Cochlear implant input-output responses can reverse polarity preference at high levels

Evidence

If neural degeneration had an effect on polarity sensitivity, we would expect the polarity effect to increase over time and to reach positive values when fibers are degenerated. This does not seem to be the case as the level difference between polarities rather tends to decrease right after deafening for several subjects and then to remain roughly constant. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2309 (#responds-to, via linked claim)

If neural degeneration had an effect on polarity sensitivity, we would expect the polarity effect to increase over time and to reach positive values when fibers are degenerated. This does not seem to be the case as the level difference between polarities rather tends to decrease right after deafening for several subjects and then to remain roughly constant. … Although the polarity effect is opposite in sign for the two species, it is interesting to note that its magnitude is similar for RPS and for TRI. For RPS-IPG, the smaller effect obtained psychophysically may be due to the fact that the delayed long, low-amplitude phase contributed to perception whereas it did not contribute to the neural responses recorded here. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2311 (#responds-to, via linked claim)

Categorization

• corroborated: 2 independent passages support this claim
• XREF: connects to: Anodic and cathodic cochlear implant stimulation differ in efficiency between humans and animals; Anodic current outperforms cathodic current in human cochlear implant users at suprathreshold levels — Dijk, Pim van, Physiology, Psychoacoustics and…, 2275; Never degeneration of neural peripheral processes may explain human anodic stimulation preference (+8 more)

Related

• Neural degeneration does not increase polarity sensitivity following deafening (similarity 0.92)
• Neural degeneration alone does not explain polarity sensitivity differences in cochlear implants (similarity 0.92)
• Pulse polarity effects on neural response differ significantly across pulse shapes (similarity 0.90)
• Species differences in final nerve geometry may drive the polarity reversal (similarity 0.90)
• Anodic current outperforms cathodic current in human cochlear implant users at suprathreshold levels (similarity 0.89)
• Neural degeneration over time does not flip cathodic-anodic stimulation efficiency in deafened guinea pigs (similarity 0.89)
• Never degeneration of neural peripheral processes may explain human anodic stimulation preference (similarity 0.89)
• Spiral ganglion degeneration does not progressively increase polarity sensitivity (similarity 0.89)
• Polarity effect magnitude is similar in guinea pigs and humans but reversed in sign (similarity 0.87)
• Anodic and cathodic cochlear implant stimulation differ in efficiency between humans and animals (similarity 0.87)
• Cochlear implant growth functions can behave non-monotonically near the top of the dynamic range (similarity 0.86)
• Anodic stimulation is more effective in human implant users but less effective in animals (similarity 0.86)
• Neural degeneration does not drive the anodic sensitivity seen in humans (similarity 0.86)
• Cathodic action potentials may block centrally at high current, explaining polarity effects (similarity 0.85)
• Nerve degeneration may flip polarity sensitivity toward anodic dominance in implant users. (similarity 0.84)

Broader Connections

• Neural degeneration alone does not explain polarity sensitivity differences in cochlear implants #responds-to (0.85) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2309
• Action potential blocking can make louder cochlear implant stimuli evoke smaller responses #qualifies (0.80)
• Neural degeneration does not increase polarity sensitivity following deafening #responds-to (0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2311