Table 1.
Overview of characteristics of working memory and episodic memory tDCS studies.
| Authors | Design | Conditions (excluding sham) | tDCS set-up | Task sample | |||||
|---|---|---|---|---|---|---|---|---|---|
| Anode–Cathode | Density (mA/cm2) | Duration (min) | N | Age | Female% | ||||
| WORKING MEMORY | |||||||||
| Berryhill et al., 2010 | Cross-over | 1 | left cheek–P4 | 0.043 | 10 | WM | 11 | 25.0 | 45 |
| 2 | P4–left cheek | 0.043 | 10 | WM | 11 | 25.0 | 45 | ||
| Tseng et al., 2012 | Cross-over | 1 | P4–left cheek | 0.094 | 15 | WM | 20 | 22.0 | 65 |
| Jones and Berryhill, 2012 | Cross-over | 1 | left cheek–P4 | 0.043 | 10 | WM | 20 | 23.25 | 60 |
| 2 | P4–left cheek | 0.043 | 10 | WM | 20 | 23.25 | 60 | ||
| Zaehle et al., 2011 | Cross-over | 1 | left mastoid–F3 | 0.029 | 15 | WM | 16 | 23.0–27.0 | 62.5 |
| 2 | F3–left mastoid | 0.029 | 15 | WM | 16 | 23.0–27.0 | 62.5 | ||
| Berryhill and Jones, 2012 | Cross-over | 1 | F3–right cheek | 0.043 | 10 | WM | 25 | 63.7 | 57 |
| 2 | F4–left cheek | 0.043 | 10 | WM | 25 | 63.7 | 57 | ||
| Nilsson et al., 2015 | Cross-over | 1 | F3–right SO | 0.029 | 25 | WM | 30 | 69.0 ± 7.0 | 46.7 |
| 2 | F3–right SO | 0.057 | 25 | WM | 30 | 69.0 ± 7.0 | 46.7 | ||
| EPISODIC MEMORY | |||||||||
| Manenti et al., 2013 | Cross-over/between | 1 | left/right DLPFC/PARC–cSO | 0.043 | LTM | 32 | 23.7 ± 3.2 | 71.9 | |
| 2 | left/right DLPFC/PARC–cSO | 0.043 | LTM | 32 | 67.9 ± 4.7 | 53.1 | |||
| Sandrini et al., 2014 | Between | 1 (reminder) | F3–right SO | 0.043 | 15 | LTM | 12 | 67.5 ± 2.7 | 66.7 |
| 2 (no reminder) | F3–right SO | 0.043 | 15 | LTM | 12 | 67.6 ± 4.3 | 66.7 | ||
| Sandrini et al., 2016 | Between | 1 | F3–right SO | 0.043 | 15 | LTM | 14 | 68.6 ± 4.2 | 64.3 |
| Smirni et al., 2015 | Cross-over/between | 1 | shoulder–F3/F4 | 0.029 | 20 | LTM | 20 | 23.6 ± 2.3 | 88.9 |
| 2 | F3/F4–shoulder | 0.029 | 20 | LTM | 16 | 24.7 ± 2.2 | 88.9 | ||
| Zwissler et al., 2014 | Between | 1 | F3–right shoulder | 0.029 | 15 | LTM | 24 | 24.8 ± 2.9 | 62.5 |
| 2 | right shoulder–F3 | 0.029 | 15 | LTM | 24 | 24.8 ± 2.9 | 62.5 | ||
| Jones et al., 2014 (tDCS-encoding) | Cross-over | 1 | P3–right cheek | 0.043 | 15 | LTM | 20 | 23.4 ± 3.3 | 75 |
| Jones et al., 2014 (tDCS-maintenance) | Cross-over | 1 | P3–right cheek | 0.043 | 15 | LTM | 20 | 22.2 ± 2.5 | 70 |
| Pisoni et al., 2015 | Between | 1 | P3–P4 | 0.043 | 15 | LTM | 15 | 23.5 ± 2.6 | |
| 2 | T3–T4 | 0.043 | 15 | LTM | 15 | 23.1 ± 3.5 | |||
| Boggio et al., 2009 | Cross-over | 1 | F3–right SO | 0.057 | 30 | LTM | 10 | 79.1 ± 8.8 | 60 |
| 2 | T7–right SO | 0.057 | 30 | LTM | 10 | 79.1 ± 8.8 | 60 | ||
| Ferrucci et al., 2008 | Cross-over | 1 | P3/T5-P6/T4–shoulder | 0.057 | 15 | LTM | 10 | 75.2 ± 7.3 | 70 |
| 2 | shoulder–P3/T5-P6/T4 | 0.057 | 15 | LTM | 10 | 75.2 ± 7.3 | 70 | ||
| Brunyé et al., 2014 | Cross-over/between | 1 | T8–CP6, FC6, FT10, TP10 | HDtDCS | up to 20 | SM | 16 | 20.1 | 0 |
| 2 | T7–CPS, FC5, FT9, TP9 | HDtDCS | up to 20 | SM | 16 | 20.1 | |||
| Hampstead et al., 2014 | Between | 1 | Pz–AF4 | 0.057 | 20 | SM | 8 | 24.6 ± 2.4 | 50 |
| 2 | AF4–Pz | 0.057 | 20 | SM | 24.4 ± 5.1 | 37.5 | |||
| Krishnamurthy et al., 2015 | Between | 1 | Pz–AF4 | 0.057 | 20 | rs-fMRI | 19–27 | 33.3 | |
| 2 | AF4–Pz | 0.057 | 20 | rs–fMRI | 19–27 | 33.3 | |||
| Flöel et al., 2012 | Cross-over | 1 | P6–left SO | 0.029 | 2 | SM | 20 | 62.1 ± 9.2 | 50 |
cSO, contralateral supraorbital cortex; SO, supraorbital cortex; HD-tDCS, high-definition tDCS; WM, working memory; LTM, long-term memory; SM, spatial memory; rs-fMRI- resting-state functional magnetic resonance imaging; N, number of participants; PARC, parietal cortex.