Posts Tagged Transcranial magnetic stimulation

[WEB SITE] Magnetic brain stimulation helps “unlearn” crippling fear of heights

 

New research suggests a little magnetic brain stimulation prior to being exposed to your greatest fear...

New research suggests a little magnetic brain stimulation prior to being exposed to your greatest fear in a VR headset could help you “unlearn” your anxiety response(Credit: DanRoss/Depositphotos)

Advances in technology over the last decade have led to a swift rise in the volume of research surrounding transcranial magnetic stimulation (TMS) and its therapeutic effects. A team from the Würzburg University Hospital in Germany has just published a new study demonstrating how TMS, in conjunction with a virtual reality experience, can help alleviate anxiety disorders and essentially help people “unlearn” fears.

Transcranial magnetic stimulation works by directing a targeted magnetic field toward specific areas in the brain. Depending on the frequencies delivered this can either stimulate or inhibit the brain activity of the targeted area. Initially conceived as a research tool allowing scientists to understand exactly what roles certain areas of the brain play, TMS has more recently been explored as a potential new tool for treating an assortment of problems.

TMS devices have already been approved to treat migraines and some major depressive disorders, but other research is looking into its uses as a learning aid and a way to help visually-impaired people navigate the world.

This new study looks at how the technology could improve a patient’s response when used in conjunction with a more traditional treatment method. Anxiety disorders are incredibly debilitating for many, from social phobias to more specific problems such as a fear of heights. Classically, the treatment for people with these disorders has been a type of cognitive behavioral therapy where one is exposed to the source of their anxiety under the supervision of a psychologist.

The team at the Würzburg University Hospital decided to examine whether this kind of classic therapy could be improved using TMS. Previous studies have shown that by targeting the frontal lobe with magnetic stimulation an anxiety response can be reduced, but the new research looks at how this could be incorporated into a specific treatment method for a targeted anxiety.

Even though the subject knows it is fake, exposure to great heights in a virtual reality...

Even though the subject knows it is fake, exposure to great heights in a virtual reality headset still triggers an anxiety response in sufferers(Credit: VTplus)

Thirty-nine subjects with an active fear of heights were split into two groups, including a control group which received fake TMS. The groups received 20 minutes of either real or fake TMS directed at the ventral medial prefrontal cortex, followed by virtual reality exposure to a dizzying height. After two sessions the group treated with the TMS prior to VR exposure exhibited reduced anxiety and avoidance symptoms compared to the control group that didn’t receive the TMS.

“The findings demonstrate that all participants benefit considerably from the therapy in virtual reality and the positive effects of the intervention are still clearly visible even after three months,” explains Professor Martin J. Herrmann, one of the researchers working on the study.

The researchers suggest that adding TMS and VR to an already well-proven treatment process increases the overall efficacy and essentially helps the brain “unlearn” its anxiety responses. The next phase for the study is to look at other forms of anxiety and see if the process is equally effective.

And the next fear that is being tackled? Arachnophobia.

The research was published in the journal Brain Stimulation.

Source: Würzburg University Hospital

Source: Magnetic brain stimulation helps “unlearn” crippling fear of heights

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[WEB SITE] Magnetic Therapy Can Provide Alternative Treatment For Depression

Depression is a leading cause of poor health, disability and suicide — and medications only help some depression patients.

Many also cannot take the side effects.

But as CBS2’s Dr. Max Gomez reported, magnets might offer relief by rewiring the patient’s brain.

Each year, Americans spend billions of dollars on antidepressants. But studies show they can be ineffective in up to 40 percent of all patients.

Bob Holmes was one of them.

“They tried to adjust my medication, but the medication had side effects that weren’t desirable,” Holmes said.

Holmes is among the 16 million people in the U.S. who suffer major depressive episodes each year — a number that has increased 18 percent over the last decade. For that reason, some doctors at UCLA are taking a different approach.

Doctors beam magnetic pulses deep inside patients’ brains to change the way depression symptoms are perceived.

“We are used to thinking of the brain as a chemical organ, but it’s also an electrical organ,” said Dr. Andrew Leuchter of UCLA Health.

“The idea that by using non-chemical means, we can change the brain and how it functions,” said Dr. Ian Cook of UCLA Health.

It is called transcranial magnetic stimulation, or TMS. It is currently approved by the Food and Drug Administration only to treat depression, but doctors say it may prove helpful in a wide range of conditions by rewiring a network of signals in the brain.

