Posts Tagged Brain stimulation

[ARTICLE] Does non-invasive brain stimulation modify hand dexterity? Protocol for a systematic review and meta-analysis – Full Text

 

Abstract

Introduction Dexterity is described as coordinated hand and finger movement for precision tasks. It is essential for day-to-day activities like computer use, writing or buttoning a shirt. Integrity of brain motor networks is crucial to properly execute these fine hand tasks. When these networks are damaged, interventions to enhance recovery are frequently accompanied by unwanted side effects or limited in their effect. Non-invasive brain stimulation (NIBS) are postulated to target affected motor areas and improve hand motor function with few side effects. However, the results across studies vary, and the current literature does not allow us to draw clear conclusions on the use of NIBS to promote hand function recovery. Therefore, we developed a protocol for a systematic review and meta-analysis on the effects of different NIBS technologies on dexterity in diverse populations. This study will potentially help future evidence-based research and guidelines that use these NIBS technologies for recovering hand dexterity.

Methods and analysis This protocol will compare the effects of active versus sham NIBS on precise hand activity. Records will be obtained by searching relevant databases. Included articles will be randomised clinical trials in adults, testing the therapeutic effects of NIBS on continuous dexterity data. Records will be studied for risk of bias. Narrative and quantitative synthesis will be done.

Strengths and limitations of this study

  • This is a novel systematic review and meta-analysis focusing specifically on dexterity.

  • We use continuous data not dependent on the evaluator or participant.

  • This work will potentially help future evidence-based research and guidelines to refine non-invasive brain stimulation.

Introduction

The hand’s somatotopy is extensively represented in the human motor cortex.1 2 Phylogenetically, this relates to the development of corticomotoneuronal cells that specialise in creating patterns of muscle activity that synergises into highly skilled movements.3 This organised hand-and-finger movement to use objects during a specific task is known as dexterity.4 Evolutionary, dexterity played a pivotal role in human survival and is fundamental to actives of daily living, and hence quality of life.5 6

This precision motor movement relies on integration of information from the cerebral cortex, the spinal cord, several neuromusculoskeletal systems and the external world to coordinate finger force control, finger independence, timing and sequence performance.7 During these tasks, multivoxel pattern decoding shows bilateral primary motor cortex activation (M1), which was responsible for muscle recruitment timing and hand movement coordination.8 9 This is related to motor cortex connectivity through the corpus callosum, to motor regions of the cerebellum and white matter integrity.10–15 Adequate motor output translates into successfully executed tasks, like picking up objects, turning over cards, manipulating cutlery, writing, using computer–hand interfaces like smartphones, playing an instrument and performing many other similarly precise skills.16

These motor tasks are negatively impacted when motor output networks are affected, as seen in stroke or Parkinson’s disease.17 18 Therapeutic interventions that restore these damaged motor networks can be vital to restore fine motor movement after injury occurs. Pharmaceutical approaches often lead to adverse effects such as dyskinesias in Parkinson’s disease. Moreover, even after intensive rehabilitation programmes, only about 5%–20% of patients with stroke fully recover their motor function.19–21 Non-invasive brain stimulation (NIBS) techniques, like transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), are proposed adjuvant or stand-alone interventions to target these affected areas and improve fine motor function.22 23 Briefly, these NIBS interventions are shown to influence the nervous system’s excitability and modulate long-term plasticity, which may be beneficial to the brain’s recovery of functions after injury.24–27

Fine hand motor ability is not studied as much in previous reviews of NIBS. Specifically, one narrative review focuses on rTMS in affected hand recovery poststroke; however, it does not consider the implications of varying International Classification of Functioning, Disability and Health (ICF) domains, data types and rater dependent outcomes, and its interpretability is limited without quantitative synthesis.28–31 The overarching conclusion was supportive of rTMS for paretic hand recovery, though with limited data to support its regular use, and a pressing need to study individualised patient parameters.28 One meta-analysis had positive and significant results when specifically studying the effects of rTMS on finger coordination and hand function after stroke.32 However, while various meta-analysis, and another systematic review, studied upper-limb movement after NIBS in distinct populations, they did not focus on precise hand function, pooled upper-limb outcomes with hand outcomes and presented mixed results.33–38

