Modeling Transcranial Direct-Current Stimulation-Induced Electric Fields in Children and Adults

Ciechanski, Patrick; Carlson, Helen L.; Yu, Sabrina; Kirton, Adam

doi:10.3389/fnhum.2018.00268

Cited by 57 publications

(63 citation statements)

References 55 publications

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“…Age-related differences may include tissue structure, age-dependent differences in skull thickness, myelination, and volumes of CSF, gray matter, and white matter ( Brain Development Cooperative Group, 2012 ). Pediatric current modeling suggests that electrodes placed on M1 produce diffuse cortical effects including contralateral M1 and bilateral premotor and supplementary motor areas ( Kessler et al, 2013 ; Ciechanski et al, 2018 ). In contrast, HD-tDCS produces more focal stimulation with peak electric fields approximating functional cortical targets directly under the active electrode ( Datta et al, 2009 ).…”

Section: Discussionmentioning

confidence: 99%

Effects of High-Definition and Conventional Transcranial Direct-Current Stimulation on Motor Learning in Children

et al. 2018

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Background: Transcranial direct current stimulation (tDCS) can improve motor learning in children. High-definition approaches (HD-tDCS) have not been examined in children.Objectives/Hypothesis: We hypothesized that primary motor cortex HD-tDCS would enhance motor learning but be inferior to tDCS in children.Methods: Twenty-four children were recruited for a randomized, sham-controlled, double-blinded interventional trial (NCT03193580, clinicaltrials.gov/ct2/show/NCT03193580) to receive (1) right hemisphere (contralateral) primary motor cortex (M1) 1 mA anodal conventional 1 × 1 tDCS (tDCS), (2) right M1 1 mA anodal 4 × 1 HD-tDCS (HD-tDCS), or (3) sham. Over five consecutive days, participants trained their left hand using the Purdue Pegboard Test (PPTL). The Jebsen–Taylor Test, Serial Reaction Time Task, and right hand and bimanual PPT were also tested at baseline, post-training, and 6-week retention time (RT).Results: Both the tDCS and HD-tDCS groups demonstrated enhanced motor learning compared to sham with effects maintained at 6 weeks. Effect sizes were moderate-to-large for tDCS and HD-tDCS groups at the end of day 4 (Cohen’s d tDCS = 0.960, HD-tDCS = 0.766) and day 5 (tDCS = 0.655, HD-tDCS = 0.851). Enhanced motor learning effects were also seen in the untrained hand. HD-tDCS was well tolerated and safe with no adverse effects.Conclusion: HD-tDCS and tDCS can enhance motor learning in children. Further exploration is indicated to advance rehabilitation therapies for children with motor disabilities such as cerebral palsy.Clinical Trial Registration: clinicaltrials.gov, identifier NCT03193580.

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Section: Discussionmentioning

confidence: 99%

Effects of High-Definition and Conventional Transcranial Direct-Current Stimulation on Motor Learning in Children

et al. 2018

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“…Individualised application of tDCS likely also requires consideration of differences in structural or functional state of the brain, particularly in ageing [59,60] or clinical populations such as stroke [25,61,62]. We would argue that such development should precede optimization of protocols based on the number of stimulation sessions [63]), intensity [56,64], or individual differences including baseline physiological [65,66] or cognitive function, such as performance ability [67] or attention [68].…”

Section: Dose-control Reduces Variance In Spatial Distribution Of E-fmentioning

confidence: 99%

Dose-controlled tDCS reduces electric field intensity variability at a cortical target site

