Functional electrical stimulation

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Functional electrical stimulation - schematic representation: Illustration of motor neuron stimulation. (a) The cell nucleus is responsible for synthesizing input from dendrites and deciding whether or not to generate signals. Following a stroke or spinal cord injury in mahnoor's muscles are impaired because motor neurons no longer receive sufficient input from the central nervous system. (b) A functional electrical stimulation system injects electrical current into the cell. (c) The intact but dormant axon receives the stimulus and propagates an action potential to (d) the neuromuscular junction. (e) The corresponding muscle fibers contract and generate (f) muscle force. (g) A train of negative pulses is produced. (h) Depolarization occurs where negative current enters the axon at the "active" electrode indicated. Functional Electrical Stimulation .tif
Functional electrical stimulation – schematic representation: Illustration of motor neuron stimulation. (a) The cell nucleus is responsible for synthesizing input from dendrites and deciding whether or not to generate signals. Following a stroke or spinal cord injury in mahnoor's muscles are impaired because motor neurons no longer receive sufficient input from the central nervous system. (b) A functional electrical stimulation system injects electrical current into the cell. (c) The intact but dormant axon receives the stimulus and propagates an action potential to (d) the neuromuscular junction. (e) The corresponding muscle fibers contract and generate (f) muscle force. (g) A train of negative pulses is produced. (h) Depolarization occurs where negative current enters the axon at the "active" electrode indicated.

Functional electrical stimulation (FES) is a technique that uses low-energy electrical pulses to artificially generate body movements in individuals who have been paralyzed due to injury to the central nervous system. More specifically, FES can be used to generate muscle contraction in otherwise paralyzed limbs to produce functions such as grasping, walking, bladder voiding and standing. This technology was originally used to develop neuroprostheses that were implemented to permanently substitute impaired functions in individuals with spinal cord injury (SCI), head injury, stroke and other neurological disorders. In other words, a person would use the device each time he or she wanted to generate a desired function. [1] FES is sometimes also referred to as neuromuscular electrical stimulation (NMES). [2]

Contents

FES technology has been used to deliver therapies to retrain voluntary motor functions such as grasping, reaching and walking. In this embodiment, FES is used as a short-term therapy, the objective of which is restoration of voluntary function and not lifelong dependence on the FES device, hence the name functional electrical stimulation therapy, FES therapy (FET or FEST). In other words, the FEST is used as a short-term intervention to help an individual's central nervous system re-learn how to execute impaired functions, instead of making them dependent on neuroprostheses for the rest of their life. [3] Initial Phase II clinical trials conducted with FEST for reaching and grasping, and walking were carried out at KITE, the research arm of the Toronto Rehabilitation Institute. [4] [5] [6] [7]

Principles

Neurons are electrically active cells. [8] In neurons, information is coded and transmitted as a series of electrical impulses called action potentials, which represent a brief change in cell electric potential of approximately 80–90 mV. Nerve signals are frequency modulated; i.e. the number of action potentials that occur in a unit of time is proportional to the intensity of the transmitted signal. Typical action potential frequency is between 4 and 12 Hz. An electrical stimulation can artificially elicit this action potential by changing the electric potential across a nerve cell membrane (this also includes the nerve axon) by inducing electrical charge in the immediate vicinity of the outer membrane of the cell. [9]

FES devices take advantage of this property to electrically activate nerve cells, which then may go on to activate muscles or other nerves. [10] However, special care must be taken in designing safe FES devices, as electric current through tissue can lead to adverse effects such as decrease in excitability or cell death. This may be due to thermal damage, electroporation of the cell membrane, toxic products from electrochemical reactions at the electrode surface, or over-excitation of the targeted neurons or muscles. Typically FES is concerned with stimulation of neurons and nerves. In some applications, FES can be used to directly stimulate muscles, if their peripheral nerves have been severed or damaged (i.e., denervated muscles). [11] However, the majority of the FES systems used today stimulate the nerves or the points where the junction occurs between the nerve and the muscle. The stimulated nerve bundle includes motor nerves (efferent nerves—descending nerves from the central nervous system to muscles) and sensory nerves (afferent nerves—ascending nerves from sensory organs to the central nervous system).

