Posts Tagged neuromodulation

[ARTICLE] Transcranial direct current stimulation and stroke recovery: opportunities and challenges – Full Text PDF

ABSTRACT

Objectives: Transcranial direct current stimulation (tDCS) is one type of neuromodulation, which is an emerging technology that holds promise for the future studies on therapeutic and diagnosis applications in treatment of neurological and psychiatric diseases. However, there is a serious question among developing countries with limited financial and human resources, about the potential returns of an investment in this field and regarding the best time to transfer this technology from controlled experimental settings to health systems in the public and private sectors. This article reviews the tDCS as tools of neuromodulation for stroke and discusses the opportunities and challenges available for clinicians and researchers interested in advancing neuromodulation therapy. The aim of this review is to highlight the usefulness of tDCS and to generate an interest that will lead to appropriate studies that assess the true clinical value of tDCS for brain diseases in developing countries.

Methods: Literature review was done on PubMed from 2016 on neuromodulation in under-developed countries (UDCs) by non-invasive brain stimulation methods, using the key words “stroke”, “rehabilitation”, and “tDCS”.

Results: We first identified articles and websites, of which were further selected for extensive analysis mainly based on clinical relevance, study quality and reliability, and date of publication.

Conclusion: Despite the promising results obtained with tDCS in basic and clinical neuroscience, further progress has been impeded by a lack of clarity to use in mostly UDCs.

INTRODUCTION
During stroke, an interruption to all or part of the brain’s
blood supply, with the subsequent deprivation of oxygen
and glucose to the affected area, causes the rapid loss
of brain function through the destruction of neuronal
function and the initiation of an ischemic cascade that
seriously damages or kills neurons1. Strokes are
classified as an ischemic (caused by embolism,
thrombosis or systemic hypoperfusion) approximately
80% and hemorrhagic (intracerebral, subarachnoid,
subdural or epidural in type) strokes(1, 2). The main
symptoms associated with stroke are weakness in
facial, speech and a loss in visual field and paralysis in
the arm or leg. These symptoms may last only a few
hours and disappear completely within 24 hours, as
with TIAs, but even under these circumstances,
immediate medical assistance should be sought, as
this will help minimise damage to the brain and help
prevent progression to larger, more serious episodes of
stroke(2). Stroke can result in lasting neurological
damage or may even cause death unless it is
diagnosed and treated promptly. When the stroke is
severe, the patient often faces a prolonged stay in
hospital and, following their discharge and depending
on the severity of the consequences, constant care.
This care is either provided by a family member or, in
the most severe cases, by a nursing home. Stroke
disease not only affects health-related quality of life
(HRQOL) of patients but it can also increase their
hospital length of stay (HLoS)(3, 4). HLoS will even be
more increased if patients are suffering with stroke
combined with diabetes mellitus and hypertension(5). […]

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[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

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[Abstract] Targeting interhemispheric inhibition with neuromodulation to enhance stroke rehabilitation

Highlights

  • This review focuses on interhemispheric inhibition and its role in the healthy and stroke lesioned brain.
  • Measurement method and movement phase should be considered when comparing studies associating interhemispheric inhibition with functional recovery.
  • Neuromodulation of interhemispheric inhibition to augment stroke recovery requires the targeting of specific neural circuitry. We discuss the effectiveness of current and novel neurostimulation techniques at targeting interhemispheric inhibition and enhancing stroke rehabilitation.

Abstract

Background/Objectives

Interhemispheric inhibition in the brain plays a dynamic role in the production of voluntary unimanual actions. In stroke, the interhemispheric imbalance model predicts the presence of asymmetry in interhemispheric inhibition, with excessive inhibition from the contralesional hemisphere limiting maximal recovery. Stimulation methods to reduce this asymmetry in the brain may be promising as a stroke therapy, however determining how to best measure and modulate interhemispheric inhibition and who is likely to benefit, remain important questions.

Methods

This review addresses current understanding of interhemispheric inhibition in the healthy and stroke lesioned brain. We present a review of studies that have measured interhemispheric inhibition using different paradigms in the clinic, as well as results from recent animal studies investigating stimulation methods to target abnormal inhibition after stroke.

