with NMES, the requirement of the processing speed, and fluctuation of MMG signals influence the technique to be prone to errors. Interestingly, although this review does not focus on machine learning, there are only few studies that have adopted it as an alternative to statistical analysis in the assessment of muscle fatigue, torque, and force. The results confirm the need for further investigation on the use of sophisticated computations of features of MMG signals from electrically stimulated muscles in muscle function assessment and assistive technology such as prosthetics control.

scholarly journals Effects of Functional Electrical Stimulation Cycling of Different Duration on Viscoelastic and Electromyographic Properties of the Knee in Patients with Spinal Cord Injury

2020 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Antonino Casabona ◽  
Maria Stella Valle ◽  
Claudio Dominante ◽  
Luca Laudani ◽  
Maria Pia Onesta ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Muscle Activity ◽  
Response Times ◽  
Electromyographic Activity ◽  
Functional Changes ◽  
Pendulum Test ◽  
Cord Injury

The benefits of functional electrical stimulation during cycling (FES-cycling) have been ascertained following spinal cord injury. The instrumented pendulum test was applied to chronic paraplegic patients to investigate the effects of FES-cycling of different duration (20-min vs. 40-min) on biomechanical and electromyographic characterization of knee mobility. Seven adults with post-traumatic paraplegia attended two FES-cycling sessions, a 20-min and a 40-min one, in a random order. Knee angular excursion, stiffness and viscosity were measured using the pendulum test before and after each session. Surface electromyographic activity was recorded from the rectus femoris (RF) and biceps femoris (BF) muscles. FES-cycling led to reduced excursion (p < 0.001) and increased stiffness (p = 0.005) of the knee, which was more evident after the 20-min than 40-min session. Noteworthy, biomechanical changes were associated with an increase of muscle activity and changes in latency of muscle activity only for 20-min, with anticipated response times for RF (p < 0.001) and delayed responses for BF (p = 0.033). These results indicate that significant functional changes in knee mobility can be achieved by FES-cycling for 20 min, as evaluated by the pendulum test in patients with chronic paraplegia. The observed muscle behaviour suggests modulatory effects of exercise on spinal network aimed to partially restore automatic neuronal processes.

The Comparison Between Therapeutic Effects of Different Classes of Antidepressant Drugs in Treatment of Genetical and Reactional Depression

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
P. Molavi ◽  
M. Karimollahi ◽  
M. Faridi
Keyword(s):  
Antidepressant Drugs ◽  
Response Speed ◽  
Point Of View ◽  
Block Type ◽  
Therapeutic Effects ◽  
Response Type ◽  
Analysis Method ◽  
Dsm Iv ◽  
Selection Of ◽  
Analyze Data

Background:Depression as a common psychiatric disorder can occur in two types: Endogenous or genetic and exogenous or Reactional. These two types of depression, from the point of view of response speed to treatment and type of appropriate drug for treatment are different. This study has been executed to compare therapeutic effects of different classes of anti-depressant drugs in treatment of genetic and Reactional depression.Materials and methods:Present survey is a clinical-trial study, a completely randomly block type, that has performed on 30 patients (male and female). Selection of study sample accomplished randomly among unipolar depressed patients that has referred to Ardabil’s psychiatry clinic diagnosed based on DSM-IV criteria. Researcher - Made questionnaire, Beck, and Catelle depression test were used to collect data. To analyze data, for completely randomly blocked designs, two-factor variance analysis method and F test were used.Results:This study showed that Genetical depression does not response treatment Rapidly and its response type is not good and persistent. From the point of view of time, Reactional depression has a delaying response but its response type is good and persistent. In addition, no difference was observed in efficacy of different classes of drugs for treatment of these two types of depression. The results of this research showed that there is no difference between treatment response of two types of depression (Genetical and Reactional).Conclusions:There is no preference in efficacy of different classes of drugs in treatment of these two types of depression.

scholarly journals Probability-Based Prediction of Activity in Multiple Arm Muscles: Implications for Functional Electrical Stimulation

2008 ◽  
Vol 100 (1) ◽  
pp. 482-494 ◽  
Author(s):  
Chad V. Anderson ◽  
Andrew J. Fuglevand
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Muscle Activity ◽  
Probability Distributions ◽  
Probabilistic Methods ◽  
Muscle Stimulation ◽  
Implanted Electrodes ◽  
Motor Behaviors ◽  
Wide Range ◽  
Arm Muscles

Functional electrical stimulation (FES) involves artificial activation of muscles with implanted electrodes to restore motor function in paralyzed individuals. The range of motor behaviors that can be generated by FES, however, is limited to a small set of preprogrammed movements such as hand grasp and release. A broader range of movements has not been implemented because of the substantial difficulty associated with identifying the patterns of muscle stimulation needed to elicit specified movements. To overcome this limitation in controlling FES systems, we used probabilistic methods to estimate the levels of muscle activity in the human arm during a wide range of free movements based on kinematic information of the upper limb. Conditional probability distributions were generated based on hand kinematics and associated surface electromyographic (EMG) signals from 12 arm muscles recorded during a training task involving random movements of the arm in one subject. These distributions were then used to predict in four other subjects the patterns of muscle activity associated with eight different movement tasks. On average, about 40% of the variance in the actual EMG signals could be accounted for in the predicted EMG signals. These results suggest that probabilistic methods ultimately might be used to predict the patterns of muscle stimulation needed to produce a wide array of desired movements in paralyzed individuals with FES.

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