The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Milos R. Popovic - One of the best experts on this subject based on the ideXlab platform.
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a randomized trial of Functional Electrical Stimulation for walking in incomplete spinal cord injury effects on walking competency
Journal of Spinal Cord Medicine, 2014Co-Authors: Naaz Kapadia, Kei Masani, Catharine B Craven, Lora Giangregorio, Sander L Hitzig, Kieva Richards, Milos R. PopovicAbstract:BackgroundMulti-channel surface Functional Electrical Stimulation (FES) for walking has been used to improve voluntary walking and balance in individuals with spinal cord injury (SCI).ObjectiveTo i...
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Functional Electrical Stimulation of walking function exercise and rehabilitation
Annals of Physical and Rehabilitation Medicine, 2008Co-Authors: Timothy A Thrasher, Milos R. PopovicAbstract:For nearly half a century, Functional Electrical Stimulation (FES) has been used to restore walking for people with paralysis and muscle weakness due to stroke and spinal cord injury. The first applications of the technology were intended to permanently replace lost neuromuscular function. Later, FES-assisted walking was found to have therapeutic benefits that include increased muscle strength, cardiovascular fitness and improved gait function that could be maintained after use of FES was terminated. In this review, we examine some of the major FES-assisted walking systems that have been developed for experimental and commercial purposes over the last four and a half decades, including foot drop stimulators, multichannel stimulators and hybrid orthotic systems.
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Functional Electrical Stimulation
IEEE Control Systems Magazine, 2008Co-Authors: Cheryl L Lynch, Milos R. PopovicAbstract:It is important to evaluate closed-loop FES (Functional Electrical Stimulation) control systems using standard time- and frequency-domain performance metrics to facilitate the discussion of results between research groups. Moreover, uniform reporting of the performance of control methods expedites the process of developing clinically useful controllers by concentrating research efforts on promising control designs. In this article, we have focused on FES applications that benefit individuals who have spinal cord injury. However, this technology is also used for rehabilitation after stroke and traumatic brain injury and can potentially be useful for managing the effects of other neuromuscular diseases and conditions.
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reducing muscle fatigue due to Functional Electrical Stimulation using random modulation of Stimulation parameters
Artificial Organs, 2005Co-Authors: Geoffrey M Graham, Adam Thrasher, Milos R. PopovicAbstract:A major limitation of many Functional Electrical Stimulation (FES) applications is that muscles tend to fatigue very rapidly. It was hypothesized that FES-induced muscle fatigue could be reduced by randomly modulating the pulse frequency, amplitude, and pulse width in a range of ± 15%. Seven subjects with spinal-cord injuries participated in this study. FES was applied to quadriceps and tibialis anterior muscles using surface electrodes. Iso- metric force was measured, and the time for the force to drop by 3 dB (fatigue time) was compared between trials. Four different modes of FES were applied in random order: constant Stimulation, randomized frequency, ran- domized amplitude, and randomized pulse width. There was no significant difference between the fatigue-time measurements for the four modes of Stimulation ( P = 0.329). Therefore, random modulation appeared to have no effect. Based on an observed correlation between maximum force measurements and trial order, we con- cluded that having 10-min rest periods between trials was
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modular transcutaneous Functional Electrical Stimulation system
Medical Engineering & Physics, 2005Co-Authors: Milos R. Popovic, Thierry KellerAbstract:A new multipurpose programmable transcutaneous electric stimulator, Compex Motion, was developed to allow users to design various custom-made neuroprostheses, neurological assessment devices, muscle exercise systems, and experimental setups for physiological studies. Compex Motion can generate any arbitrary Stimulation sequence, which can be controlled or regulated in real-time using any external sensor or laboratory equipment. Compex Motion originated from the existing Compex 2 electric stimulator, manufactured by a Swiss based company, Compex SA. The Compex Motion stimulator represents a further evolution and expansion of the ETHZ-ParaCare Functional Electrical Stimulation system. This stimulator provides all the advanced Functional Electrical Stimulation (FES) application and control features and can be easily incorporated into any standard rehabilitation program. Compex Motion has successfully been applied as a neuroprosthesis for walking, reaching and grasping in more than 100 stroke and spinal cord injured patients. This system has also been used to strengthen muscles and to investigate muscle properties in able-bodied subjects. Compex Motion is a multipurpose FES system specially designed to promote sharing and exchanging of Stimulation protocols, sensors, and user interfaces. To the best of our knowledge an FES system that has similar capabilities does not exist yet.
