TABLE 5.

Studies and experimental characteristics of tES literature for epilepsy.

Authors	Subjects	Stimulation parameters				Neuroimaging		Conclusion
		Type	Current	Duration	Location	Type	Feature
Meiron et al., 2019	1	HD-tDCS	1 mA, 20 min	5 sessions per week for 4 weeks	Anode: frontal-parietal cortex (AF8, F2, C2, PO4), cathode :C6	EEG	Power spectral in theta band (4–8 Hz), alpha (8–12 Hz), beta (13–30 Hz), spike frequency, duration, and amplitude.	tDCS reduces the interictal epileptic discharges and change in seizure-related delta activity.
Yang et al., 2019a	7	tDCS	1 or 2 mA, 40 min	14 sessions consecutive days	Anode: left or right supra-orbital area, cathode: P4 or P3	EEG	Seizure frequency and seizure reduction.	Repeated tDCS (cathode located in the bilateral parietal area) could safely reduce seizure frequency for epilepsy patients.
Lin et al., 2018	9	tDCS	2 mA, 20 min	6 sessions in one month	Anode: contralateral shoulder area, cathode: epileptogenic focus	EEG	Seizure frequency and phase lag index/	tDCS may be considered an alternative treatment option for patients with refractory epilepsy. Its effect might be cumulative after repeated stimulations and associated with a decrease in the phase lag index.
Tecchio et al, 2018	6	tDCS	1 mA, 20 min	1 session	Anode: opposite homologous, cathode: epileptogenic focus.	EEG	Functional connectivity and power spectrum.	The neurological alternation (functional connectivity) indicated that the cathode tDCS might contribute to epilepsy and provide a new therapy to modulate the epileptic people.
Meiron et al., 2018	1	HD-tDCS	0.1–1 mA, 20 min	5 sessions per week for 2 weeks	Anode: PO3, P6, AF3, F6, FC4, O1, CP3, C1, FC8, C6, FCz, FC3, O4, F2, CP4, PO4, O2, AF8, C2, cathode: C2, TP8, CP8, O3, TP8, T8	EEG	Mean number spikers, mean peak amplitude, mean absolute power.	HD-tDCS showed safety and feasibility of early-onset epileptic encephalopathy. It provides the first evidence of HD-tDCS effects on paroxysmal EEG features in electroclinical cases under the age of 36 months. Extending HD-tDCS treatment may enhance electrographic findings and clinical effects.
Karvigh et al., 2017	10	HD-tDCS	2 mA, 20 min	10 consecutive days	Anode: frontal-parietal-temporal cortex (F3/F4, P3/P4, Cz, T3/T4) Cathode: PF1/PF2, Fz, Tz/T8, C3/C4	EEG	Seizure frequency	The statistical analysis for the whole group does not show the effect of the tDCS since the change of epileptiform discharge was not significant. However, the clinical score (i.e., working memory performance) was improved.
San-Juan et al., 2016	1	tACS	1 mA, 3 Hz, 60 min	4 sessions consecutive days	Anode: frontal cortex (Fp1 and Fp2)	EEG	Spike-low wave at 3 Hz, polis piker-slow wave at 3–4 Hz, and slow rhythmic waves at 4 Hz	At the 1-month follow-up, the patients reported a 75% increase in seizure frequency. At the 2-month follow-up, the patient reported a 15-day seizure-free period.
Tekturk et al., 2016	12	tDCS	2 mA, 30 min	3 sessions consecutive days	Anode: temporal region (T3 and T4); cathode: contralateral supraorbital region	EEG	Seizure frequency	Our small series suggested that cathodal tDCS may be used as an additional treatment option in MTLE-HS. It may be tried in patients with TLE-HS waiting for or rejecting epilepsy surgery or even with ineffective surgical results.
Liu et al., 2016	37	tDCS	2 mA, 20 mins	5 sessions Consecutive days	Anode: DLPFC (F3, F4), cathode: right supraorbital area	EEG	Power spectral in delta (1–4 Hz), theta band (5–7 Hz), low alpha (8–10 Hz), high alpha (11–13 Hz), beta (14–32 Hz), low gamma (33–35 Hz).	tDCS improved the symptoms of depression for temporal lobe epilepsy. There were no changes in memory function immediately following or persisting after a stimulation course.
Del Felice et al., 2015	12	So-tDCS	0.75 Hz, 30 mins	1 session	Anode: frontal-temporal (F7-T3 or F8-T8), cathode: ipsilateral mastoid	EEG	Spindle frequency and Cortical sources	Anodal so-tDCS over the affected temporal lobe improves declarative and visuospatial memoryperformance by modulating slow sleep spindles cortical source generators.
Auvichayapat et al., 2013	36	tDCS	1 mA, 20 min	1 session	Anode: Contralateral shoulder area, cathode: epileptogenic focus	EEG	Spikes and sharp waves	A single session of cathodal tDCS improves epileptic EEG abnormalities for 48 h and is well tolerated in children.
Fregni et al., 2006	19	tDCS	1 mA, 20 min	1 session	Anode: silent area. cathode: epileptogenic focus	EEG	Seizure frequency	Cathodal tDCS polarization does not induce seizures and is well tolerated in patients with refractory epilepsy and MCDs. tDCS might have an antiepileptic effect based on clinical and electrophysiological criteria.
Faria et al., 2012	17	tDCS	1 mA, 30 min	3 sections for three weeks	Anode: central prefrontal area (FPz), cathode: CP6 Cp5.	EEG	The average number of epileptiform	Continuous monitoring of epileptic activity throughout tDCS improves safety and permits detailed evaluation of epileptic activity changes induced by tDCS in patients.
San-Juan et al., 2016	28	tDCS	2 mA, 30 min	3 or 5 sessions in consecutive days	Anode: silent area. cathode: most active interictal epileptiform discharges area	EEG	Seizure frequency	Cathodal tDCS (applied 3 and 5 sessions) reduced seizure frequency and interictal epileptiform discharges for patients with epilepsy and hippocampal sclerosis compared to placebo tDCS.