Evidence map›Paper›PMID 31653475›Full record

ArticleBrain stimulation

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

Carys Evans, Clarissa Bachmann, Jenny S A Lee, Evridiki Gregoriou, Nick Ward, Sven Bestmann

Abstract read
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In one paragraph

Article in Brain stimulation. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 95 papers, 7 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
95citing papers in PubMed, 7 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

95 citing papers in PubMed, 7 syntheses or guidelines pooled it.

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  15. 2 mA is NOT 2 mA: Electric field variability in high-definition tDCS and its implications for precision neuromodulation in aging.Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology · 2026
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35 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

6 authors.

Carys EvansDepartment for Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK. Electronic address: carys.evans@ucl.ac.uk.
Clarissa BachmannDepartment for Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
Jenny S A LeeDepartment for Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
Evridiki GregoriouDepartment for Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
Nick WardDepartment for Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
Sven BestmannDepartment for Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, UK.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundVariable 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 (E-field) intensities at a cortical target site.

objectiveTo characterise the variability in E-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.

methodsThe intensity and distribution of the E-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 (1 mA & 2 mA) and individualised dose-controlled tDCS targeting left M1.

resultsWith a fixed-dose (1 mA & 2 mA), E-field intensity in left M1 varied by more than 100% across individuals, with substantial variation observed throughout the brain as well. Individualised dose-control 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.

conclusionsIndividualised dose-control can eliminate the variance in E-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.

Indexed as

Biological Variation, PopulationAdultBrain WavesEvoked Potentials, MotorFemaleHumansMaleModels, NeurologicalMotor CortexRandom AllocationTranscranial Direct Current StimulationBrain stimulationCurrent flow modelIndividualizationInter-individual variabilityTranscranial electrical stimulation

Identifiers

PMID31653475

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.