Main findings/Discussion

The degree to which asymmetric interhemispheric inhibition impacts on stroke recovery is controversial, and we consider sources of variation between studies which may contribute to this debate. We suggest that interhemispheric inhibition is not static following stroke in terms of the movement phase in which it is aberrantly engaged. Instead it may be dynamically increased onto perilesional areas during early movement, thus impairing motor initiation. Hence, its effect on stroke recovery may differ between studies depending on the technique and movement phase of eliciting the measurement. Finally, we propose how modulating excitability in the brain through more specific targeting of neural elements underlying interhemispheric inhibition via stimulation type, location and intensity may raise the ceiling of recovery following stroke and enhance functional return.

Source: Targeting interhemispheric inhibition with neuromodulation to enhance stroke rehabilitation – Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation

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[Abstract] Targeting interhemispheric inhibition with neuromodulation to enhance stroke rehabilitation. – Brain Stimulation

Highlights

  • This review focuses on interhemispheric inhibition and its role in the healthy and stroke lesioned brain.
  • Measurement method and movement phase should be considered when comparing studies associating interhemispheric inhibition with functional recovery.
  • Neuromodulation of interhemispheric inhibition to augment stroke recovery requires the targeting of specific neural circuitry. We discuss the effectiveness of current and novel neurostimulation techniques at targeting interhemispheric inhibition and enhancing stroke rehabilitation.

Abstract

Background/Objectives

Interhemispheric inhibition in the brain plays a dynamic role in the production of voluntary unimanual actions. In stroke, the interhemispheric imbalance model predicts the presence of asymmetry in interhemispheric inhibition, with excessive inhibition from the contralesional hemisphere limiting maximal recovery. Stimulation methods to reduce this asymmetry in the brain may be promising as a stroke therapy, however determining how to best measure and modulate interhemispheric inhibition and who is likely to benefit, remain important questions.

Methods

This review addresses current understanding of interhemispheric inhibition in the healthy and stroke lesioned brain. We present a review of studies that have measured interhemispheric inhibition using different paradigms in the clinic, as well as results from recent animal studies investigating stimulation methods to target abnormal inhibition after stroke.

Main findings/Discussion

The degree to which asymmetric interhemispheric inhibition impacts on stroke recovery is controversial, and we consider sources of variation between studies which may contribute to this debate. We suggest that interhemispheric inhibition is not static following stroke in terms of the movement phase in which it is aberrantly engaged. Instead it may be dynamically increased onto perilesional areas during early movement, thus impairing motor initiation. Hence, its effect on stroke recovery may differ between studies depending on the technique and movement phase of eliciting the measurement. Finally, we propose how modulating excitability in the brain through more specific targeting of neural elements underlying interhemispheric inhibition via stimulation type, location and intensity may raise the ceiling of recovery following stroke and enhance functional return.

Source: Targeting interhemispheric inhibition with neuromodulation to enhance stroke rehabilitation – Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation

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[Abstract] Evidence-based guidelines on the therapeutic use of transcranial direct current stimulation (tDCS) – Clinical Neurophysiology

Highlights

  • A group of European experts reviewed current evidence for therapeutic efficacy of tDCS.
  • Level B evidence (probable efficacy) was found for fibromyalgia, depression and craving.
  • The therapeutic relevance of tDCS needs to be further explored in these and other indications.

Abstract

A group of European experts was commissioned by the European Chapter of the International Federation of Clinical Neurophysiology to gather knowledge about the state of the art of the therapeutic use of transcranial direct current stimulation (tDCS) from studies published up until September 2016, regarding pain, Parkinson’s disease, other movement disorders, motor stroke, poststroke aphasia, multiple sclerosis, epilepsy, consciousness disorders, Alzheimer’s disease, tinnitus, depression, schizophrenia, and craving/addiction.

The evidence-based analysis included only studies based on repeated tDCS sessions with sham tDCS control procedure; 25 patients or more having received active treatment was required for Class I, while a lower number of 10–24 patients was accepted for Class II studies. Current evidence does not allow making any recommendation of Level A (definite efficacy) for any indication. Level B recommendation (probable efficacy) is proposed for: (i) anodal tDCS of the left primary motor cortex (M1) (with right orbitofrontal cathode) in fibromyalgia; (ii) anodal tDCS of the left dorsolateral prefrontal cortex (DLPFC) (with right orbitofrontal cathode) in major depressive episode without drug resistance; (iii) anodal tDCS of the right DLPFC (with left DLPFC cathode) in addiction/craving. Level C recommendation (possible efficacy) is proposed for anodal tDCS of the left M1 (or contralateral to pain side, with right orbitofrontal cathode) in chronic lower limb neuropathic pain secondary to spinal cord lesion. Conversely, Level B recommendation (probable inefficacy) is conferred on the absence of clinical effects of: (i) anodal tDCS of the left temporal cortex (with right orbitofrontal cathode) in tinnitus; (ii) anodal tDCS of the left DLPFC (with right orbitofrontal cathode) in drug-resistant major depressive episode.