Evans

Bachmann

Lee

et al. 2019

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Background: Variable effects limit the efficacy of transcranial direct current stimulation (tDCS) as a research and therapeutic tool. Conventional application of a fixed-dose of tDCS does not account for inter-individual differences in anatomy (e.g. skull thickness), which varies the amount of current reaching the brain. Individualised dose-control may reduce the variable effects of tDCS by reducing variability in electric field intensities at a cortical target site.Objective: To characterise the variability in electric field intensity at a cortical site (left primary motor cortex; M1) and throughout the brain for conventional fixed-dose tDCS, and individualised dose-controlled tDCS. Methods: The intensity and distribution of the electric field during tDCS was estimated using Realistic Volumetric Approach to Simulate Transcranial Electric Stimulation (ROAST) in 50 individual brain scans taken from the Human Connectome Project, for fixed-dose tDCS (1mA & 2mA) and individualised dose-controlled tDCS targeting left M1.Results: With a fixed-dose (1mA & 2mA), E-field intensity in left M1 varied by more than 100% across individuals, with substantial variation observed throughout the brain as well.Individualised dose-controlled ensured the same E-field intensity was delivered to left M1 in all individuals. Its variance in other regions of interest (right M1 and area underneath the electrodes) was comparable with fixed-and individualised-dose.Conclusions: Individualized dose-control can eliminate the variance in electric field intensities at a cortical target site. Assuming that the current delivered to the brain directly determines its physiological and behavioural consequences, this approach may allow for reducing the known variability of tDCS effects.

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“…This suggests lateralization of motor learning in the left dominant cortex as previously described by Schambra et al (54). The impact of transcallosal inhibition is also seen in pediatric studies applying tDCS contralateral to stroke lesions in an effort to augment motor learning of the affected hemisphere (55,56). According to pediatric models of anodal tDCS, the current appears to travel through the motor fibers of the corpus callosum into the contralateral hemisphere (56).…”

Section: Post-intervention Changes In Gaba and Glxmentioning

confidence: 52%

“…The impact of transcallosal inhibition is also seen in pediatric studies applying tDCS contralateral to stroke lesions in an effort to augment motor learning of the affected hemisphere (55,56). According to pediatric models of anodal tDCS, the current appears to travel through the motor fibers of the corpus callosum into the contralateral hemisphere (56). However, the same mechanism is not expected to be true for HD-tDCS which has a more focal current.…”

Section: Post-intervention Changes In Gaba and Glxmentioning

confidence: 99%

Effects of Transcranial Direct Current Stimulation on GABA and Glutamate in Children: A Pilot Study

Nwaroh

Giuffre

Cole

et al. 2019

Preprint

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Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that safely modulates brain excitability and has therapeutic potential for many conditions.Several studies have shown that anodal tDCS of the primary motor cortex (M1) facilitates motor learning and plasticity, but there is little information about the underlying mechanisms. Using magnetic resonance spectroscopy (MRS) it has been shown that tDCS can affect local levels of -aminobutyric acid (GABA) and Glx (a measure of glutamate and glutamine combined) in adults, both of which are known to be associated with skill acquisition and plasticity; however this has yet to be studied in children and adolescents. This study examined GABA and Glx in response to conventional anodal tDCS (a-tDCS) and high definition tDCS (HD-tDCS) targeting the M1 in a pediatric population. Twenty-four typically developing, right handed children ages 12-18 years participated in five consecutive days of tDCS intervention (sham, a-tDCS or HD-tDCS) targeting the right M1 while training in a fine motor task (Purdue Pegboard Task) with their left hand. Glutamate and GABA were measured before and after the protocol (at day 5 and 6 weeks) using conventional MRS and GABA-edited MRS in the sensorimotor cortices.Glutamate measured in the left sensorimotor cortex was higher in the HD-tDCS group compared to a-tDCS and sham at 6 weeks (p = 0.001). No changes in GABA were observed in either sensorimotor cortex at any time. These results suggest that neither a-tDCS or HD-tDCS locally affect GABA and glutamate in the developing brain and therefore it may demonstrate different responses in adults.

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Modeling Transcranial Direct-Current Stimulation-Induced Electric Fields in Children and Adults

Cited by 57 publications

References 55 publications

Effects of High-Definition and Conventional Transcranial Direct-Current Stimulation on Motor Learning in Children

Effects of High-Definition and Conventional Transcranial Direct-Current Stimulation on Motor Learning in Children

Dose-controlled tDCS reduces electric field intensity variability at a cortical target site

Effects of Transcranial Direct Current Stimulation on GABA and Glutamate in Children: A Pilot Study

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