“What TMS is doing is changing how that network functions, really rebooting the network to improve symptoms of mood, anxiety and chronic pain,” Leuchter said.

That may be why patients treated for depression also say it helps relieve their pain, raising provocative questions about whether TMS could one day become a viable alternative to opioids.

“This is a really transformative kind of therapy,” Cook said.

But for now, it has made a dramatic difference in Holmes’ depression.

“It provided that kind of jolt to get my brain to start work again normally,” he said.

Reportedly, TMS can feel a bit uncomfortable at first — but many patients quickly get used to it. They report substantial relief from their symptoms of depression within a few weeks.

Even though the NeuroStar system has been approved for depression since 2008, it is only recently that doctors have realized its effectiveness for everything from post-traumatic stress disorder to obsessive-compulsive disorder.

Source: https://medium.com/@pemfindia/magnetic-therapy-can-provide-alternative-treatment-for-depression-941a687a79f

Source: Magnetic Therapy Can Provide Alternative Treatment For Depression | Samir Singhal | Pulse | LinkedIn

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[ARTICLE] Domiciliary VR-Based Therapy for Functional Recovery and Cortical Reorganization: Randomized Controlled Trial in Participants at the Chronic Stage Post Stroke – Full Text

ABSTRACT

Background: Most stroke survivors continue to experience motor impairments even after hospital discharge. Virtual reality-based techniques have shown potential for rehabilitative training of these motor impairments. Here we assess the impact of at-home VR-based motor training on functional motor recovery, corticospinal excitability and cortical reorganization.

Objective: The aim of this study was to identify the effects of home-based VR-based motor rehabilitation on (1) cortical reorganization, (2) corticospinal tract, and (3) functional recovery after stroke in comparison to home-based occupational therapy.

Methods: We conducted a parallel-group, controlled trial to compare the effectiveness of domiciliary VR-based therapy with occupational therapy in inducing motor recovery of the upper extremities. A total of 35 participants with chronic stroke underwent 3 weeks of home-based treatment. A group of subjects was trained using a VR-based system for motor rehabilitation, while the control group followed a conventional therapy. Motor function was evaluated at baseline, after the intervention, and at 12-weeks follow-up. In a subgroup of subjects, we used Navigated Brain Stimulation (NBS) procedures to measure the effect of the interventions on corticospinal excitability and cortical reorganization.

Results: Results from the system’s recordings and clinical evaluation showed significantly greater functional recovery for the experimental group when compared with the control group (1.53, SD 2.4 in Chedoke Arm and Hand Activity Inventory). However, functional improvements did not reach clinical significance. After the therapy, physiological measures obtained from a subgroup of subjects revealed an increased corticospinal excitability for distal muscles driven by the pathological hemisphere, that is, abductor pollicis brevis. We also observed a displacement of the centroid of the cortical map for each tested muscle in the damaged hemisphere, which strongly correlated with improvements in clinical scales.

Conclusions: These findings suggest that, in chronic stages, remote delivery of customized VR-based motor training promotes functional gains that are accompanied by neuroplastic changes.

Introduction

After initial hospitalization, many stroke patients return home relatively soon despite still suffering from impairments that require continuous rehabilitation [1]. Therefore, ¼ to ¾ of patients display persistent functional limitations for a period of 3 to 6 months after stroke [2]. Although clinicians may prescribe a home exercise regimen, reports indicate that only one-third of patients actually accomplish it [3]. Consequently, substantial gains in health-related quality of life during inpatient stroke rehabilitation may be followed by equally substantial declines in the 6 months after discharge [4]. Multiple studies have shown, however, that supported discharge combined with at home rehabilitation services does not compromise clinical inpatient outcomes [57] and may enhance recovery in subacute stroke patients [8]. Hence, it is essential that new approaches are deployed that help to manage chronic conditions associated with stroke, including domiciliary interventions [9] and the augmentation of current rehabilitation approaches in order to enhance their efficiency. There should be increased provision of home-based rehabilitation services for community-based adults following stroke, taking cost-effectiveness, and a quick family and social reintegration into account [10].

