## 3 Results
### Correlation between Insertion Force and Friction Coefficient  
As shown above, insertion or rather pulling speed strongly influences insertion force and friction conditions. Interestingly, the speed-induced impact on these biomechanical properties was found to be similar (Figures 2b and 3b). Referring to this observation, a correlation analysis between the insertion force and the friction coefficient were performed to investigate a statistical dependence. In Figure 4, the correlation of insertion force and friction coefficient showing cluster formation, depending on different insertion speeds. Analyzing cluster location, these two biomechanical properties showing a non-linear course, depending on applied speeds. While the correlation of the insertion forces and friction coefficients, detected at the speed of 1.5 mm/s, showing cluster formation farthest from the zero point (Table S4), values  
Figure 3: Cochlear electrode insertion force at five different insertion speeds. (**a**) Insertion forces of the cochlear electrode recorded during the placement into a scale model. Mean insertion force curves over a 30 mm insertion depth (distance) are shown. Insertion speeds were set to 0.1 mm/s (black), 0.5 mm/s (blue), 1.0 mm/s (orange), 1.5 mm/s (green), 2.0 mm/s (violet). n = 10 independent repetitions were performed for each insertion speed. Lines represent the standard deviation. (**b**) Insertion forces of the cochlear electrode over a 30 mm distance. Insertion speeds are 0.1, 0.5, 1.0, 1.5, and 2.0 mm/s. n = 10 independent repetitions were performed for each insertion speed. Data are presented as mean with positive standard deviation (lines). _p_-values were calculated by One-Way ANOVA followed by [PERSON]’s Multiple Comparison post hoc test. * \(p\) < 0.05, *** \(p\) < 0.001 and n. s. = not significant compared to mean insertion force at 0.5 mm/s. detected at the speed of 2.0 mm/s are formatting a cluster closer to zero point (Table S5) followed by 1.0 mm/s (Table S3). Complementary, a speed of 0.5 mm/s leads to a cluster formation nearest to the zero point (Table S2). Especially, no cluster formation was found at a speed of 0.1 mm/s (Table S1). Correlation analysis between insertion force mean values and friction coefficient mean values (outlier excluded) reveal a correlation coefficient (r\({}_{\text{means}}\)) of 0.9. The \(p\)-value between the insertion force and the friction coefficient is 0.03 (Table 1). In summary, our data reveal a statistical dependence between electrode insertion force and friction behavior under the impact of applied speeds, shown by the pointed-out cluster formations and subsequent correlation coefficient (r\({}_{\text{means}}\)) of 0.9. Certain insertion \begin{table}
\begin{tabular}{c c c} \hline \hline
**Speed [mm/s]** & **Insertion Force [N]** & **Friction Coefficient** \\ \hline
**0.1** & 0.020 \(\pm\) 0.008 & 0.24 \(\pm\) 0.13 \\
**0.5** & 0.014 \(\pm\) 0.003 & 0.26 \(\pm\) 0.12 \\
**1.0** & 0.016 \(\pm\) 0.001 & 0.27 \(\pm\) 0.14 \\
**1.5** & 0.025 \(\pm\) 0.007 & 0.59 \(\pm\) 0.12 \\
**2.0** & 0.019 \(\pm\) 0.003 & 0.45 \(\pm\) 0.11 \\ \hline \hline
**Correlation coefficient (r\({}_{\text{means}}\))** & 0.9129 & \\ \(p\)**-value** (insertion force vs. friction coefficient) & 0.03 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Insertion force and friction coefficient of electrode array generated at five different speeds and calculated correlation coefficient. Mean values with standard deviation are listed. Correlation coefficient r\({}_{\text{means}}\) and \(p\)-value were calculated between insertion force and friction coefficient at 0.1 mm/s (n = 9, outlier excluded), 0.5 mm/s (n = 7), 1.0 mm/s (n = 10), 1.5 mm/s (n = 10) and 2.0 mm/s (n = 10). Figure 4: Correlation dot plot showing relationship between insertion force and friction coefficient. Small dots represent the average values of each individual measurement of insertion force and friction coefficient at different speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s).