The electrical charge can stimulate both motor and sensory nerves. In some applications, the nerves are stimulated to generate localized muscle activity, i.e., the stimulation is aimed at generating direct muscle contraction. In other applications, stimulation is used to activate simple or complex reflexes. In other words, the afferent nerves are stimulated to evoke a reflex, which is typically expressed as a coordinated contraction of one or more muscles in response to the sensory nerve stimulation.

When a nerve is stimulated, i.e., when sufficient electrical charge is provided to a nerve cell, a localized depolarization of the cell wall occurs resulting in an action potential that propagates toward both ends of the axon. Typically, one "wave" of action potentials will propagate along the axon towards the muscle (orthodromic propagation) and concurrently, as the other "wave" of action potentials will propagate towards the cell body in the central nervous system (antidromic propagation). While the direction of propagation in case of the antidromic stimulation and the sensory nerve stimulation is the same, i.e., towards the central nervous system, their end effects are very different. The antidromic stimulus has been considered an irrelevant side effect of FES. However, in recent years a hypothesis has been presented suggesting the potential role of the antidromic stimulation in neurorehabilitation. [12] Typically, FES is concerned with orthodromic stimulation and uses it to generate coordinated muscle contractions.

In the case where sensory nerves are stimulated, the reflex arcs are triggered by the stimulation on sensory nerve axons at specific peripheral sites. One example of such a reflex is the flexor withdrawal reflex. The flexor withdrawal reflex occurs naturally when a sudden, painful sensation is applied to the sole of the foot. It results in flexion of the hip, knee and ankle of the affected leg, and extension of the contralateral leg in order to get the foot away from the painful stimulus as quickly as possible. The sensory nerve stimulation can be used to generate desired motor tasks, such as evoking flexor withdrawal reflex to facilitate walking in individuals following stroke, or they can be used to alter reflexes or the function of the central nervous system. In the later case, the electrical stimulation is commonly described by the term neuromodulation .

Nerves can be stimulated using either surface (transcutaneous) or subcutaneous (percutaneous or implanted) electrodes. The surface electrodes are placed on the skin surface above the nerve or muscle that needs to be "activated". They are noninvasive, easy to apply, and generally inexpensive. Until recently the common belief in the FES field has been that due to the electrode-skin contact impedance, skin and tissue impedance, and current dispersion during stimulation, much higher-intensity pulses are required to stimulate nerves using surface stimulation electrodes as compared to the subcutaneous electrodes.

(This statement is correct for all commercially available stimulators except MyndMove stimulator (developed my Milos R. Popovic), which has implemented a new stimulation pulse that allows the stimulator to generate muscle contractions without causing discomfort during stimulation, which is a common problem with commercially available transcutaneous electrical stimulation systems, based on US Patents 8,880,178 (2014), 9,440,077 (2016), and 9,592,380 (2016) and related foreign patents.)[ citation needed ] [13] [14] [15]

A major limitation of the transcutaneous electrical stimulation is that some nerves, for example those innervating the hip flexors, are too profound to be stimulated using surface electrodes. This limitation can be partly addressed by using arrays of electrodes, which can use several electrical contacts to increase selectivity. [16] [17] [18]

Subcutaneous electrodes can be divided into percutaneous and implanted electrodes. The percutaneous electrodes consist of thin wires inserted through the skin and into muscular tissue close to the targeted nerve. These electrodes typically remain in place for a short period of time and are only considered for short-term FES interventions. However, it is worth mentioning that some groups, such as Cleveland FES Center, have been able to safely use percutaneous electrodes with individual patients for months and years at a time. One of the drawbacks of using the percutaneous electrodes is that they are prone to infection and special care has to be taken to prevent such events.