One of the latest approaches in rehabilitation science is based on the use of robotics and virtual reality (VR), which allow remote delivery of customized treatment by combining dedicated interface devices with automatized training scenarios [1012]. Several studies have tested the acceptability of VR-based setups as an intervention and evaluation tool for rehabilitation [1315]. One example of this technology is the, so called, Rehabilitation Gaming System (RGS) [16], which has been shown to be effective in the rehabilitation of the upper extremities in the acute and the chronic phases of stroke [13]. However, so far little work exists on the quantitative assessment of the clinical impact of VR based approaches and their effects on neural reorganization that can directly inform the design of these systems and their application in the domiciliary context. The main objective of this paper is to further explore the potential and limitations of VR technologies in domiciliary settings. Specifically, we examine the efficacy of a VR-based therapy when used at home for (1) assessing functional improvement, (2) facilitating functional recovery of the upper-limbs, and (3) inducing cortical reorganization. This is the first study testing the effects of VR-based therapy on cortical reorganization and corticospinal integrity using NBS.

Methods

Design

We conducted a parallel-group, controlled trial in order to compare the effectiveness of domiciliary VR-based therapy versus domiciliary occupational therapy (OT) in inducing functional recovery and cortical reorganization in chronic stroke patients.

Participants

Participants were first approached by an occupational therapist from the rehabilitation units of Hospital Esperanza and Hospital Vall d’Hebron from Barcelona to determine their interest in participating in a research project. Recruited participants met the following inclusion criteria: (1) mild-to-moderate upper-limbs hemiparesis (Proximal MRC>2) secondary to a first-ever stroke (>12 months post-stroke), (2) age between 45 and 85 years old, (3) absence of any major cognitive impairment (Mini-Mental State Evaluation, MMSE>22), and (4) previous experience with RGS in the clinic. The ethics committee of clinical research of the Parc de Salut Mar and Vall d’Hebron Research Institute approved the experimental guidelines. Thirty-nine participants at the chronic stage post-stroke were recruited for the study by two occupational therapists, between October 2011 and January 2012, and were assigned to a RGS (n=20) or a control group (n=19) using stratified permuted block randomization methods for balancing the participants’ demographics and clinical scores at baseline (Table 1). One participant in the RGS group refused to participate. Prior to the experiment, participants signed informed consent forms. This trial was not registered at or before the onset of participants’ enrollment because it is a pilot study that evaluates the feasibility of a prototype device. However, this study was registered retrospectively in ClinicalTrials.gov and has the identifier NCT02699398.

Instrumentation

Description of the Rehabilitation Gaming System

The RGS integrates a paradigm of goal-directed action execution and motor imagery [17], allowing the user to control a virtual body (avatar) through an image capture device (Figure 1). For this study, we developed training and evaluation scenarios within the RGS framework. In the Spheroids training scenario (Figure 1), the user has to perform bilateral reaching movements to intercept and grasp a maximum number of spheres moving towards him [16]. RGS captures only joint flexion and extension and filters out the participant’s trunk movements, therefore preventing the execution of compensatory body movements [18]. This task was defined by three difficulty parameters, each of them associated with a specific performance descriptor: (1) different trajectories of the spheres require different ranges of joint motion for elbow and shoulder, (2) the size of the spheres require different hand and grasp precision and perceptual abilities, and (3) the velocity of the spheres require different movement speeds and timing. All these parameters, also including the range of finger flexion and extension required to grasp and release spheroids, were dynamically modulated by the RGS Adaptive Difficulty Controller [19] to maintain the performance ratio (ie, successful trials over the total trials) above 0.6 and below 0.8, optimizing effort and reinforcement during training [20]. […]

Figure 1. Experimental setup and protocol: (A) Movements of the user’s upper limbs are captured and mapped onto an avatar displayed on a screen in first person perspective so that the user sees the movements of the virtual upper extremities. A pair of data gloves equipped with bend sensors captures finger flexion. (B) The Spheroids is divided into three subtasks: hit, grasp, and place. A white separator line divides the workspace in a paretic and non-paretic zone only allowing for ipsilateral movements.(C) The experimental protocol. Evaluation periods (Eval.) indicate clinical evaluations using standard clinical scales and Navigated Brain Stimulation procedures (NBS). These evaluations took place before the first session (W0), after the last session of the treatment (day 15, W3), and at follow-up (week 12, W12).

Continue —>  JSG-Domiciliary VR-Based Therapy for Functional Recovery and Cortical Reorganization: Randomized Controlled Trial in Participants at the Chronic Stage Post Stroke | Ballester | JMIR Serious Games

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[VIDEO] Transcranial Magnetic Stimulation (TMS ): An interview – YouTube

Published on Sep 10, 2016

John O’Reardon, MD is a leading expert on the use of transcranial magnetic stimulation (TMS) in the treatment of mental disorder. In this 30-minute interview, he gives mental health clinicians essential information about this important treatment option.