Zoran Nenadic - One of the best experts on this subject based on the ideXlab platform.
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brain controlled Functional Electrical Stimulation therapy for gait rehabilitation after stroke a safety study
Journal of Neuroengineering and Rehabilitation, 2015Co-Authors: Colin M Mccrimmon, Po T Wang, Christine E King, Zoran Nenadic, Steven C Cramer, An H DoAbstract:Background Many stroke survivors have significant long-term gait impairment, often involving foot drop. Current physiotherapies provide limited recovery. Orthoses substitute for ankle strength, but they provide no lasting therapeutic effect. Brain-computer interface (BCI)-controlled Functional Electrical Stimulation (FES) is a novel rehabilitative approach that may generate permanent neurological improvements. This study explores the safety and feasibility of a foot-drop-targeted BCI-FES physiotherapy in chronic stroke survivors.
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the feasibility of a brain computer interface Functional Electrical Stimulation system for the restoration of overground walking after paraplegia
Journal of Neuroengineering and Rehabilitation, 2015Co-Authors: Christine E King, Po T Wang, Colin M Mccrimmon, Cathy Chou, Zoran NenadicAbstract:Background Direct brain control of overground walking in those with paraplegia due to spinal cord injury (SCI) has not been achieved. Invasive brain-computer interfaces (BCIs) may provide a permanent solution to this problem by directly linking the brain to lower extremity prostheses. To justify the pursuit of such invasive systems, the feasibility of BCI controlled overground walking should first be established in a noninvasive manner. To accomplish this goal, we developed an electroencephalogram (EEG)-based BCI to control a Functional Electrical Stimulation (FES) system for overground walking and assessed its performance in an individual with paraplegia due to SCI.
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brain computer interface controlled Functional Electrical Stimulation system for ankle movement
Journal of Neuroengineering and Rehabilitation, 2011Co-Authors: An H Do, Po T Wang, Christine E King, Ahmad Abiri, Zoran NenadicAbstract:Background Many neurological conditions, such as stroke, spinal cord injury, and traumatic brain injury, can cause chronic gait function impairment due to foot-drop. Current physiotherapy techniques provide only a limited degree of motor function recovery in these individuals, and therefore novel therapies are needed. Brain-computer interface (BCI) is a relatively novel technology with a potential to restore, substitute, or augment lost motor behaviors in patients with neurological injuries. Here, we describe the first successful integration of a noninvasive electroencephalogram (EEG)-based BCI with a noninvasive Functional Electrical Stimulation (FES) system that enables the direct brain control of foot dorsiflexion in able-bodied individuals.
An H Do - One of the best experts on this subject based on the ideXlab platform.
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brain controlled Functional Electrical Stimulation therapy for gait rehabilitation after stroke a safety study
Journal of Neuroengineering and Rehabilitation, 2015Co-Authors: Colin M Mccrimmon, Po T Wang, Christine E King, Zoran Nenadic, Steven C Cramer, An H DoAbstract:Background Many stroke survivors have significant long-term gait impairment, often involving foot drop. Current physiotherapies provide limited recovery. Orthoses substitute for ankle strength, but they provide no lasting therapeutic effect. Brain-computer interface (BCI)-controlled Functional Electrical Stimulation (FES) is a novel rehabilitative approach that may generate permanent neurological improvements. This study explores the safety and feasibility of a foot-drop-targeted BCI-FES physiotherapy in chronic stroke survivors.
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brain computer interface controlled Functional Electrical Stimulation system for ankle movement
Journal of Neuroengineering and Rehabilitation, 2011Co-Authors: An H Do, Po T Wang, Christine E King, Ahmad Abiri, Zoran NenadicAbstract:Background Many neurological conditions, such as stroke, spinal cord injury, and traumatic brain injury, can cause chronic gait function impairment due to foot-drop. Current physiotherapy techniques provide only a limited degree of motor function recovery in these individuals, and therefore novel therapies are needed. Brain-computer interface (BCI) is a relatively novel technology with a potential to restore, substitute, or augment lost motor behaviors in patients with neurological injuries. Here, we describe the first successful integration of a noninvasive electroencephalogram (EEG)-based BCI with a noninvasive Functional Electrical Stimulation (FES) system that enables the direct brain control of foot dorsiflexion in able-bodied individuals.