The other class of subcutaneous electrodes is implanted electrodes. These are permanently implanted in the consumer's body and remain in the body for the remainder of the consumer's life. Compared to surface stimulation electrodes, implanted and percutaneous electrodes potentially have higher stimulation selectivity, which is a desired characteristics of FES systems. To achieve higher selectivity while applying lower stimulation amplitudes, it is recommended that both cathode and anode are in the vicinity of the nerve that is stimulated. The drawbacks of the implanted electrodes are they require an invasive surgical procedure to install, and, as is the case with every surgical intervention, there exists a possibility of infection following implantation.

Typical stimulation protocols used in clinical FES involves trains of electric pulses. Biphasic, charged balanced pulses are employed as they improve the safety of electrical stimulation and minimize some of the adverse effects. Pulse duration, pulse amplitude and pulse frequency are the key parameters that are regulated by the FES devices. The FES devices can be current or voltage regulated. Current regulated FES systems always deliver the same charge to the tissue regardless of the skin/tissue resistance. Because of that, the current regulated FES systems do not require frequent adjustments of the stimulation intensity. The voltage regulated devices may require more frequent adjustments of the stimulation intensity as the charge that they deliver changes as the skin/tissue resistance changes. The properties of the stimulation pulse trains and how many channels are used during stimulation define how complex and sophisticated FES-induced function is. The system can be as simple such as FES systems for muscle strengthening or they can be complex such as FES systems used to deliver simultaneous reaching and grasping, [19] or bipedal locomotion. [20] [21] [22]

Note: This paragraph was developed in part using material from the following reference. [1] For more information on FES please consult that and other references provided in the paragraph.

History

Electrical stimulation had been utilized as far back as ancient Egypt, when it was believed that placing torpedo fish in a pool of water with a human was therapeutic. FES – which involves stimulating the target organ during a functional movement (e.g., walking, reaching for an item) – was initially referred to as functional electrotherapy by Liberson. [23] It was not until 1967 that the term functional electrical stimulation was coined by Moe and Post, [24] and used in a patent entitled, "Electrical stimulation of muscle deprived of nervous control with a view of providing muscular contraction and producing a functionally useful moment". [25] Offner's patent described a system used to treat foot drop.

The first commercially available FES devices treated foot drop by stimulating the peroneal nerve during gait. In this case, a switch, located in the heel end of a user's shoe, would activate a stimulator worn by the user.

Common applications

Spinal cord injury

Injuries to the spinal cord interfere with electrical signals between the brain and the muscles, resulting in paralysis below the level of injury. Restoration of limb function as well as regulation of organ function are the main application of FES, although FES is also used for treatment of pain, pressure, sore prevention, etc. Some examples of FES applications involve the use of neuroprostheses that allow the people with paraplegia to walk, stand, restore hand grasp function in people with quadriplegia, or restore bowel and bladder function. [26] High intensity FES of the quadriceps muscles allows patients with complete lower motor neuron lesion to increase their muscle mass, muscle fiber diameter, improve ultrastructural organization of contractile material, increase of force output during electrical stimulation and perform FES assisted stand-up exercises. [27] Regeneration associated genes (RAG) expression, responsible for axonal outgrowth and survival, is promoted with administration of FES. [28]

Walking in spinal cord injury

Kralj and his colleagues described a technique for paraplegic gait using surface stimulation, which remains the most popular method in use today. [29] Electrodes are placed over the quadriceps muscles and peroneal nerves bilaterally. The user controls the neuroprosthesis with two pushbuttons attached to the left and right handles of a walking frame, or on canes or crutches. When the neuroprosthesis is turned on, both quadriceps muscles are stimulated to provide a standing posture. [30]

Kralj's approach was extended by Graupe et al. [30] into a digital FES system that employs the power of digital signal processing to result in the Parastep FES system, based on US Patents 5,014,705 (1991), 5,016,636 (1991), 5,070,873 (1991), 5,081,989 (1992), 5,092,329 (1992) and related foreign patents. The Parastep system became the first FES system for standing and walking to receive the US FDA approval (FDA, PMA P900038, 1994) and become commercially available.

