Posts Tagged Stroke

[ARTICLE] Brain-actuated functional electrical stimulation elicits lasting arm motor recovery after stroke – Full Text

Abstract

Brain-computer interfaces (BCI) are used in stroke rehabilitation to translate brain signals into intended movements of the paralyzed limb. However, the efficacy and mechanisms of BCI-based therapies remain unclear. Here we show that BCI coupled to functional electrical stimulation (FES) elicits significant, clinically relevant, and lasting motor recovery in chronic stroke survivors more effectively than sham FES. Such recovery is associated to quantitative signatures of functional neuroplasticity. BCI patients exhibit a significant functional recovery after the intervention, which remains 6–12 months after the end of therapy. Electroencephalography analysis pinpoints significant differences in favor of the BCI group, mainly consisting in an increase in functional connectivity between motor areas in the affected hemisphere. This increase is significantly correlated with functional improvement. Results illustrate how a BCI–FES therapy can drive significant functional recovery and purposeful plasticity thanks to contingent activation of body natural efferent and afferent pathways.

Introduction

Despite considerable efforts over the last decades, the quest for novel treatments for arm functional recovery after stroke remains a priority1. Synergistic efforts in neural engineering and restoration medicine are demonstrating how neuroprosthetic approaches can control devices and ultimately restore body function2,3,4,5,6,7. In particular, non-invasive brain-computer interfaces (BCI) are reaching their technological maturity8,9 and translate neural activity into meaningful outputs that might drive activity-dependent neuroplasticity and functional motor recovery10,11,12. BCI implies learning to modify the neuronal activity through progressive practice with contingent feedback and reward —sharing its neurobiological basis with rehabilitation13.

Most attempts to use non-invasive BCI systems for upper limb rehabilitation after stroke have coupled them with other interventions, although not all trials reported clinical benefits. The majority of these studies are case reports of patients who operated a BCI to control either rehabilitation robots14,15,16,17,18,19 or functional electrical stimulation (FES)20,21,22,23. A few works have described changes in functional magnetic resonance imaging (fMRI) that correlate with motor improvements17,18,22.

Recent controlled trials have shown the potential benefit of BCI-based therapies24,25,26,27. Pichiorri et al.26recruited 28 subacute patients and studied the efficacy of motor imagery with or without BCI support via visual feedback, reporting a significant and clinically relevant functional recovery for the BCI group. As a step forward in the design of multimodal interventions, BCI-aided robotic therapies yielded significantly greater motor gains than robotic therapies alone24,25,27. In the first study, involving 30 chronic patients24, only the BCI group exhibited a functional improvement. In the second study, involving 14 subacute and chronic patients, both groups improved, probably reflecting the larger variance in subacute patients’ recovery and a milder disability25. The last study27 showed that in a mixed population of 74 subacute and chronic patients, the percentage of patients who achieved minimally clinical important difference in upper limb functionality was higher in the BCI group. The effect in favor of the BCI group was only evident in the sub-population of chronic patients. Moreover, the conclusions of this study are limited due to differences between experimental and control groups prior to the intervention, such as number of patients and FMA-UE scores, which were always in favor of the BCI group.

In spite of promising results achieved so far, BCI-based stroke rehabilitation is still a young field where different works report variable clinical outcomes. Furthermore, the efficacy and mechanisms of BCI-based therapies remain largely unclear. We hypothesize that, for BCI to boost beneficial functional activity-dependent plasticity able to attain clinically important outcomes, the basic premise is contingency between suitable motor-related cortical activity and rich afferent feedback. Our approach is designed to deliver associated contingent feedback that is not only functionally meaningful (e.g., via virtual reality or passive movement of the paretic limb by a robot), but also tailored to reorganize the targeted neural circuits by providing rich sensory inputs via the natural afferent pathways28, so as to activate all spare components of the central nervous system involved in motor control. FES fulfills these two properties of feedback contingent on appropriate patterns of neural activity; it elicits functional movements and conveys proprioceptive and somatosensory information, in particular via massive recruitment of Golgi tendon organs and muscle spindle feedback circuits. Moreover, several studies suggest that FES has an impact on cortical excitability29,30.

To test our hypothesis, this study assessed whether BCI-actuated FES therapy targeting the extension of the affected hand (BCI–FES) could yield stronger and clinically relevant functional recovery than sham-FES therapy for chronic stroke patients with a moderate-to-severe disability, and whether signatures of functional neuroplasticity would be associated with motor improvement. Whenever the BCI decoded a hand-extension attempt, it activated FES of the extensor digitorum communis muscle that elicited a full extension of the wrist and fingers. Patients in the sham-FES group wore identical hardware and received identical instructions as BCI–FES patients, but FES was delivered randomly and not driven by neural activity.

As hypothesized, our results confirm that only the BCI group exhibit a significant functional recovery after the intervention, which is retained 6–12 months after the end of therapy. Besides the main clinical findings, we have also attempted to shed light on possible mechanisms underlying the proposed intervention. Specifically, electroencephalography (EEG) imaging pinpoint significant differences in favor of the BCI group, mainly an increase in functional connectivity between motor areas in the affected hemisphere. This increase is significantly correlated with functional improvement. Furthermore, analysis of the therapeutic sessions substantiates that contingency between motor-related brain activity and FES occurs only in the BCI group and contingency-based metrics correlate with the functional improvement and increase in functional connectivity, suggesting that our BCI intervention might have promoted activity-dependent plasticity.[…]

Continue —> Brain-actuated functional electrical stimulation elicits lasting arm motor recovery after stroke | Nature Communications

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[BLOG POST] A Dual-Therapy Approach to Boost Motor Recovery After a Stroke

Stroke victims have a reason to finally smile as a new therapy approach promises to help them recover greater use of their paralyzed leg and/or arm. In a recent study, researchers managed to demonstrate that indeed, broken sensory nerve connections can be reconstructed without surgery, but using two therapies at the same time.

