Evidence map›Paper›PMID 29258808›Full record

ReviewBrain stimulation

Incomplete evidence that increasing current intensity of tDCS boosts outcomes.

Zeinab Esmaeilpour, Paola Marangolo, Benjamin M Hampstead, Sven Bestmann, Elisabeth Galletta, Helena Knotkova, Marom Bikson

Abstract readReview
PubMed Full text at PMC Publisher
In one paragraph

Review in Brain stimulation. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 106 papers, 6 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
106citing papers in PubMed, 6 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

106 citing papers in PubMed, 6 syntheses or guidelines pooled it.

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  15. Efficacy and safety of transcranial direct current stimulation as an add-on treatment for obsessive-compulsive disorder: a randomized, sham-controlled trial.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2021
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46 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Zeinab EsmaeilpourDepartment of Biomedical Engineering, The City College of New York of CUNY, New York, NY 10031, USA; Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran. Electronic address: zesmaeilpour@ccny.cuny.edu.
Paola MarangoloDipartimento di Studi Umanistici, University Federico II, Naples and IRCCS Fondazione Santa Lucia, Rome Italy.
Benjamin M HampsteadVA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI 48105, USA.
Sven BestmannSobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, UK.
Elisabeth GallettaRusk Rehabilitation Medicine, New York University Langone Medical Center, USA.
Helena KnotkovaMJHS Institute for Innovation in Palliative Care, New York, NY, USA; Department of Family and Social Medicine, Albert Einstein College of Medicine, The Bronx, NY, USA.
Marom BiksonDepartment of Biomedical Engineering, The City College of New York of CUNY, New York, NY 10031, USA.

Funding

Michigan Alzheimer's Disease Core CenterP30AG053760 · NIA · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI PAULSON, HENRY L · 2016 to 2020
$10.1M
Temporal dynamics of neurophysiological patterns as treatment targets in SzR01MH109289 · NIMH · NATHAN S. KLINE INSTITUTE FOR PSYCH RES · PI JAVITT, DANIEL C. · 2016 to 2020
$3.7M
A tool-box to control and enhance tDCS spatial precisionR01MH111896 · NIMH · CITY COLLEGE OF NEW YORK · PI BIKSON, MAROM · 2016 to 2019
$2.2M
The coupled vascular hypothesis for transcranial direct current stimulation (tDCS)R01NS101362 · NINDS · CITY COLLEGE OF NEW YORK · PI BIKSON, MAROM · 2017 to 2021
$1.7M
Effects of direct-current stimulation on synaptic plasticityR01NS095123 · NINDS · CITY COLLEGE OF NEW YORK · PI PARRA, LUCAS C · 2016 to 2020
$1.7M
Promoting adaptive neuroplasticity in mild cognitive impairmentI01RX001534 · VA · VETERANS HEALTH ADMINISTRATION · PI HAMPSTEAD, BENJAMIN MICHAEL · 2015 to 2022
–
NIA NIH HHS P30 AG053760NIMH NIH HHS R01 MH109289NIMH NIH HHS R01 MH111896NINDS NIH HHS R01 NS095123NINDS NIH HHS R01 NS101362RRD VA I01 RX001534
6 · The paper itself

Abstract

backgroundTranscranial direct current stimulation (tDCS) is investigated to modulate neuronal function by applying a fixed low-intensity direct current to scalp.

objectivesWe critically discuss evidence for a monotonic response in effect size with increasing current intensity, with a specific focus on a question if increasing applied current enhance the efficacy of tDCS.

methodsWe analyzed tDCS intensity does-response from different perspectives including biophysical modeling, animal modeling, human neurophysiology, neuroimaging and behavioral/clinical measures. Further, we discuss approaches to design dose-response trials.

resultsPhysical models predict electric field in the brain increases with applied tDCS intensity. Data from animal studies are lacking since a range of relevant low-intensities is rarely tested. Results from imaging studies are ambiguous while human neurophysiology, including using transcranial magnetic stimulation (TMS) as a probe, suggests a complex state-dependent non-monotonic dose response. The diffusivity of brain current flow produced by conventional tDCS montages complicates this analysis, with relatively few studies on focal High Definition (HD)-tDCS. In behavioral and clinical trials, only a limited range of intensities (1-2 mA), and typically just one intensity, are conventionally tested; moreover, outcomes are subject brain-state dependent. Measurements and models of current flow show that for the same applied current, substantial differences in brain current occur across individuals. Trials are thus subject to inter-individual differences that complicate consideration of population-level dose response.

conclusionThe presence or absence of simple dose response does not impact how efficacious a given tDCS dose is for a given indication. Understanding dose-response in human applications of tDCS is needed for protocol optimization including individualized dose to reduce outcome variability, which requires intelligent design of dose-response studies.

Indexed as

AnimalsBrainHumansIndividualityNeuroimagingTranscranial Direct Current StimulationTranscranial Magnetic StimulationTreatment OutcomeDose-controlDose-responseNeuromodulationTranscranial direct current stimulation (tDCS)

Identifiers

PMID29258808
PMCPMC7050474

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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.