Table 5.

Numeric sensation scores during experimental conditions under reference electrode

Sensation		M1 tDCS			UHCDS tDCS			Sham
		Day 1	Day 2	Day 3	Day 1	Day 2	Day 3	Day 1	Day 2	Day 3
Tingling	Beginning	2.05±0.10	2.16±0.16	2.05±0.18	2.02±0.11	2.20±0.18	2.20±0.16	1.83±0.14	2±0.20	2±0.19
	Middle	1.55±0.08	1.55±0.09	1.61±0.11	1.78±0.05	1.60±0.07	1.67±0.09	1.72±0.07	1.63±0.07	1.61±0.10
	End	0.66±0.08	0.80±0.10	0.80±0.11	0.83±0.05	0.80±0.05	0.77±0.07	0.72±0.07	0.80±0.06	0.75±0.08
Itching	Beginning	2± 0.30	2.11±0.30	2.11±0.29	1.95±0.24	1.95±0.25	2±0.25	1.77±0.20	1.83±0.21	1.72±0.21
	Middle	1.11±0.17	1.27±0.22	1.33±0.22	1.19±0.17	1.25±0.21	1.20±0.21	1.16±0.18	1.27±0.24	1.16±0.21
	End	0.27±0.10	0.27±0.11	0.50±0.20	0.47±0.13	0.55±0.17	0.40±0.17	0.39±0.14	0.50±0.18	0.39±0.18
Burning	Beginning	-	-	-	-	-	-	-	-	-
	Middle	-	-	-	-	-	-	-	-	-
	End	-	-	-	-	-	-	-	-	-

Scores are reported as Mean±SEM (SEM: Standard Error of Measurement).

According to the participants’ reports, itching and tingling were the most important side effects under both active and reference electrodes. Three of the participants in the a-tDCSUHCDS group and two of the participants in the M1 a-tDCS group reported burning sensation at the beginning of the stimulation. There were no other side effects such as discomfort or pain through three stages of brain stimulation over three consecutive days. In addition, the perceptions of participants on the stimulation condition after the last stimulation session are summarized in Table 6. The results of Pearson’s chi-square test revealed no significant differences between the active and sham tDCS groups (χ²=3.73, P=0.44). The active or sham tDCS groups properly guessed only in 13.2% of groups (except the “cannot say” responses) (Table 6).