Electric field distribution in deep brain structures during transcranial direct current stimulation (tDCS) with extracephalic montages: a computational study

AbstractObjectiveCerebellar transcranial direct current stimulation (ctDCS) is challenging due to the complexity of the cerebellar structure. Therefore, our objective is to develop a freely available computational pipeline to perform cerebellar atlas-based electric field analysis using magnetic resonance imaging (MRI) guided subject-specific head modeling.MethodsWe present a freely available computational pipeline to determine subject-specific lobular electric field distribution during ctDCS. The computational pipeline can isolate subject-specific cerebellar lobules based on a spatially unbiased atlas (SUIT) for the cerebellum, and then calculates the lobular electric field distribution during ctDCS. The computational pipeline was tested in a case study using a subject-specific head model as well as using a Colin 27 Average Brain. The 5cmx5cm anode was placed 3 cm lateral to inion, and the same sized cathode was placed on the contralateral supraorbital area (called Manto montage) and buccinators muscle (called Celnik montage). A 4×1 HD-ctDCS electrode montage was also implemented for a comparison using analysis of variance (ANOVA).ResultsEta-squared effect size after three-way ANOVA for electric field strength was 0.05 for lobule, 0.00 for montage, 0.04 for head model, 0.01 for lobule*montage interaction, 0.01 for lobule* head model interaction, and 0.00 for montage*head model interaction in case of Enorm. Here, the electric field strength of both the Celnik and the Manto montages affected the lobules Crus II, VIIb, VIII, IX of the targeted cerebellar hemispheres while Manto montage had more bilateral effect. The HD-ctDCS montage primarily affected the lobules Crus I, Crus II, VIIb of the targeted cerebellar hemisphere. Our freely available computational modeling approach to analyze subject-specific lobular electric field distribution during ctDCS provided an insight into healthy human anodal ctDCS results

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Influence of electrode configuration on the electric field distribution during transcutaneous spinal direct current stimulation of the cervical spine

2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) ◽

10.1109/embc.2016.7591390 ◽

2016 ◽

Cited By ~ 3

Author(s):

Sofia R. Fernandes ◽

Ricardo Salvador ◽

Cornelia Wenger ◽

Mamede A. de Carvalho ◽

Pedro C. Miranda

Keyword(s):

Cervical Spine ◽

Electric Field ◽

Field Distribution ◽

Direct Current ◽

Electric Field Distribution ◽

Electrode Configuration ◽

Direct Current Stimulation ◽

Stimulation Of

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Multiscale Coupling of Transcranial Direct Current Stimulation to Neuron Electrodynamics: Modeling the Influence of the Transcranial Electric Field on Neuronal Depolarization

Computational and Mathematical Methods in Medicine ◽

10.1155/2014/360179 ◽

2014 ◽

Vol 2014 ◽

pp. 1-14 ◽

Cited By ~ 9

Author(s):

Edward T. Dougherty ◽

James C. Turner ◽

Frank Vogel

Keyword(s):

Electric Field ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Three Dimensional ◽

Human Head ◽

Multiscale Model ◽

Medical Intervention ◽

Medical Community ◽

Computational Grids ◽

Direct Current Stimulation

Transcranial direct current stimulation (tDCS) continues to demonstrate success as a medical intervention for neurodegenerative diseases, psychological conditions, and traumatic brain injury recovery. One aspect of tDCS still not fully comprehended is the influence of the tDCS electric field on neural functionality. To address this issue, we present a mathematical, multiscale model that couples tDCS administration to neuron electrodynamics. We demonstrate the model’s validity and medical applicability with computational simulations using an idealized two-dimensional domain and then an MRI-derived, three-dimensional human head geometry possessing inhomogeneous and anisotropic tissue conductivities. We exemplify the capabilities of these simulations with real-world tDCS electrode configurations and treatment parameters and compare the model’s predictions to those attained from medical research studies. The model is implemented using efficient numerical strategies and solution techniques to allow the use of fine computational grids needed by the medical community.

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Determinants of the electric field during transcranial direct current stimulation

NeuroImage ◽

10.1016/j.neuroimage.2015.01.033 ◽

2015 ◽

Vol 109 ◽

pp. 140-150 ◽

Cited By ~ 299

Author(s):

Alexander Opitz ◽

Walter Paulus ◽

Susanne Will ◽

Andre Antunes ◽

Axel Thielscher

Keyword(s):

Electric Field ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Direct Current Stimulation

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Exploring the neural, behavioural, and clinical effects of transcranial direct current stimulation in patients with a Prolonged Disorder of Consciousness; protocol for a double-blind randomised crossover feasibility study

10.21203/rs.3.rs-15515/v1 ◽

2020 ◽

Author(s):

Davinia Fernández-Espejo ◽

Davide Aloi ◽

Antonio Incisa della Rocchetta ◽

Damon Hoad ◽

Richard Greenwood ◽

...

