Archive for category Functional Electrical Stimulation (FES)

[VIDEO] What is Functional Electrical Stimulation Billy Woods from Active Linx – YouTube

Functional Electrical Stimulation (FES) is an innovation in the field of muscle stimulation, which allows people with a complete spinal cord injury and paralyzed muscles to move again. It can be combined with a BerkelBike or EasyLegs. The technology allows patients with a spinal cord injury to bike using their own leg muscles.


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[VIDEO] Kid getting treatment with foot drop system – YouTube

Slow motion shot of a child receiving treatment with functional electrical stimulation. He wearing foot drop system


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[VIDEO] Smart FES Treatment for Foot Drop – YouTube

Smart Functional Electrical Stimulation System.

Treatment for foot drop patient.

It can be used when an upper motor neuron injury has caused a foot injury.

  • – Multiple sclerosis (MS)
  • – Stroke (CVA)
  • – Incomplete spinal cord injury (SCI)
  • – Cerebral palsy (CP)
  • – Traumatic brain injury (TBI)

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[VIDEO] Product video Functional Electrical Stimulation – YouTube

What is Functional Electrical Stimulation? This video posted by Active Linx demonstrates the benefits of FES.


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[BLOG POST] Understanding the factors that impact the effectiveness of Functional Electrical Stimulation (FES) – pulse width and charge & torque

In the final of a series of blog articles, we are going to look at the factors that impact the effectiveness of FES. This one covers pulse width and charge & torque.

Read the first article here

Read the second article here

Pulse width

The available pulse widths in FES devices vary, most commonly between 150 and 300us, however much wider variations (50us to 2500us) in pulse width can have differing effects upon the target muscle tissue.

Practically, a longer pulse width causes the stimulus to remain in the tissues for longer, depolarising a greater number of nerve fibres, indiscriminate of motor, sensory or pain. Higher pulse widths have been shown to generate greater levels of torque and can often allow tetanic muscle contractions resulting in physiological joint movement at lower levels of amplitude, which can be useful when attempting to maximise torque in those with intact sensation.

However, when looking for a specific muscle contraction, for example a bicep’s, if too great a pulse width is applied it is common to see overflow into surrounding or opposing muscle groups. Compared to pulse frequency and current amplitude, the role of pulse duration is less appreciated in its possible influence on maximising torque output.

Alon et al back in 1983 showed that motor stimulation could be achieved with pulse durations in the range of 20 to 200 microseconds, without stimulation of pain response. In contrast, Hultman et al (1983) showed that a pulse duration of 500 microseconds resulted in 40% greater torque output compared to 150 microseconds.

Moreover, a pulse duration of 450 microseconds has been shown to be effective in conducting electrically induced resistance training in individuals with spinal cord injury (Kendell et al., 2006, Burnham et al., 1997, cited by Dolbow and Gorgey, 2016).

However, despite this evidence, most researchers have used pulse durations of 300 microseconds or below in their studies, which could potentially limit the outcome of Neuromuscular Electric Stimulation (NMES) protocols in maximising elicited torque output. The controversy regarding pulse duration selection reflects the limited amount of knowledge regarding the optimal pulse duration required to maximise torque output.

Charge & Torque

Total charge, the product of combined amplitude and pulse width, determines the force produced from the resultant muscle contraction. Maximising the charge, by applying maximal amplitude and pulse width, is likely to result in the maximum torque.

However, as stated above, patient tolerance is the determinant of how much charge may be applied. Manipulating both amplitude and pulse width can help to generate sufficient charge to result in a forceful muscle contraction, without becoming unbearable for the patient.

This article is taken from our white paper “The integration of Functional Electrical Stimulation (FES) technology and neurorehabilitation”.

via Understanding the factors that impact the effectiveness of Functional Electrical Stimulation (FES) – pulse width and charge & torque | Cyclone

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[Abstract + References] A Multi-channel EMG-Driven FES Solution for Stroke Rehabilitation – Conference paper


Functional electrical stimulation (FES) has been applied to stroke rehabilitation for many years. However, users are usually involved in open-loop fixed cycle FES systems in clinical, which is easy to cause muscle fatigue and reduce rehabilitation efficacy. This paper proposes a multi-surface EMG-driven FES integration solution for enhancing upper-limb stroke rehabilitation. This wireless portable system consists of sEMG data acquisition module and FES module, the former is used to capture sEMG signals, the latter of multi-channel FES output can be driven by the sEMG. Preliminary experiments proved that the system has outperformed existing similar systems and that sEMG can be effectively employed to achieve different FES intensity, demonstrating the potential for active stroke rehabilitation.