Motivated by this gap in the evidence for NIBS in dexterity, we will do a systematic review and meta-analysis of the literature on these brain stimulation technologies using outcomes that focus exactly on manual dexterity. These outcomes will be continuous and not dependent on the participant’s or rater’s observation (ie, they will be measured in seconds, or number of blocks/pegs placed, and not by an individual’s interpretation). They will be comprised of multiple domains as defined by the ICF, providing an appreciation of function rather than only condition or disease.29–31 By focusing on the ICF model, we will be able to study dexterity across a larger sample of studies, NIBS techniques and conditions in order to provide a better understanding of brain stimulation efficacy on hand function in various populations.[…]

Continue —. Does non-invasive brain stimulation modify hand dexterity? Protocol for a systematic review and meta-analysis | BMJ Open

, , , , , , ,

Leave a comment

[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).

, , , , , , , , , , , , ,

Leave a comment

[Abstract] The treatment of fatigue by non-invasive brain stimulation

Summary

The use of non-invasive brain neurostimulation (NIBS) techniques to treat neurological or psychiatric diseases is currently under development. Fatigue is a commonly observed symptom in the field of potentially treatable pathologies by NIBS, yet very little data has been published regarding its treatment. We conducted a review of the literature until the end of February 2017 to analyze all the studies that reported a clinical assessment of the effects of NIBS techniques on fatigue. We have limited our analysis to repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). We found only 15 studies on this subject, including 8 tDCS studies and 7 rTMS studies. Of the tDCS studies, 6 concerned patients with multiple sclerosis while 6 rTMS studies concerned fibromyalgia or chronic fatigue syndrome. The remaining 3 studies included patients with post-polio syndrome, Parkinson’s disease and amyotrophic lateral sclerosis. Three cortical regions were targeted: the primary sensorimotor cortex, the dorsolateral prefrontal cortex and the posterior parietal cortex. In all cases, tDCS protocols were performed according to a bipolar montage with the anode over the cortical target. On the other hand, rTMS protocols consisted of either high-frequency phasic stimulation or low-frequency tonic stimulation. The results available to date are still too few, partial and heterogeneous as to the methods applied, the clinical profile of the patients and the variables studied (different fatigue scores) in order to draw any conclusion. However, the effects obtained, especially in multiple sclerosis and fibromyalgia, are really carriers of therapeutic hope.

Source: The treatment of fatigue by non-invasive brain stimulation

, , , , , , , , ,

Leave a comment

[Abstract] Bilateral sequential motor cortex stimulation and skilled task performance with non-dominant hand

Highlights

  • Both, contralateral M1 iTBS and ipsilateral M1 cTBS improved non-dominant skilled-task performance.
  • Bilateral sequential M1 TBS (contralateral cTBS followed by ipsilateral iTBS) improved skilled-task performance more than unilateral or sham TBS.
  • Bilateral sequential M1 TBS may be particularly effective in improving motor learning, also in the neurorehabilitation setting.

Abstract

Objective

To check whether bilateral sequential stimulation (BSS) of M1 with theta burst stimulation (TBS), using facilitatory protocol over non-dominant M1 followed by inhibitory one over dominant M1, can improve skilled task performance with non-dominant hand more than either of the unilateral stimulations do. Both, direct motor cortex (M1) facilitatory non-invasive brain stimulation (NIBS) and contralateral M1 inhibitory NIBS were shown to improve motor learning.

Methods

Forty right-handed healthy subjects were divided into 4 matched groups which received either ipsilateral facilitatory (intermittent TBS [iTBS] over non-dominant M1), contralateral inhibitory (continuous TBS [cTBS] over dominant M1), bilateral sequential (contralateral cTBS followed by ipsilateral iTBS), or placebo stimulation. Performance was evaluated by Purdue peg-board test (PPT), before (T0), immediately after (T1), and 30 min after (T2) an intervention.

Results

In all groups and for both hands, the PPT scores increased at T1 and T2 in comparison to T0, showing clear learning effect. However, for the target non-dominant hand only, immediately after BSS (at T1) the PPT scores improved significantly more than after either of unilateral interventions or placebo.

