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Author Spotlight: Advancements in Impedance Monitoring for Cochlear Implant Surgery
Published on: August 4, 2023
Impedance, neural response telemetry, and speech perception outcomes after reimplantation of cochlear implants in
Catherine S Birman1, Halit Sanli, William P R Gibson
1*Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney; †Sydney Children's Hospital Network (Children's Hospital at Westmead); ‡The Sydney Cochlear Implant Centre; §Emeritus Professor, Sydney Medical School, University of Sydney; and ∥Department of Linguistics, Faculty of Human Sciences, Macquarie University, Sydney, New South Wales, Australia.
Insights
Pediatric cochlear implant explant-reimplant procedures result in higher impedance levels, particularly with the Contour array. Auditory perception typically recovers within six months post-reimplantation.
Area of Science:
- Otolaryngology
- Biomedical Engineering
- Pediatric Audiology
Background:
- Cochlear implants are vital for pediatric hearing restoration.
- Device explantation and reimplantation are necessary in some cases.
- Understanding the impact of reimplantation on device performance and hearing is crucial.
Purpose of the Study:
- To compare impedance levels, neural response telemetry (NRT), and auditory perception in pediatric patients undergoing cochlear implant explant-reimplant surgery.
- To evaluate outcomes associated with different cochlear implant electrode arrays (Contour vs. straight).
Main Methods:
- Retrospective case review of pediatric patients (0-16 years) who underwent cochlear implant explant-reimplant.
- Analysis of impedance, NRT, and auditory perception at multiple time points post-initial implant and reimplantation.
- Comparison between initial implants and explant-reimplant procedures.
Main Results:
- Explant-reimplant with the Cochlear Contour array showed significantly higher impedance levels compared to initial implants.
- The Cochlear straight array also demonstrated marginally significant increases in impedance post-reimplantation.
- Infection correlated with greater impedance increases in the Contour reimplant group.
- Neural response telemetry (NRT) showed a non-significant trend towards increase post-reimplantation.
- Auditory perception recovered to pre-explant levels within 6 months in 61% of children.
Conclusions:
- Cochlear implant explant-reimplant procedures lead to persistently elevated impedance levels, especially with the Contour array.
- The straight array also shows increased impedance, though to a lesser extent.
- While impedance is affected, auditory outcomes show recovery in a majority of pediatric cases.
Objective:
To compare mean impedance levels, neural response telemetry (NRT), and auditory perception after initial and explant-reimplant pediatric cochlear implants.
Study Design:
Retrospective case review.
Setting:
Tertiary referral hospital and cochlear implant program.
Patients:
Children 0 to 16 years inclusive who have undergone explant-reimplant of their cochlear implant.
Intervention:
Impedance levels, NRT, and speech perception performance.
Main Outcome Measures:
Impedance, NRT, and auditory perception at switch on, 3 months, 12 months, 3 years, and 5 years after initial cochlear implant and reimplantation.
Results:
The explant-reimplant group receiving Cochlear contour array had significantly (p < 0.001) raised impedance at switch on, 3 months, 12 months, and 3 years, compared with their initial implant. The explant-reimplant group receiving Cochlear straight array had marginally significant (p = 0.045) raised impedance at switch on, 3 months, 12 months, and 3 and 5 years. Infection was associated with greater increases in impedance in the reimplant Contour group. NRT was increased in the explant-reimplant group but not significantly (p = 0.06). Auditory perception returned to preexplant levels within 6 months in 61% of children.
Conclusion:
Impedance is higher after explant-reimplant and remains increased for years after explant-reimplant with Cochlear contour and to a lesser degree the straight array device.
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