Christine E King - One of the best experts on this subject based on the ideXlab platform.
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brain controlled Functional Electrical Stimulation therapy for gait rehabilitation after stroke a safety study
Journal of Neuroengineering and Rehabilitation, 2015Co-Authors: Colin M Mccrimmon, Po T Wang, Christine E King, Zoran Nenadic, Steven C Cramer, An H DoAbstract:Background Many stroke survivors have significant long-term gait impairment, often involving foot drop. Current physiotherapies provide limited recovery. Orthoses substitute for ankle strength, but they provide no lasting therapeutic effect. Brain-computer interface (BCI)-controlled Functional Electrical Stimulation (FES) is a novel rehabilitative approach that may generate permanent neurological improvements. This study explores the safety and feasibility of a foot-drop-targeted BCI-FES physiotherapy in chronic stroke survivors.
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the feasibility of a brain computer interface Functional Electrical Stimulation system for the restoration of overground walking after paraplegia
Journal of Neuroengineering and Rehabilitation, 2015Co-Authors: Christine E King, Po T Wang, Colin M Mccrimmon, Cathy Chou, Zoran NenadicAbstract:Background Direct brain control of overground walking in those with paraplegia due to spinal cord injury (SCI) has not been achieved. Invasive brain-computer interfaces (BCIs) may provide a permanent solution to this problem by directly linking the brain to lower extremity prostheses. To justify the pursuit of such invasive systems, the feasibility of BCI controlled overground walking should first be established in a noninvasive manner. To accomplish this goal, we developed an electroencephalogram (EEG)-based BCI to control a Functional Electrical Stimulation (FES) system for overground walking and assessed its performance in an individual with paraplegia due to SCI.
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brain computer interface controlled Functional Electrical Stimulation system for ankle movement
Journal of Neuroengineering and Rehabilitation, 2011Co-Authors: An H Do, Po T Wang, Christine E King, Ahmad Abiri, Zoran NenadicAbstract:Background Many neurological conditions, such as stroke, spinal cord injury, and traumatic brain injury, can cause chronic gait function impairment due to foot-drop. Current physiotherapy techniques provide only a limited degree of motor function recovery in these individuals, and therefore novel therapies are needed. Brain-computer interface (BCI) is a relatively novel technology with a potential to restore, substitute, or augment lost motor behaviors in patients with neurological injuries. Here, we describe the first successful integration of a noninvasive electroencephalogram (EEG)-based BCI with a noninvasive Functional Electrical Stimulation (FES) system that enables the direct brain control of foot dorsiflexion in able-bodied individuals.
W E Dixon - One of the best experts on this subject based on the ideXlab platform.
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automatic control of cycling induced by Functional Electrical Stimulation with electric motor assistance
IEEE Transactions on Automation Science and Engineering, 2017Co-Authors: Matthew J. Bellman, Anup Parikh, Ryan J Downey, W E DixonAbstract:Cycling induced by automatic control of Functional Electrical Stimulation provides a means of therapeutic exercise and Functional restoration for people affected by paralysis. During cycling induced by Functional Electrical Stimulation, various muscle groups are stimulated according to the cycle crank angle; however, because of kinematic constraints on the cycle-rider system, Stimulation is typically only applied in a subsection of the crank cycle. Therefore, these systems can be considered as switched control systems with autonomous, state-dependent switching with potentially unstable modes. Previous studies have included an electric motor in the system to provide additional control authority, but no studies have considered the effects of switched control in the stability analysis of the motorized Functional Electrical Stimulation cycling system. In this paper, a model of the motorized cycle-rider system with Functional Electrical Stimulation is developed that includes the effects of a switched control input. A novel switching strategy for the electric motor is designed to only provide assistance in the regions of the crank cycle where the kinematic effectiveness of the rider's muscles is low. A switched sliding-mode controller is designed, and global, exponentially stable tracking of a desired crank trajectory is guaranteed via Lyapunov methods for switched systems, despite parametric uncertainty in the nonlinear model and unknown, time-varying disturbances. Experimental results from five able-bodied, passive riders are presented to validate the control design, and the developed control system achieves an average cadence tracking error of $0.00\pm 2.91$ revolutions per minute for a desired trajectory of 50 revolutions per minute.