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via A Multi-channel EMG-Driven FES Solution for Stroke Rehabilitation | SpringerLink

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[Abstract] Combining functional electrical stimulation and mirror therapy for upper limb motor recovery following stroke: a randomised trial

Introduction: There is a growing need to develop effective rehabilitation interventions for people presenting with stroke as healthcare services experience ever-increasing pressures on staff and resources. The primary objective of this research is to examine the effect that mirror therapy combined with functional electrical stimulation has on upper limb motor recovery and functional outcome for a sample of people admitted to an inpatient stroke unit.

Methods: A total of 50 participants were randomised to one of three treatment arms; Functional Electrical Stimulation, Mirror therapy or a combined intervention of Functional Electrical Stimulation with Mirror therapy. Socio-demographic and health information was collected at recruitment together with admission dates, medical diagnoses and baseline measures. Blinded assessments were undertaken at baseline and at discharge post-stroke by a registered physiotherapist and a clinical nurse specialist.

Results: The Action Research Arm Test and the Fugl–Meyer Upper Extremity assessment revealed statistically superior results for Functional Electrical Stimulation compared with Mirror therapy alone (p = 0.03). There were no other significant differences between the three groups.

Conclusion: The theory of combining interventions requires further investigation and warrants further research. Combining current interventions may have the potential to enhance stroke rehabilitation, improve functional outcomes and help reduce the overall burden of stroke.


via Combining functional electrical stimulation and mirror therapy for upper limb motor recovery following stroke: a randomised trial: European Journal of Physiotherapy: Vol 0, No 0

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[Abstract + References] Using Orientation Sensors to Control a FES System for Upper-Limb Motor Rehabilitation


Contralaterally controlled functional electrical stimulation (CCFES) is a recent therapy aimed at improving the recovery of impaired limbs after stroke. For hemiplegic patients, CCFES uses a control signal from the non-impaired side of the body to regulate the intensity of electrical stimulation delivered to the affected muscles of the homologous limb on the opposite side of the body. CCFES permits an artificial muscular contraction synchronized with the patient’s intentionality to carry out functional tasks, which is a way to enhance neuroplasticity and to promote motor learning. This work presents an upper extremity motor rehabilitation system based on CCFES, using orientation sensors for control. Thus, the stimulation intensity (current amplitude) delivered to the paretic extremity is proportional to the degree of joint amplitude of the unaffected extremity. The implemented controller uses a control strategy that allows the delivered electrical stimulation intensity, to be comparable to the magnitude of movement. It was carried out a set of experiments to validate the overall system, for executing five bilateral mirror movements that include human wrist and elbow joints. Obtained results showed that movements voluntary signals acquired from right upper-limb were replicated successfully on left upper-limb using the FES system.


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via Using Orientation Sensors to Control a FES System for Upper-Limb Motor Rehabilitation | SpringerLink

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[ARTICLE] FES-UPP: A Flexible Functional Electrical Stimulation System to Support Upper Limb Functional Activity Practice – Full Text

There is good evidence supporting highly intensive, repetitive, activity-focused, voluntary-initiated practice as a key to driving recovery of upper limb function following stroke. Functional electrical stimulation (FES) offers a potential mechanism to efficiently deliver this type of therapy, but current commercial devices are too inflexible and/or insufficiently automated, in some cases requiring engineering support. In this paper, we report a new, flexible upper limb FES system, FES-UPP, which addresses the issues above. The FES-UPP system consists of a 5-channel stimulator running a flexible FES finite state machine (FSM) controller, the associated setup software that guides therapists through the setup of FSM controllers via five setup stages, and finally the Session Manager used to guide the patient in repeated attempts at the activities(s) and provide feedback on their performance. The FSM controller represents a functional activity as a sequence of movement phases. The output for each phase implements the stimulations to one or more muscles. Progression between movement phases is governed by user-defined rules. As part of a clinical investigation of the system, nine therapists used the FES-UPP system to set up FES-supported activities with twenty two patient participants with impaired upper-limbs. Therapists with little or no FES experience and without any programming skills could use the system in their usual clinical settings, without engineering support. Different functional activities, tailored to suit the upper limb impairment levels of each participant were used, in up to 8 sessions of FES-supported therapy per participant. The efficiency of delivery of the therapy using FES-UPP was promising when compared with published data on traditional face-face therapy. The FES-UPP system described in this paper has been shown to allow therapists with little or no FES experience and without any programming skills to set up state-machine FES controllers bespoke to the patient’s impairment patterns and activity requirements, without engineering support. The clinical results demonstrated that the system can be used to efficiently deliver high intensity, activity-focused therapy. Nevertheless, further work to reduce setup time is still required.