It remains to be clarified whether the probable or possible therapeutic effects of tDCS are clinically meaningful and how to optimally perform tDCS in a therapeutic setting. In addition, the easy management and low cost of tDCS devices allow at home use by the patient, but this might raise ethical and legal concerns with regard to potential misuse or overuse. We must be careful to avoid inappropriate applications of this technique by ensuring rigorous training of the professionals and education of the patients.

Source: Evidence-based guidelines on the therapeutic use of transcranial direct current stimulation (tDCS) – Clinical Neurophysiology

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[WEB SITE] Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy – NEUROSURGERY Report

Abstract

BACKGROUND: Neuromodulation-based treatments have become increasingly important in epilepsy treatment. Most patients with epilepsy treated with neuromodulation do not achieve complete seizure freedom, and, therefore, previous studies of vagus nerve stimulation (VNS) therapy have focused instead on reduction of seizure frequency as a measure of treatment response.

OBJECTIVE: To elucidate rates and predictors of seizure freedom with VNS.

METHODS: We examined 5554 patients from the VNS therapy Patient Outcome Registry, and also performed a systematic review of the literature including 2869 patients across 78 studies.

RESULTS: Registry data revealed a progressive increase over time in seizure freedom after VNS therapy. Overall, 49% of patients responded to VNS therapy 0 to 4 months after implantation (≥50% reduction seizure frequency), with 5.1% of patients becoming seizure-free, while 63% of patients were responders at 24 to 48 months, with 8.2% achieving seizure freedom. On multivariate analysis, seizure freedom was predicted by age of epilepsy onset >12 years (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.38-2.58), and predominantly generalized seizure type (OR, 1.36; 95% CI, 1.01-1.82), while overall response to VNS was predicted by nonlesional epilepsy (OR, 1.38; 95% CI, 1.06-1.81). Systematic literature review results were consistent with the registry analysis: At 0 to 4 months, 40.0% of patients had responded to VNS, with 2.6% becoming seizure-free, while at last follow-up, 60.1% of individuals were responders, with 8.0% achieving seizure freedom.

CONCLUSION: Response and seizure freedom rates increase over time with VNS therapy, although complete seizure freedom is achieved in a small percentage of patients.

Source: Open Access: Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy | NEUROSURGERY Report

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[ARTICLE] Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy – Full Text

Abstract

BACKGROUND: Neuromodulation-based treatments have become increasingly important in epilepsy treatment. Most patients with epilepsy treated with neuromodulation do not achieve complete seizure freedom, and, therefore, previous studies of vagus nerve stimulation (VNS) therapy have focused instead on reduction of seizure frequency as a measure of treatment response.

OBJECTIVE: To elucidate rates and predictors of seizure freedom with VNS.

METHODS: We examined 5554 patients from the VNS therapy Patient Outcome Registry, and also performed a systematic review of the literature including 2869 patients across 78 studies.

RESULTS: Registry data revealed a progressive increase over time in seizure freedom after VNS therapy. Overall, 49% of patients responded to VNS therapy 0 to 4 months after implantation (≥50% reduction seizure frequency), with 5.1% of patients becoming seizure-free, while 63% of patients were responders at 24 to 48 months, with 8.2% achieving seizure freedom. On multivariate analysis, seizure freedom was predicted by age of epilepsy onset >12 years (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.38-2.58), and predominantly generalized seizure type (OR, 1.36; 95% CI, 1.01-1.82), while overall response to VNS was predicted by nonlesional epilepsy (OR, 1.38; 95% CI, 1.06-1.81). Systematic literature review results were consistent with the registry analysis: At 0 to 4 months, 40.0% of patients had responded to VNS, with 2.6% becoming seizure-free, while at last follow-up, 60.1% of individuals were responders, with 8.0% achieving seizure freedom.