The technique combines functional electrical stimulation (FES) and brain-computer interface BCI to help “resurrect” the use of paralyzed limb (arm/leg). In most cases, paralysis happens to be the most general but hard to bear effects of a stroke. Fortunately, research now seems to have a solution for treating this effect.

Communication Between Nerve Pathways

While the approach may not be something completely out of the horizon, this is the first time experts considered deploying two therapies at the same time on stroke effects (FES + BCI). The therapy works to help reestablish communication between nerve pathways, which ideally corrects how signals come in and go out of the nerve segment endings.

“The goal is to stimulate those nerves thought to have been silenced by the paralysis. This should be the work of the brain. But as the part of the brain tasked to do this may no longer be active enough, the therapy steps in to help reestablish the links between (the brain) and the nerve pathways,” explains Jose del R. Millan, one of the scientists involve in the research, which was pioneered by the Defitech Foundation Brain and Machine Interface.

Degrees of Paralysis

The work, which also appears in the latest issue of Nature Communications focused on mid-age and aged adults of between 36 to 76, and involved 27 volunteers with varying stroke effects. A section of the patients had moderate paralysis, while for the rest the cases were considered as severe arm paralysis occurring less than a year prior to the dual-therapy.

Representing half of the volunteering team, 14 of the patients took the dual-therapy and the results found a significant lasting improvement in the ability to initiate control of their affected arms. The other half of the volunteers took the functional electrical stimulation (FES) treatment only and acted as a control team to help monitor progress.

Hunting for the Brain Signals

Now, the scientists introduced the BCI system to access the patient’s brain response, linking the same to computers via electrodes. The exact task was to pinpoint the specific areas the electrical signals showed up in the brain as the patient tried to pick something using the affected arm.

When the electrical activity was spotted the system immediately stimulated the concerned muscle in the wrist and finger to have it respond to the signal. Patients in the “control” group had their muscles stimulated but not as often as the first team. That was done on purpose to help establish the motor-function improvement that could directly be attributed to the BCI system and the reliability of the same.

Reactivated Tissue and How this Changes Stroke Effect Therapy

Source: braceworks

What makes the research outstanding is that some patients in the first group registered a significant improvement in arm mobility within the first ten one-hour therapy sessions. Using a special test that evaluates motor recovery on post-stroke hemiplegia, called the Fugl-Meyer Assessment, a good number of the patients in the first group improved in their mobility twice in score compared to their counterparts.

The scientists also found an overall increase in connection among the motor cortex areas of their damaged brain, which corresponded with the overall ease in undertaking the associated tasks.

This might, without doubt, be the complete game changer of the way effects of stroke should be treated, because, even after 6 and 12 months – looking at the progress of the patients, their recovered mobility from the dual-therapy was maintained.

 

via A Dual-Therapy Approach to Boost Motor Recovery After a Stroke – Sanvada

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[ARTICLE] Randomized controlled trial of robot-assisted gait training with dorsiflexion assistance on chronic stroke patients wearing ankle-foot-orthosis – Full Text

Abstract

Background

Robot-assisted ankle-foot-orthosis (AFO) can provide immediate powered ankle assistance in post-stroke gait training. Our research team has developed a novel lightweight portable robot-assisted AFO which is capable of detecting walking intentions using sensor feedback of wearer’s gait pattern. This study aims to investigate the therapeutic effects of robot-assisted gait training with ankle dorsiflexion assistance.

Methods

This was a double-blinded randomized controlled trial. Nineteen chronic stroke patients with motor impairment at ankle participated in 20-session robot-assisted gait training for about five weeks, with 30-min over-ground walking and stair ambulation practices. Robot-assisted AFO either provided active powered ankle assistance during swing phase in Robotic Group (n = 9), or torque impedance at ankle joint as passive AFO in Sham Group (n = 10). Functional assessments were performed before and after the 20-session gait training with 3-month Follow-up. Primary outcome measure was gait independency assessed by Functional Ambulatory Category (FAC). Secondary outcome measures were clinical scores including Fugl-Meyer Assessment (FMA), Modified Ashworth Scale (MAS), Berg Balance Scale (BBS), Timed 10-Meter Walk Test (10MWT), Six-minute Walk Test (SMWT), supplemented by gait analysis. All outcome measures were performed in unassisted gait after patients had taken off the robot-assisted AFO. Repeated-measures analysis of covariance was conducted to test the group differences referenced to clinical scores before training.

Results

After 20-session robot-assisted gait training with ankle dorsiflexion assistance, the active ankle assistance in Robotic Group induced changes in gait pattern with improved gait independency (all patients FAC ≥ 5 post-training and 3-month follow-up), motor recovery, walking speed, and greater confidence in affected side loading response (vertical ground reaction force + 1.49 N/kg, peak braking force + 0.24 N/kg) with heel strike instead of flat foot touch-down at initial contact (foot tilting + 1.91°). Sham Group reported reduction in affected leg range of motion (ankle dorsiflexion − 2.36° and knee flexion − 8.48°) during swing.