He answers many practical questions that occurred to me about TMS. Which patients are ideal to be referred for TMS? How can we find out if the patient’s insurance will pay for it? How exactly is TMS delivered? Why is it important for TMS to be delivered by an expert? What should be done if the patient does respond to TMS? What should be done if the patient does not respond to the TMS? He briefly answers all these and many more.

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[ARTICLE] Impact of Transcranial Magnetic Stimulation on Functional Movement Disorders: Cortical Modulation or a Behavioral Effect? – Full Text

Introduction: Recent studies suggest that repeated transcranial magnetic stimulation (TMS) improves functional movement disorders (FMDs), but the underlying mechanisms are unclear. The objective was to determine whether the beneficial action of TMS in patients with FMDs is due to cortical neuromodulation or rather to a cognitive-behavioral effect.

Method: Consecutive patients with FMDs underwent repeated low-frequency (0.25 Hz) magnetic stimulation over the cortex contralateral to the symptoms or over the spinal roots [root magnetic stimulation (RMS)] homolateral to the symptoms. The patients were randomized into two groups: group 1 received RMS on day 1 and TMS on day 2, while group 2 received the same treatments in reverse order. We blindly assessed the severity of movement disorders before and after each stimulation session.

Results: We studied 33 patients with FMDs (dystonia, tremor, myoclonus, Parkinsonism, or stereotypies). The median symptom duration was 2.9 years. The magnetic stimulation sessions led to a significant improvement (>50%) in 22 patients (66%). We found no difference between TMS and RMS.

Conclusion: We suggest that the therapeutic benefit of TMS in patients with FMDs is due more to a cognitive-behavioral effect than to cortical neuromodulation.

Introduction

Individuals with functional movement disorders (FMDs) account for 3–20% of all patients seen in movement-disorder clinics (13). There is no consensus treatment for FMDs (46). These movement disorders are not due to irreversible brain damage but their outcome is nonetheless poor: symptoms are persistent or worse after 1.5–7 years of follow-up in between 44 and 90% of patients (6, 7). FMDs generate major healthcare costs, as well as indirect costs due to unemployment and disability (8).

Recent studies suggest a beneficial effect of repeated supraliminal low-frequency transcranial magnetic stimulation (TMS) (i.e., TMS ≤ 1 Hz) on functional motor symptoms (914) [Ref. (15) for a review]. Among these studies, only one included a blinded assessment (11), and only one included a control group (sham treatment) (9). Focusing on FMDs more specifically, two studies showed a beneficial effect of supraliminal low-frequency TMS, with a mean improvement rate of 67% (11) and 97% (13). It is unclear whether the therapeutic benefit is due to cortical neuromodulation, i.e., to changes in cortical excitability and in connectivity between brain areas (15, 16). The alternative hypothesis is a cognitive-behavioral effect, a therapeutic effect that is linked to suggestion and/or motor relearning.

To address this issue, we blindly compared the therapeutic effect of repeated TMS and repeated root magnetic stimulation (RMS) in patients with FMDs. RMS was chosen as the control treatment to mimic TMS-induced movement without directly stimulating the cortex.

Continue —>  Frontiers | Impact of Transcranial Magnetic Stimulation on Functional Movement Disorders: Cortical Modulation or a Behavioral Effect? | Neurology

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[BLOG POST] UCLA offers transcranial magnetic stimulation to treat patients with depression

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Americans spend billions of dollars each year on antidepressants, but the National Institutes of Health estimates that those medications work for only 60 percent to 70 percent of people who take them. In addition, the number of people with depression has increased 18 percent since 2005, according to the World Health Organization, which this year launched a global campaign encouraging people to seek treatment.

The Semel Institute for Neuroscience and Human Behavior at UCLA is one of a handful of hospitals and clinics nationwide that offer a treatment that works in a fundamentally different way than drugs. The technique, transcranial magnetic stimulation, beams targeted magnetic pulses deep inside patients’ brains — an approach that has been likened to rewiring a computer.

TMS has been approved by the FDA for treating depression that doesn’t respond to medications, and UCLA researchers say it has been underused. But new equipment being rolled out this summer promises to make the treatment available to more people.

