Table 2.

RR, QT_e, QT_p, and T_e interval data in the healthy elderly volunteers who underwent sham and active tDCS

Variables	Age <60 years	Age ≥60 years	P-values
Sham tDCS
Patients, n	29	21
RR mean, ms	903±126	914±106	ns
RR variance, ms2	1,552 (1,741)	637 (1,050)	0.014
QTe mean	334±24	346±24*	ns
QTe variance, ms2	6 (6)	14 (17)	0.020
QTp mean	260±22	267±23	ns
QTp variance, ms2	16 (13)	25 (21)	ns
Te mean	75±11	79±12*	ns
Te variance, ms2	21 (20)	36 (34)	ns
QTe →RR, coherence	0.205±0.030	0.202±0.033	ns
QTp →RR, coherence	0.223±0.044	0.212±0.032	ns
Te →RR, coherence	0.206±0.035	0.205±0.029	ns
Te →QTp, coherence	0.683±0.199	0.663±0.134	ns
QTe VI	−1.44 (0.60)	−0.86 (1.15)*	0.004
QTp VI	−0.95 (0.68)	−0.57 (0.85)	0.007
Te VI	0.30 (0.70)	0.68 (0.70)	0.004
Anodal tDCS
Patients, n	29	21
RR mean, ms	897±125	930±130	ns
RR variance, ms2	1,543 (1,915)	723 (106)	0.004
QTe mean	334±28	353±30*	0.032
QTe variance, ms2	7 (6)	12 (17)	0.033
QTp mean	256±24	266±28	ns
QTp variance, ms2	16 (23)	23 (21)	ns
Te mean	78±10	84±11*	0.030
Te variance, ms2	22 (24)	35 (27)	0.033
QTe →RR, coherence	0.213±0.37	0.204±0.32	ns
QTp →RR, coherence	0.223±0.041	0.211±0.043	ns
Te →RR, coherence	0.205±0.027	0.202±0.025	ns
Te →QTp, coherence	0.726±0.148	0.697±0.129	ns
QTe VI	−1.70 (0.60)	−1.08 (0.93)*	0.006
QTp VI	−1.05 (0.58)	−0.55 (0.68)	0.009
Te VI	0.14 (0.45)	0.69 (0.62)	0.003

Notes: Values expressed as mean ± SD or median (interquartile range 75th percentile to 25th percentile).

^*P<0.05 sham vs tDCS. QT_e, QT interval (from q to end of T wave); QT_p, QT_p interval (from q to peak of T wave); T_e, T_e interval (from peak to end of T wave).

Abbreviations: tDCS, transcranial direct current stimulation; ns, nonsignificant; SD, standard deviation.