Conclusions

Robot-assisted gait training with ankle dorsiflexion assistance could improve gait independency and help stroke patients developing confidence in weight acceptance, but future development of robot-assisted AFO should consider more lightweight and custom-fit design.

Background

Stroke is caused by intracranial haemorrhage or thrombosis, which cuts off arterial supply to brain tissue and usually damages the motor pathway of the central nervous system affecting one side of the body. About half of the stroke survivors cannot walk at stroke onset, but they have 60% chance to regain independent walking after rehabilitation [1]. Reduced descending neural drive to the paretic ankle joint causes muscle weakness and spasticity, often accompanied with drop foot which is characterized by the foot pointing downward and dragging on the ground during walking [23]. To maintain sufficient foot clearance in swing phase, people with dropped foot have to compensate either by hip hiking with exaggerated flexion in hip and knee joints, or circumduction gait with the body leaning on the unaffected side and the leg swinging outward through an arc away from the midline [456]. These inefficient asymmetric gait patterns hinder the walking ability and contribute to slower walking speed [78], increasing risk of falling [910], and greater energy expenditure [11]. Poor mobility results in sedentary lifestyle and limited physical exercise [12], which further deteriorates lower-limb functionality.

Foot drop can be managed using ankle-foot-orthosis (AFO), which is rigid or articulated ankle brace that controls ankle range of motion (ROM). Meta-analysis shows walking in conventional AFO has immediate or short-term beneficial effects on gait pattern and mobility of stroke patients, including an overall increase in ankle dorsiflexion throughout gait cycle, improvements in Functional Ambulatory Category (FAC), walking speed, and stairs-climbing speed [131415]. Recent development in robot-assisted AFO demonstrates power assistance at ankle joint can facilitate walking of patients presenting with foot drop, by actively assisting ankle dorsiflexion for foot clearance in swing phase and minimizing occurrence of foot slap at initial contact [161718]. Previous studies only evaluated the immediate effects of stroke patients walking in passive AFO [1415] or robot-assisted AFO [1920], but they were not sure whether any assistive effects could be carried over to unassisted gait after the patients had taken off the devices, i.e. the therapeutic effects.

Neuroscience studies suggest the brain is capable of altering its functions and structures for adapting to internal and external environment; an ability known as neuroplasticity [22122]. Researches show intensive repetitive skill training can enhance neuroplasticity and promote motor relearning of stroke patients [2324], which is achievable utilizing robot-assistance in clinical setting. The Anklebot that was developed in MIT can provide power assistance to stroke patients performing repetitive voluntary ankle sagittal movements in seated position, and a single-arm pilot study reports stroke patients (n = 8) had improved volitional ankle control and spatial-temporal gait parameters after 6-week 18-session training using the Anklebot [25]; 30-min seated skill training at ankle joint can induce plastic changes in cortical excitability in area controlling dorsiflexor [26]. Thus robot-assisted AFO with dorsiflexion assistance can potentially stimulate motor recovery of stroke patients with foot drop problem. Neuroscience studies further show the functional outcome of neuroplasticity is task-specific and dependent on the training nature [2212227]. It implies that in order to improve independent walking ability, stroke patients are expected to practise real over-ground walking instead of seated training. Incorporation of stair ambulation into gait training could facilitate generalization towards activity of daily-living, which requires stroke patients to perform skilled ankle dorsiflexion and plantarflexion when they are negotiating steps. Another characteristics of neuroplasticity is the importance of salient experiences for motor relearning from error correction [22122]. During gait training, powered ankle assistance from a robot-assisted AFO could serve as a source of salient proprioceptive feedback synchronized to gait pattern [28]. The robot can strengthen the experience-driven neuroplasticity by producing this proprioceptive feedback at each successfully triggered ankle power assistance [28]. In summary, researches on experience-driven neuroplasticity suggest stroke patients presenting with foot drop problem can potentially restore some level of independent walking ability through robot-assisted gait training with ankle dorsiflexion assistance on over-ground walking and stair ambulation.

To our knowledge, up to now no randomized controlled trial (RCT) has been carried out to validate the rehabilitation approach of robot-assisted AFO [2930]. The current study aims to evaluate whether gait training with robot-assisted AFO with dorsiflexion assistance can bring greater improvement in independent walking ability than training with passive AFO. In each session, stroke patients were trained in 20-min over-ground walking and 10-min stair ambulation. Assessments on the participating stroke patients focused on functional changes in unassisted gait after they had discontinued to wear the devices, i.e. the therapeutic effects. A meta-analysis study recommends FAC to be the primary outcome measure for clinical trials involving electromechanical gait training [30]. FAC is a reliable measurement of independent walking ability on level ground walking and stair ambulation, which is a good prediction of independent community walking post-stroke [31]. The demonstration of safety and effectiveness of the robot-assisted gait training can have positive impact on post-stroke rehabilitation and can potentially establish a new treatment method for stroke patients presenting with foot drop.[…]

 

Continue —>  Randomized controlled trial of robot-assisted gait training with dorsiflexion assistance on chronic stroke patients wearing ankle-foot-orthosis | Journal of NeuroEngineering and Rehabilitation | Full Text

Figure 1

Fig. 1a Robot-assisted AFO, and b Stroke patients walking on stairs wearing the robot-assisted AFO

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[ARTICLE] Post-stroke Spasticity: A Review of Epidemiology, Pathophysiology, and Treatments – Full Text

Summary

Spasticity is a common condition in stroke survivors, and may be associated with pain and joint contracture, leading to poor quality of life and increased caregiver burden. Although the underlying mechanisms are not well-understood, it may be due to disruption of the balance of supra-spinal inhibitory and excitatory sensory inputs directed to the spinal cord, leading to a state of disinhibition of the stretch reflex. The treatment options include physical therapy, modality and pharmacological treatments, neurolysis with phenol and botulinum toxin, and surgical treatment. A successful treatment of spasticity depends on a clear comprehension of the underlying pathophysiology, natural history, and impact on patient’s performances. This review focuses on the epidemiology, presumed mechanism, clinical manifestation, and recent evidences of management.

