Posts Tagged Brain stimulation

[Abstract + References] Perspectives: Hemianopia—Toward Novel Treatment Options Based on Oscillatory Activity?

Stroke has become one of the main causes of visual impairment, with more than 15 million incidences of first-time strokes, per year, worldwide. One-third of stroke survivors exhibit visual impairment, and most of them will not fully recover. Some recovery is possible, but this usually happens in the first few weeks after a stroke.

Most of the rehabilitation options that are offered to patients are compensatory, such as optical aids or eye training. However, these techniques do not seem to provide a sufficient amount of improvement transferable to everyday life.

Based on the relatively recent idea that the visual system can actually recover from a chronic lesion, visual retraining protocols have emerged, sometimes even in combination with noninvasive brain stimulation (NIBS), to further boost plastic changes in the residual visual tracts and network.

The present article reviews the underlying mechanisms supporting visual retraining and describes the first clinical trials that applied NIBS combined with visual retraining. As a further perspective, it gathers the scientific evidence demonstrating the relevance of interregional functional synchronization of brain networks for visual field recovery, especially the causal role of α and γ oscillations in parieto-occipital regions.

Because transcranial alternating current stimulation (tACS) can induce frequency-specific entrainment and modulate spike timing–dependent plasticity, we present a new promising interventional approach, consisting of applying physiologically motivated tACS protocols based on multifocal cross-frequency brain stimulation of the visuoattentional network for visual field recovery.

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[WEB PAGE] Upper arm rehabilitation after severe stroke: where are we? – Physics World

10 Sep 2019 Andrea Rampin 
EEG cap

Stroke is the second leading cause of death worldwide and the third cause of induced disability, according to estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study. Treatments based on constraint-induced movement therapy, occupational practice, virtual reality and brain stimulation can work well for patients with mild impairment of upper limb movement, but they are not as effective for those burdened by severe disability. Therefore, novel individualized approaches are needed for this patient group.

Martina Coscia from the Wyss Center for Bio and Neuroengineering in Geneva, and colleagues from several other Swiss institutes, have published a review paper summarizing the most advanced techniques in use today for treatment of severe, chronic stroke patients. The researchers describe techniques being developed for upper limb motor rehabilitation: from robotics and muscular electrical stimulation, to brain stimulation and brain–computer/machine interfaces (Brain 10.1093/brain/awz181).

Robot-aided rehabilitation approaches include movement-assisting exoskeletons and end-effector devices, which enable upper arm movement by stimulating the peripheral nervous system. These techniques can also trigger reorganization of the impaired peripheral nervous system and encourage rehabilitation of the damaged somatosensory system. Several studies have reported the efficiency of robot-aided rehabilitation, alone or in combination with other techniques, in the treatment of upper limb motor impairment. One study that included severely impaired individuals also demonstrated encouraging results.

Muscular electrical stimulation can help improve the connection of motor neurons to the spinal cord and the motor cortex. Researchers have also demonstrated that application of electrical stimuli to the muscles provides positive effects on the neurons responsible for sensory signal transduction to the brain, thereby improving the motion control loop function. By modulating motor neurons’ sensitivity, muscular electrical stimulation inhibits the muscle spasms observed in other treatments.

More recently, therapies have moved on from the simple use of currents to harnessing coordinated stimuli to orchestrate more complex, task-related movements. Although this particular set of techniques didn’t show a particular advantage over physiotherapy in long-term studies of patients with mild upper limb impairment, it did seem to have a stronger effect for chronic severe patients.

Stimulating the brain

Brain stimulation, meanwhile, stimulates cortical neurons in order to improve their ability to form new connections within the affected neural network. Brain stimulation techniques can be divided into two branches – electrical and magnetic – both of which can activate or inhibit neural activity, depending on the polarity and intensity of the stimulus.

Transcranial magnetic stimulation

Researchers have achieved encouraging results using both techniques. In particular, magnetic field-triggered inhibition of the contralesional hemisphere (the hemisphere that was not affected by the stroke) activity yielded positive results. Magnetic, low-frequency stimulation of the contralesional hemisphere also proved encouraging – improving the reach to grasp ability of patients, although only for small objects. Excitingly, some studies suggest that coupling contralesional cortex inhibition with magnetic stimulation of the chronically affected area could achieve effective results.

Within these techniques, one promising approach is invasive brain stimulation, in which a device is surgically implanted in a superficial region of the brain. Such techniques allow for more sustained and spatially-oriented stimulation of the desired brain regions. The Everest trial used such methods and showed significant improvement for a larger percentage of patients after 24 weeks, compared with standard rehabilitation protocols.

Another promising recent development is non-invasive deep-brain stimulation, achieved by temporally interfering electric fields. The authors envision that a deeper understanding of the complex mechanisms involved in the brain’s reactions to magnetic and electrical stimulation will provide an important assistance in clinical application of these techniques.