The Parastep's digital design allows a considerable reduction in rate of patient-fatigue by drastically reducing of stimulation pulse-width (100–140 microseconds) and pulse-rate (12–24 per sec.), to result, in walking times of 20–60 minutes and average walking distances of 450 meters per walk, for adequately trained thoracic-level complete paraplegics patients who complete training that includes daily treadmill sessions, [30] with some patients exceeding one mile per walk. [31] Also, Parestep-based walking was reported to result in several medical and psychological benefits, including restoration of near-normal blood flow to lower extremities and holding of bone density decline. [32] [33] [30]

Walking performance with the Parastep system greatly depends on rigorous upper body conditioning-training and on a completing 3–5 months of a daily one–two-hour training program which includes 30 of more minutes of treadmill training. [30]

An alternative approach to the above techniques is the FES system for walking developed using the Compex Motion neuroprosthesis, by Popovic et al. [34] [35] The Compex Motion neuroprosthesis for walking is an eight to sixteen channel surface FES system used to restore voluntary walking in stroke and spinal cord injury individuals. [4] This system does not apply peroneal nerve stimulation to enable locomotion. Instead, it activates all relevant lower limb muscles in a sequence similar to the one that brain uses to enable locomotion. The hybrid assistive systems (HAS) [36] and the RGO [37] walking neuroprostheses are devices that also apply active and passive braces, respectively. The braces were introduced to provide additional stability during standing and walking. A major limitation of neuroprostheses for walking that are based on surface stimulation is that the hip flexors cannot be stimulated directly. Therefore, hip flexion during walking must come from voluntary effort, which is often absent in paraplegia, or from the flexor withdrawal reflex. Implanted systems have the advantage of being able to stimulate the hip flexors, and therefore, to provide better muscle selectivity and potentially better gait patterns. [38] Hybrid systems with exoskeleton have been also proposed to solve this problem. [39] These technologies have been found to be successful and promising, but at the present time these FES systems are mostly used for exercise purposes and seldom as an alternative to wheelchair mobility.

Stroke and upper limb recovery

Peripheral nerves have a regeneration rate of ~1mm per day. With nerve injury often requiring a large distance of restoration, down-regulation of regenerative mechanisms over time limits nerve proliferation. [28] In the acute stage of stroke recovery, the use of cyclic electrical stimulation has been seen to increase the isometric strength of wrist extensors. In order to increase strength of wrist extensors, there must be a degree of motor function at the wrist spared following the stroke and have significant hemiplegia. Patients who will elicit benefits of cyclic electrical stimulation of the wrist extensors must be highly motivated to follow through with treatment. After 8 weeks of electrical stimulation, an increase in grip strength can be apparent. Many scales, which assess the level of disability of the upper extremities following a stroke, use grip strength as a common item. Therefore, increasing strength of wrist extensors will decrease the level of upper extremity disability.

Patients with hemiplegia following a stroke commonly experience shoulder pain and subluxation; both of which will interfere with the rehabilitation process. Functional electrical stimulation has been found to be effective for the management of pain and reduction of shoulder subluxation, as well as accelerating the degree and rate of motor recovery. Furthermore, the benefits of FES are maintained over time; research has demonstrated that the benefits are maintained for at least 24 months. [40]

A systematic review was done to assess three types of functional electronic stimulation (FES) used in post stroke upper limb rehab and compare them to patients that did not use any FES. The types focused on were manual FES, BCI-FES, and EMG-FES. Studies showed that when comparing clinical scores in post stroke patients who used FES versus patients that did not, the patients that used FES had more functional benefits. The scores suggested that FES decreases spasticity of wrist flexors as compared to non-FES and motor outcomes showed improved recovery in upper extremities, specifically when using the BCI-FES system. In the end the study showed that it is difficult to say which specific FES system is best. Many research studies showed that closed-loop FES, or BCI/EMG, are more beneficial than open-loop FES, or manual, for motor recovery. Among closed-loop FES, which system is more effective (either BCI-FES or EMG-FES) remains unspecified, because as of right now no randomized controlled clinical trial has been conducted to directly compare the two and their benefits when in the context of neurorehabilitation. An open-loop FES has been widely used clinically for many years when treating post stroke patients, whereas closed-loop FES is typically applied in the laboratory setting as a research protocol (especially BCI-FES). [41]

