Electrode deactivation in post‐meningitic cochlear implant recipients

Abstract

Objective:To assess the frequency of electrode deactivation over time in post meningitic cochlear implant (CI) recipients Study Design:Retrospective chart review Methods:A retrospective chart review of all post meningitic cochlear implant recipients at New York University from 1984 2008 was conducted. Patients with more than 2 years of follow up programming and speech perception data were included. Percent of active electrodes was calculated relative to maximum number of programmable electrodes. Frequency and pattern of electrode deactivation over time was analyzed and compared to published data on non meningitic CI patients Results:A total of 14 patients with 17 implanted ears were included. Length of follow up ranged from 2 25 years (average 7.3). A total of 9 (53%) ears experienced a reduction in active electrodes. Of these, 3 patients had deactivation of 1 electrode, 4 patients lost 2 electrodes, and the remaining 2 patients had had 5 and 6 electrodes deactivated, respectively. All patients except one had a minimum of 11 active electrodes at all times. Rate of deactivation over time was variable with loss of electrodes occurring up to 4 years post operatively. Three of the 9 ears with electrode deactivation received Nucleus 24 double array devices. Loss of electrodes was not correlated with a decline in speech perception, age at implantation or duration of deafness. There was one device failure. Conclusions:Deactivation of CI electrodes over time is common in post meningitic CI recipients (53%) and exceeds rates from non meningitic patients (1%.). Although electrode deactivation is multi factorial, anatomic considerations, such as ongoing compromise of the electrode neural interface by labyrinthitis ossificans, may contribute to deactivation in both the short and long term.A retrospective chart review of all post meningitic CI recipients at New York University from 1984 2008 was conducted. Patients with more than 2 years of follow up programming and speech perception data were included. Those with cochlear ossification resulting from processes other than meningitis, including otosclerosis, chronic otitis media, ototoxic agents, trauma or idiopathic processes were excluded. Maximum number of programmable electrodes were determined by type of device and number of electrodes inserted during implantation. Electrodes were deactivated for subjective complaints or for objective evidence of electrode malfunction. Number of deactivated electrodes following initial CI stimulation was recorded.The present study examined CI electrode deactivation over time in post meningitic CI recipients and found 9 of 17 ears (53%) with at least 1 deactivated electrode. This rate is higher than that found by previous authors in non meningitic populations. Zeitler et al (2008) found that 1% of CI recipients undergo 1 or more electrode deactivations following initial stimulation. Loss of 5 or more electrodes was correlated with device failure. 5 Carlson et al. (2010) found slightly higher rates 9% of patients in their study exp...

3D printed biomimetic cochleae and machine learning co-modelling provides clinical informatics for cochlear implant patients

“…Clinically, a CI electrode array is inserted into the scala tympani, one of the three cochlear ducts 13 (Fig.1a). As a coarse-grained approach to replicate the electroanatomical features of a CI implanted cochlea, we approximate the cochlea as one ensemble spiral cavity with continuously narrowing diameter, and omit the inner soft-tissue membranous structures of a cochlea, such as the basilar membrane and Reissner’s membrane.…”

“…We anticipate that this unique capability might enable long-term monitoring of patients’ cochlear health after CI implantation. For example, it has been suggested that the electrical properties of cochlear tissues can be affected by a variety of physiological and otologic diseases, such as post-implantation fibrosis and neo-ossification, post-operative electrode extrusion and medications 13,49,50 . Hence, the cochlear tissue resistivities informed by patients’ EFI profiles might be used as a diagnostic indicator to detect early abnormalities, without resorting to ionizing radiation of patients (which particularly should be avoided in children).…”

“…In particular, cochlear anatomy (in terms of size and shape) is variable, with different levels of volumetric conductance of cochlear fluids affecting the intracochlear voltage that results from stimulation. Moreover, pathophysiological conditions could affect electrical conductivity of the cochlear bony walls, and thus CI induced electric fields 13 . As the cochlea is embedded deep inside the temporal bone and has a complex anatomy, electrical characteristics are difficult to quantify in a living subject.…”

Predictors of Postoperative Electrode Deactivation Among Adult Cochlear Implantees

“…Much of this work has been performed in pediatric and mixed pediatric and adult populations (14). Furthermore, the largest analysis of patients with electrode deactivation for any reason was done in 1999 with 100 patients with Cochlear Nucleus CIs having at least 1 deactivated electrode (13).…”