The final category, brain–computer or brain–machine interfaces (BCIs or BMIs), exploit electroencephalogram (EEG) patterns to trigger feedback or an action output from an external device. Devices that produce feedback are used to train the patient to recruit the correct zone of the brain and help reorganize its interconnections. These techniques have only recently transitioned to the clinic; however, early results and observations are promising. For example, a BCI technique coupled with muscular electrical stimulation restored patients’ ability to extend their fingers.

In recent years, researchers have also tested combinations of the techniques described above. For example, combinations of robotics and muscular electrical stimulation have shown encouraging results, especially when more than one articulation was targeted by the treatment. Combining brain stimulation with muscular electrical stimulation and robotics has proved more effective in severe than in moderate cases. Also, coupling of muscular electrical stimulation with magnetic inhibitory brain stimulation provided better results than either individual technique. Interestingly, addition of electrical brain stimulation to a BCI system coupled with a robotic motor feedback enhanced the outcome, helping to achieve adaptive brain remodelling at the expense of inappropriate reorganization.

Coscia and co-authors highlight that all the techniques studied share a range of limitations that should be addressed, such as small sample size, limited understanding of the underlying mechanisms, lack of treatment personalization and minimal attention to the training task, which they note is often of limited importance for daily life. Addressing these limitations might be key to improving the clinical outcome for patients with severe stroke-induced upper limb paralysis treated with neurotechnology-aided interventions. Moreover, the authors plan to begin a clinical trial to test the use of a novel personalized therapy approach that will include a combination of the described techniques.

 

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[WEB SITE] What is neurohacking and can it actually rewire your brain?

Marc Bordons / Stocksy

What is neurohacking and can it actually rewire your brain?

Although at one point, “hack” referred to a creative solution to a tech problem, the term can apply to pretty much anything now. There are kitchen hacks, productivity hacks, personal finance hacks. Brain hacks, or neurohacks, are among the buzziest, though, thanks largely to the Silicon Valley techies who often swear by them as a way to boost their cognitive function, focus, and creativity. Mic asked a neuroscientist to explain neurohacking, which neurohacking methods are especially promising, which are mostly hype, and how to make neurohacking work for you.

First things first: Neurohacking, is a broad umbrella term that encompasses anything that involves “manipulating brain function or structure to improve one’s experience of the world,” says neuroscientist Don Vaughn of Santa Clara University and the University of California, Los Angeles. Like the other myriad forms of hacking, neurohacking uses an engineering approach, treating the brain as a piece of hardware that can be systematically modified and upgraded.

Neurohacking techniques can fall under a number of categories — here are a few of the most relevant ones, as well as the thinking behind them.

Brain stimulation

This involves applying an electric or magnetic field to certain regions of the brain in non-neurotypical people to make their activity more closely resemble that seen in a neurotypical brain. In 2008, the Food and Drug Administration approved transcranial magnetic stimulation (TMS) — a noninvasive form of brain stimulation which delivers magnetic pulses to the brain in a noninvasive manner — for major depression. Since then, the FDA has also approved TMS for pain associated with migraines with auras, as well as obsessive-compulsive disorder. Established brain stimulation techniques (such as TMS or electroconvulsive therapy) performed by an expert provider, such as a psychiatrist or neuroscientist, are generally safe, Vaughn says.

Neurofeedback

This one involves using a device that measures brain activity, such as an electroencephalogram (EEG) or a functional magnetic resonance imaging (fMRI) machine. People with neuropsychological disorders receive feedback on their own brain activity — often in the form of images or sound — and focus on trying to make it more closely resemble the brain activity in a healthy person, Vaughn says. This could happen through changing their thought patterns, Vaughn says. Another possibility is that the feedback itself, or the person’s thoughts about the feedback, may somehow lead to a change in their brain’s wiring.

Reducing cognitive load

This means minimizing how much apps, devices, and other tech compete for your attention. Doing so can sharpen and sustain your focus, or what Vaughn refers to as your attention quotient (AQ). To boost his AQ, Vaughn listens to brown noise, which he likens to “white noise, but deeper.” (Think the low rush of a waterfall versus pure static.) He also chews gum, which he says provides an outlet for his restless “monkey mind” while still allowing him to focus on the task at hand.

Reducing cognitive load can also deepen your connection with others. Vaughn uses Voicea, an app based on an AI assistant that takes and store notes of meetings, whether over the phone or in-person, allowing him to focus solely on the conversation, not on recording it. “If we can quell those disruptions that occur because of the way work is done these days, it will allow us to focus and be more empathic with each other,” he says.

Monitoring sleep

Tracking your sleep patterns and adjusting them accordingly. Every night, you go through around five or so stages of sleep, each one deeper than the last. “People are less groggy and make fewer errors when they wake up in a lighter stage of sleep,” Vaughn says. He uses Sleep Cycle, an app that tracks your sleep patterns based on your movements in bed to rouse you during your lightest sleep stage.

