## 3 Results
### Implantation Recommendation Based on Single Hearing Loss Parameters  
Figure 9 shows scatterplots of individual hearing loss parameters that are grouped with regard to the predicted recommendation 'implant'/'no implant'. Each circle corresponds to one subject. To improve visibility, a small jitter was added to the positions along the x-axes. The largest differences were observed in IHCL parameters. In particular, the 'no implant' subjects appeared to cluster below 10 dB, whereas the majority of the 'implant' subjects appeared to cluster above 10 dB. 'No implant' subjects with large I\({}_{\text{s}}\) values existed, but large I\({}_{\text{s}}\) values were much more frequent in the 'implant' subject group. Differences between the groups were also observed for N\({}_{\text{fib}}\). In particular, 'no implant' subjects with few functional synapses were rare. In contrast, group effects of CGL parameters appeared to be negligible. A more formal approach towards thresholding-based distinction of 'implant' and 'no implant' subjects using single hearing loss parameters is reported in the subsequent paragraph. Figure 7: AN firing rates with regard to fiber index and time. The subject showed moderate to severe CS. (a) Normal hearing reference. (b) Unaided hearing, with hearing loss parameters (I\({}_{\text{r}}\), I\({}_{\text{s}}\), O\({}_{\text{f}}\), O\({}_{\text{s}}\), and N\({}_{\text{fib}}\)). (c) Sole acoustical amplification, with amplification parameters (I\({}_{\text{r}}\) and L\({}_{\text{s}}\)). (d) Sole electrical stimulation, with insertion depth of the CI. (e) Electrical stimulation combined with acoustic amplification, with insertion depth of the CI and amplification parameter L\({}_{\text{f}}\). LAP refers to the cost-adjusted loss of action potentials. Figure 10 shows the ROC curves for the distributions shown in Figure 9. The area under the curves (AUC) were largest for the IHCL parameters I\({}_{\text{f}}\) and I\({}_{\text{s}}\), i.e., 0.96 and 0.92, respectively, reflecting large differences between these parameters in the 'implant' and 'no implant' group. The cut-off thresholds of I\({}_{\text{f}}\) and I\({}_{\text{s}}\) were estimated as 10.1 dB and 11.9 dB, respectively, corresponding to approximately 69% and 75% of damaged IHCs, respectively. The asterisks and thresholds THR refer to cut-off threshold classification. The optima of THR were found by maximizing the perpendicular distance between the line of equality (dashed line) and the curve. The AUC was substantially smaller for the CS parameter, i.e., 0.57, and even smaller for the CGL parameters, i.e., 0.5 and 0.51. Figure 8: Bar charts of the cost-adjusted loss of action potentials (LAP). Four cases selected for detailed analysis, i.e., the cases reported in Figures 4–7. The bar charts (**a–d**) reflect for each of the four subjects personalized predictions of LAP with regard to the hearing prosthesis options. The shortest bars in each of (**a–d**) reflect the recommended hearing prosthesis option. Their colors are made distinct. The bar charts may be displayed to clinicians as personalized recommendation charts. They provide a concise overview of the prosthesis options, enabling quick judgement of absolute and relative bar heights. Unaided hearing (ua), sole acoustical amplification (ac), sole electrical stimulation (el), and electric stimulation combined with acoustical amplification (co). Figure 9: Hearing loss parameters \(\Psi=\{\text{I}_{\text{f}},\text{I}_{\text{s}},\text{O}_{\text{f}},\text{O}_{ \text{s}},\text{N}_{\text{fib}}\}\) with regard to implantation recommendation. Shown are (**a**) the flat and (**b**) sloping components of the loss of IHCs, i.e., I\({}_{\text{f}}\) and I\({}_{\text{s}}\); (**c**) the flat and (**d**) sloping components of the cochlear gain loss, i.e., O\({}_{\text{f}}\) and O\({}_{\text{s}}\); and (**e**) the average number of active fibers per IHC N\({}_{\text{fib}}\), reflecting cochlear synaptopathy.