## 3 Results
### Implantation Recommendation Based on Single Hearing Loss Parameters
Figure 11 shows the optimal cut-off threshold of \(\mathrm{I_{f}}\) color-coded with respect to amplification cost \(\lambda_{\mathrm{amp}}\) and implantation cost \(\lambda_{\mathrm{imp}}\). The implantation cost influenced the threshold more strongly than the amplification cost. Two operating points are shown (yellow asterisks). One was at \(\lambda_{\mathrm{amp}}=0.01\) and \(\lambda_{\mathrm{amp}}=0.05\), where \(\mathrm{THR}=10.1\) dB. The cost parameters of this operating point have been used throughout the manuscript. For comparison, the other operating point is shown at \(\lambda_{\mathrm{amp}}=\lambda_{\mathrm{imp}}=0\), where \(\mathrm{THR}=4.5\) dB. Figure 12 shows scatter plots of the minimum LAP score achieved with and without implantation. The dashed lines are the lines of equality, which were the boundary for the 'implant'/'no implant' decision. The IHCL was color-coded. Each dot reflects one subject. Only subjects with IHCL are reported. The plots show distinct types of hearing loss, i.e., (a) IHCL, (b) CGL + IHCL, (c) IHCL + CS, and (d) CGL + IHCL + CS. A clear relationship between the \(\mathrm{I_{f}}\) and the position across the coordinate systems was observed. In particular, subjects with a small \(\mathrm{I_{f}}\) tended to lie to the left of the line of equality, and vice versa. Two distinct patterns were observed in the plots with and without CGL, i.e., for smallest \(\mathrm{I_{f}}\), subjects with CGL were closer to the line of equality than subjects without CGL, which reflects that the lowest possible LAP was larger for CGL subjects' than for subjects without CGL. Figure 10: ROC curves regarding binary prediction of implantation recommendation. The used single predictors are as follows: (a) the flat component of the IHC loss (\(\mathrm{I_{f}}\)), (b) the sloping component of the IHC loss (\(\mathrm{I_{s}}\)), (c) the flat component of the cochlear gain loss (\(\mathrm{O_{f}}\)), (d) the sloping component of the cochlear gain loss (\(\mathrm{O_{s}}\)), and (e) the number of active fibers attached to each IHC (\(\mathrm{N_{fib}}\)). Yellow asterisks and cut-off thresholds THR were obtained at maximal perpendicular distances of the ROC curves to the lines of equality. Figure 13 shows scatter plots of the minimum LAP score achieved with and without implantation. The dashed lines are the lines of equality. The number of functional synapses per IHC is color-coded. Each dot reflects one subject. Only subjects with CS are reported. The plots show distinct types of hearing loss, i.e., (a) CS, (b) CGL + CS, (c) IHCL + CS, and (d) CGL + IHCL + CS. A relationship between the degree of CS and the position across the coordinate systems was observed. In particular, subjects with mild CS, i.e., higher number of fibers, tended to lie on the left side of the line of equality, and vice versa. This trend appears to be fuzzier with IHCL (bottom row), as some subjects with low CS were located to the right of the line of equality. These were supposedly subjects with severe IHCL. As in Figure 12, two distinct patterns were observed in the plots with and without CGL. In contrast to what was observed for IHCL and CS, no clear relationship between the degree of CS and the position across the coordinate system was observed (not shown here).