Table 1.
Studies resulting from the systematic search organized by executive functioning domain.
| Executive functioning domain | Study | Substance | N (♂-♀) | Age [mean (SD)] | Task | Outcome | Technique | Stimulation parameters | No. of sessions | Results | PEDro scores |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Attention | Xu et al., 2013 | Nicotine | 24 (21–3) | 45 (7.6) | Visual attention | Reaction time | tDCS (left) | Anodal lDLPFC, reference right supra-orbital area, 35 cm2, 2 mA, anodal 0.057 mA/cm2, 20 min | 1 | No effect | Medium |
| Hit rate | No effect | ||||||||||
| Herremans et al., 2013 | Alcohol (clinical) | 29 (19–10) | 48.15 (9.32) | Go-Nogo task | Commisssion errors | HF-rTMS (right) | 20 Hz, 110% RMT, 40 trains of 1.9 s | 1 | No effect | Medium | |
| Mean reaction time Go trials | No effect | ||||||||||
| Intra-individual reaction time variability | Positive effect | ||||||||||
| Cognitive flexibility | Huang et al., 2016 | Nicotine comorbid schizophrenia sample (no intention to reduce smoking) | 37 (37–0) | 40.58 (3.01)# | Wisconsin card sorting test | Total errors | HF-rTMS (left) | 10 Hz, 110% MT, 20 trains of 10 s | 21 | No effect | High |
| Del Felice et al., 2016 | Alcohol (clinical) | 17 (13–4) | 44.7 (unknown) | Stroop task | Accuracy in incongruent condition | HF-rTMS (left) | 10 Hz, 100% RMT, 20 trains of 5 s | 4 | Positive effect | High | |
| Response inhibition | Del Felice et al., 2016 | Alcohol (clinical) | 17 (13–4) | 44.7 (unknown) | Go-NoGo task | Mean accuracy | HF-rTMS (left) | 10 Hz, 100% RMT, 20 trains of 5 s | 4 | Positive effect | High |
| Sheffer et al., 2013 | Nicotine | 16 (unknown) | Unknown | Delay discounting task monetary gains | Discounting rate | HF-rTMS (left) | 10 Hz & 20 Hz, 110% RMT, 90 trains & 45 trains ∧∧ | 1 | Positive effect | Medium | |
| Delay discounting task cigarette gains | Positive effect | ||||||||||
| Delay discounting task monetary losses | Negative effect | ||||||||||
| Delay discounting task cigarette losses | No effect | ||||||||||
| Memory and learning | Su et al., 2017 | Methamphetamine (clinical) | 30 (30–0) | 32.35 (4.96) | International shopping list task | Total number of correct responses | HF-rTMS (left) | 10 Hz, 80% RMT, 24 trains of 5 s | 5 | Positive effect | High |
| N-back Task | Proportion of correct responses | No effect | |||||||||
| Continuous paired association learning task | Total number of errors | No effect | |||||||||
| Qiao et al., 2016 | Alcohol (clinical) | 38 (25–13) | Active: 49##Sham: 48## | Hopkins verbal learning test revised | Total score | HF-rTMS (right) | 10 Hz, 80% RMT, 8 trains of 10 s | 4 | Positive effect | High | |
| Brief visuospatialmemory test revised | Positive effect | ||||||||||
| Problem solving | Su et al., 2017 | Methamphetamine (clinical) | 30 (30–0) | 32.35 (4.96) | Groton maze learning task | Total number of errors | HF-rTMS (left) | 10 Hz, 80% RMT, 24 trains of 5 s | 5 | No effect | High |
| Social cognition | Su et al., 2017 | Methamphetamine (clinical) | 30 (30–0) | 32.35 (4.96) | Social emotionalcognition task | Proportion of correct responses | HF-rTMS (left) | 10 Hz, 80% RMT, 24 trains of 5 s | 5 | Positive effect | High |
| Risk taking | Pripfl et al., 2013 | Nicotine | 18 (8–10) | 22.4 (2.5) | Hot columbiacard task | Number of cards chosen | tDCS (left) * | Anodal lDLPFC, reference rDLPFC, 0.45 mA, 5.3 cm2, anodal 0.085 mA/cm2, 15 min | 1 | No effect | Medium |
| tDCS (right) * | Anodal rDLPFC, reference lDLPFC, 0.45 mA, 5.3 cm2, anodal 0.085 mA/cm2, 15 min | Positive effect | |||||||||
| Cold columbia card task | Number of cards chosen | tDCS (left) * | Anodal lDLPFC, reference rDLPFC, 0.45 mA, 5.3 cm2, anodal 0.085 mA/cm2, 15 min | 1 | Positive effect | ||||||
| tDCS (right) * | Anodal rDLPFC, reference lDLPFC, 0.45 mA, 5.3 cm2, anodal 0.085 mA/cm2, 15 min | No effect | |||||||||
| Gorini et al., 2014 | Cocaine (clinical) | 18 (10–8) | 38.4 (8.2) | Balloon analog risk task | Average numberof pumps onunexplodedballoon | tDCS (left) | Anodal lDLPFC, reference rDLPFC, 1.5 mA, 32 cm2, anodal 0.047 mA/cm2, 20 min | 1 | Positive effect | Medium | |