Andrey Popov / Shutterstock

Microdosing

Microdosing is the routinely consumption of teensy doses of psychedelics like LSD, ecstasy, or magic mushrooms. Many who practice microdosing follow the regimen recommended by James Fadiman, psychologist and author of The Psychedelic Explorer’s Guide: Safe, Therapeutic, and Sacred Journeys: a twentieth to a tenth of a regular dose, once every three days for about a month. While a regular dose may make you trip, a microdose has subtler effects, with some users reporting, for instance, enhanced energy and focus, per The Cut.

Nootropics

These are OTC supplements or drugs taken to enhance cognitive function. They range from everyday caffeine and vitamin B12 (B12 deficiency has been associated with cognitive decline) to prescription drugs like Ritalin and Adderall, used to treat ADHD and narcolepsy, as well as Provigil (modafinil), used to treat extreme drowsiness resulting from narcolepsy and other sleep disorder. (All three of these drugs promote wakefulness.) The science behind nootropic supplements in particular remains rather murky, though.

Does neurohacking work, though?

Vaughn finds microdosing, neurostimulation, and neurofeedback especially promising for neuropsychological disorders. Although studies suggest that larger doses of psychedelics could help with disorders such as PTSD and treatment-resistant major depression, there are few studies on microdosing psychedelics. “The little science that has been done…is mixed—perhaps slightly positive,” Vaughn says. “Microdosing is promising mainly because of anecdotal evidence.” Meanwhile, neurostimulation can be used noninvasively in some cases, and TMS has already received FDA approval for a handful of conditions. Neurofeedback is not only non-invasive, but offers immediate feedback, and studies suggest it could be effective for PTSD and addiction.

But it’s important to note that just because these methods could positively alter brain function in people with neuropsychological disorders, that “doesn’t mean it’s going to take a normal system and make it superhuman,” Vaughn says. “I think there are lots of small hacks to be done that could add up to something big,” rather than huge hacks that can vastly upgrade cognitive function, a la Limitless. Thanks to millions of years of evolution, the human brain is already pretty damn optimized. “I just don’t know how much more we can tweak it to make it better,” Vaughn says.

As far as enhancements for neurotypical brains, he says that “you’ll probably see a much greater improvement” from removing distractions in your environment to reduce cognitive load than say, increasing your B12 intake — which brings us to an important disclaimer about nootropic supplements in particular. As with all supplements, they aren’t FDA-regulated, meaning that companies that sell them don’t need to provide evidence that they’re safe or effective. Vaughn recommends trying nootropics that research has shown to be safe and effective, like B12 or caffeine.

How can I start neurohacking?

As tempting as it is, adopting every neurohack under the sun is “not the answer,” Vaughn says. Remember, everyone is different. While your best friend may gush about how much her mood has improved since she began microdosing shrooms, your brain might not respond to microdosing—or maybe taking psychedelics just doesn’t align with your ethics.

Start by exploring different neurohacks, and of course, be skeptical of any product that makes outrageous claims. Since neurofeedback isn’t a common medical treatment, talk to your doctor about enrolling in academic studies on neurofeedback, or companies that offer it if you’re interested, Vaughn says. You should also talk to your doctor if you want to try brain stimulation. A doctor can prescribe you Adderall, Ritalin, or Provigil but only for their indicated medical uses, not for cognitive enhancement.

Ultimately, neurohacks are tools, Vaughn says. “You have to find the one that works for you.” If anything, taking this DIY approach to improving your brain function will leave you feeling empowered, a benefit that probably rivals anything a supplement or sleep tracking app could offer.

 

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[WEB PAGE] The Use of Noninvasive Brain Stimulation, Specifically Transcranial Direct Current Stimulation After Stroke

Motor impairment is a leading cause of disability after stroke. Approaches such as noninvasive brain stimulation are being investigated to attempt to increase effectiveness of stroke rehabilitation interventions. There are several types of noninvasive brain stimulation: repetitive transcranial magnetic stimulation, transcranial direct stimulation (tDCS), transcranial alternative current stimulation, and transcranial pulsed ultrasound to name a few. Of the types of noninvasive brain stimulation, repetitive transcranial magnetic stimulation and tDCS have been most extensively tested to modulate brain activity and potentially behavior. These two techniques have distinctive modes of action. Repetitive transcranial magnetic stimulation directly stimulates neurons in the brain and, given the appropriate conditions, leads to new action potentials. On the other hand, tDCS polarizes neuronal tissue including neurons and glia modulating ongoing firing patterns. There are also differences in cost, utility, and knowledge skill required to apply tDCS and repetitive transcranial magnetic stimulation. Transcranial direct stimulation is relatively inexpensive, easy to administer, portable, and may be applied while undergoing therapy, with lasting excitability changes detectable up to 90 minutes after administration. Repetitive transcranial magnetic stimulation equipment is bulkier, expensive, technically more challenging, and a patient’s head must remain still when treatment is being applied therefore needs to be administered before or after a session of rehabilitation. Because of these differences, tDCS has been more accessible and has rapidly grew as a potential tool to be used in neurorehabilitation to facilitate retraining of activities of daily living (ADL) capacity and possibly to improve restoration of neurological function after stroke.