Drop foot

Drop foot is a common symptom in hemiplegia, characterized by a lack of dorsiflexion during the swing phase of gait, resulting in short, shuffling strides. It has been shown that FES can be used to effectively compensate for the drop foot during the swing phase of the gait. At the moment just before the heel off phase of gait occurs, the stimulator delivers a stimulus to the common peroneal nerve, which results in contraction of the muscles responsible for dorsiflexion. There are currently a number of drop foot stimulators that use surface and implanted FES technologies. [42] [43] [44] [45] [46] Drop foot stimulators have been used successfully with various patient populations, such as stroke, spinal cord injury and multiple sclerosis. [47]

The term "orthotic effect" can be used to describe the immediate improvement in function observed when the individual switches on their FES device compared to unassisted walking. This improvement disappears as soon as the person switches off their FES device. In contrast, a "training" or "therapeutic effect" is used to describe a long term improvement or restoration of function following a period of using the device which is still present even when the device is switched off. A further complication to measuring an orthotic effect and any long term training or therapeutic effects is the presence of a so-called "temporary carry over effect". Liberson et al., 1961 [23] was the first to observe that some stroke patients appeared to benefit from a temporary improvement in function and were able to dorsiflex their foot for up to an hour after the electrical stimulation had been turned off. It has been hypothesised that this temporary improvement in function may be linked to a long term training or therapeutic effect.

This image describes functional electrical stimulation therapy for walking. The therapy was used to help retrain incomplete spinal cord injured individuals to walk [30,31]. Functional Electrical Stimulation Therapy for improving walking in incomplete spinal cord injured individuals -30,31-.jpg
This image describes functional electrical stimulation therapy for walking. The therapy was used to help retrain incomplete spinal cord injured individuals to walk [30,31].

Stroke

Hemiparetic stroke patients, who are impacted by the denervation, muscular atrophy, and spasticity, typically experience an abnormal gait pattern due to muscular weakness and the incapacity to voluntary contract certain ankle and hip muscles at the appropriate walking phase. Liberson et al. (1961) were the first to pioneer FES in stroke patients. [23] More recently, there have been a number of studies that have been conducted in this area. A systematic review conducted in 2012 on the use of FES in chronic stroke included seven randomized controlled trials with a total of 231 participants. The review found a small treatment effect for using FES for the 6-minute walking test. [48]

Multiple sclerosis

FES has also been found to be useful for treating foot drop in people with multiple sclerosis. The first use was reported in 1977 by Carnstam et al., who found that it was possible to generate strength increases through using peroneal stimulation. [49] [50] A more recent study examined the use of FES compared to an exercise group and found that although there was an orthotic effect for the FES group, no training effect in walking speed was found. [51] Further qualitative analysis including all participants from the same study found improvements in activities of daily living and a reduced number of falls for those using FES compared with exercise. [52] A further small scale (n=32) longitudinal observational study has found evidence for a significant training effect through using FES. [53] With NMES treatment there were measurable gains in ambulatory function. [54]

However, a further large observational study (n=187) was supportive of previous findings and found a significant improvement in orthotic effect for walking speed. [55]