Keywords

  • stroke,
  • muscle spasticity,
  • mechanism,
  • symptom management

1. Introduction

Stroke is one of the leading causes of mortality and morbidity in adults in most countries.12 ;  3 Spasticity is a common, but not an inevitable condition, in patients with stroke. Spasticity following stroke is often associated with pain, soft tissue stiffness, and joint contracture, and may lead to abnormal limb posture, decreased quality of life, increased treatment cost, and increased caregiver burden.4 Early detection and management of post-stroke spasticity may not only reduce these complications, but may also improve function and increase independency in patients with spasticity.

Spasticity was first described by Lance5 in 1980 as a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes (muscle tone), with exaggerated tendon jerks, resulting from hyper-excitability of the neurons involved in stretch reflex, as a component of the upper motor neuron syndrome. This definition is useful in clinical practice, because the guideline “velocity-dependent increase in tonic stretch reflexes,” can distinguish spasticity from other similar movement disorders such as hypertonia, rigidity, and hyperreflexia. However, this definition ignores the important aspect of sensory input in the experience of spasticity. Some studies have found that abnormal processing of sensory inputs from muscle spindles leads to excessive reflex activation of alpha-motoneurons, and increases spasticity. The new definition from the Support Program for Assembly of a Database for Spasticity Measurement (SPASM) project defines spasticity as “disordered sensory-motor control, resulting from an upper motor neuron lesion, presenting as intermittent or sustained involuntary activation of muscles”.6This definition takes into account the contribution of viscoelastic properties of soft tissue to joint stiffness, and the roles of proprioceptive and cutaneous sensory pathways.[…]

Continue —>  Post-stroke Spasticity: A Review of Epidemiology, Pathophysiology, and Treatments

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[WEB SITE] Kessler Foundation partners with Motek to develop new rehabilitation treatments

Researchers will investigate virtual reality-based interventions to improve cognitive and motor deficits in individuals with disabilities

KESSLER FOUNDATION

IMAGE

IMAGE: PARTICIPANT WALKING ON C-MILL WITH RESEARCH SCIENTIST AT KESSLER FOUNDATION.

Kessler Foundation, a major nonprofit organization in the field of disability, has partnered with Motek, a leader in virtual reality (VR) rehabilitation technologies, to develop new treatments to improve cognitive and motor impairments in individuals with disabilities.

Mobility deficits due to disease, trauma, or aging, adversely affect a person’s quality of life. Specifically, the inability to adjust one’s gait to one’s environment – such as to maneuver a doorstep, puddle of water or other obstacles – leads to increased risk of falling. Using a VR-based device called C-Mill, investigators at Kessler Foundation are exploring interventions to improve disabling deficits in individuals with multiple sclerosis, spinal cord injury, and stroke. The C-Mill is a state-of-the-art treadmill that trains the user in obstacle avoidance and influences gait pattern by projecting virtual cues on a safe walking surface.

“The flexibility of the C-Mill allows researchers to program for specific environments, enabling better training and evaluation of gait pattern and gait adaptability,” said Guang Yue, PhD, director of Human Performance and Engineering Research at Kessler Foundation. “New technologies such as C-Mill enable researchers to develop universal standards for measuring and improving mobility. This exciting collaboration advances our mission to improve mobility, independence and quality of life for individuals with disabilities caused by a range of neurological conditions.”

Investigators will use advanced brain imaging technology at the Rocco Ortenzio Neuroimaging Center at Kessler Foundation to examine the neurofunctional changes underlying cognitive and motor improvements in individuals in studies testing the C-Mill. The findings of these studies may help reduce loss of independence and improve daily functioning in people with disabilities by providing critical biomarkers for post-intervention changes in learning and memory, fatigue, gait and balance.

“Motek gives clinicians and researchers the tools they need to provide dynamic, high-quality technology solutions that can be customized to meet the patient’s needs,” said Frans Steenbrink, PhD, Head of Clinical Applications & Research at Motek. “With this strategic partnership, Motek and Kessler Foundation aim to facilitate both the integration of our technology in clinical settings and the accommodation of different patient populations. Together, we will create a strong scientific network that will push evidence-based clinical research into the underlying mechanisms of impaired gait and balance control. Furthermore, we hope to extend this strategic partnership with Kessler Foundation to the entire DIH Group, laying the groundwork for numerous future innovations.”

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For more information, or to enroll in a Kessler Foundation study, contact our Research Recruitment Specialist: researchstudies@kesslerfoundation.org.