Conclusion

M1 BSS TBS is an effective intervention for improving motor performance.

Significance

M1 BSS TBS seems as a promising tool for motor learning improvement with potential uses in neurorehabilitation.

Source: Bilateral sequential motor cortex stimulation and skilled task performance with non-dominant hand – Clinical Neurophysiology

, , , , , , , , , , ,

Leave a comment

[WEB SITE] Electrical brain stimulation could boost benefits of stroke rehabilitation. | Science | The Guardian

Research indicates that transcranial direct current stimulation (tCDS) during rehabilitation therapy might help stroke patients recover more movement

Scans showing the effects of hemorrhagic and ischemic stroke.

Scans showing the effects of hemorrhagic and ischemic stroke on the brain. Photograph: Alamy

Electrical brain stimulation could benefit stroke patients by boosting the effects of rehabilitation therapy, new research suggests.

Writing in the journal Science Translational Medicine, the authors reveal that patients who were given electrical brain stimulation during a rehabilitation programme performed better on a range of tasks than those taking part in the rehabilitation programme.

“It is an exciting message because there is so much frustration about people not reaching their true recovery potential,” said Professor Heidi Johansen-Berg, an author of the study from the University of Oxford, highlighting the fact that the cost of programmes and limited availability of therapists often restricts the amount of rehabilitation offered to patients.

To probe the effects of brain stimulation, the researchers chose 24 patients who had experienced a stroke at least six months before, and who had difficulties with moving one hand. The participants were then split into two groups.

The first group underwent nine consecutive days of rehabilitation training, with each session lasting an hour. For the first 20 minutes, the patients had two electrodes placed on their heads and a direct current applied, a process known as anodal transcranial direct current stimulation (tDCS). This is stimulation is thought to prime the brain for learning.

The second group also underwent the nine-day programme, but while they too had electrodes placed on their head for the first 20 minutes, the current was turned off after the first 10 seconds, leading to a placebo trial.

The results indicate that brain stimulation bolstered the effect of the rehabilitation therapy, with patients who underwent the stimulation scoring appreciably higher on two of the tests – those related to carrying out particular tasks with the hand such as picking up a paper-clip – in assessments carried out three months after the therapy. For third test, which measured effects such as the strength of grip, brain stimulation was not linked to improvements.

“If we take at face value what the results are telling us, it is that the stimulation doesn’t completely change the way that the brain can produce a movement, in that it doesn’t make you stronger, but it makes the brain better at being able to carry out a particular task like lifting up an object,” said Johansen-Berg.

However not everyone is convinced. Jane Burridge, professor of restorative neuroscience at the University of Southampton, who was not involved with the study, said the smaller effect for the third test could simply be down to the small size of the study. “You do need to have bigger trials to be certain of the results,” she said.

The research also found that patients who underwent the brain stimulation had larger increases in activity in regions of the brain associated with movement than those who had been given the placebo treatment – an effect that was seen from fMRI scans taken immediately after the nine-day programme and one month later.

“What is particularly important about [the study] is that it does relate the functional improvements with the neuroimaging changes – and that is very encouraging,” said Burridge.

But Burridge also cautions that the results should not be taken as a sign that brain stimulation will benefit all stroke patients. “One has to remember that this is one quite small study,” she said. “The overall view at the moment of when we put all the data [from many studies] together is that there is no clear benefit.”

Johansen-Berg also admits the new research has its limitations. “One thing it doesn’t allow us to do at all is get at the question of variability ,” she says. “We wouldn’t expect this to work for everybody, there will be some people it will work well for and some people who it won’t and we haven’t got anything like the numbers you’d need to tease that apart.”

The results were welcomed by health charities. “This study is an important step toward larger trials to test the effectiveness of non-invasive, electrical brain stimulation to improve the motor recovery of stroke survivors and support their rehabilitation after stroke,” said Dr Shamim Quadir of the Stroke Association. “Stroke is one of the largest causes of disability, and more than half of stroke survivors are left dependent on others for help with everyday activities. It is crucial that we find alternative ways to help improve the recovery rates from this devastating condition.”

