The Effects of Transcranial Direct Current Stimulation on the Cognitive Functions in Older Adults with Mild Cognitive Impairment: A Pilot Study
Table 3
Digit span test score.
Participant
Digit span test
Baseline
After first baseline (A1)
After sham tDCS (B)
After tDCS (C)
After last baseline (A2)
Immediate effect (%) (C versus baseline)
After-effect (%) (A2 versus C)
tDCS versus sham tDCS (C versus B)
1
Forward score
15
16
16
15
16
0
3.33
−3.33
Backward score
6
8
10
8
9
6.66
3.33
−6.66
Total score
21
24
26
23
25
6.66
6.66
−9.99
2
Forward score
14
15
14
15
16
3.33
3.33
3.33
Backward score
5
5
7
6
8
3.33
6.66
−3.33
Total score
19
19
21
21
24
6.66
9.99
0
3
Forward score
14
16
16
16
16
6.66
0
0
Backward score
9
9
9
9
13
0
13.32
0
Total score
23
25
25
25
29
6.66
13.32
0
4
Forward score
16
16
16
16
16
0
0
0
Backward score
7
8
5
8
8
3.33
0
9.99
Total score
23
24
21
24
24
3.33
0
9.99
5
Forward score
13
16
16
16
16
9.99
0
0
Backward score
4
4
5
7
5
9.99
−6.66
6.66
Total score
17
20
21
23
22
19.98
−3.33
6.66
Immediate effect (C versus baseline) is the gain (%) after the application of tDCS compared with the baseline; after-effect (A2 versus C) is the maintenance or gain (%) after tDCS withdrawal in phase C; tDCS versus sham tDCS (C versus B) is the comparison in terms of gain (%) between tDCS and sham tDCS. A positive ratio implies improvement, a neutral ratio implies maintenance, and a negative ratio implies decrement in terms of accuracy.