About Motek

Motek is the global leader in virtual reality and robotics research and rehabilitation, combining almost 20 years of experience in high-level technologies. We excel in building the most versatile devices, integrating latest VR, motion capture and multiple sensory technologies and ensuring real-time feedback, data quality and synchronization. Our treadmill- and balance platform-based systems, arm movement tools or body weight supports are easily interconnected through our in-house software platform. From global knowledge exchange to unique research set-ups: with our all-round support package, we are the perfect partner for every stage of your research on human movement. Motek is a proud partner of DIH International and Hocoma and is part of the DIH Rehabilitation Division.

About Human Performance & Engineering Research at Kessler Foundation

Under the leadership of Guang Yue, PhD, six areas of specialized research are headed by experts in biomechanics, bioengineering, movement analysis, robotics, neurophysiology and neuroimaging. All areas of specialized research contribute to the common goal to improve mobility and motor function so individuals with disabilities can participate fully in school, work, and community activities. Their efforts fuel innovative approaches to address disabling conditions, including brain injury, spinal cord injury, multiple sclerosis, cerebral palsy, arthritis and cancer.

Research is funded by the National Institute on Disability, Independent Living & Rehabilitation Research, National Institutes of Health, Department of Defense, Reeve Foundation, New Jersey Commission on Spinal Cord Injury Research, Craig H. Neilsen Foundation, and Children’s Specialized Hospital.

About Kessler Foundation

Kessler Foundation, a major nonprofit organization in the field of disability, is a global leader in rehabilitation research that seeks to improve cognition, mobility and long-term outcomes, including employment, for people with neurological disabilities caused by diseases and injuries of the brain and spinal cord. Kessler Foundation leads the nation in funding innovative programs that expand opportunities for employment for people with disabilities.

Learn more by visiting http://www.KesslerFoundation.org.Stay Connected

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via Kessler Foundation partners with Motek to develop new rehabilitation treatments | EurekAlert! Science News

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[ARTICLE] Combining Upper Limb Robotic Rehabilitation with Other Therapeutic Approaches after Stroke: Current Status, Rationale, and Challenges – Full Text

Abstract

A better understanding of the neural substrates that underlie motor recovery after stroke has led to the development of innovative rehabilitation strategies and tools that incorporate key elements of motor skill relearning, that is, intensive motor training involving goal-oriented repeated movements. Robotic devices for the upper limb are increasingly used in rehabilitation. Studies have demonstrated the effectiveness of these devices in reducing motor impairments, but less so for the improvement of upper limb function. Other studies have begun to investigate the benefits of combined approaches that target muscle function (functional electrical stimulation and botulinum toxin injections), modulate neural activity (noninvasive brain stimulation), and enhance motivation (virtual reality) in an attempt to potentialize the benefits of robot-mediated training. The aim of this paper is to overview the current status of such combined treatments and to analyze the rationale behind them.

1. Introduction

Significant advances have been made in the management of stroke (including prevention, acute management, and rehabilitation); however cerebrovascular diseases remain the third most common cause of death and the first cause of disability worldwide [16]. Stroke causes brain damage, leading to loss of motor function. Upper limb (UL) function is particularly reduced, resulting in disability. Many rehabilitation techniques have been developed over the last decades to facilitate motor recovery of the UL in order to improve functional ability and quality of life [710]. They are commonly based on principles of motor skill learning to promote plasticity of motor neural networks. These principles include intensive, repetitive, task-oriented movement-based training [1119]. A better understanding of the neural substrates of motor relearning has led to the development of innovative strategies and tools to deliver exercise that meets these requirements. Treatments mostly target the neurological impairment (paresis, spasticity, etc.) through the activation of neural circuits or by acting on peripheral effectors. Robotic devices provide exercises that incorporate key elements of motor learning. Advanced robotic systems can offer highly repetitive, reproducible, interactive forms of training for the paretic limb, which are quantifiable. Robotic devices also enable easy and objective assessment of motor performance in standardized conditions by the recording of biomechanical data (i.e., speed, forces) [2022]. This data can be used to analyze and assess motor recovery in stroke patients [2326]. Since the 1990s, many other technology-based approaches and innovative pharmaceutical treatments have also been developed for rehabilitation, including virtual reality- (VR-) based systems, botulinum neurotoxin (BoNT) injections, and noninvasive brain stimulation (NIBS) (Direct Current Stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS)). There is currently no high-quality evidence to support any of these innovative interventions, despite the fact that some are used in routine practice [27]. By their respective mechanisms of action, each of these treatments could potentiate the effects of robotic therapy, leading to greater improvements in motor capacity. The aim of this paper is to review studies of combined treatments based on robotic rehabilitation and to analyze the rationale behind such approaches.[…]

 

Continue —> Combining Upper Limb Robotic Rehabilitation with Other Therapeutic Approaches after Stroke: Current Status, Rationale, and Challenges

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[WEB SITE] What is clonus? Everything you need to know

Clonus is a neurological condition that occurs when nerve cells that control the muscles are damaged. This damage causes involuntary muscle contractions or spasms.

Clonus spasms often occur in a rhythmic pattern. Symptoms are common in a few different muscles, especially in the extremities. These include the:

  • ankles
  • knees
  • calves
  • wrists
  • jaw
  • biceps

Damaged nerves can cause muscles to misfire, leading to involuntary contractions, muscle tightness, and pain.

Clonus can cause a muscle to pulse for an extended period. This pulsing can lead to muscle fatigue, which may make it difficult for a person to use the muscle later.

Clonus can make everyday activities strenuous and can even be debilitating. In this article, learn more about the causes and treatment.

Causes

Nerve cells in muscles causing clonus

Damaged nerve cells cause clonus.

