Detecting and managing partial shorts in Cochlear implants: A validation of scalp surface potential testing.


Change log
Abstract

OBJECTIVE: To investigate the value of scalp surface potentials to identify and manage partial short circuits to ground in cochlear implant electrodes. DESIGN: A retrospective review of patients with suspected partial short circuits. MAIN OUTCOME MEASURE: Electrical output of individual electrodes was measured using scalp surface potentials for patients reporting a change in hearing function. Electrical output was compared to functional performance and impedance measurements to determine if devices with suspected partial short circuits were experiencing a decrease in performance as a result of reduced electrical output. Electrical output was checked in an artificial cochlea for two implants following explant surgery to confirm scalp surface potential results. RESULTS: All patients with suspected partial short circuits (n = 49) had reduced electrical output, a drop in impedances to approximately ½ of previously stable measurements or to below 2 kΩ, an atypical electrical field measurement (EFI) and a decline in hearing function. Only devices with an atypical EFI showed reduced electrical output. Results of scalp based surface potentials could be replicated in an artificial cochlea following explantation of the device. All explant reports received to date (n = 42) have confirmed partial short circuits, with an additional four devices failing integrity tests. CONCLUSION: Surface potential measurements can detect partial shorts and had 100% correlation with atypical EFI measurements, which are characteristic of a partial short to ground in this device. Surface potentials can help determine the degree to which the electrode array is affected, particularly when behavioural testing is limited or not possible.

Description

Funder: Advanced Bionics


Funder: Anatomical Society; Id: http://dx.doi.org/10.13039/100012070


Funder: Cambridge Hearing Trust


Funder: Cochlear; Id: http://dx.doi.org/10.13039/100008626


Funder: MED‐EL Medical Electronics


Funder: MRC Confidence in Concept Fund


Funder: Oticon Medical; Id: http://dx.doi.org/10.13039/501100020045

Keywords
Cochlear implant, SCINSEVs, V1 fault, electrical field imaging, electrode fault, partial short circuit, surface potential, ultra V1, Cochlea, Cochlear Implantation, Cochlear Implants, Electric Impedance, Hearing Tests, Humans, Scalp
Journal Title
Clin Otolaryngol
Conference Name
Journal ISSN
1749-4478
1749-4486
Volume Title
Publisher
Wiley