In the United Kingdom there are more than 100,000 new stroke cases each year and approximately 1.2 million people living with the consequences of stroke (Stroke Association, 2017). In the United Kingdom, during their entire in-patient stay, a typical patient will receive around 5 h of physiotherapy (McHugh and Swain, 2014), with much of that time focused on the rehabilitation of posture, balance and walking (Wit et al., 2005). The consequences of this are that patients do not receive anything approaching the intensity of upper limb therapy that research suggests is needed to drive functional recovery (Clarke et al., 2015). Possibly as a result, long term recovery of the upper limb remains very poor. Almost three quarters of stroke survivors are left with upper limb motor problems (Lawrence et al., 2001), which seriously impact on their quality of life.

There is strong evidence supporting intensive (Lohse et al., 2014), repetitive, activity-focused (Winstein et al., 2004Alon et al., 2007Langhorne et al., 2009), voluntary-initiated (Peckham and Knutson, 2005Knutson et al., 2009) practice for upper limb functional recovery. However, to enable such an approach, without significantly increasing the number of therapists, we need to look to rehabilitation technologies.

A number of rehabilitation technologies have been developed to encourage the recovery of upper limb motor function after stroke, including robotic devices, virtual reality and functional electrical stimulation (FES) systems (Howlett et al., 2015). Studies have shown positive results for FES in the rehabilitation of reaching and grasping function (Thrasher et al., 2008Knutson et al., 2009), elbow extension (Thrasher et al., 2008Hughes et al., 2010), shoulder motion (Hara et al., 2009), and stabilization of wrist joints (Malešević et al., 2012). In addition, FES offers the potential to increase therapy dose at a reasonable cost (Kitago and Krakauer, 2013), in a way that does not need the dedicated attention of a therapist.

Current upper limb FES systems can be categorized according to the methods of control over stimulation. The first group of systems use a push button operated by the patient’s unaffected hand, and/or are pre-programmed to repeat a fixed sequence of timed stimulations (Mann et al., 2005). Commercial systems of this type, which tend to be used largely for passive exercising, include Odstock Medical’s Microstim 2 and 4 Channel Stimulator Kit, and the Bioness H200. The Odstock 2 and 4 channel stimulators offer flexibility over which muscles are stimulated; the H200 (Snoek et al., 2000) offers 5 channels of stimulation, but is limited to stimulation of hand and wrist. Previous studies have suggested that cyclical stimulation is less clinically effective than voluntary triggered stimulation (de Kroon et al., 2005), although debate on this issue continues (Wilson et al., 2016). A recent report identified that the carryover, or therapeutic effect, in drop foot patients was only observed in patients who showed brain activation patterns consistent with movement planning (Gandolla et al., 2016). This supports Rushton’s hypothesis (Rushton, 2003) which proposed that when the F wave resulting from stimulation coincides with voluntary intention to move, connectivity between the intact upper motor and lower motor neurons is strengthened at the spinal cord level. These studies suggest that stimulation delivered without the active involvement of the patient may not be the most effective approach.

The second group of systems attempt to ensure that stimulation coincides with voluntary intention to move; thus increasing the likelihood of effective motor relearning. Examples of systems which use voluntary initiated neural signals to control FES include the EMG-based MeCFES (Thorsen et al., 2001) and STIWELL med4 (Rakos et al., 2007) systems and a small number of demonstrator projects which use brain-computer interface approaches (Müller-Putz et al., 2005Ajiboye et al., 2017). However, reliable surface EMG signal(s) from appropriate muscles are frequently either difficult to measure or absent in people with paretic upper limbs (Bolton et al., 2004Gazzoni, 2010), making EMG-controlled FES difficult to use with certain patients. Additionally, the voluntary effort in producing an EMG signal can increase spasticity, opposing the movement that is intended. Although systems using brain-implanted electrodes have been reported, most of the current EEG controlled systems use non-invasive electrodes, which provide limited information transfer rate, require patients to complete a significant amount of training prior to first use (Scherberger, 2009Bouton et al., 2016), and need frequent re-calibration (Ajiboye et al., 2017).