While researchers do not understand the exact cause of clonus, it appears to be due to damaged nerve passageways in the brain.

A number of chronic conditions are associated with clonus. As these conditions require specialized treatment, the outcome may vary in each case.

Conditions associated with clonus include:

Multiple sclerosis (MS) is an autoimmune disorder that attacks the protective sheath around the nerves. The resulting damage disrupts the nerve signals in the brain.

A stroke starves a part of the brain of oxygen, usually due to a blood clot. A stroke may cause clonus if it damages the area in the brain that controls movement.

Infections, such as meningitis or encephalitis, can damage brain cells or nerves if they become severe.

Major injuries, such as head trauma from a major accident, may also damage the nerves in the brain or spinal cord.

Serotonin syndrome is a potentially dangerous reaction that occurs if too much serotonin builds up in the body. This buildup could be due to drug abuse, but it may also be caused by taking high doses of medications or mixing certain medical drugs.

A brain tumor that pushes against the motor neurons in the brain or causes these areas to swell may lead to clonus.

Other causes of clonus include anything that has the potential to affect the nerves or brain cells, including:

  • cerebral palsy
  • Lou Gehrig’s disease
  • anoxic brain injury
  • hereditary spastic paraparesis
  • kidney or liver failure
  • overdoses of drugs such as Tramadol, which is a strong painkiller

Clonus tests

Clonus may be diagnosed using an MRI scan.

An MRI scan may be used to diagnose clonus.

To diagnose clonus, doctors may first physically examine the area that is most affected. If a muscle contracts while a person is in the doctor’s office, they may monitor the contraction to see how fast the muscle is pulsing and how many times it contracts before stopping.

Doctors will then order a specific series of tests to help them confirm the diagnosis. They may use magnetic resonance imaging (MRI) to check for damage to the cells or nerves.

Blood tests may also help identify markers for various conditions associated with clonus.

A physical test may also help doctors identify clonus. During this test, they will ask the person to quickly flex their foot, so their toes are pointing upward and then hold the muscle there.

This may cause a sustained pulsing in the ankle. A series of these pulses may indicate clonus. Doctors do not rely on this test to diagnose clonus, but it can help point them in the right direction during the diagnostic process.

Treatment

Treatment for clonus varies depending on the underlying cause. Doctors may try many different treatment methods before finding the one that works best for each person.

Medications

Sedative medications and muscle relaxers help reduce clonus symptoms. Doctors often recommend these drugs in the first instance for people experiencing clonus.

Medications that may help with clonus contractions include:

  • baclofen (Lioresal)
  • dantrolene (Dantrium)
  • tizanidine (Zanaflex)
  • gabapentin (Neurotonin)
  • diazepam (Valium)
  • clonazepam (Klonopin)

Sedatives and anti-spasticity medications can cause drowsiness or sleepiness. People taking these medications should not drive a car or operate heavy machinery.

Other side effects may include mental confusion, lightheadedness, or even trouble walking. A person should discuss these side effects with a doctor, especially if they are likely to disrupt a person’s work or everyday activities.

Other treatments

Clonus may be treated with physical therapy.

Physical therapy may help treat clonus.

Other than medication, treatments that may help reduce clonus include:

Physical therapy

Working with a physical therapist to stretch or exercise the muscles may help increase the range of motion in the damaged area. Some therapists may recommend wrist or ankle splints for some people as they can provide structure and improve stability, reducing the risk of accidents.

Botox injections

Some people with clonus respond well to Botox injections. Botox therapy involves injecting specific toxins to paralyze muscles in the area. The effects of Botox injections wear off over time so a person will require repeat injections on a regular basis.

Surgery

Surgery is often the last resort. During a procedure to treat clonus, surgeons will cut away parts of the nerve that are causing abnormal muscle movements, which should relieve symptoms.

Home remedies

While medical treatments for clonus are important, home remedies can be valuable in supporting these efforts.

Using heat packs or taking warm baths may relieve pain, while applying cold packs may help reduce muscle aches. Stretching and yoga may help promote an increased range of motion.

Some people may also find a magnesium supplement or magnesium salt bath helps relax the muscles. People should speak to a doctor before trying magnesium, as it may interact with other medications.

Outlook

The outlook for clonus may vary according to the underlying cause. Where a sudden injury or illness causes clonus and muscle spasms, the symptoms will likely go away over time or respond well to physical therapy.

Chronic conditions such as multiple sclerosis, meningitis, or a stroke may require long-term treatments for symptom management.

Clonus may sometimes get worse if the underlying condition progresses. Many people find they can manage symptoms by working closely with a doctor and physical therapist.

via Clonus: Definition, causes, tests, and treatment

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[Abstract+References] Greater Cortical Thickness Is Associated With Enhanced Sensory Function After Arm Rehabilitation in Chronic Stroke

