Fig. 4

Recording lead migration affects features of the ECAP component in ESR. A Diagram of implanted leads with recording lead shifting rostrally to three predetermined locations. Circular markers located left of the first lead indicate stimulating contacts 7 (yellow, anodic) and 8 (red, cathodic). Contact 11 (white square) located on the second lead indicates the recording channel that was used for the reported ECAP component quantifications. The four different recording locations were defined as location ‘I’, ‘II’, ‘III’, and ‘IV’. B Median representative waveform out of 300 recorded trials with the ESR following the end of the stimulation artifact. Latency was measured as the time between the end of the stimulation artifact and the maximum negative ECAP component peak. C Median waveform from 300 trials recorded in an animal at all four locations with a stimulation amplitude of 2 mA. Here, 0 ms indicates the end of stimulation. D Averaged latency across subjects (n = 4) showing the latency increased as the recording lead was shifted rostrally. ECAP latency increased significantly as the recording electrode was shifted rostrally for all lead configurations (p < 0.001). E Percent changes to ECAP strength (shown as area-under-the-curve, AUC) are plotted averaged across all subjects (n = 4). As the distance between the stimulating and recording contacts increased, the percent decrease in the ECAP magnitude compared to the magnitude at the initial position, I, increased (p < 0.001 tested against null hypothesis of no change in ECAP magnitude)