Fig. 2

Comparison of the AGF slope values between the AP-ECAP and FM-ECAP under different FSANs. There was no significant difference in the slope values of the AGF between the AP-ECAP and FM-ECAP under the “normal” FSAN, and the slope values were similar across the electrodes within groups (a). However, there was a significant difference in the slopes of the AGF between electrodes 1 and 2 and electrodes 3 and 4 in the AP-ECAP under the “abnormal” FSAN (b). AGF: amplitude growth function, AP-ECAP: alternating polarity electrically evoked compound action potential, FM-ECAP: forward-masking subtraction electrically evoked compound action potential, FSANs: functional states of the auditory nerve, A: AP-ECAP, F: FM-ECAP, E1-E4: electrode 1–electrode 4, *p < 0.01, Kruskal–Wallis by ranks version of one-way ANOVA, followed by Dunn’s method. Data represent the mean ± SEM