Table 1 Behavioral data and statistics: Composite z-score (online) is the mean of four z-scores: spatial span backward maximum length, digit span backward maximum length, online letter n-back accuracy, and online spatial n-back accuracy. Composite z-score (offline) is the mean of three z-scores: offline letter n-back accuracy, offline spatial n-back accuracy, and BTA raw score. Composite z-score (full battery) is the mean of five z-scores: spatial span backward maximum length, digit span backward maximum length, letter n-back accuracy (mean of online and offline percentages), spatial n-back accuracy (mean of online and offline percentages), and BTA raw score. Also included are means and standard deviations for 1-back, 2-back, and 3-back for letter and spatial n-back, both online and offline
|  | Sham | Left anodal | Right anodal | Repeated measures ANOVA F(2,22) | Friedman’s Test χ2 | p value |
|---|---|---|---|---|---|---|
WMS-III, spatial span backward, longest span (blocks) | 4.8 (0.9) | 6.2 (1.8) | 6.0 (0.9) | Â | 9.24 | 0.01 |
WMS-III, digit span backward, longest span (digits) | 5.3 (1.5) | 5.5 (1.6) | 5.4 (2.0) | 0.12 | Â | 0.891 |
Spatial n-back accuracy (online) | 62.4% (25.0%) | 68.6% (22.1%) | 66.7% (23.2%) | Â | 3.17 | 0.205 |
 1-back | 74.7% (23.1%) | 80.0% (19.9%) | 79.6% (21.4%) |  |  |  |
 2-back | 61.4% (27.9%) | 68.5% (26.4%) | 66.2% (25.5%) |  |  |  |
 3-back | 49.7% (25.8%) | 55.6% (22.9%) | 52.7% (25.0%) |  |  |  |
Letter n-back accuracy (online) | 69.6% (30.2%) | 76.2% (22.5%) | 76.3% (26.8%) | Â | 0.5 | 0.779 |
 1-back | 77.3% (26.6%) | 82.9% (19.9%) | 84.8% (21.7%) |  |  |  |
 2-back | 70.4% (32.4%) | 76.0% (26.0%) | 76.2% (29.3%) |  |  |  |
 3-back | 61.1% (33.1%) | 69.7% (24.2%) | 68.1% (29.7%) |  |  |  |
Composite z-score (online) | −0.25 (0.74) | 0.15 (0.87) | 0.09 (0.81) | 7.68 |  | 0.003 |
Spatial n-back accuracy (offline) | 63.9% (24.9%) | 70.6% (20.9%) | 67.7% (24.2) | 0.55 | Â | 0.758 |
 1-back | 76.2% (21.9%) | 85.1% (20.2%) | 78.4% (21.7%) |  |  |  |
 2-back | 63.2% (29.0%) | 70.5% (24.3%) | 69.8% (26.8%) |  |  |  |
 3-back | 52.5% (26.5%) | 56.3% (21.8%) | 54.6% (26.0) |  |  |  |
Letter n-back accuracy (offline) | 72.3% (29.8%) | 78.5% (22.5%) | 76.5% (25.9%) | Â | 0.17 | 0.92 |
 1-back | 80.7% (23.2%) | 86.1% (20.7%) | 84.3% (21.6%) |  |  |  |
 2-back | 71.1% (33.2%) | 77.8% (22.3%) | 77.8% (27.2%) |  |  |  |
 3-back | 65.1% (33.6%) | 71.6% (26.2%) | 67.4% (30.0) |  |  |  |
Brief Test of Attention (offline) | 6.8 (2.5) | 7.4 (2.2) | 7.9 (2.5) | Â | 7.09 | 0.029 |
Composite z-score (offline) | −0.18 (0.92) | 0.09 (0.77) | 0.09 (0.93) |  | 7.17 | 0.028 |
Spatial n-back accuracy combined (mean of online and offline percentages) | 63.2% (24.7%) | 69.6% (20.7%) | 67.3% (23.6%) | Â | 0.67 | 0.717 |
Letter n-back accuracy combined (mean of online and offline percentages) | 71.0% (29.8%) | 77.4% (22.1%) | 76.4% (26.3%) | Â | 0.17 | 0.92 |
Composite z-score (full battery) | −0.25 (0.71) | 0.13 (0.82) | 0.11 (0.81) | 12.85 |  | 0.0002 |