## 3 Results
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Feature** & **Group** & **IMF1** & **IMF2** & **IMF3** & **IMF4** \\ \hline \multirow{3}{*}{\(\log\left(ASR_{area}\right)\)} & noCAN & \(-\)6.777 \(\pm\) 0.770 b & \(-\)7.399 \(\pm\) 0.338 b  & \(-\)7.424 \(\pm\) 0.287 b  & \(-\)7.300 \(\pm\) 0.432 b  \\  & subCAN & \(-\)7.655 \(\pm\) 0.382 b  & \(-\)7.739 \(\pm\) 0.268 b  & \(-\)7.694 \(\pm\) 0.450 b  & \(-\)7.712 \(\pm\) 0.224 b  \\ \hline \multirow{3}{*}{\(\log\left(SODP_{area}\right)\)} & noCAN & \(-\)0.654 \(\pm\) 0.665 b  & \(-\)1.878 \(\pm\) 0.609 b  & \(-\)2.810 \(\pm\) 0.488 ab  & \(-\)3.598 \(\pm\) 0.527 ab  \\  & subCAN & \(-\)1.957 \(\pm\) 0.802 c  & \(-\)2.374 \(\pm\) 0.740 c  & \(-\)3.294 \(\pm\) 0.584 a  & \(-\)4.071 \(\pm\) 0.557 ac  \\  & estCAN & \(-\)1.086 \(\pm\) 0.759 b  & \(-\)2.963 \(\pm\) 0.703 b  & \(-\)3.733 \(\pm\) 0.733 b  \\ \hline \multirow{3}{*}{\(\log\left(PSD_{pkamp}\right)\)} & noCAN & \(0.773\)\(\pm\) 0.268 b  & \(0.887\)\(\pm\) 0.173 b  & \(0.317\)\(\pm\) 0.180 ab  & \(0.694\)\(\pm\) 0.234 ab  \\  & subCAN & \(0.887\)\(\pm\) 0.209 b  & \(0.941\)\(\pm\) 0.105 & \(0.531\)\(\pm\) 0.276 ac  & \(0.868\)\(\pm\) 0.143 ac  \\  & estCAN & \(0.981\)\(\pm\) 0.037 b  & \(0.987\)\(\pm\) 0.029 b  & \(0.750\)\(\pm\) 0.253 bc  \\ \hline \multirow{3}{*}{\(\log\left(PSD_{pkow}\right)\)} & noCAN & \(-\)3.480 \(\pm\) 0.574 b  & \(-\)3.899 \(\pm\) 0.432 b  \\  & subCAN & \(-\)3.897 \(\pm\) 0.668 c  & \(-\)4.166 \(\pm\) 0.564 c  & \(-\)4.288 \(\pm\) 0.388 ac  \\  & estCAN & \(-\)4.492 \(\pm\) 0.654 b  & \(-\)4.749 \(\pm\) 0.622 b  \\ \hline \multirow{3}{*}{\(\log\left(PSD_{pkamp}\right)\)} & noCAN & \(-\)2.562 \(\pm\) 0.617 b  & \(-\)2.771 \(\pm\) 0.435 b [[PERSON]'s power spectral density estimation plots of the intrinsic mode functions for the three groups (noCAN, subCAN, and estCAN) are demonstrated in Figure 5; the frequency content decreases as the IMF index increases. The power of all IMFs shows a decreasing trend from the noCAN group to the subCAN group and further to the estCAN group. When examining each group's IMFs individually, the noCAN group exhibits a higher power in IMF\({}_{1}\), while the subCAN and estCAN groups show higher powers in IMF\({}_{3}\) and IMF\({}_{4}\). Figure 3: The analytic signal representation (ASR) of the first four intrinsic mode functions obtained after the empirical mode decomposition analysis of the RR interval signals for the three groups: noCAN—individuals with type 2 diabetes (T2 DM) without cardiovascular autonomic neuropathy (CAN); subCAN—individuals with T2 DM with subclinical CAN; and estCAN—with T2 DM with established CAN. Note: The zoomed plots of the estCAN group are presented in the top corner of each IMF plot. Figure 4: The second-order difference plots for the first four intrinsic mode functions (IMFs) obtained after empirical mode decomposition analysis of the RR interval signal for the three groups are as follows: noCAN—individuals with type 2 diabetes (T2 DM) without cardiovascular autonomic neuropathy (CAN); subCAN—individuals with T2 DM with subclinical CAN; and estCAN—individuals with T2 DM with established CAN. Note: The zoomed plots of the estCAN group are presented in the top corner of each IMF plot. Figure 5: The power spectral density (PSD) estimation for the first four intrinsic mode functions (IMFs) was obtained after the empirical mode decomposition analysis of the RR interval signals for the three groups: noCAN—individuals with type 2 diabetes (T2 DM) without cardiovascular autonomic neuropathy (CAN); subCAN—individuals with T2 DM with subclinical CAN; and estCAN—individuals with T2 DM with established CAN. Note: The plots have different scales on the y-axis for better visualization. All features derived from the four EMD-extracted IMF components exhibited significant differences between the extreme groups (noCAN and estCAN). When comparing the noCAN and subCAN groups, the third and fourth components were particularly effective in distinguishing between them.