Objective. Somatosensory function is critical to normal motor control. After stroke, dysfunction of the sensory systems prevents normal motor function and degrades quality of life. Structural neuroplasticity underpinnings of sensory recovery after stroke are not fully understood. The objective of this study was to identify changes in bilateral cortical thickness (CT) that may drive recovery of sensory acuity. Methods. Chronic stroke survivors (n = 20) were treated with 12 weeks of rehabilitation. Measures were sensory acuity (monofilament), Fugl-Meyer upper limb and CT change. Permutation-based general linear regression modeling identified cortical regions in which change in CT was associated with change in sensory acuity. Results. For the ipsilesional hemisphere in response to treatment, CT increase was significantly associated with sensory improvement in the area encompassing the occipital pole, lateral occipital cortex (inferior and superior divisions), intracalcarine cortex, cuneal cortex, precuneus cortex, inferior temporal gyrus, occipital fusiform gyrus, supracalcarine cortex, and temporal occipital fusiform cortex. For the contralesional hemisphere, increased CT was associated with improved sensory acuity within the posterior parietal cortex that included supramarginal and angular gyri. Following upper limb therapy, monofilament test score changed from 45.0 ± 13.3 to 42.6 ± 12.9 mm (P = .063) and Fugl-Meyer score changed from 22.1 ± 7.8 to 32.3 ± 10.1 (P < .001). Conclusions. Rehabilitation in the chronic stage after stroke produced structural brain changes that were strongly associated with enhanced sensory acuity. Improved sensory perception was associated with increased CT in bilateral high-order association sensory cortices reflecting the complex nature of sensory function and recovery in response to rehabilitation.

Keywords 

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via Greater Cortical Thickness Is Associated With Enhanced Sensory Function After Arm Rehabilitation in Chronic Stroke – Svetlana Pundik, Aleka Scoco, Margaret Skelly, Jessica P. McCabe, Janis J. Daly, 2018

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[WEB SITE] Electrically Stimulating the Brain May Restore Movement After Stroke

Findings Suggest Potential for Brain Implants to Treat Stroke Patients

UC San Francisco scientists have improved mobility in rats that had experienced debilitating strokes by using electrical stimulation to restore a distinctive pattern of brain cell activity associated with efficient movement. The researchers say they plan to use the new findings to help develop brain implants that might one day restore motor function in human stroke patients.

After a stroke, roughly one-third of patients recover fully, one-third have significant lingering movement problems, and one-third remain virtually paralyzed, said senior author Karunesh Ganguly, MD, PhD, associate professor of neurology and a member of the UCSF Weill Institute for Neurosciences. Even patients who experience partial recovery often continue to struggle with “goal-directed” movements of the arms and hands, such as reaching and manipulating objects, which can be crucial in the workplace and in daily living.

Headshot of Karunesh Ganguly, MD, PhD, associate professor of neurology, study's senior author.
Karunesh Ganguly, MD, PhD, associate professor of neurology, study’s senior author.

 

“Our main impetus was to understand how we can develop implantable neurotechnology to help stroke patients,” said Ganguly, who conducts research at the San Francisco VA Health Care System. “There’s an enormous field growing around the idea of neural implants that can help neural circuits recover and improve function. We were interested in trying to understand the circuit properties of an injured brain relative to a healthy brain and to use this information to tailor neural implants to improve motor function after stroke.”

Over the past 20 years, neuroscientists have presented evidence that coordinated patterns of neural activity known as oscillations are important for efficient brain function.  More recently, low-frequency oscillations (LFOs)—which were first identified in studies of sleep—have been specifically found to help organize the firing of neurons in the brain’s primary motor cortex. The motor cortex controls voluntary movement, and LFOs chunking the cells’ activity together to ensure that goal-directed movements are smooth and efficient.

In the new study, published in the June 18, 2018 issue of Nature Medicine, the researchers first measured neural activity in rats while the animals reached out to grab a small food pellet, a task designed to emulate human goal-directed movements. They detected LFOs immediately before and during the action, which inspired the researchers to investigate how these activity patterns might change after stroke and during recovery.

To explore these questions, they caused a stroke in the rats that impaired the animals’ movement ability, and found that LFOs diminished. In rats that were able to recover, gradually making faster and more precise movements, the LFOs also returned. There was a strong correlation between recovery of function and the reemergence of LFOs: animals that fully recovered had stronger low-frequency activity than those that partially recovered, and those that didn’t recover had virtually no low-frequency activity at all.

To try to boost recovery, the researchers used electrodes to both record activity and to deliver a mild electrical current to the rats’ brains, stimulating the area immediately surrounding the center of the stroke damage. This stimulation consistently enhanced LFOs in the damaged area and appeared to improve motor function: when the researchers delivered a burst of electricity right before a rat made a movement, the rat was up to 60 percent more accurate at reaching and grasping for a food pellet.

“Interestingly, we observed this augmentation of LFOs only on the trials where stimulation was applied,” said Tanuj Gulati, PhD, a postdoctoral researcher in the Ganguly lab who is co-first author of the study, along with Dhakshin Ramanathan, MD, PhD, now assistant professor of psychiatry at UC San Diego, and Ling Guo, a neuroscience graduate student at UCSF.

“We are not creating a new frequency, we are amplifying the existing frequency,” added Ganguly. “By amplifying the weak low-frequency oscillations, we are able to help organize the task-related neural activity. When we delivered the electrical current in step with their intended actions, motor control actually got better.”

The researchers wanted to know whether their findings might also apply to humans, so they analyzed recordings made from the surface of the brain of an epilepsy patient who had suffered a stroke that had impaired the patient’s arm and hand movements. The recordings revealed significantly fewer LFOs than recordings made in two epilepsy patients who hadn’t had a stroke. These findings suggest that, just like in rats, the stroke had caused a loss of low-frequency activity that impaired the patient’s movement.

