Figure 7
From: Ramped pulse shapes are more efficient for cochlear implant stimulation in an animal model
Comparison of measured wave II thresholds and predicted thresholds from the lowpass filter model. (a–d) Input waveform (dashed, grey) and the filtered signal (solid, color) plotted on top for phase durations of (a) 25 µs (b) 50 µs and (c) 75 µs and (d) an interpulse gap of 2.9 ms with Rec (black), rampUP (green) rampDOWN (orange) and rampLONG (purple). Note the input level has an arbitrary unit. Only cathodic-first polarity is shown. (e,f) Threshold in charge (e) and current (f) from the mouse data (averaged across polarity and across mice) of wave II (blue circle) and model predictions (red cross) with 25 µs/phase and an interpulse gap of 10 µs for all four waveforms. n = 12. (g,h) Threshold in current (g) and charge (h) from mouse data (averaged across polarity and of 1st and 2nd phase, across mice) of wave II (blue circle) and model predictions (red cross) with 25 µs/phase and an interpulse gap of 2.9 ms for all four waveforms. n = 6. (i,j) Threshold in current (j) and charge (j) from the mouse data (averaged across polarity and across mice) of wave II (black; Rec, green; rampUP) and model predictions (grey; Rec, pink; rampUP) as a function of phase durations. n = 12 for 25 µs/phase and 50 µs/phase, n = 9 for 75 µs/phase. Error bars are SEM.