But Dr Nick Ward from University College London warns that the study is unlikely to lead to a change in treatment programmes any time soon. “I would call this a proof of principle study,” he said. “This is not something that you can translate into the NHS or any other clinical service immediately.”

For Ward, the most interesting revelation is the level of improvement shown by the patients who did not receive brain stimulation, calling the results “dramatic”. While he cautions that the size of the effect might be down to the very selective nature of the group, if shown to apply more generally it would support the idea that “doing more physical therapy is a good thing.”

Johansen-Berg also believes the research offers a wider message of hope. “With the two weeks of intense therapy, both groups show significant improvement, it is just that they are slightly boosting that with the tDCS,” she said. “ What this shows is if you do two weeks of intensive practice with your bad hand, you will get much better.”

Source: Electrical brain stimulation could boost benefits of stroke rehabilitation | Science | The Guardian

, , ,

Leave a comment

[Abstract] Enhancement of motor relearning and functional recovery in stroke patients: non-invasive strategies for modulating the central nervous system. – PubMed

INTRODUCTION: Most of the stroke survivors do not recover the basal state of the affected upper limb, suffering from a severe disability which remains during the chronic phase of the illness. This has an extremely negative impact in the quality of life of these patients. Hence, neurorehabilitation strategies aim at the minimization of the sensorimotor dysfunctions associated to stroke, by promoting neuroplasticity in the central nervous system.

DEVELOPMENT: Brain reorganization can facilitate motor and functional recovery in stroke subjects. None-theless, after the insult, maladaptive neuroplastic changes can also happen, which may lead to the appearance of certain sensori-motor disorders such as spasticity. Noninvasive brain stimulation strategies, like transcranial direct current stimulation or transcranial magnetic stimulation, are widely used techniques that, when applied over the primary motor cortex, can modify neural networks excitability, as well as cognitive functions, both in healthy subjects and individuals with neurological disorders. Similarly, brain-machine-interface systems also have the potential to induce a brain reorganization by the contingent and simultaneous association between the brain activation and the peripheral stimulation.

CONCLUSION: This review describes the positive effects of the previously mentioned neurorehabilitation strategies for the enhancement of cortical reorganization after stroke, and how they can be used to alleviate the symptoms of the spasticity syndrome.

Source: [Enhancement of motor relearning and functional recovery in stroke patients: non-invasive strategies for modulating the central nervous system]. – PubMed – NCBI

, , , , , , , ,

Leave a comment

[ARTICLE] Underlying neural mechanisms of mirror therapy: Implications for motor rehabilitation in stroke. – Full Text 

Abstract

Mirror therapy (MT) is a valuable method for enhancing motor recovery in poststroke hemiparesis. The technique utilizes the mirror-illusion created by the movement of sound limb that is perceived as the paretic limb. MT is a simple and economical technique than can stimulate the brain noninvasively. The intervention unquestionably has neural foundation. But the underlying neural mechanisms inducing motor recovery are still unclear. In this review, the neural-modulation due to MT has been explored. Multiple areas of the brain such as the occipital lobe, dorsal frontal area and corpus callosum are involved during the simple MT regime. Bilateral premotor cortex, primary motor cortex, primary somatosensory cortex, and cerebellum also get reorganized to enhance the function of the damaged brain. The motor areas of the lesioned hemisphere receive visuo-motor processing information through the parieto-occipital lobe. The damaged motor cortex responds variably to the MT and may augment true motor recovery. Mirror neurons may also play a possible role in the cortico-stimulatory mechanisms occurring due to the MT.

Introduction

The science of mirror therapy (MT) is getting due attention in the management of half-sided paresis due to stroke. The technique was first introduced by Ramachandran and Roger-Ramachandran to manage phantom sensations among the subjects with a unilateral amputation.[1]

Figure 1: Illustrates the arrangement of mirror therapy regime; the affected upper extremity (left) is placed inside the box (shown as dotted line) while the sound limb (right) is facing the mirror

Figure 1: Illustrates the arrangement of mirror therapy regime; the affected upper extremity (left) is placed inside the box (shown as dotted line) while the sound limb (right) is facing the mirror