There are three current stimulation approaches using tDCS to modulate corticomotor regions after stroke. In anodal stimulation mode, the anode electrode is placed over the lesioned brain area and a reference electrode is applied over the contralateral orbitofrontal cortex. Anodal tDCS is placed over the ipsilesional hemisphere to improve the responses of perilesional areas to training protocols. In cathodal stimulation, the cathode electrode is placed over the nonlesioned brain area and reference electrode over the contralateral (ipsilesional) orbitofrontal cortex. This approach has been predicated on the hypothesis that the nonstroke hemisphere will be inhibited by tDCS resulting in an increased activation of the ipsilesional hemisphere due to rebalancing of a presumably abnormal interhemispheric interaction. Although some studies have shown this approach to be beneficial, the causative role of interhemispheric interaction imbalance has been recently challenged and refuted.1 Thus, if cathodal stimulation approaches are beneficial, the behavioral effect cannot be explained by a presumed correction of abnormal interhemispheric connectivity. Finally, dual tDCS approach involves simultaneous application of the anode over the ipsilesional and the cathode over the contralesional side. Here again, the intended mechanism of action is to rebalance the presumably abnormal interhemispheric interaction.

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CLINICAL QUESTIONS ADDRESSED

What is the best tDCS type and electrical configuration? What are the effects of tDCS with rehabilitation program for upper limb recovery after stroke?

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RESEARCH FINDINGS OF tDCS

This short article discusses data obtained from a network meta-analysis of randomized controlled trials and a recent meta-analysis. The network meta-analysis included 12 randomized controlled trials including 284 participants examining the effect of tDCS on ADL function in the acute, subacute, and chronic phases after stroke.2 The meta-analysis included 9 studies with 371 participants in any stage after stroke.3

The network meta-analysis found evidence of a significant moderate effect in favor of cathodal tDCS without significant effects of dual tDCS, anodal tDCS, or sham tDCS. There was no difference in safety (as assessed by dropouts and adverse events) between sham tDCS, physical rehabilitation, cathodal tDCS, dual tDCS, and anodal tDCS. Elsner in a previous review of tDCS in 2016 found an effect on improving ADL, as well as function of the arm and lower limb, muscle strength, and cognition. Thus, the findings from the most recent meta-analysis indicating cathodal that tDCS improves ADL capacity are in line with previous meta-analyses. Of note, there was no evidence of an effect of either cathodal or other tDCS stimulation approaches on upper paretic limb impairment after stroke as measured by the Fugl-Meyer scale.

A meta-analysis that included participants in any stage after the stroke showed that tDCS in conjunction with multiple sessions of rehabilitation had no significant effect over delivering therapy alone for upper limb impairment and activity after stroke. This negative finding might be due to patient’s being in an acute, subacute, or chronic stage after stroke as well as variations in the type of therapy performed paired with tDCS (ie, conventional vs. constraint-induced movement therapy vs. robot protocol).

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RECOMMENDATIONS FOR PHYSIATRIC PRACTICE

There seems to be a modest effect supporting the use of tDCS as a co-adjuvant of rehabilitation interventions to improve ADLs after stroke. Cathodal tDCS seems to be the most promising approach, especially when applied early after the stroke. However, the evidence remains preliminary and does not warrant a widespread change in clinical rehabilitation practice at this time.

There is no evidence supporting the use of tDCS to improve motor impairment (as measured by the FMS) at this point.

Importantly, tDCS remains as a very safe intervention, with no differences in safety when real vs. control tDCS is applied.

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REFERENCES

1. Xu J, Branscheidt M, Schambra H, et al: Rethinking interhemispheric imbalance as a target for stroke neurorehabilitation. Ann Neurol 2019;85:502–13

2. Elsner B, Kwakkel G, Kugler J, et al: Transcranial direct current stimulation (tDCS) for improving capacity in activities and arm function after stroke: a network meta-analysis of randomised controlled trials. J Neuroeng Rehabil 2017;14:

3. Tedesco Triccas L, Burridge J, Hughes A, et al: Multiple sessions of transcranial direct current stimulation and upper extremity rehabilitation in stroke: a review and meta-analysis. Clin Neurophysiol2016;127:946–55

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[ARTICLE] Neurotechnology-aided interventions for upper limb motor rehabilitation in severe chronic stroke – Full Text