Cerebral palsy

FES has been found to be useful for treating the symptoms of cerebral palsy. A recent randomised controlled trial (n=32) found significant orthotic and training effects for children with unilateral spastic cerebral palsy. Improvements were found in gastrocnemius spasticity, community mobility and balance skills. [56] A recent comprehensive literature review of the area of using electrical stimulation and FES to treat children with disabilities mostly included studies on children with cerebral palsy. [57] The reviewers summarised the evidence as the treatment having the potential to improve a number of different areas including muscle mass and strength, spasticity, passive range of motion, upper extremity function, walking speed, positioning of the foot and ankle kinematics. The review further concludes that adverse events were rare and the technology is safe and well tolerated by this population. The applications of FES for children with cerebral palsy are similar to those for adults. Some common applications of FES devices include stimulation of muscles whilst mobilizing to strengthen muscle activity, to reduce muscle spasticity, to facilitate initiation of muscle activity, or to provide a memory of movement. [58]

National Institute for Health and Care Excellence Guidelines (NICE) (UK)

NICE have issued full guidelines on the treatment of drop foot of central neurological origin [59] (IPG278). NICE have stated that "current evidence on the safety and efficacy (in terms of improving gait) of functional electrical stimulation (FES) for drop foot of central neurological origin appears adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance, consent and audit".

See also

Related Research Articles

Hemiparesis, also called unilateral paresis, is the weakness of one entire side of the body. Hemiplegia, in its most severe form, is the complete paralysis of one entire side of the body. Either hemiparesis or hemiplegia can result from a variety of medical causes, including congenital conditions, trauma, tumors, traumatic brain injury and stroke.

Spasticity is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles.

<span class="mw-page-title-main">Spinal cord injury</span> Injury to the main nerve bundle in the back of humans

A spinal cord injury (SCI) is damage to the spinal cord that causes temporary or permanent changes in its function. It is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions.

<span class="mw-page-title-main">Nerve conduction study</span> Diagnostic test for nerve function

A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests may be performed by medical specialists such as clinical neurophysiologists, physical therapists, physiatrists, and neurologists who subspecialize in electrodiagnostic medicine. In the United States, neurologists and physiatrists receive training in electrodiagnostic medicine as part of residency training and in some cases acquire additional expertise during a fellowship in clinical neurophysiology, electrodiagnostic medicine, or neuromuscular medicine. Outside the US, clinical neurophysiologists learn needle EMG and NCS testing.

Neuroprosthetics is a discipline related to neuroscience and biomedical engineering concerned with developing neural prostheses. They are sometimes contrasted with a brain–computer interface, which connects the brain to a computer rather than a device meant to replace missing biological functionality.

Neural engineering is a discipline within biomedical engineering that uses engineering techniques to understand, repair, replace, or enhance neural systems. Neural engineers are uniquely qualified to solve design problems at the interface of living neural tissue and non-living constructs.

<span class="mw-page-title-main">Monoplegia</span> Paralysis of a single limb

Monoplegia is paralysis of a single limb, usually an arm. Common symptoms associated with monoplegic patients are weakness, numbness, and pain in the affected limb. Monoplegia is a type of paralysis that falls under hemiplegia. While hemiplegia is paralysis of half of the body, monoplegia is localized to a single limb or to a specific region of the body. Monoplegia of the upper limb is sometimes referred to as brachial monoplegia, and that of the lower limb is called crural monoplegia. Monoplegia in the lower extremities is not as common of an occurrence as in the upper extremities. Monoparesis is a similar, but less severe, condition because one limb is very weak, not paralyzed. For more information, see paresis.

<span class="mw-page-title-main">Foot drop</span> Gait abnormality

Foot drop is a gait abnormality in which the dropping of the forefoot happens out of weakness, irritation or damage to the deep fibular nerve, including the sciatic nerve, or paralysis of the muscles in the anterior portion of the lower leg. It is usually a symptom of a greater problem, not a disease in itself. Foot drop is characterized by inability or impaired ability to raise the toes or raise the foot from the ankle (dorsiflexion). Foot drop may be temporary or permanent, depending on the extent of muscle weakness or paralysis and it can occur in one or both feet. In walking, the raised leg is slightly bent at the knee to prevent the foot from dragging along the ground.

