## 2 Materials and Methods
### Data Analysis
Right Panel: Emotiv EPOC (14-electrode) system with CMS at P3 and DRL at P4. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{10}{c}{**(A)**} \\ \hline  & \multicolumn{4}{c}{**EPOC**} & \multicolumn{10}{c}{**Brainvision**} \\ \hline
**Band** & \multicolumn{2}{c}{**Mental State**} & \multicolumn{1}{c}{**z**} & \multicolumn{1}{c}{\(p\)} & \multicolumn{1}{c}{\(\mu^{2}\)} & \multicolumn{2}{c}{**Mental State**} & \multicolumn{1}{c}{**z**} & \multicolumn{1}{c}{\(p\)} & \multicolumn{1}{c}{\(\mu^{2}\)} \\ \cline{2-11}  & **Low** & **High** & \multicolumn{4}{c}{**(IAPS, Arousal)**} \\ Delta & 1.96 & 2.76 & \(-\)3.30 & \(<\)0.001 & 0.78 & 7.97 & 7.24 & 3.17 & 0.002 & 0.72 \\ Theta & **1.42** & **1.78** & \(-\)**3.11** & **0.002** & **0.69** & **5.80** & **6.00** & \(-\)**3.18** & **0.001** & **0.72** \\ Alpha & 2.21 & 2.48 & \(-\)2.93 & 0.003 & 0.61 & 8.79 & 9.03 & \(-\)1.48 & 0.140 & 0.16 \\ Beta & **1.73** & **1.93** & \(-\)**3.30** & **\(<\)0.001** & **0.78** & **14.57** & **15.39** & \(-\)**3.30** & \(<\)**0.001** & **0.78** \\ Gamma & **0.42** & **0.63** & \(-\)**3.31** & **\(<\)0.001** & **0.78** & **14.53** & **15.22** & \(-\)**3.24** & **0.001** & **0.75** \\ \hline  & \multicolumn{10}{c}{**(IAPS, Valence)**} \\ Delta & 1.75 & 2.80 & \(-\)3.30 & \(<\)0.001 & 0.78 & 7.66 & 6.99 & 3.30 & \(<\)0.001 & 0.78 \\ Theta & 1.35 & 2.05 & \(-\)3.23 & 0.001 & 0.75 & 5.98 & 5.84 & 2.00 & 0.046 & 0.29 \\ Alpha & **2.04** & **2.78** & \(-\)**3.30** & **\(<\)0.001** & **0.78** & **10.04** & **10.28** & \(-\)**1.92** & **0.055 \({}^{*}\)** & **0.26** \\ Beta & 1.80 & 2.30 & \(-\)3.30 & \(<\)0.001 & 0.78 & 15.07 & 15.02 & 0.67 & 0.506 & 0.03 \\ Gamma & 0.39 & 0.69 & \(-\)3.31 & \(<\)0.001 & 0.78 & 14.57 & 14.15 & 3.30 & \(<\)0.001 & 0.78 \\ \hline  & \multicolumn{10}{c}{**(n-Back 1,3,5)**} \\ Delta & 2.70 & 2.39 & 2.45 & 0.014 & 0.43 & 2.89 & 2.72 & 1.23 & 0.221 & 0.11 \\ Theta & 1.95 & 2.05 & \(-\)1.54 & 0.124 & 0.17 & 3.07 & 2.95 & 1.29 & 0.198 & 0.12 \\ Alpha & 2.75 & 2.69 & 0.47 & 0.638 & 0.02 & 3.08 & 3.07 & 0.44 & 0.660 & 0.01 \\ Beta & 2.77 & 2.75 & 0.03 & 0.975 & 0.00 & 3.92 & 4.23 & \(-\)3.30 & \(<\)0.001 & 0.78 \\ Gamma & 0.95 & 0.93 & 0.59 & 0.556 & 0.02 & 4.25 & 4.49 & \(-\)2.86 & 0.004 & 0.58 \\ \hline  & \multicolumn{10}{c}{**(n-Back 2,4,6)**} \\ Delta & 4.58 & 2.35 & 3.30 & \(<\)0.001 & 0.78 & 2.28 & 2.30 & \(-\)0.19 & 0.851 & 0.00 \\ Theta & 2.90 & 1.98 & 3.30 & \(<\)0.001 & 0.78 & 2.78 & 3.11 & \(-\)2.79 & 0.005 & 0.56 \\ Alpha & 4.08 & 2.55 & 3.30 & \(<\)0.001 & 0.78 & 2.65 & 2.94 & \(-\)3.20 &Two-tailed paired Wilcoxon Signed Rank Tests were used to evaluate data to determine if there was a significant difference between the measures of each wave type at high and low states. To balance for Type I error likelihood, given the low statistical power (since the item analysis was limited to n = 14, the number of electrode-associated repeated measurements), we adopted a correction of the p-value with a generalization (family-wise average rate of false discovery rate) of the Hochberg-Benjamini procedure [65] with alpha 0.09, which gives a significance threshold of \(p\) = 0.054. Eta squared (\(\mu^{2}\)) was computed as a measure of the effect size of the difference between high and low states. Finally, the value of EPOC electrode measurements was represented proportionally to the value of electrode measurements obtained by Brainvision, as a measure of EEG signal measurement _efficiency_. For example, if for gamma waves EPOC detected a signal amplitude of 1.5 \(\upmu\)V, while Brainvision detected a signal amplitude of 15 \(\upmu\)V, Emotiv would be represented as sensing 10% of what Brainvision did. Lastly, two confirmatory additional \"control\" analyses were performed (their results are not reported here but are available upon request). Firstly, we repeated the same analyses done on the vincentized averages for the data relative to each of the three professional observers.