Abstract

Upper limb motor deficits in severe stroke survivors often remain unresolved over extended time periods. Novel neurotechnologies have the potential to significantly support upper limb motor restoration in severely impaired stroke individuals. Here, we review recent controlled clinical studies and reviews focusing on the mechanisms of action and effectiveness of single and combined technology-aided interventions for upper limb motor rehabilitation after stroke, including robotics, muscular electrical stimulation, brain stimulation and brain computer/machine interfaces. We aim at identifying possible guidance for the optimal use of these new technologies to enhance upper limb motor recovery especially in severe chronic stroke patients. We found that the current literature does not provide enough evidence to support strict guidelines, because of the variability of the procedures for each intervention and of the heterogeneity of the stroke population. The present results confirm that neurotechnology-aided upper limb rehabilitation is promising for severe chronic stroke patients, but the combination of interventions often lacks understanding of single intervention mechanisms of action, which may not reflect the summation of single intervention’s effectiveness. Stroke rehabilitation is a long and complex process, and one single intervention administrated in a short time interval cannot have a large impact for motor recovery, especially in severely impaired patients. To design personalized interventions combining or proposing different interventions in sequence, it is necessary to have an excellent understanding of the mechanisms determining the effectiveness of a single treatment in this heterogeneous population of stroke patients. We encourage the identification of objective biomarkers for stroke recovery for patients’ stratification and to tailor treatments. Furthermore, the advantage of longitudinal personalized trial designs compared to classical double-blind placebo-controlled clinical trials as the basis for precise personalized stroke rehabilitation medicine is discussed. Finally, we also promote the necessary conceptual change from ‘one-suits-all’ treatments within in-patient clinical rehabilitation set-ups towards personalized home-based treatment strategies, by adopting novel technologies merging rehabilitation and motor assistance, including implantable ones.

Introduction

Stroke constitutes a major public health problem affecting millions of people worldwide with considerable impacts on socio-economics and health-related costs. It is the second cause of death (Langhorne et al., 2011), and the third cause of disability-adjusted life-years worldwide (Feigin et al., 2014): ∼8.2 million people were affected by stroke in Europe in 2010, with a total cost of ∼€64 billion per year (Olesen et al., 2012). Due to ageing societies, these numbers might still rise, estimated to increase 1.5–2-fold from 2010 to 2030 (Feigin et al., 2014).

Improving upper limb functioning is a major therapeutic target in stroke rehabilitation (Pollock et al., 2014Veerbeek et al., 2017) to maximize patients’ functional recovery and reduce long-term disability (Nichols-Larsen et al., 2005Veerbeek et al., 2011Pollock et al., 2014). Motor impairment of the upper limb occurs in 73–88% first time stroke survivors and in 55–75% of chronic stroke patients (Lawrence et al., 2001). Constraint-induced movement therapy (CIMT), but also standard occupational practice, virtual reality and brain stimulation-based interventions for sensory and motor impairments show positive rehabilitative effects in mildly and moderately impaired stroke victims (Pollock et al., 2014Raffin and Hummel, 2018). However, stroke survivors with severe motor deficits are often excluded from these therapeutic approaches as their deficit does not allow easily rehabilitative motor training (e.g. CIMT), treatment effects are negligible and recovery unpredictable (Byblow et al., 2015Wuwei et al., 2015Buch et al., 2016Guggisberg et al., 2017).

Recent neurotechnology-supported interventions offer the opportunity to deliver high-intensity motor training to stroke victims with severe motor impairments (Sivan et al., 2011). Robotics, muscular electrical stimulation, brain stimulation, brain computer/machine interfaces (BCI/BMI) can support upper limb motor restoration including hand and arm movements and induce neuro-plastic changes within the motor network (Mrachacz-Kersting et al., 2016Biasiucci et al., 2018).

The main hurdle for an improvement of the status quo of stroke rehabilitation is the fragmentary knowledge about the physiological, psychological and social mechanisms, their interplay and how they impact on functional brain reorganization and stroke recovery. Positive stimulating and negatively blocking adaptive brain reorganization factors are insufficiently characterized except from some more or less trivial determinants, such as number and time of treatment sessions, pointing towards the more the better (Kwakkel et al., 1997). Even the long accepted model of detrimental interhemispheric inhibition of the overactive contralesional brain hemisphere on the ipsilesional hemisphere is based on an oversimplification and lack of differential knowledge and is thus called into question (Hummel et al., 2008Krakauer and Carmichael, 2017Morishita and Hummel, 2017).

