Transcranial magnetic stimulation and stroke: A computer-based human model study

Wagner, Tim; Fregni, Felipe; Eden, Uri T.; Ramos-Estébanez, Ciro; Grodzinsky, Alan J.; Zahn, M.; Pascual‐Leone, Álvaro

doi:10.1016/j.neuroimage.2005.04.046

Cited by 114 publications

(80 citation statements)

References 68 publications

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“…The behavior of the current density distribution directly under the coil center was very similar to the analogous atrophy models, but far less predictable along the widened sulci borders, similar to the results seen in stroke (Wagner 2001;Wagner et al 2005) and heterogeneity studies (Wagner 2001;Miranda et al 2003). There were locations directly below the most posterior portion of the figure-of-eight coil, along the widened central sulci border, where current density magnitudes were within ±15% of the maximums found under the coil center (3.59, −0.85, 6.61, and 14.35%, respectively for the base, 95, 90, and 85% widened sulci models).…”

Section: Effects Of Widened Sulci On the Induced Stimulating Currentssupporting

confidence: 65%

“…For the TMS frequency spectrum and given tissue resistive values implemented in the model, the current density vector distribution is governed by the condition that the normal current density vector components must be continuous across boundaries of media with differing conductivities (Zahn 2003;Wagner et al 2005). Thus, when one goes from the highly conductive CSF to the less conductive cerebral tissue at the widened sulci borders (or from the more conductive gray matter to the less conductive white matter), a jump in the normal component of the electrical field dictating final current density direction and magnitude along sulcal borders is expected.…”

Section: Widened Sulci Modelsmentioning

confidence: 99%

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Transcranial magnetic stimulation and brain atrophy: a computer-based human brain model study

et al. 2008

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This paper is aimed at exploring the effect of cortical brain atrophy on the currents induced by transcranial magnetic stimulation (TMS). We compared the currents induced by various TMS conditions on several different MRI derived finite element head models of brain atrophy, incorporating both decreasing cortical volume and widened sulci. The current densities induced in the cortex were dependent upon the degree and type of cortical atrophy and were altered in magnitude, location, and orientation when compared to healthy head models. Predictive models of the degree of current density attenuation as a function of the scalp-to-cortex distance were analyzed, concluding that those which ignore the electromagnetic field-tissue interactions lead to inaccurate conclusions. Ultimately, the precise site and population of neural elements stimulated by TMS in an atrophic brain cannot be predicted based on healthy head models which ignore the effects of the altered cortex on the stimulating currents. Clinical applications of TMS should be carefully considered in light of these findings.

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Section: Effects Of Widened Sulci On the Induced Stimulating Currentssupporting

confidence: 65%

Section: Widened Sulci Modelsmentioning

confidence: 99%

Transcranial magnetic stimulation and brain atrophy: a computer-based human brain model study

et al. 2008

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“…Additional points to keep in mind are that: (1) application of TMS or tDCS to one cortical site will probably influence distant cortical or subcortical sites through trans-synaptic effects 85,86 ; (2) in patients with brain lesions, expected models of current flow elicited by rTMS or tDCS may differ from those in healthy volunteers 87 ; and (3) both techniques may potentially influence attention, fatigue, discomfort, or mood, which underscores the importance of controlling for these factors in the design of double-blind clinical trials.…”

Section: Noninvasive Brain Stimulationmentioning

confidence: 99%

Noninvasive brain stimulation in stroke rehabilitation

Webster

Celnik

Cohen

2006

NeuroRX

145

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Summary:Stroke is a common disorder that produces a major burden to society, largely through long-lasting motor disability in survivors. Recent studies have broadened our understanding of the processes underlying recovery of motor function after stroke. Bilateral motor regions of the brain experience substantial reorganization after stroke, including changes in the strength of interhemispheric inhibitory interactions. Our understanding of the extent to which different forms of reorganization contribute to behavioral gains in the rehabilitative process, although still limited, has led to the formulation of novel interventional strategies to regain motor function. Transcranial magnetic (TMS) and DC (tDCS) electrical stimulation are noninvasive brain stimulation techniques that modulate cortical excitability in both healthy individuals and stroke patients. These techniques can enhance the effect of training on performance of various motor tasks, including those that mimic activities of daily living. This review looks at the effects of TMS and tDCS on motor cortical function and motor performance in healthy volunteers and in patients with stroke. Both techniques can either enhance or suppress cortical excitability, and may move to the clinical arena as strategies to enhance the beneficial effects of customarily used neurorehabilitative treatments after stroke.

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“…The specific anatomy, the pathologic alterations and the influx of cortico-spinal fluid change the conductivity with respect to healthy tissue due to the creation of new shunting routes for the currents, which can distort the electric field produced by the stimulation (Wagner et al, 2006). Thus, we need to ensure that the desired brain regions are targeted by the stimulation (Plow et al, 2009).…”

Section: Modeling the Current Flowmentioning

confidence: 99%

Bcci - A Bidirectional Cortical Communication Interface

Walter

Bensch

Brugger

et al. 2009

Proceedings of the International Joint Conference on Computational Intelligence

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Abstract:Therapeutic methods based on efferent signals from the patients' brain have been studied extensively in the field of brain-computer interfaces and applied to paralysed and stroke patients. Invasive stimulation is used as a therapeutic tool for patients with Parkinson disease, intractable chronic pain and other neurological diseases.We give a short review of currently used applications for cortical stimulation for stroke patients and braincomputer interfaces for paralyzed patients. We propose a refined approach for stroke rehabilitation as well as the extension of the use of invasive cortical stimulation to ALS patients with an experimental setup inspired by classical conditioning to facilitate the communication with brain-computer interfaces for LIS and CLIS patients. A closed-loop system is described with sophisticated methods for the identification of recording and stimulation sites, feature extraction and adaptation of stimulation algorithms to the patient in order to design a bidirectional cortical communication interface (BCCI).

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Transcranial magnetic stimulation and stroke: A computer-based human model study

Cited by 114 publications

References 68 publications

Transcranial magnetic stimulation and brain atrophy: a computer-based human brain model study

Transcranial magnetic stimulation and brain atrophy: a computer-based human brain model study

Noninvasive brain stimulation in stroke rehabilitation

Bcci - A Bidirectional Cortical Communication Interface

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