## 3 Results
### Evaluating EEG Frequency Band Responsiveness to TEAS  
For this section, EEGNet was employed to classify various phases, using each EEG frequency band: delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and gamma (30-50 Hz) to investigate the responsiveness of each frequency band to the stimulation. The classification accuracies were averaged across different EEG frequency bands during various phases of TEAS.  
Figure 4 summarizes the averaged classification accuracies over all combinations of the phases for each frequency band under various TEAS frequencies (Table S12a-l in the Supplementary Material show the classification accuracies of each combination). As shown in Figure 4, in the delta (1-4 Hz) frequency band, the classification accuracies were relatively uniform across all TEAS frequencies, including the sham condition, with values ranging from approximately 39.82% to 41.21%. This uniformity suggests that the delta band may not be significantly affected by the variations in TEAS frequency.  
\begin{table}
\begin{tabular}{l c} \hline \hline \multicolumn{3}{c}{**Demographic Factors**} \\ \hline
**Factor** & **Classification Accuracy (\%)** \\ Sex (Female) & 93–100 \\ Sex (Male) & 90–95 \\ Age (\(>\)45) & 92–98 \\ Age (\(<\)45) & 90–99 \\ \hline \multicolumn{3}{c}{**Clinical Factors**} \\ \hline
**Factor** & **Classification Accuracy (\%)** \\ High relaxation & 90–100 \\ Low relaxation & 90–97 \\ High anxiety & 90–100 \\ Low anxiety & 90–97 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Summary of classification accuracy across time slots (pre-stimulation, during stimulation, and post-stimulation) for demographic and clinical factors.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Metric\textbackslash{Frequency}** & **2.5 pps** & **10 pps** & **80 pps** & **Sham** \\ \hline Accuracy & 95.98 \(\pm\) 0.42 & 95.68 \(\pm\) 0.18 & 96.36 \(\pm\) 0.60 & 93.52 \(\pm\) 0.52 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Total classification accuracy during the stimulation phase across different TEAS frequencies.  
For the theta (4-8 Hz) band, the classification accuracies were higher, indicating a greater sensitivity to TEAS. The accuracies ranged from approximately 68.69% to 73.48%, with the highest accuracy observed at 2.5 pps. This could indicate that the theta band is moderately responsive to TEAS. The alpha (8-13 Hz) band showed a more pronounced increase in classification accuracy with TEAS application, with values ranging from approximately 72.43% to 79.29%. The highest accuracy was again observed at 2.5 pps. The alpha band is often associated with a relaxed, yet alert state, and these results may suggest that TEAS has a more noticeable impact on this state.  
In the beta (13-30 Hz) band, there was a significant increase in classification accuracy when TEAS was applied. The accuracies ranged from approximately 90.28% in the 80 pps condition to about 95% at 10 and 2.5 pps. Beta frequency is associated with active thinking, focus, and cognitive processing. Changes in beta frequency may indicate that TEAS enhances alertness and cognitive function, possibly by reducing anxiety and stress. Finally, the gamma (30-50 Hz) band exhibited the highest classification accuracies. The accuracies ranged from approximately 94.15% in the sham condition to 96.24% at 10 pps. Gamma frequency is linked to high-level cognitive functions, such as information processing, memory, and consciousness. Changes in gamma activity could suggest improved neural synchrony and integration of sensory information.