The characteristic property of a mirror that reflects an image after altering its right-left orientation is a commonly known fact. In humans, the movement of right side of the body is primarily controlled by the left brain, and vice versa. The mirror feature and the brain behaviour collectively form the concept of MT. The paradigm allows an individual to perform the movements of an unaffected body part in front of the arranged mirror-box while hiding the affected part. The technique induces a visual illusion that appears to mimic the movement of the paretic part [Figure 1]. The perception, more than being a simple feedback mechanism, has been found to enhance motor recovery of the impaired body side.[2],[3],[4] The neural mechanisms leading to the favourable improvement are components of a complex phenomenon that need to be explored and comprehended…

Continue —> Underlying neural mechanisms of mirror therapy: Implications for motor rehabilitation in stroke Arya KN Neurol India

, , , , , ,

Leave a comment

[WEB SITE] Novel Brain Stimulation May Boost Creativity, Treat Depression

Application of a weak electric current to the frontal areas of the brain boosts creativity and may lead to a novel method of treating depression, a new proof-of-concept study suggests.

Applying 10 Hz of stimulation via electrodes to healthy individuals, the team was able to increase alpha oscillations in the brain and improve performance on a commonly used measure of creativity.

They now hope to use the findings as a springboard to improve alpha oscillations in individuals with depression and so improve symptoms.

Explaining how alpha oscillations may mediate creativity, coauthor Flavio Frohlich, PhD, assistant professor at the University of North Carolina (UNC) School of Medicine, Chapel Hill, said in a release, “For a long time, people thought alpha waves represented the brain idling.”

“But over the past 20 years, we’ve developed much better insight. Our brains are not wasting energy, creating these patterns for nothing. When the brain is decoupled from the environment, it still does important things.”

The team believes that the stimulation may also enhance phase synchronization between the frontal regions, further boosting creativity.

The research is published in the June issue of Cortex.

Continue —> Novel Brain Stimulation May Boost Creativity, Treat Depression.

, ,

Leave a comment

[WEB SITE] #MindGames Forever – Where is NeuroGaming headed? — Blog Neuroelectrics

…WHAT IS NEUROGAMING?

Well to start with NeuroGaming refers to combining a videogame with physiological (ECG, GSR, etc.) and neurophysiological (EEG, NIRS, etc.) monitoring. In this context the signals obtained affect the game specifically by moving objects or creating movement, or generally by adjusting the game difficulty and other general parameters. Additionally, recently, brain stimulation such as transcranial current stimulation (tCS) has been added to the NeuroGaming definition as it increases brain plasticity during game play…

Continue–> #MindGames Forever – Where is NeuroGaming headed? | Blog Neuroelectrics.

, , , ,

Leave a comment

[ARTICLE] A Combined Therapeutic Approach in Stroke Rehabilitation: A Review on Non-Invasive Brain Stimulation plus Pharmacotherapy -Full Text PDF

Abstract

Stroke is a leading cause of disability in the United States. Available treatments for stroke have only a modest effect on motor rehabilitation and about 50-60% of stroke patients remain with some degree of motor impairment after standard treatment.

Non-invasive brain stimulation (NIBS) techniques have been proposed as adjuvant treatments to physical therapy for motor recovery after stroke. High frequency rTMS and anodal tDCS can be delivered over the affected motor cortex in order to increase cortical excitability and induce brain plasticity with the intention to enhance motor learning and achieve functional goals in stroke patients. Similarly, low frequency rTMS and cathodal tDCS can be delivered to the unaffected motor cortex to reduce interhemispheric inhibition and hinder maladaptive plasticity.

The use of several drugs such as amphetamines, selective serotonin reuptake inhibitors (SSRIs), levodopa and cholinergic agents have been also proposed to enhance the motor function. Given that both NIBS and pharmacotherapy might provide some treatment effect independently for motor rehabilitation in stroke and with the rationale that they could work in a synergistic fashion, we believe that a combined therapy- NIBS plus pharmacotherapy- can lead to better outcomes than one or the other alone. In this paper we review the literature that support the potential use of a combined approach in stroke recovery and present the studies that have already investigated this idea

Full Text PDF

, , , , , , , , , ,

Leave a comment

%d bloggers like this: