## 2 Methodology
### Generalization of the SVM-ML Model
Based on the results in Table 4 and Figure 5, the comparisons of the accuracies of the SVM-ML model with respect to fabric stimulations when considering arm differences are presented in Figure 6. In the SA group (Figure 6a), significant differences in accuracies with respect to the fabric stimulations were obtained in the higher frequency bands, i.e., beta (\(p<0.001\), [PERSON] with [PERSON] post-hoc test) and gamma (\(p<0.05\), [PERSON] with [PERSON] post-hoc test) bands. No significant differences were found between nylon and wool in the delta, theta, and alpha bands (\(p>0.05\), [PERSON] with [PERSON] post-hoc test). In the SU group (Figure 6b), significant differences in accuracies with  
Figure 5: Comparisons of the overall classification accuracies of the SVM-ML model with respect to fabric stimulations in the delta, theta, alpha, beta, and gamma bands. The significant intergroup differences are indicated by *** (\(p<0.001\), Kruskal–Wallis with Bonferroni post-hoc test). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{2}{c}{**Fabric**} & \multicolumn{5}{c}{**Accuracy**} \\ \cline{2-7}
**Stimulation** & \multicolumn{2}{c}{**Delta**} & **Theta** & **Theta** & **Delta** & **Beta** & **Gamma** \\ \hline \multirow{4}{*}{SA} & Cotton & 47.9\% \(\pm\) 0.09 & 28.8\% \(\pm\) 0.11 & 28.5\% \(\pm\) 0.10 & 48.9\% \(\pm\) 0.10 & 59.7\% \(\pm\) 0.08 \\ \cline{2-7}  & Nylon & 26.8\% \(\pm\) 0.09 & 31.9\% \(\pm\) 0.08 & 54.1\% \(\pm\) 0.11 & 64.3\% \(\pm\) 0.10 & 76.2\% \(\pm\) 0.06 \\ \cline{2-7}  & Wool & 22.9\% \(\pm\) 0.09 & 21.7\% \(\pm\) 0.08 & 51.1\% \(\pm\) 0.11 & 53.6\% \(\pm\) 0.08 & 78.9\% \(\pm\) 0.04 \\ \cline{2-7}  & \(p\)-value & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** \\ \hline \multirow{4}{*}{SU} & Cotton & 48.3\% \(\pm\) 0.08 & 40.9\% \(\pm\) 0.13 & 27.0\% \(\pm\) 0.09 & 69.3\% \(\pm\) 0.05 & 91.0\% \(\pm\) 0.04 \\ \cline{2-7}  & Nylon & 15.5\% \(\pm\) 0.07 & 40.5\% \(\pm\) 0.13 & 61.7\% \(\pm\) 0.04 & 74.9\% \(\pm\) 0.01 & 91.2\% \(\pm\) 0.03 \\ \cline{2-7}  & Wool & 50.3\% \(\pm\) 0.03 & 27.8\% \(\pm\) 0.08 & 40.1\% \(\pm\) 0.04 & 84.9\% \(\pm\) 0.04 & 91.6\% \(\pm\) 0.01 \\ \cline{2-7}  & \(p\)-value & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.05 \\ \hline \multirow{4}{*}{UD} & Cotton & 51.4\% \(\pm\) 0.14 & 31.6\% \(\pm\) 0.10 & 22.0\% \(\pm\) 0.12 & 35.3\% \(\pm\) 0.12 & 78.0\% \(\pm\) 0.10 \\ \cline{2-7}  & Nylon & 24.0\% \(\pm\) 0.09 & 51.9\% \(\pm\) 0.07 & 39.2\% \(\pm\) 0.10 & 53.7\% \(\pm\) 0.05 & 83.4\% \(\pm\) 0.01 \\ \cline{2-7}  & Wool & 19.8\% \(\pm\) 0.09 & 30.0\% \(\pm\) 0.11 & 36.9\% \(\pm\) 0.10 & 71.9\% \(\pm\) 0.08 & 84.1\% \(\pm\) 0.06 \\ \cline{2-7}  & \(p\)-value & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** & \textless{}0.001 *** \\ \hline \hline \end{tabular} Note: Data are given as mean \(\pm\) SD. The significant intergroup differences are indicated by *** (\(p<0.001\), Kruskal-Wallis test).  
\end{table} 
Table 5: Accuracies of the SVM-ML model for classifying the three upper-limb groups with different fabric stimulations. respect to fabric stimulations were found in the delta (\(p<0.001\), [PERSON] with [PERSON] post-hoc test), alpha (\(p<0.001\), [PERSON] with [PERSON] post-hoc test), and beta (\(p<0.05\), [PERSON] with [PERSON] post-hoc test) bands. No significant difference was observed between cotton and nylon in the theta band (\(p>0.05\), [PERSON] with [PERSON] post-hoc test). In the UD group (Figure 6c), significant differences in accuracies with respect to fabric stimulations were found in almost all frequency bands (\(p<0.001\), [PERSON] with [PERSON] post-hoc test), except for the difference between nylon and wool in the gamma band (\(p>0.05\), [PERSON] with [PERSON] post-hoc test).