| tDCS (right) | Anodal rDLPFC, reference lDLPFC, 1.5 mA, 32 cm2, anodal 0.047 mA/cm2, 20 min | 1 | Positive effect | ||||||||
| Game of dice task | Average number of conservative bets | tDCS (left) | Anodal lDLPFC, reference rDLPFC, 1.5 mA, 32 cm2, anodal 0.047 mA/cm2, 20 min | 1 | Negative effect | ||||||
| tDCS (right) | Anodal rDLPFC, reference lDLPFC, 1.5 mA, 32 cm2, anodal 0.047 mA/cm2, 20 min | Positive effect | |||||||||
| Fecteau et al., 2014 | Nicotine | 12 (5–7) | 36.3 (Unknown) | Ultimatum game money | Acceptance rate | tDCS (right) | Anodal rDLPFC, reference lDLPFC, 2 mA, 35 cm2, anodal 0.057 mA/cm2, 30 min | 5 | No effect | High | |
| Ultimatum game cigarettes | Positive effect | ||||||||||
| Risk task money | Choice of low risk vs.high risk options | tDCS (right) | Anodal rDLPFC, reference lDLPFC, 2 mA, 35 cm2, anodal 0.057 mA/cm2, 30 min | 5 | No effect | ||||||
| Risk task cigarettes | No effect | ||||||||||
| Boggio et al., 2010 | Marijuana | 25 (15–10) | 22.8 (2.6) | Risk task | Percentage lowrisk choice | tDCS (left)* | Anodal lDLPFC, reference rDLPFC, 2 mA, 35 cm2, anodal 0.057 mA/cm2, 15 min | 1 | Negative effect | High | |
| Decision time | No effect | ||||||||||
| Risk task | Percentage lowrisk choice | tDCS (right)* | Anodal rDLPFC, reference lDLPFC, 2 mA, 35 cm2, anodal 0.057 mA/cm2, 15 min | 1 | Negative effect | ||||||
| Decision time | No effect | ||||||||||
| Sheffer et al., 2013 | Nicotine | 16 (unknown) | Unknown | Risk task | Total points earned | HF-rTMS (left) | 10 Hz & 20 Hz, 110% RMT,90 trains & 45 trains | 1 | No effect | Medium | |
| Total time to completetask | No effect | ||||||||||
| Cognitive bias | den Uyl et al., 2015 | Alcohol | 41 (15–26) | 21.7 (3.0) | Affective implicit association task | Reaction time | tDCS (left) | Anodal lDLPFC, reference right supra-orbital region, 1 mA, 35 cm2, anodal 0.029 mA/cm2, 10 min | 1 | Positive effect | High |
| Bias score (accuracy) | No effect | ||||||||||
| Motivation implicit association task | Reaction time | No effect | |||||||||
| Bias score (accuracy) | No effect | ||||||||||
| den Uyl et al., 2016a | Alcohol (clinical) | 91 (61–30) | 47 (8.8) | Alcohol approach task | Approach bias | tDCS (left) (+ CBM) | Anodal lDLPFC, reference rDLPFC, 2 mA, 35 cm2, anodal 0.057 mA/cm2, 20 min | 8 | No effect | High | |
| den Uyl et al., 2016b | Alcohol | 78 (27–51) | 21.8 (3.2) | Alcohol approach task | Approach bias | tDCS (left) (+ CBM) | Anodal lDLPFC, reference right supra-orbital region, 1 mA, 35 cm2, anodal 0.029 mA/cm2, 15 min | 3 | No effect | High | |
| Implicit association task | Approach associationbias | tDCS (left) (+ CBM) | No effect | ||||||||
| Overall executive functioning | Da Silva et al., 2013 | Alcohol (clinical) | 13 (13–0) | 49## | Frontal assessment battery | Total score | tDCS (left) | Anodal lDLPFC, reference right supradeltoid area, 2 mA, 35 cm2, anodal 0.057 mA/cm2, 20 min | 5 | Positive effect | High |
| Klauss et al., 2014 | Alcohol (clinical) | 33 (32–1) | 44.8 (8.3) | Frontal assessment battery | Total score | tDCS (right) | Anodal rDLPFC, reference lDLPFC, 2 mA, 35 cm2, 0.057 mA/cm2, 2 × 13 min | 5 | No effect | High |
Some studies address the effect of non-invasive neuromodulation on several executive functioning domains and are therefore reported multiple times in this table. When one study assessed the effect of left as well as right stimulation this was done in two separate sessions. Results for both protocols were the same when compared to sham and are therefore reported in the same line of the table. lDLPFC, left DLPFC; rDLPFC, right DLPFC; MT, motor threshold; RMT, resting motor threshold.
#
This number represents the mean of the active treatment group;
##
median age per group;
*
online (task performance during stimulation) stimulation protocol;
∧∧
with this protocol participants are stimulated with 20 Hz (45 trains) or 10 Hz (90 trains). Colors in the results column indicate a positive effect (green), no effect (blue) or negative effect (red).