Here, we take a pragmatic approach of comparing effectiveness data, keeping this lack of knowledge of mechanisms in mind and providing novel ideas towards precision medicine-based approaches to individually tailor treatments to the characteristics and needs of the individual patient with severe chronic stroke to maximize rehabilitative outcome.[…]

Continue —>   Neurotechnology-aided interventions for upper limb motor rehabilitation in severe chronic stroke | Brain | Oxford Academic

Conceptualization of longitudinal personalized rehabilitation-treatment designs for patients with severe chronic stroke. Ideally, each patient with severe chronic stroke with a stable motor recovery could be stratified based on objective biomarkers of stroke recovery in order to select the most appropriate/promising neurotechnology-aided interventions and/or their combination for the specific case. Then, these interventions can be administered in the clinic and/or at home in sequence, moving from one to another only when patient’s motor recovery plateaus. In this way, comparisons of the efficacy of each intervention (grey arrows) are still possible, and if the selected interventions and/or their combination are suitable, motor recovery could increase.

Conceptualization of longitudinal personalized rehabilitation-treatment designs for patients with severe chronic stroke. Ideally, each patient with severe chronic stroke with a stable motor recovery could be stratified based on objective biomarkers of stroke recovery in order to select the most appropriate/promising neurotechnology-aided interventions and/or their combination for the specific case. Then, these interventions can be administered in the clinic and/or at home in sequence, moving from one to another only when patient’s motor recovery plateaus. In this way, comparisons of the efficacy of each intervention (grey arrows) are still possible, and if the selected interventions and/or their combination are suitable, motor recovery could increase.

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[WEB SITE] How to help patients recover after a stroke

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Credit: CC0 Public Domain

The existing approach to brain stimulation for rehabilitation after a stroke does not take into account the diversity of lesions and the individual characteristics of patients’ brains. This was the conclusion made by researchers of the Higher School of Economics (HSE University) and the Max Planck Institute of Cognitive Sciences in their article, “Predicting the Response to Non-Invasive Brain Stimulation in Stroke.”

Among the most common causes of death worldwide,  ranks second only to myocardial infarction (heart attack). In addition, a stroke is also a chronic disease that leaves patients disabled for many years.

In , non-invasive neuromodulation methods such as electric and magnetic stimulation of various parts of the nervous system have been increasingly used to rehabilitate patients after a stroke. Stimulation selectively affects different parts of the , which allows you to functionally enhance activity in some areas while suppressing unwanted processes in others that impede the restoration of brain functions. This is a promising mean of rehabilitation after a stroke. However, its results in patients remain highly variable.

The study authors argue that the main reason for the lack of effectiveness in neuromodulation approaches after a stroke is an inadequate selection of patients for the application of a particular brain stimulation technique.

According to the authors, the existing approach does not take into account the diversity of lesions after a stroke and the variability of individual responses to brain stimulation as a whole. Researchers propose two criteria for selecting the optimal brain  strategy. The first is an analysis of the interactions between the hemispheres. Now, all patients, regardless of the severity of injury after a stroke, are offered a relatively standard treatment regimen. This approach relies on the idea of interhemispheric competition.

“For a long time, it was believed that when one hemisphere is bad, the second, instead of helping it, suppresses it even more,” explains Maria Nazarova, one of the authors of the article and a researcher at the HSE Institute of Cognitive Neurosciences. “In this regard, the suppression of the activity of the “unaffected” hemisphere should help restore the affected side of the brain. However, the fact is that this particular scheme does not work in many  after a stroke. Each time it is necessary to check what the impact of the unaffected hemisphere is—whether it is suppressive or activating.”

The second criterion, scientists call the neuronal phenotype. This is an individual characteristic of the activity of the brain, which is “as unique to each person as their fingerprints.” Such a phenotype is determined, firstly, by the ability of the brain to build effective structural and functional connections between different areas (connectivity). And, secondly, the individual characteristics of neuronal dynamics, including its ability to reach a . This is the state of the neuronal system in which it is the most plastic and capable of change.

Only by taking these criteria into account, the authors posit, can neuromodulation methods be brought to a new level and be effectively used in clinical practice. To do this, it is necessary to change the paradigm of the universal approach and select methods based on the individual characteristics of the brain of a particular person and the course of his or her disease.


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How electrical stimulation reorganizes the brain

 

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[WEB SITE] Neurotechnology-Aided Rehab Holds Promise for Chronic Stroke Patients

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Personalized neurotechnology-aided rehabilitation of the arm could improve recovery in severe chronic stroke patients, according to a study published recently in the journal Brain.

Neurotechnology-based therapies, including brain-machine interfaces, robotics, and brain stimulation among others, will lead to largest treatment effects and success if they are tailored to the needs of individual patients, and used in combination, according to the authors from the Wyss Center for Bio and Neuroengineering, Swiss Federal Institute of Technology Lausanne (EPFL), Scuola Superiore Sant’Anna, University of Geneva Faculty of Medicine and Clinique Romande de Réadaptation.

In their study, they call for longitudinal clinical studies to show the rehabilitation benefits of individual therapies as well as the use of multiple complementary therapies used in combination over long time periods.

“Our findings show that neurotechnology-aided upper limb rehabilitation is promising for severe chronic stroke patients,” says lead author Dr. Martina Coscia, Staff Engineer at the Wyss Center, in a media release.

