Table 1.

Summary of randomized controlled trials of anodal transcranial direct current stimulation for migraine prevention

Study	N	Age range	Migraine type	Concomitant preventatives, %	Stimulation type	Electrode surface area (cm2)	Current intensity (mA)	Session duration (min)	Baseline observation (before the first tDCS session)	Follow-up (after the last tDCS session)
Ahdab, 2019 [18]	42 (cross-over)	18-60	Episodic	7	Cathodal	35	2	20	1 week	2 weeks
Andrade, 2017 [19]	6 active (M1), 3 active (DLPFC), 4 (sham)	18-65	Chronic	NR	Anodal	25	2	20	1 day	1 day
Antal, 2011 [20]	13 active, 13 sham	20-53	Episodic/chronic	0	Cathodal	35	1	15	8 weeks	8 weeks
Auvichapayat, 2012 [21]	20 active, 17 sham	18-65	Episodic	0	Anodal	35	2	20	4 weeks	12 weeks
Dalla Volta, 2020 [22]	28 active, 17 sham	18-65	Chronic, without aura	100 (topiramate)	Cathodal	35	1.5	15	NR	120 days
DaSilva, 2012 [23]	8 active, 5 sham	18-60	Chronic	NR	Anodal	35	2	20	1 week	120 days
De Icco, 2021 [24]	10 active, 10 sham	18-65	Chronic (with medication overuse)	0	Anodal	Anode: 9 Cathode: 24	2	20	1 month	6 months
Grazzi, 2020 [25]	44 active (anodal), 45 active (cathodal), 46 sham	18-65	Chronic (with medication overuse)	NR	Anodal/cathodal	35	2	20	1 month	12 months
Mansour, 2019 [26]	18 (cross-over)	18-60	Medication overuse	28	Anodal/cathodal	35	2	20	1 week	2 weeks
Pohl, 2020 [27]	11 active, 12 sham	18-80	Episodic	NR	Anodal	Anode: 35 Cathode: 100	1	20	4 weeks	4 months
Rahimi, 2020 [28]	15 active (M1), 15 active (S1), 15 sham	18-60	Episodic/chronic	0	Cathodal	Cathode: 15 Anode: 35	1	20	4 weeks	12 months
Rocha, 2015 [29]	10 active, 5 sham	18-50	Episodic/chronic	0	Cathodal	35	2	20	30 days	30 days
Wickmann, 2015 [30]	8 active, 8 sham	NR	Menstrual	0	Cathodal	35	2	20	12 weeks	12 weeks

DLPFC indicates dorsolateral prefrontal cortex, M1 primary motor area, NR not reported, S1 primary somatosensory area