“We are actually changing how the brain circuits are arranged, how they talk to each other,” said Dr. Ian Cook, director of the UCLA Depression Research and Clinic Program. “The brain is an amazingly changeable organ. In fact, every time people learn something new, there are physical changes in the brain structure that can be detected.”

Nathalie DeGravel, 48, of Los Angeles had tried multiple medications and different types of therapy, not to mention many therapists, for her depression before she heard about magnetic stimulation. She discussed it with her psychiatrist earlier this year, and he readily referred her to UCLA.

Within a few weeks, she noticed relief from the back pain she had been experiencing; shortly thereafter, her depression began to subside. DeGravel says she can now react more “wisely” to life’s daily struggles, feels more resilient and is able to do much more around the house. She even updated her resume to start looking for a job for the first time in years.

During TMS therapy, the patient sits in a reclining chair, much like one used in a dentist’s office, and a technician places a magnetic stimulator against the patient’s head in a predetermined location, based on calibrations from brain imaging.

The stimulator sends a series of magnetic pulses into the brain. People who have undergone the treatment commonly report the sensation is like having someone tapping their head, and because of the clicking sound it makes, patients often wear earphones or earplugs during a session.

TMS therapy normally takes 30 minutes to an hour, and people typically receive the treatment several days a week for six weeks. But the newest generation of equipment could make treatments less time-consuming.

“There are new TMS devices recently approved by the FDA that will allow patients to achieve the benefits of the treatment in a much shorter period of time,” said Dr. Andrew Leuchter, director of the Semel Institute’s TMS clinical and research service. “For some patients, we will have the ability to decrease the length of a treatment session from 37.5 minutes down to 3 minutes, and to complete a whole course of TMS in two weeks.”

Leuchter said some studies have shown that TMS is even better than medication for the treatment of chronic depression. The approach, he says, is underutilized. “We are used to thinking of psychiatric treatments mostly in terms of either talk therapies, psychotherapy or medications,” Leuchter said. “TMS is a revolutionary kind of treatment.”

Bob Holmes of Los Angeles is one of the 16 million Americans who report having a major depressive episode each year, and he has suffered from depression his entire life. He calls the TMS treatment he received at UCLA Health a lifesaver.

“What this did was sort of reawaken everything, and it provided that kind of jolt to get my brain to start to work again normally,” he said.

Doctors are also exploring whether the treatment could also be used for a variety of other conditions including schizophrenia, epilepsy, Parkinson’s disease and chronic pain.

“We’re still just beginning to scratch the surface of what this treatment might be able to do for patients with a variety of illnesses,” Leuchter said. “It’s completely noninvasive and is usually very well tolerated.”

Source: UCLA offers transcranial magnetic stimulation to treat patients with depression

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[WEB SITE] Doctors use magnetic stimulation to ‘rewire’ the brain for people with depression

Doctors use magnetic stimulation to ‘rewire’ the brain for people with depression

Dr. Andrew Leuchter talks with a patient who is about to undergo transcranial magnetic stimulation, which treats depression by sending magnetic pulses to a specific area of the brain. Credit: UCLA Health

Americans spend billions of dollars each year on antidepressants, but the National Institutes of Health estimates that those medications work for only 60 percent to 70 percent of people who take them. In addition, the number of people with depression has increased 18 percent since 2005, according to the World Health Organization, which this year launched a global campaign encouraging people to seek treatment.

The Semel Institute for Neuroscience and Human Behavior at UCLA is one of a handful of hospitals and clinics nationwide that offer a  that works in a fundamentally different way than drugs. The technique, , beams targeted magnetic pulses deep inside patients’ brains—an approach that has been likened to rewiring a computer.

TMS has been approved by the FDA for treating  that doesn’t respond to medications, and UCLA researchers say it has been underused. But new equipment being rolled out this summer promises to make the treatment available to more people.

“We are actually changing how the brain circuits are arranged, how they talk to each other,” said Dr. Ian Cook, director of the UCLA Depression Research and Clinic Program. “The brain is an amazingly changeable organ. In fact, every time people learn something new, there are physical changes in the brain structure that can be detected.”

Nathalie DeGravel, 48, of Los Angeles had tried multiple medications and different types of therapy, not to mention many therapists, for her depression before she heard about magnetic stimulation. She discussed it with her psychiatrist earlier this year, and he readily referred her to UCLA.