Keyword(s):

Individual Differences ◽

Feasibility Study ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Brain Activity ◽

Brain Structures ◽

Clinical Effects ◽

Disorder Of Consciousness ◽

Double Blind ◽

Direct Current Stimulation

Abstract Background: Therapeutic options for patients with prolonged disorders of consciousness (PDOC) are very limited, and patients often show little to no progress over time. It is widely recognized that some PDOC patients retain a higher level of cognition that may be apparent on the basis of their external responses, and simply are unable to produce purposeful motor behaviours. This dissociation has been linked to specific impairments in the motor network that lead to a reduction in thalamo-cortical coupling. Here, we will assess whether transcranial direct current stimulation (tDCS) can modulate thalamo-cortical coupling and improve patients’ responsiveness. We will focus on characterising the mechanisms of action of tDCS and the bases for potential individual differences in responsiveness to the stimulation across participants.Methods: This is a multi-centre double-blind randomised crossover feasibility study. It is divided into two streams: (a) MRI stream: 5 PDOC patients will complete 5 anodal, cathodal, and sham stimulation sessions (paired with passive mobilisation of the thumb) in separate weeks. We will measure brain activity and connectivity with functional magnetic resonance imaging and electroencephalography (EEG). We will look at brain structures to assess differences associated with responsiveness. (b) Bedside stream: 10 patients will complete one session of anodal or cathodal stimulation and one session of sham. We will measure brain activity and connectivity with EEG and we will conduct follow up assessments at 3 and 6 months. In both streams we will also look at changes in the clinical profile of patients with the Coma Recovery Scale Revised and in command following behaviour with electromyography and motion tracking. We will assess feasibility on measures of eligibility, recruitment, retention, and completion of tests.Discussion: This feasibility study is the first step towards developing personalised tDCS interventions to restore external responsiveness in PDOC patients. Our results will inform the design of a future trial fully powered for characterising neural, behavioural, and clinical effects of tDCS in PDOC as well as the mechanisms underlying individual differences in responsiveness.

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High-Definition Transcranial Direct Current Stimulation Improves Delayed Memory in Alzheimer’s Disease Patients: A Pilot Study Using Computational Modeling to Optimize Electrode Position

Journal of Alzheimer s Disease ◽

10.3233/jad-210378 ◽

2021 ◽

pp. 1-17

Author(s):

Ingrid Daae Rasmussen ◽

Nya Mehnwolo Boayue ◽

Matthias Mittner ◽

Martin Bystad ◽

Ole K. Grnli ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Electric Field ◽

Computational Modeling ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Cortical Atrophy ◽

Brain Anatomy ◽

High Definition ◽

Direct Current Stimulation

Background: The optimal stimulation parameters when using transcranial direct current stimulation (tDCS) to improve memory performance in patients with Alzheimer’s disease (AD) are lacking. In healthy individuals, inter-individual differences in brain anatomy significantly influence current distribution during tDCS, an effect that might be aggravated by variations in cortical atrophy in AD patients. Objective: To measure the effect of individualized HD-tDCS in AD patients. Methods: Nineteen AD patients were randomly assigned to receive active or sham high-definition tDCS (HD-tDCS). Computational modeling of the HD-tDCS-induced electric field in each patient’s brain was analyzed based on magnetic resonance imaging (MRI) scans. The chosen montage provided the highest net anodal electric field in the left dorsolateral prefrontal cortex (DLPFC). An accelerated HD-tDCS design was conducted (2 mA for 3×20 min) on two separate days. Pre- and post-intervention cognitive tests and T1 and T2-weighted MRI and diffusion tensor imaging data at baseline were analyzed. Results: Different montages were optimal for individual patients. The active HD-tDCS group improved significantly in delayed memory and MMSE performance compared to the sham group. Five participants in the active group had higher scores on delayed memory post HD-tDCS, four remained stable and one declined. The active HD-tDCS group had a significant positive correlation between fractional anisotropy in the anterior thalamic radiation and delayed memory score. Conclusion: HD-tDCS significantly improved delayed memory in AD. Our study can be regarded as a proof-of-concept attempt to increase tDCS efficacy. The present findings should be confirmed in larger samples.

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