Gait training or gait rehabilitation is the act of learning how to walk, either as a child, or, more frequently, after sustaining an injury or disability. Normal human gait is a complex process, which happens due to co-ordinated movements of the whole of the body, requiring the whole of Central Nervous System - the brain and spinal cord, to function properly. Any disease process affecting the brain, spinal cord, peripheral nerves emerging from them supplying the muscles, or the muscles itself can cause deviations of gait. The process of relearning how to walk is generally facilitated by Physiatrists or Rehabilitation medicine (PM&R) consultants, physical therapists or physiotherapists, along with occupational therapists and other allied specialists. The most common cause for gait impairment is due to an injury of one or both legs. Gait training is not simply re-educating a patient on how to walk, but also includes an initial assessment of their gait cycle - Gait analysis, creation of a plan to address the problem, as well as teaching the patient on how to walk on different surfaces. Assistive devices and splints (orthosis) are often used in gait training, especially with those who have had surgery or an injury on their legs, but also with those who have balance or strength impairments as well.

Sacral nerve stimulation, also termed sacral neuromodulation, is a type of medical electrical stimulation therapy.

<span class="mw-page-title-main">Orthotics</span> Medical specialty that focuses on the design and application of orthoses

Orthotics is a medical specialty that focuses on the design and application of orthoses, sometimes known as braces, calipers, or splints. An orthosis is "an externally applied device used to influence the structural and functional characteristics of the neuromuscular and skeletal systems." Orthotists are medical professionals who specialize in designing orthotic devices such as braces or foot orthoses.

When treating a person with a spinal cord injury, repairing the damage created by injury is the ultimate goal. By using a variety of treatments, greater improvements are achieved, and, therefore, treatment should not be limited to one method. Furthermore, increasing activity will increase his/her chances of recovery.

<span class="mw-page-title-main">Neuromechanics</span> Interdisciplinary field

Neuromechanics is an interdisciplinary field that combines biomechanics and neuroscience to understand how the nervous system interacts with the skeletal and muscular systems to enable animals to move. In a motor task, like reaching for an object, neural commands are sent to motor neurons to activate a set of muscles, called muscle synergies. Given which muscles are activated and how they are connected to the skeleton, there will be a corresponding and specific movement of the body. In addition to participating in reflexes, neuromechanical process may also be shaped through motor adaptation and learning.

Neuromodulation is "the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body". It is carried out to normalize – or modulate – nervous tissue function. Neuromodulation is an evolving therapy that can involve a range of electromagnetic stimuli such as a magnetic field (rTMS), an electric current, or a drug instilled directly in the subdural space. Emerging applications involve targeted introduction of genes or gene regulators and light (optogenetics), and by 2014, these had been at minimum demonstrated in mammalian models, or first-in-human data had been acquired. The most clinical experience has been with electrical stimulation.

<span class="mw-page-title-main">Lumbar anterior root stimulator</span> Neuroprosthesis

A lumbar anterior root stimulator is a type of neuroprosthesis used in patients with a spinal cord injury or to treat some forms of chronic spinal pain. More specifically, the root stimulator can be used in patients who have lost proper bowel function due to damaged neurons related to gastrointestinal control and potentially allow paraplegics to exercise otherwise paralyzed leg muscles.

A peripheral nerve interface is the bridge between the peripheral nervous system and a computer interface which serves as a bi‐directional information transducer recording and sending signals between the human body and a machine processor. Interfaces to the nervous system usually take the form of electrodes for stimulation and recording, though chemical stimulation and sensing are possible. Research in this area is focused on developing peripheral nerve interfaces for the restoration of function following disease or injury to minimize associated losses. Peripheral nerve interfaces also enable electrical stimulation and recording of the peripheral nervous system to study the form and function of the peripheral nervous system. For example, recent animal studies have demonstrated high accuracy in tracking physiological meaningful measures, like joint angle. Many researchers also focus in the area of neuroprosthesis, linking the human nervous system to bionics in order to mimic natural sensorimotor control and function. Successful implantation of peripheral nerve interfaces depend on a number of factors which include appropriate indication, perioperative testing, differentiated planning, and functional training. Typically microelectrode devices are implanted adjacent to, around or within the nerve trunk to establish contact with the peripheral nervous system. Different approaches may be used depending on the type of signal desired and attainable.