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switched control of cadence during stationary cycling induced by Functional Electrical Stimulation
International Conference of the IEEE Engineering in Medicine and Biology Society, 2016Co-Authors: Matthew J. Bellman, Ryan J Downey, Tenghu Cheng, Chris J Hass, W E DixonAbstract:Functional Electrical Stimulation (FES) can be used to activate the dysFunctional lower limb muscles of individuals with neurological disorders to produce cycling as a means of rehabilitation. However, previous literature suggests that poor muscle control and nonphysiological muscle fiber recruitment during FES-cycling causes lower efficiency and power output at the cycle crank than able-bodied cycling, thus motivating the investigation of improved control methods for FES-cycling. In this paper, a Stimulation pattern is designed based on the kinematic effectiveness of the rider's hip and knee joints to produce a forward torque about the cycle crank. A robust controller is designed for the uncertain, nonlinear cycle-rider system with autonomous, state-dependent switching. Provided sufficient conditions are satisfied, the switched controller yields ultimately bounded tracking of a desired cadence. Experimental results on four able-bodied subjects demonstrate cadence tracking errors of 0.05 $\pm $ 1.59 and 5.27 $\pm $ 2.14 revolutions per minute during volitional and FES-induced cycling, respectively. To establish feasibility of FES-assisted cycling in subjects with Parkinson's disease, experimental results with one subject demonstrate tracking errors of 0.43 $\pm $ 4.06 and 0.17 $\pm $ 3.11 revolutions per minute during volitional and FES-induced cycling, respectively.
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stationary cycling induced by switched Functional Electrical Stimulation control
Advances in Computing and Communications, 2014Co-Authors: Matthew J. Bellman, Ryan J Downey, Tenghu Cheng, W E DixonAbstract:Functional Electrical Stimulation (FES) is used to activate the dysFunctional lower limb muscles of individuals with neuromuscular disorders to produce cycling as a means of exercise and rehabilitation. In this paper, a Stimulation pattern for quadriceps femoris-only FES-cycling is derived based on the effectiveness of knee joint torque in producing forward pedaling. In addition, a switched sliding-mode controller is designed for the uncertain, nonlinear cycle-rider system with autonomous state-dependent switching. The switched controller yields ultimately bounded tracking of a desired trajectory in the presence of an unknown, time-varying, bounded disturbance, provided a reverse dwell-time condition is satisfied by appropriate choice of the control gains and a sufficient desired cadence. Stability is derived through Lyapunov methods for switched systems, and experimental results demonstrate the performance of the switched control system under typical cycling conditions.
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stationary cycling induced by switched Functional Electrical Stimulation control
arXiv: Systems and Control, 2013Co-Authors: Matthew J. Bellman, Ryan J Downey, Tenghu Cheng, W E DixonAbstract:Functional Electrical Stimulation (FES) is used to activate the dysFunctional lower limb muscles of individuals with neuromuscular disorders to produce cycling as a means of exercise and rehabilitation. However, FES-cycling is still metabolically inefficient and yields low power output at the cycle crank compared to able-bodied cycling. Previous literature suggests that these problems are symptomatic of poor muscle control and non-physiological muscle fiber recruitment. The latter is a known problem with FES in general, and the former motivates investigation of better control methods for FES-cycling.In this paper, a Stimulation pattern for quadriceps femoris-only FES-cycling is derived based on the effectiveness of knee joint torque in producing forward pedaling. In addition, a switched sliding-mode controller is designed for the uncertain, nonlinear cycle-rider system with autonomous state-dependent switching. The switched controller yields ultimately bounded tracking of a desired trajectory in the presence of an unknown, time-varying, bounded disturbance, provided a reverse dwell-time condition is satisfied by appropriate choice of the control gains and a sufficient desired cadence. Stability is derived through Lyapunov methods for switched systems, and experimental results demonstrate the performance of the switched control system under typical cycling conditions.
