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Evaluation of focused multipolar stimulation for cochlear implants: a preclinical safety study
Robert K Shepherd1,2, Andrew K Wise1,2, Ya Lang Enke3
1The Bionics Institute, East Melbourne 3002, Australia.
Journal of Neural Engineering
|June 14, 2017
Summary
Focused multipolar (FMP) stimulation for cochlear implants (CIs) is safe for long-term use. This study found FMP stimulation did not harm neural function or electrode integrity in animal models, supporting its clinical use.
Area of Science:
- Otoacoustic emissions and auditory evoked potentials
- Neuroscience and neurobiology
- Biomaterials and implantable devices
Background:
- Cochlear implants (CIs) face limitations in stimulation channels due to cochlear conductivity.
- Focused multipolar (FMP) stimulation aims to improve speech perception by reducing channel interaction.
- Concerns exist regarding the long-term safety of complex FMP stimulation protocols.
Purpose of the Study:
- To evaluate the long-term safety of intracochlear FMP stimulation.
- To assess the impact of FMP stimulation on neural function and electrode integrity.
- To investigate potential adverse effects in a preclinical model of deafness.
Main Methods:
- Bilateral implantation of electrode arrays in deafened cats.
- Continuous unilateral FMP stimulation for up to 182 days.
- Monitoring of electrode impedance, ECAPs, EABRs, and histological analysis.
Main Results:
- No significant differences in electrode impedance or neural thresholds (ECAP, EABR) between stimulated and control cochleae.
- Chronic FMP stimulation did not affect spiral ganglion neuron (SGN) survival.
- A small, statistically significant increase in inflammatory response was observed in stimulated cochleae, with no platinum corrosion.
Conclusions:
- Long-term intracochlear FMP stimulation is safe, with no adverse effects on neural thresholds or SGN survival.
- FMP stimulation does not compromise electrode integrity.
- Findings support the safe clinical application of FMP stimulation strategies in cochlear implants.
