Evidence map›Paper›PMID 23082174›Full record

Trial reportPloS one2012

Rethinking clinical trials of transcranial direct current stimulation: participant and assessor blinding is inadequate at intensities of 2mA.

Neil E O'Connell, John Cossar, Louise Marston, Benedict M Wand, David Bunce, G Lorimer Moseley, Lorraine H De Souza

Registry-linked trialAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in PloS one, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT02051959 (Long-Term Treatment of Patients Experiencing Phantom Limb Pain With Transcranial Direct Current Stimulation), which is not on this map. Cited by 106 papers, 8 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
106citing papers in PubMed, 8 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.

NCT02051959 nasuspendednot on this mapstarted 2015, after this paper: background citation

Long-Term Treatment of Patients Experiencing Phantom Limb Pain With Transcranial Direct Current Stimulation (tDCS)

TypeinterventionalSponsorSheba Medical CenterRan2015 to 2017Enrolled24ConditionsPhantom Limb PainArmsAnodal stimulation of M1 + sham, Sham + Anodal stimulation of M1, Cathodal stimulation of M1 + sham, Sham + Cathodal stimulation of M1
3 · Its place in the literature

Who cites it

106 citing papers in PubMed, 8 syntheses or guidelines pooled it.

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  7. Non-invasive brain stimulation techniques for chronic pain.The Cochrane database of systematic reviews · 2018
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  8. Non-invasive brain stimulation techniques for chronic pain.The Cochrane database of systematic reviews · 2018
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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.

Neil E O'ConnellCentre for Research in Rehabilitation, School of Health Sciences and Social Care, Brunel University, London, United Kingdom. neil.oconnell@brunel.ac.uk
John Cossar
Louise Marston
Benedict M Wand
David Bunce
G Lorimer Moseley
Lorraine H De Souza

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundMany double-blind clinical trials of transcranial direct current stimulation (tDCS) use stimulus intensities of 2 mA despite the fact that blinding has not been formally validated under these conditions. The aim of this study was to test the assumption that sham 2 mA tDCS achieves effective blinding.

methodsA randomised double blind crossover trial. 100 tDCS-naïve healthy volunteers were incorrectly advised that they there were taking part in a trial of tDCS on word memory. Participants attended for two separate sessions. In each session, they completed a word memory task, then received active or sham tDCS (order randomised) at 2 mA stimulation intensity for 20 minutes and then repeated the word memory task. They then judged whether they believed they had received active stimulation and rated their confidence in that judgement. The blinded assessor noted when red marks were observed at the electrode sites post-stimulation.

resultstDCS at 2 mA was not effectively blinded. That is, participants correctly judged the stimulation condition greater than would be expected to by chance at both the first session (kappa level of agreement (κ) 0.28, 95% confidence interval (CI) 0.09 to 0.47 p=0.005) and the second session (κ=0.77, 95%CI 0.64 to 0.90), p=<0.001) indicating inadequate participant blinding. Redness at the reference electrode site was noticeable following active stimulation more than sham stimulation (session one, κ=0.512, 95%CI 0.363 to 0.66, p<0.001; session two, κ=0.677, 95%CI 0.534 to 0.82) indicating inadequate assessor blinding.

conclusionsOur results suggest that blinding in studies using tDCS at intensities of 2 mA is inadequate. Positive results from such studies should be interpreted with caution.

Indexed as

ElectricityAdolescentAdultDouble-Blind MethodElectric Stimulation TherapyFemaleHumansJudgmentMaleMemoryMiddle AgedSkinTask Performance and AnalysisYoung Adult

Identifiers

PMID23082174
PMCPMC3474749

What OpenQuestion holds

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Registered trials

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.