TABLE 3.
Transcranial electrical stimulation effect detected by EEG/MEG.
| Reference | tES Electrode position (anode–cathode and “i” = ipsilateral; “c” = contralateral) | EEG Electrode position | Stimulation parameter |
Result | Motor task | Effects | Cohort | ||||
| I (mA) | J (mA/cm2) | t (min) | f (Hz) | Days | |||||||
| EEG | |||||||||||
| Antal et al. (2008) | iM1-cSO | Cz, C3, C4 | 0.4 | 0.03 | 5 | 1;10;15;30;45 | 1 | No significant effect | SRTT | Short term (5 min) | Healthy |
| Terney et al. (2008) | iM1-cSO | Cz, C3, C4 | 1 | 0.06 | 10 | 0–640 | 1 | No significant effect | SRTT | Online and short term (0–60 min) | Healthy |
| Polanía et al. (2011a) | iM1-cSO | 62 channels | 1 | 0.06 | 10 | 0 | 1 | FC increased in PMd, M1 in 60–90 Hz | Index–thumb grasp–release | Short term (after intervention) | Healthy |
| Notturno et al. (2014) | iM1-cSO cSO-iM1 | 32 channels | 1 | 0.03 | 20 | 0 | 1 | An increment of low alpha band ERD in bilateral central, frontal areas and in the left inferior parietal region; An increment of beta ERD in frontocentral and parieto-occipital regions | Sequential finger opposition | Short term (after intervention) | Healthy |
| Dutta et al. (2014) | iM1-cSO | F3, F4, P3, P4 | 1.66 | 0.53 | 15 | 0 | 1 | Decreased the slope of post-tDCS SCP | Ankle dorsiflexions | Online and short term (10 min) | Healthy |
| Marquez et al. (2015) | iM1-cSO | 64 channels | 1 | 0.03 | 20 | 0 | 1 | No significant effect | JTT; muscle strength | Short term (after intervention) | Older adults |
| Choe et al. (2016) | M1 redial fashion1 DLPFC radial fashion2 | 32 channels | 2 | 0.04 | 60 | 0 | 1 | Parietal alpha activity increased1; midline frontal theta activity increased2 | Pilot | Online | Healthy |
| Berger et al. (2018) | Parietal | F3, Fz, F4, Cz, Pz | 1 | 0.32 | 20 | 10;20 | 1 | Parietal alpha activity increased | Bimanual | Short term (0 s, 30 min) and long term (1 day) | Healthy |
| Schoellmann et al. (2019) | iM1-cSO | 25 channels | 1 | 0.03 | 20 | 0 | 1 | Reduced coherence from 22 to 27 Hz over the left sensorimotor and right frontotemporal area | Grip task | Short term (3 and 29 min) | Parkinson disease and healthy |
| Del Felice et al. (2019) | EEG power spectral difference locations | 32 channels | 1– 2 | 0.03– 0.06 | 30 | 4;30;0-100 | 10 | A reduction of beta rhythm offline over right sensorimotor area and left parietal area and follow-up over right sensorimotor area and left frontal area | Physical therapy | Short term (after intervention) and long term (4 weeks) | Parkinson disease |
| Berntsen et al. (2019) | P3-FP2; between F5 and F7 – FP2; C3-FP2 | 64 channels | 1 | 0.11 | 20 | IAF | 1 | Enhanced the motor performance after prefrontal IAF-tACS; A reduction in low beta ERD | Sequential hand motion | Short term (after intervention) | Healthy |
In “Effects” section, “online” refers to motor changes happened during the tES, “short term” refers to changes in a short time (<1 day) after the tES, “long term” refers to changes in a long time (>1 day) after tES. FC, functional connectivity; ERD, event-related desynchronization; SCP, slow cortical potentials that are defined as those positive or negative polarizations of the EEG that last from 300 ms to several seconds before electromyography onset with magnitudes up to 50 μV; IAF, individual alpha frequency, individual’s maximum amplitude between 8 and 12 Hz over parietal and occipital electrodes; CMC, corticomuscular coupling; SRTT, serial reaction time task; JTT, Jebsen Taylor hand function test. Sequential finger opposition: sequential tapping of the index, middle, ring, and fourth finger against the thumb. Superscript numbers link the settings and the findings accordingly.