CONCLUSION: Response and seizure freedom rates increase over time with VNS therapy, although complete seizure freedom is achieved in a small percentage of patients.

 

Approximately 1% of the population has epilepsy, and seizures are refractory to antiepileptic drugs (AEDs) in approximately 30% of these individuals.1 Many patients with drug-resistant temporal or extratemporal lobe epilepsy can become seizure-free with surgical resection or ablation, but other patients with epilepsy are not candidates for resection given the presence of primary generalized seizures, nonlocalizable or multifocal seizure onset, or seizure onset from an eloquent brain region.2-5 Treatments based on neuromodulation, such as vagus nerve stimulation (VNS), have, therefore, become an increasingly important part of multimodal epilepsy treatment. VNS therapy was approved by the US Food and Drug Administration in 1997 as an adjunctive therapy for reducing seizures in patients with medically refractory epilepsy, and more than 80 000 patients have received treatment with VNS.6-8 The efficacy of VNS therapy has been evaluated by randomized controlled trials,9,10 retrospective case series,11,12 meta-analysis,13 and registry-based studies.14 These studies show that about 50% to 60% of patients achieve ≥50% reduction in seizure frequency after 2 years of treatment, and response rates increase over time, likely related to neuromodulatory effects with ongoing stimulation.13 Complete seizure freedom, however, is less common with VNS therapy and other neuromodulation treatment modalities.

Given that a minority of patients achieve seizure freedom with VNS, rates and predictors of seizure freedom have not been well studied and remain poorly understood. The vast majority of studies that evaluate VNS therapy focus on rate of response over time (defined as ≥50% reduction in seizures) and predictors of response; there has never been a large-scale evaluation of seizure freedom as a primary end point in patients treated with VNS. However, seizure freedom is the single best predictor of quality of life in patients with epilepsy,15,16 and therefore a better understanding of seizure freedom rates and predictors in patients treated with VNS therapy is critically needed. Importantly, this information may lead to improved patient selection and counseling in the treatment of drug-resistant epilepsy.

Here, we provide the first large-scale study of VNS therapy with a primary goal of defining seizure freedom rates and predictors, and comparing predictors of seizure freedom with those of overall response to treatment. Our study includes univariate and multivariate analyses of registry data including 5554 patients treated with VNS, and also includes a systematic review of the literature including 2869 patients across 78 studies, to help confirm registry-based results.

Continue —> Rates and Predictors of Seizure Freedom With Vagus Nerve Sti… : Neurosurgery

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[ARTICLE] Neurorestoration after stroke – JNS – Full Text

Abstract

Recent advancements in stem cell biology and neuromodulation have ushered in a battery of new neurorestorative therapies for ischemic stroke. While the understanding of stroke pathophysiology has matured, the ability to restore patients’ quality of life remains inadequate. New therapeutic approaches, including cell transplantation and neurostimulation, focus on reestablishing the circuits disrupted by ischemia through multidimensional mechanisms to improve neuroplasticity and remodeling. The authors provide a broad overview of stroke pathophysiology and existing therapies to highlight the scientific and clinical implications of neurorestorative therapies for stroke.

Continue —> JNS – Neurosurgical Focus –

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[BOOK CHAPTER] Effects of Noninvesive Neuromodulation in Spasticity – Google Books

Εξώφυλλο

Spasticity, Second Edition: Diagnosis and Management

Allison Brashear, MD

[BOOK CHAPTER] Effects of Noninvesive Neuromodulation in Spasticity – Google Books

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[ARTICLE] Non Invasive Neuromodulation in Motor Recovery after Stroke: State of the Art, Open Questions and Future Perspectives – Open Access

Abstract

Stroke is the leading cause of adult disability. Unfortunately, less than 40% of stroke survivors completely recover, despite intensive acute care and rehabilitation training.

Non invasive brain stimulation (NIBS) techniques have been recognized as a promising intervention to improve motor recovery after stroke. Repeated sessions of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) can, indeed, induce changes in cortical excitability and long term plasticity.

Several protocols of stimulation have been already tested and proven efficient in modulating the lesioned as well as the unlesioned hemisphere after stroke.

However, not all patients can be considered as responder to NIBS. We provide an overview of the rationale, open questions and future perspectives for NIBS after stroke.

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