Within a few weeks, she noticed relief from the back pain she had been experiencing; shortly thereafter, her depression began to subside. DeGravel says she can now react more “wisely” to life’s daily struggles, feels more resilient and is able to do much more around the house. She even updated her resume to start looking for a job for the first time in years.

During TMS therapy, the patient sits in a reclining chair, much like one used in a dentist’s office, and a technician places a magnetic stimulator against the patient’s head in a predetermined location, based on calibrations from brain imaging.

The stimulator sends a series of  into the brain. People who have undergone the treatment commonly report the sensation is like having someone tapping their head, and because of the clicking sound it makes, patients often wear earphones or earplugs during a session.

TMS therapy normally takes 30 minutes to an hour, and people typically receive the treatment several days a week for six weeks. But the newest generation of equipment could make treatments less time-consuming.

“There are new TMS devices recently approved by the FDA that will allow patients to achieve the benefits of the treatment in a much shorter period of time,” said Dr. Andrew Leuchter, director of the Semel Institute’s TMS clinical and research service. “For some patients, we will have the ability to decrease the length of a treatment session from 37.5 minutes down to 3 minutes, and to complete a whole course of TMS in two weeks.”

Leuchter said some studies have shown that TMS is even better than medication for the treatment of chronic depression. The approach, he says, is underutilized.

“We are used to thinking of psychiatric treatments mostly in terms of either talk therapies, psychotherapy or medications,” Leuchter said. “TMS is a revolutionary kind of treatment.”

Bob Holmes of Los Angeles is one of the 16 million Americans who report having a major depressive episode each year, and he has suffered from depression his entire life. He calls the TMS treatment he received at UCLA Health a lifesaver.

“What this did was sort of reawaken everything, and it provided that kind of jolt to get my  to start to work again normally,” he said.

Doctors are also exploring whether the treatment could also be used for a variety of other conditions including schizophrenia, epilepsy, Parkinson’s disease and chronic pain.

“We’re still just beginning to scratch the surface of what this treatment might be able to do for patients with a variety of illnesses,” Leuchter said. “It’s completely noninvasive and is usually very well tolerated.”

 Explore further: Study finds non-invasive method that may help speed relief from depression

Source: Doctors use magnetic stimulation to ‘rewire’ the brain for people with depression

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[Abstract] Changes in transcranial magnetic stimulation outcome measures in response to upper-limb physical training in stroke: A systematic review of randomized controlled trials

Abstract

Background

Physical training is known to be an effective intervention to improve sensorimotor impairments after stroke. However, the link between brain plastic changes, assessed by transcranial magnetic stimulation (TMS), and sensorimotor recovery in response to physical training is still misunderstood. We systematically reviewed reports of randomized controlled trials (RCTs) involving the use of TMS over the primary motor cortex (M1) to probe brain plasticity after upper-limb physical training interventions in people with stroke.

Methods

We searched 5 databases for articles published up to October 2016, with additional studies identified by hand-searching. RCTs had to investigate pre/post-intervention changes in at least one TMS outcome measure. Two independent raters assessed the eligibility of potential studies and reviewed the selected articles’ quality by using 2 critical appraisal scales.

Results

In total, 14 reports of RCTs (pooled participants = 358; mean 26 ± 12 per study) met the selection criteria. Overall, 11 studies detected plastic changes with TMS in the presence of clinical improvements after training, and these changes were more often detected in the affected hemisphere by using map area and motor evoked potential (MEP) latency outcome measures. Plastic changes mostly pointed to increased M1/corticospinal excitability and potential interhemispheric rebalancing of M1 excitability, despite sometimes controversial results among studies. Also, the strength of the review observations was affected by heterogeneous TMS methods and upper-limb interventions across studies as well as several sources of bias within the selected studies.

Conclusions

The current evidence encourages the use of TMS outcome measures, especially MEP latency and map area to investigate plastic changes in the brain after upper-limb physical training post-stroke. However, more studies involving rigorous and standardized TMS procedures are needed to validate these observations.

Keywords

  • Transcranial magnetic stimulation,
  • Stroke,
  • Upper-limb physical training,
  • Systematic review,
  • Brain plasticity,
  • Clinical outcome

Source: Elsevier: Article Locator

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[ARTICLE] Non-Invasive Brain Stimulation to Enhance Upper Limb Motor Practice Poststroke: A Model for Selection of Cortical Site – Full Text

Motor practice is an essential part of upper limb motor recovery following stroke. To be effective, it must be intensive with a high number of repetitions. Despite the time and effort required, gains made from practice alone are often relatively limited, and substantial residual impairment remains. Using non-invasive brain stimulation to modulate cortical excitability prior to practice could enhance the effects of practice and provide greater returns on the investment of time and effort. However, determining which cortical area to target is not trivial. The implications of relevant conceptual frameworks such as Interhemispheric Competition and Bimodal Balance Recovery are discussed. In addition, we introduce the STAC (Structural reserve, Task Attributes, Connectivity) framework, which incorporates patient-, site-, and task-specific factors. An example is provided of how this framework can assist in selecting a cortical region to target for priming prior to reaching practice poststroke. We suggest that this expanded patient-, site-, and task-specific approach provides a useful model for guiding the development of more successful approaches to neuromodulation for enhancing motor recovery after stroke.

Poststroke Arm Impairment

Upper limb motor impairment following stroke is highly prevalent and often persists even after intensive rehabilitation efforts (14). It is also one of the most disabling of stroke sequela, limiting functional independence and precluding return to work and other roles (5).

Upper extremity motor control relies heavily on input transmitted via the corticospinal tract (CST). The CST descends through the posterior limb of the internal capsule, an area vulnerable to middle cerebral artery stroke and in which CST fibers are densely packed. Thus, even a small lesion in this location can have devastating effects on motor function (69). A loss of voluntary wrist and finger extension is particularly common and appears to be related to the extent of CST damage (10). There is also evidence that those who retain wrist extension and have considerable CST sparing are more likely to be responsive to existing therapies (7811).

However, even individuals who lack voluntary wrist and finger extension often retain some ability to move the shoulder and elbow. Unfortunately, only a few stereotyped movement patterns can be performed and these are often not functional. The combination of shoulder flexion with elbow extension that is required for most functional reaching tasks, for example, is frequently lost. Nevertheless, previous studies have demonstrated that reaching practice with trunk restraint can improve unconstrained reaching ability, even in patients who lack wrist and finger extension (1215). Still, a great deal of time and effort is required and the improvements are relatively small.

Non-Invasive Brain Stimulation

Non-invasive brain stimulation offers a potential method of enhancing the effects of practice and thus giving patients greater returns on their investment of time and effort. Approaches to non-invasive brain stimulation are rapidly expanding but generally fall into two major categories: transcranial magnetic stimulation (TMS) and transcranial electrical stimulation [TES; see Ref. (16) for overview of non-invasive techniques for neuromodulation]. These modalities are applied to the scalp overlying a specific cortical area that is being targeted. The level of spatial specificity varies depending on many factors including the modality used (TMS is generally more precise than TES), the stimulation intensity (higher intensity results in a more widespread effect), and the architecture of the underlying tissue. The excitability of the underlying pool of neurons can be modulated by varying stimulation parameters such as the frequency and temporal pattern of the stimuli. Therefore, stimulation can be used to temporarily inhibit or facilitate the underlying cortical area for a sustained period of time after the stimulation ends (usually 20–40 min). In this way, non-invasive brain stimulation could be used to “prime” relevant cortical areas before a bout of practice, potentially enhancing the effects of practice. However, there is little guidance for how such cortical sites might be selected and in which direction (inhibition or facilitation) their activity should be modulated. Conceptual models that could offer such guidance are considered below.

Mechanistic Models to Guide Neuromodulation

Continue —> Frontiers | Non-Invasive Brain Stimulation to Enhance Upper Limb Motor Practice Poststroke: A Model for Selection of Cortical Site | Neurology

Figure 1. On randomly delivered trials, transcranial magnetic stimulation (TMS) perturbation was applied just after a “Go” cue. The effect of this pre-movement perturbation on the speed of the subsequent reaching movement is expressed relative to that in trials with no TMS perturbation. The amount of slowing due to TMS perturbation of the lesioned vs. non-lesioned hemispheres is shown for patients with good structural reserve (left) and patients with poor structural reserve (right).

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[ARTICLE] Using Brain Oscillations and Corticospinal Excitability to Understand and Predict Post-Stroke Motor Function – Full Text

What determines motor recovery in stroke is still unknown and finding markers that could predict and improve stroke recovery is a challenge. In this study, we aimed at understanding the neural mechanisms of motor function recovery after stroke using neurophysiological markers by means of cortical excitability (Transcranial Magnetic Stimulation – TMS) and brain oscillations (electroencephalography – EEG). In this cross-sectional study, fifty-five subjects with chronic stroke (62±14 yo, 17 women, 32±42 months post-stroke) were recruited in two sites. We analyzed TMS measures (i.e. motor threshold – MT – of the affected and unaffected sides) and EEG variables (i.e. power spectrum in different frequency bands and different brain regions of the affected and unaffected hemispheres) and their correlation with motor impairment as measured by Fugl-Meyer. Multiple univariate and multivariate linear regression analyses were performed to identify the predictors of good motor function. A significant interaction effect of MT in the affected hemisphere and power in beta bandwidth over the central region for both affected and unaffected hemispheres was found. We identified that motor function positively correlates with beta rhythm over the central region of the unaffected hemisphere, while it negatively correlates with beta rhythm in the affected hemisphere. Our results suggest that cortical activity in the affected and unaffected hemisphere measured by EEG provides new insights on the association between high frequency rhythms and motor impairment, highlighting the role of excess of beta in the affected central cortical region in poor motor function in stroke recovery.

Introduction

Stroke is a leading cause of morbidity, mortality, and disability worldwide (12). Among the sequels of stroke, motor impairment is one of the most relevant, since it conditions the quality of life of patients, it reduces their capability to perform their daily activities and it impairs their autonomy (3). Despite the advancements of the acute stroke therapy, patients require an intensive rehabilitation program that will partially determine the extent of their recovery (4). These rehabilitation programs aim at stimulating cortical plasticity to improve motor performance and functional recovery (5). However, what determines motor improvement is still unknown. Indeed, finding markers that could predict and enhance stroke recovery is still a challenge (6). Different types of biomarkers exist: diagnostic, prognostic, surrogate outcome, and predictive biomarkers (7). The identification of these biomarkers is critical in the management of stroke patients. In the field of stroke research, great attention has been put to biomarkers found in the serum, especially in acute care. However, research on biomarkers of stroke recovery is still limited, especially using neurophysiological tools.

A critical research area in stroke is to understand the neural mechanisms underlying motor recovery. In this context, neurophysiological techniques such as transcranial magnetic stimulation (TMS) and electroencephalography (EEG) are useful tools that could be used to identify potential biomarkers of stroke recovery. However, there is still limited data to draw further conclusions on neural reorganization in human trials using these techniques. A few studies have shown that, in acute and sub-acute stage, stroke patients present increased power in low frequency bands (i.e., delta and theta bandwidths) in both affected and unaffected sides, as well as increased delta/alpha ratio in the affected brain area; these patterns being also correlated to functional outcome (811). Recently, we have identified that, besides TMS-indexed motor threshold (MT), an increased excitability in the unaffected hemisphere, coupled with a decreased excitability in the affected hemisphere, was associated with poor motor function (12), as measured by Fugl-Meyer (FM) [assessing symptoms severity and motor recovery in post-stroke patients with hemiplegia—Fugl-Meyer et al. (13); Gladstone et al. (14)]. However, MT measurement is associated with a poor resolution as it indexes global corticospinal excitability. Therefore, combining this information with direct cortical measures such as cortical oscillations, as measured by EEG, can help us to understand further neural mechanisms of stroke recovery.

To date, there are very few studies looking into EEG and motor recovery. For that reason, we aimed, in the present study, to investigate the relationship between motor impairment, EEG, and TMS variables. To do so, we conducted a prospective multicenter study of patients who had suffered from a stroke, in which we measured functional outcome using FM and performed TMS and EEG recordings. Based on our preliminary work, we expected to identify changes in interhemispheric imbalances on EEG power, especially in frequency bands associated with learning, such as alpha and beta bandwidths. […]

Continue —> Frontiers | Using Brain Oscillations and Corticospinal Excitability to Understand and Predict Post-Stroke Motor Function | Neurology

Figure 1. Topoplots showing the topographic distribution of high-beta bandwidth (25 Hz) for every individual. Red areas represent higher high-beta activity, while blue areas represent lower high-beta activity. Central region (C3 or C4) in red stands for the affected side. For patients with poor motor function, a higher beta activity of the affected central region as compared to the affected side is observed in 16 out of 28 individuals. For patients with good motor function, a similar activity over central regions bilaterally, or higher activity over the unaffected central area can be identified in 21 out of 27 individuals. FM = Fugl-Meyer.

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