Physical therapy is the only treatment currently available to aid stroke patients in their recovery. It can help people who are able to recover neurologically get back to being fully functional more quickly, but not those whose stroke damage is too extensive. Ganguly hopes that electrical brain stimulation can offer a much-needed alternative for these latter patients, helping their brain circuits to gain better control of motor neurons that are still functional. Electrical brain stimulation is already widely used to help patients with Parkinson’s disease and epilepsy, and Ganguly believes stroke patients may be the next to benefit.

Other UCSF contributors to the work included Gray Davidson; April Hishinuma; Seok-Joon Won, PhD, associate adjunct professor of neurology; Edward Chang, MD, professor of neurosurgery and William K. Bowes Jr. Biomedical Investigator; and Raymond Swanson, MD, professor of neurology. They were joined by Robert T. Knight, MD, professor of psychology and neuroscience at UC Berkeley.

The research was supported in part by funding from the National Institute of Neurological Disorders and Stroke; the National Institute of Mental Health; the Agency for Science, Technology, and Research (A*STAR), in Singapore; the U.S. Department of Veterans Affairs, and the Burroughs Wellcome Fund.

 

via Electrically Stimulating the Brain May Restore Movement After Stroke | UC San Francisco

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[ARTICLE] Measurements by A LEAP-Based Virtual Glove for the Hand Rehabilitation – Full Text

Abstract

Hand rehabilitation is fundamental after stroke or surgery. Traditional rehabilitation requires a therapist and implies high costs, stress for the patient, and subjective evaluation of the therapy effectiveness. Alternative approaches, based on mechanical and tracking-based gloves, can be really effective when used in virtual reality (VR) environments. Mechanical devices are often expensive, cumbersome, patient specific and hand specific, while tracking-based devices are not affected by these limitations but, especially if based on a single tracking sensor, could suffer from occlusions. In this paper, the implementation of a multi-sensors approach, the Virtual Glove (VG), based on the simultaneous use of two orthogonal LEAP motion controllers, is described. The VG is calibrated and static positioning measurements are compared with those collected with an accurate spatial positioning system. The positioning error is lower than 6 mm in a cylindrical region of interest of radius 10 cm and height 21 cm. Real-time hand tracking measurements are also performed, analysed and reported. Hand tracking measurements show that VG operated in real-time (60 fps), reduced occlusions, and managed two LEAP sensors correctly, without any temporal and spatial discontinuity when skipping from one sensor to the other. A video demonstrating the good performance of VG is also collected and presented in the Supplementary Materials. Results are promising but further work must be done to allow the calculation of the forces exerted by each finger when constrained by mechanical tools (e.g., peg-boards) and for reducing occlusions when grasping these tools. Although the VG is proposed for rehabilitation purposes, it could also be used for tele-operation of tools and robots, and for other VR applications.

1. Introduction

Hand rehabilitation is extremely important for recovering from post-stroke or post-surgery residual impairments and its effectiveness depends on frequency, duration and quality of the rehabilitation sessions [1]. Traditional rehabilitation requires a therapist for driving and controlling patients during sessions. Procedure effectiveness is evaluated subjectively by the therapist, basing on experience. In the last years, several automated (tele)rehabilitation gloves, based on mechanical devices or tracking sensors, have been presented [2,3,4,5,6,7,8,9,10]. These gloves allow the execution of therapy at home and rehabilitation effectiveness can be analytically calculated and summarized in numerical parameters, controlled by therapists through Internet. Moreover, these equipment can be easily interfaced with virtual reality (VR) environments [11], which have been proven to increase rehabilitation efficacy [12]. Mechanical devices are equipped with pressure sensors and pneumatic actuators for assisting and monitoring the hand movements and for applying forces to which the patient has to oppose [13,14]. However, they are expensive, cumbersome, patient specific (different patients cannot reuse the same system) and hand specific (the patient cannot use the same system indifferently with both hands). Tracking-based gloves consist of computer vision algorithms for the analysis and interpretation of videos from depth sensing sensors to calculate hand kinematics in real time [10,15,16,17,18,19]. Besides depth sensors, LEAP [20] is a small and low-cost hand 3D tracking device characterized by high-resolution and high-reactivity [21,22,23], used in VR [24], and has been recently presented and tested with success in the hand rehabilitation, with exercises designed in VR environments [25]. Despite the advantages of using LEAP with VR, a single sensor does not allow accurate quantitative evaluation of hand and fingers tracking in case of occlusions. The system proposed in [10] consisted on two orthogonal LEAPs designed to reduce occlusions and to improve objective hand-tracking evaluation. The two sensors were fixed to a wood support that maintained them orthogonal each other. The previous prototype was useful to test the robustness of each sensor, in presence of the other, to the potential infra-red interferences, to evaluate the maintenance of the maximum operative range of each sensor and, finally, to demonstrate the hand tracking idea. However, it was imprecise, due to the usage of raw VG support and positioning system, the non-optimal reciprocal positioning of the sensors, and the impossibility of performing a reciprocal calibration independent of the sensors measurements. This fact did not allow the evaluation of the intrinsic precision of the VG and to perform accurate, real-time quantitative hand tracking measurements. In this paper, we present a method for constructing an engineered version of the LEAP based VG, a technique for its accurate calibration and for collecting accurate positioning measurements and high-quality evaluation of positioning errors, specific of VG. Moreover, real-time experimental hand tracking measurements were collected (a video demonstrating its real-time performance and precision was also provided in the Supplementary Materials), presented and discussed.[…]

 

Continue —>  Measurements by A LEAP-Based Virtual Glove for the Hand Rehabilitation

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Figure 1
VG mounted on its aluminium support.

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