“However, we also found that the ‘one size fits all’ approach doesn’t lead to the best outcome. We suggest a move towards a personalized combination of neurotechnology-based stroke rehabilitation therapies, ideally in a home-based environment where prolonged therapy is more feasible than in a clinic.

“We believe that by sequentially introducing stroke therapies according to individual progress, we could allow patients to continue their recovery beyond what is possible today.”

One of the most common consequences of stroke is impaired upper arm function, which has a direct impact on daily tasks and quality of life. Rehabilitation therapies generally have the largest effect in the first three months after stroke. After this time, patients are considered chronic and the likelihood of further natural recovery is limited; this is especially true for those most severely affected.

“What we would like to see in the future are long-term trials in which multiple neurotechnology-based therapies are used within the same patient,”  Professor Friedhelm Hummel from EPFL (Director, Defitech Chair of Clinical Neuroengineering) and the University of Geneva Medical School, shares in the release.

“We believe that this synergistic approach could uncover previously undiscovered treatment pathways for chronic stroke patients.”

In their study, the authors compared effectiveness data from 64 clinical studies on upper limb neurotechnology-aided treatments in chronic stroke patients. The interventions analyzed in the paper included robotics, functional electrical stimulation of muscles, brain stimulation, and brain-computer interfaces as well as their use in combination.

The interdisciplinary research team is now starting a clinical trial to test these ideas. The trial uses a new experimental design with a personalized therapy approach using brain-computer interfaces, robotics, functional electrical stimulation, and brain stimulation specifically chosen to maximize treatment effects in each individual patient. The goal is to keep incrementally improving recovery by using new personalized, neurotechnology-based therapies in combination. The trial will start in Switzerland in summer 2019.

[Source(s): Wyss Center for Bio and Neuroengineering, Science Daily]

 

via Neurotechnology-Aided Rehab Holds Promise for Chronic Stroke Patients – Rehab Managment

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[NEWS] Researchers propose new approach for post-stroke rehabilitation

The existing approach for brain stimulation to rehabilitate patients after a stroke does not take into account the diversity of lesions and the individual characteristics of patients’ brains, a study has found.

In recent decades, non-invasive neuromodulation methods such as electric and magnetic stimulation of various parts of the nervous system have been increasingly used to rehabilitate patients after a stroke.

Stimulation selectively affects different parts of the brain, which allows you to functionally enhance activity in some areas while suppressing unwanted processes in others that impede the restoration of brain functions.

This is a promising mean of rehabilitation after a stroke. However, its results in patients remain highly variable.

Authors of the study, which was published in the journal ‘Frontiers in Neurology’, argued that the main reason for the lack of effectiveness in neuromodulation approaches after a stroke is an inadequate selection of patients for the application of a particular brain stimulation technique.

They said the existing approach does not take into account the diversity of lesions after a stroke and the variability of individual responses to brain stimulation as a whole.

The researchers have proposed two criteria for selecting the optimal brain stimulation strategy.

The first is an analysis of the interactions between the hemispheres. Now, all patients, regardless of the severity of injury after a stroke, are offered a relatively standard treatment regimen. This approach relies on the idea of interhemispheric competition.

“For a long time, it was believed that when one hemisphere is bad, the second, instead of helping it, suppresses it even more,” said

Maria Nazarova, researcher at the HSE Institute of Cognitive Neurosciences.

“In this regard, the suppression of the activity of the “unaffected” hemisphere should help restore the affected side of the brain. However, the fact is that this particular scheme does not work in many patients after a stroke. Each time it is necessary to check what the impact of the unaffected hemisphere is — whether it is suppressive or activating,” she said.

According to the researchers, the second criterion is the neuronal phenotype.

This is an individual characteristic of the activity of the brain, which is ‘unique to each person like their fingerprints’.

Such a phenotype is determined, firstly, by the ability of the brain to build effective structural and functional connections between different areas (connectivity).

Secondly, the individual characteristics of neuronal dynamics, including its ability to reach a critical state. This is the state of the neuronal system in which it is the most plastic and capable of change.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.

First Published: Fri, June 28 2019. 15:20 IST

 

via Researchers propose new approach for post-stroke rehabilitation | Business Standard News

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[WEB SITE] Depression: Brain stimulation may be a good alternative treatment

A new review, which appears in The BMJ journal, examines the benefits of non-invasive brain stimulation for treating major depression and finds that the technique is a valid alternative to existing treatments.

doctor talking to patient

Doctors should consider brain stimulation as an alternative treatment for people living with severe depression, finds a new review

Over 17 million adults in the United States have had an episode of major depression at one point in their lives.

Some of these people have treatment-resistant depression, which means common prescription drugs do not alleviate the symptoms.

Recent studies have pointed to alternative treatment methods for major depression, such as non-invasive brain stimulation techniques.

