Table 7.
Correlation between cognitive state indicators.
| Cognitive state | Attention | Mental workload | Vigilance | Mental fatigue | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (SMR + Middleβ)/θ | AF3 | AF4 | T7 | T8 | θ/β | (θ + β)/(α + γ) | α/(β + γ) | θ/α | θ/β | (θ + α)/β | α/β | (θ + α)/(α + β) | ||
| Attention | (SMR + Middleβ)/θ | 1.000 | 0.691 | 0.698 | 0.633 | 0.670 | −0.744 | −0.510 | −0.250 | −0.633 | −0.744 | −0.679 | −0.251 | −0.793 |
| Mental workload | AF3 | *** | 1.000 | 0.673 | 0.568 | 0.572 | −0.630 | −0.128 | −0.600 | −0.289 | −0.630 | −0.702 | −0.605 | −0.560 |
| AF4 | *** | *** | 1.000 | 0.455 | 0.702 | −0.653 | −0.180 | −0.576 | −0.330 | −0.653 | −0711 | −0.575 | −0.584 | |
| T7 | *** | *** | *** | 1.000 | 0.601 | −0.592 | −0.286 | −0.393 | −0.406 | −0.592 | −0.605 | −0.397 | −0.585 | |
| T8 | *** | *** | *** | *** | 1.000 | −0.660 | −0.205 | −0.575 | −0.363 | −0.660 | −0.716 | −0.574 | −0.616 | |
| Vigilance | θ/β | ** | *** | *** | *** | *** | 1.000 | 0.506 | 0.482 | 0.655 | 1.000 | 0.958 | 0.479 | 0.916 |
| (θ + β)/(α + γ) | *** | ** | * | *** | 1.000 | −0.356 | 0.977 | 0.506 | 0.288 | −0.359 | 0.772 | |||
| α/(β + γ) | * | *** | *** | *** | *** | *** | *** | 1.000 | −0.183 | 0.482 | 0.712 | 0.997 | 0.200 | |
| Mental fatigue | θ/α | *** | ** | ** | *** | *** | *** | *** | 1.000 | 0.655 | 0.465 | −0.184 | 0.885 | |
| θ/β | *** | *** | *** | *** | *** | *** | *** | *** | *** | 1.000 | 0.958 | 0.479 | 0.916 | |
| (θ + α)/β | *** | *** | *** | *** | *** | *** | ** | *** | *** | *** | 1.000 | 0.711 | 0.800 | |
| α/β | * | *** | *** | *** | *** | *** | ** | *** | *** | *** | 1.000 | 0.200 | ||
| (θ + α)/(α + β) | *** | *** | *** | *** | *** | *** | *** | *** | *** | *** | 1.000 | |||
*: P < 0.05, **: P < 0.01, ***: P < 0.001.