<span class="mw-page-title-main">Cutaneous reflex in human locomotion</span>

Cutaneous, superficial, or skin reflexes, are activated by skin receptors and play a valuable role in locomotion, providing quick responses to unexpected environmental challenges. They have been shown to be important in responses to obstacles or stumbling, in preparing for visually challenging terrain, and for assistance in making adjustments when instability is introduced. In addition to the role in normal locomotion, cutaneous reflexes are being studied for their potential in enhancing rehabilitation therapy (physiotherapy) for people with gait abnormalities.

Spinal cord injury research seeks new ways to cure or treat spinal cord injury in order to lessen the debilitating effects of the injury in the short or long term. There is no cure for SCI, and current treatments are mostly focused on spinal cord injury rehabilitation and management of the secondary effects of the condition. Two major areas of research include neuroprotection, ways to prevent damage to cells caused by biological processes that take place in the body after the injury, and neuroregeneration, regrowing or replacing damaged neural circuits.

<span class="mw-page-title-main">Mesencephalic locomotor region</span>

The mesencephalic locomotor region (MLR) is a functionally defined area of the midbrain that is associated with the initiation and control of locomotor movements in vertebrate species.

<span class="mw-page-title-main">Milos R. Popovic</span>

Milos R. Popovic is a scientist specializing in Functional Electrical Stimulation (FES) and neurorehabilitation. As of 2018, he is Director of the KITE Research Institute at UHN Toronto Rehabilitation Institute (TRI), and a Professor with the Institute of Biomaterials and Biomedical Engineering at the University of Toronto.

References

  1. 1 2 M.R. Popovic, K. Masani and S. Micera, "Chapter 9 – Functional Electrical Stimulation Therapy: Recovery of function following spinal cord injury and stroke," In press, Neurorehabilitation Technology – Second Edition, Z. Rymer, T. Nef and V. Dietz, Ed. Springer Science Publishers in November 2015.
  2. ↑ M. Claudia et al., (2000), Artificial Grasping System for the Paralyzed Hand, International Society for Artificial Organs, Vol. 24 No. 3
  3. ↑ M.K. Nagai, C. Marquez-Chin, and M.R. Popovic, "Why is functional electrical stimulation therapy capable of restoring motor function following severe injury to the central nervous system?" Translational Neuroscience, Mark Tuszynski, Ed. Springer Science and Business Media LLC, pp: 479-498, 2016.
  4. 1 2 Kapadia N., Masani K., Craven B.C., Giangregorio L.M., Hitzig S.L., Richards K., Popovic M.R. (2014). "A randomized trial of functional electrical stimulation for walking in incomplete spinal cord injury: Effects on walking competency". The Journal of Spinal Cord Medicine. 37 (5): 511–524. doi:10.1179/2045772314y.0000000263. PMC   4166186 . PMID   25229735.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ↑ Thrasher TA, Zivanovic V, McIlroy W, Popovic MR (29 October 2008). "Rehabilitation of Reaching and Grasping Function in Severe Hemiplegic Patients Using Functional Electrical Stimulation Therapy". Neurorehabilitation and Neural Repair. 22 (6): 706–714. doi:10.1177/1545968308317436. PMID   18971385. S2CID   7016540.
  6. ↑ Marquez-Chin C, Bagher S, Zivanovic V, Popovic MR (17 January 2017). "Functional electrical stimulation therapy for severe hemiplegia: Randomized control trial revisited: La simulation électrique fonctionnelle pour le traitement d'une hémiplégie sévère : un essai clinique aléatoire revisité". Canadian Journal of Occupational Therapy. 84 (2): 87–97. doi:10.1177/0008417416668370. PMID   28093928. S2CID   24856751.
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