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Electrocochleographic Patterns Predicting Increased Impedances and Hearing Loss after Cochlear Implantation
Christofer Bester1,2, Adrian Dalbert1,3,2, Aaron Collins1
1Department of Surgery, The University of Melbourne, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia.
Ear and Hearing
|December 23, 2022
Summary
Cochlear implant electrocochleography patterns reveal that apical-peak (AP) responses correlate with lower impedances and better hearing preservation. Mid-peak (MP) and apical-to-mid-peak (AP-MP) patterns are linked to higher impedances and poorer hearing outcomes.
Area of Science:
- Otorhinolaryngology
- Neuroscience
- Biomedical Engineering
Background:
- Electrococleography (ECoG) patterns post-cochlear implantation (CI) vary.
- The clinical significance of these ECoG patterns remains unclear.
- Understanding these patterns may improve CI outcomes.
Purpose of the Study:
- To correlate peri- and postoperative electrocochleographic patterns with impedance measurements.
- To assess the relationship between ECoG patterns and hearing preservation after CI.
- To investigate the implications of different ECoG response locations along the electrode array.
Main Methods:
- Prospective study of 39 subjects with residual low-frequency hearing receiving slim-straight CI electrode arrays.
- Intracochlear electrocochleography and four-point impedance measurements taken perioperatively and at 3 months post-surgery.
- Hearing preservation assessed at 3 months post-surgery.
Main Results:
- Apical-peak (AP) ECoG patterns (n=22) observed in 56% of subjects perioperatively.
- Mid-peak (MP) patterns (n=17) observed in 44%, with some shifting to AP-MP patterns by 3 months.
- AP patterns showed significantly lower impedances (222 Ω) and better hearing preservation (13 dB loss) compared to MP (295 Ω, 28 dB loss) and AP-MP (234 Ω, 35 dB loss) patterns at 3 months.
Conclusions:
- MP and AP-MP ECoG patterns are associated with higher intracochlear impedances.
- These higher impedances suggest increased intracochlear fibrosis.
- AP response patterns correlate with better hearing preservation post-cochlear implantation.
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