Motion-controlled FES systems offer an attractive alternative (Mann et al., 2011Sun et al., 2016a,b). An example of a motion controlled system is the Bionic Glove (Prochazka et al., 1997) which uses data from a wrist position sensor to control stimulation of hand and wrist muscles in C6/7 spinal cord injury (SCI) patients. More recently, the Southampton group have reported on a system based on iterative learning control (Meadmore et al., 2014) in which stimulation is applied to the triceps, anterior deltoid and wrist/finger extensors muscles to support specified reaching activities. Stimulation levels are adjusted cycle-to-cycle based on kinematic data collected from previous attempts in such a way that the patient is always challenged. These motion controlled FES systems have the potential to deliver appropriately timed neural inputs to promote re-learning and hence recovery (Rushton, 2003Sheffler and Chae, 2007) and recent studies have reported positive results (Knutson et al., 2012Meadmore et al., 2014), including sustained improvements in function (Persch et al., 2012), and improvements even in patients with severe hand arm paralysis (Popovic et al., 2005Thrasher et al., 2008). However, these systems are generally inflexible in terms of the number and location of muscles to be stimulated (Snoek et al., 2000Alon and McBride, 2003Mann et al., 2011) and/or require engineering support to accommodate a wide range of upper limb activities (Tresadern et al., 2008). Relatively little attention has been paid to the development of easy to use, flexible systems able to support a range of patients in practicing varied, yet challenging functional activities (Rakos et al., 2007Tresadern et al., 2008). In particular, if such systems are to be widely adopted, they must be sufficiently user-friendly to remove the need for routine engineering support.

In this paper, we report on a new, flexible upper limb FES system, FES-UPP, which address the issues discussed above. Below we report on the design of the upper limb FES controller and the setup software. Finally, we show data from a clinical investigation study of the system carried out without on-site engineering support to illustrate the potential for the system to be used in the delivery of intensive FES-supported practice.[…]


Continue —-> Frontiers | FES-UPP: A Flexible Functional Electrical Stimulation System to Support Upper Limb Functional Activity Practice | Neuroscience

FIGURE 1. Example set-up of the FES-UPP system for the “Sweeping coins” activity. (A) Anterior view; and (B) Lateral view (informed consent was obtained from all participants).

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[Abstract] Hybrid robotic system combining passive exoskeleton and functional electrical stimulation for upper limb stroke rehabilitation: Preliminary results of the retrainer multi-center randomized controlled trial


Stroke is the main cause of acquired adult disability with major impact on arm function. The combined use of Functional Electrical Stimulation (FES) and robotic technologies is strongly advocated to improve rehabilitation outcomes after stroke. We present the preliminary data of a multi-center Randomized Controlled Trial aimed at evaluating the effectiveness of this system with respect to conventional therapy for sub-acute stroke upper limb rehabilitation.

Material and method

The RETRAINER system consists of a lightweight and non-cumbersome passive arm exoskeleton for weight relief, a current-controlled stimulator with 2 channels of stimulation and 2 channels of EMG recordings.

In this work we are presenting the preliminary results of 39 sub-acute stroke patients with a distance from the acute event between two weeks and nine months. The inclusion criteria was: age between 18 and 85 years, Motricity Index (MI) < 80%, muscular activity for arm and shoulder at least 1 Medical Research Council (MRC) with a visible contraction, no joint limitation, pain or spasticity. They were randomized in two group: 1 conventional rehabilitation methods, 2 experimental group using Retrainer System. Each participant performed 9 weeks of treatment 3 times for week. We measured MI, Action Research Arm Test (ARAT) and Motor Activity Log (MAL) at beginning (T0) and at the end of treatment (T1).


Results are showed in the next Table 1.


Both groups showed statistical improvement in outcome measures. Experimental group showed a statistical better improvement regarding time and group effect.


via Hybrid robotic system combining passive exoskeleton and functional electrical stimulation for upper limb stroke rehabilitation: Preliminary results of the retrainer multi-center randomized controlled trial – ScienceDirect

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