For instance, a study that appeared at the end of last year showed that using small electric currents to stimulate a brain area called the orbitofrontal cortex significantly improves the mood of people who did not benefit from conventional antidepressants.

An even more recent trial of a form of brain stimulation called “transcranial alternating current stimulation” (tACS) found that the technique halved depression symptoms in almost 80 percent of the study participants.

Despite such promising results, doctors do not use these techniques widely, as there is not enough data available on their efficacy.

So, a team of researchers led by Julian Mutz at the Institute of Psychiatry, Psychology & Neuroscience at King’s College London, United Kingdom, set out to review some clinical trials that have examined the benefits of non-invasive brain stimulation techniques for people living with depression.

Brain stimulation as additional treatment

Specifically, Mutz and team examined the results of 113 clinical trials. Overall, these trials included 6,750 participants who were 48 years old, on average, and were living with major depressive disorder or bipolar depression.

The original clinical trials involved randomly assigning these participants to 18 treatment interventions or “sham” therapies. The reviewers focussed on the response, or “efficacy” of the treatment, as well as the “discontinuation of treatment for any reason” — or “acceptability” of the therapies. Mutz and colleagues also rated the trials’ risk of bias.

The therapies included in the review were “electroconvulsive therapy (ECT), transcranial magnetic stimulation (repetitive (rTMS), accelerated, priming, deep, and synchronized), theta burst stimulation, magnetic seizure therapy, transcranial direct current stimulation (tDCS), or sham therapy.”

Of these, the treatments that the researchers in the original trial examined most often were high frequency left rTMS and tDCS, which they tested against sham therapy. On the other hand, not many trials covered more recent forms of brain stimulation, such as magnetic seizure therapy and bilateral theta burst stimulation, the review found.

Kutz and his team deemed 34 percent of the trials they reviewed as having a low risk of bias. They considered half of the trials to have an “unclear” risk of bias, and finally, 17 percent to have a high risk of bias. The newer the treatments, the higher was the uncertainty of the trials’ results.

The review found that bitemporal ECT, high dose right unilateral ECT, high frequency left rTMS and tDCS were all significantly more effective than sham therapy both in terms of efficacy and acceptability.

When considering “discontinuation of treatment for any reason,” the researchers found that the participants were not any likelier to discontinue brain stimulation treatments than they were sham therapy. Mutz and colleagues conclude:

These findings provide evidence for the consideration of non-surgical brain stimulation techniques as alternative or add-on treatments for adults with major depressive episodes.”

“These findings also highlight important research priorities in the specialty of brain stimulation, such as the need for further well-designed randomized controlled trials comparing novel treatments, and sham-controlled trials investigating magnetic seizure therapy,” the authors add.

Finally, the researchers also note that their results have clinical implications, “in that they will inform clinicians, patients, and healthcare providers on the relative merits of multiple non-surgical brain stimulation techniques.”

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[Abstract] Modulation of Cerebellar Cortical Plasticity Using Low-Intensity Focused Ultrasound for Poststroke Sensorimotor Function Recovery

Background. Stroke affects widespread brain regions through interhemispheric connections by influencing bilateral motor activity. Several noninvasive brain stimulation techniques have proved their capacity to compensate the functional loss by manipulating the neural activity of alternative pathways. Over the past few decades, brain stimulation therapies have been tailored within the theoretical framework of modulation of cortical excitability to enhance adaptive plasticity after stroke.

Objective. However, considering the vast difference between animal and human cerebral cortical structures, it is important to approach specific neuronal target starting from the higher order brain structure for human translation. The present study focuses on stimulating the lateral cerebellar nucleus (LCN), which sends major cerebellar output to extensive cortical regions.

Methods. In this study, in vivo stroke mouse LCN was exposed to low-intensity focused ultrasound (LIFU). After the LIFU exposure, animals underwent 4 weeks of rehabilitative training.

Results. During the cerebellar LIFU session, motor-evoked potentials (MEPs) were generated in both forelimbs accompanying excitatory sonication parameter. LCN stimulation group on day 1 after stroke significantly enhanced sensorimotor recovery compared with the group without stimulation. The recovery has maintained for a 4-week period in 2 behavior tests. Furthermore, we observed a significantly decreased level of brain edema and tissue swelling in the affected hemisphere 3 days after the stroke.

Conclusions. This study provides the first evidence showing that LIFU-induced cerebellar modulation could be an important strategy for poststroke recovery. A longer follow-up study is, however, necessary in order to fully confirm the effects of LIFU on poststroke recovery.

via Modulation of Cerebellar Cortical Plasticity Using Low-Intensity Focused Ultrasound for Poststroke Sensorimotor Function Recovery – Hongchae Baek, Ki Joo Pahk, Min-Ju Kim, Inchan Youn, Hyungmin Kim, 2018

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