Pulse shapes require measurably different current levels to evoke equal neural responses
Evidence
The difference in level between SYM-C and the various asymmetric pulse shapes RPS-C, RPS-IPG-C and TRI-C when they all produced the same response amplitude was determined. The response amplitude at which the pulse shapes were compared was equal to 50 % of the maximum amplitude of SYM-C. Given there was no effect of duration of deafness on the magnitude of these effects, the data were averaged across sessions for each animal and analyzed in a one-way repeated measures ANOVA. The star symbols in Fig. 4d show the mean across animal subjects. The effect of pulse shape was highly significant (F(3,18) = 22.76, p < 0.001). RPS-IPG required 2.2 dB less current than SYM (p < 0.05) while TRI required 2.7 dB more. There was no significant difference between SYM and RPS. For comparison, the filled symbols show the effect of pulse shape as observed in human CI listeners. For these data, however, the level difference was obtained using loudness balancing between anodic pulse shapes. Here again, the magnitude of the effect of pulse shape is similar in both species. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2320
Categorization
Category: Factual Claims
Related
- Asymmetric pulse shapes with long delayed phases are more electrically efficient than symmetric pulses (similarity 0.90)
- Asymmetric pulse shapes amplify polarity sensitivity beyond symmetric pulses (similarity 0.89)
- Pseudomonophasic pulses with a gap need less current than symmetric pulses (similarity 0.88)
- Pulse polarity effects on neural response differ significantly across pulse shapes (similarity 0.87)
- Pulse-shape efficiency ordering holds across animal and human studies (similarity 0.86)
- Pulse shape strongly determines cochlear implant stimulation current efficiency (similarity 0.84)
- Cathodic current pulses produce larger neural responses than anodic ones (similarity 0.83)
- Pulse polarity differences translate to roughly 30 dB of acoustic hearing range (similarity 0.83)
- At suprathreshold levels louder electrical pulses can sometimes evoke smaller neural responses (similarity 0.83)
- Cathodic pulses evoke larger inferior colliculus responses than anodic pulses (similarity 0.82)
- Polarity effect magnitude is similar across species even though its direction is reversed. (similarity 0.81)
- Polarity effect magnitude is similar in guinea pigs and humans but reversed in sign (similarity 0.81)
- Cathodic pulse superiority holds across all four tested pulse shapes (similarity 0.81)
- Anodic stimulation exceeds cathodic at suprathreshold levels in human CI users (similarity 0.80)
- Some cathodic responses decrease as current rises, growing non-monotonically (similarity 0.79)
Broader Connections
- Neural signals encode auditory information through spike timing patterns
#expands(0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 566