Matched Cohort Comparison Indicates Superiority of Precurved Electrode Arrays

Abstract

Objective: Characterize differences in adult cochlear implant outcomes and programming parameters for a straight (CI422/522) and a precurved (CI532) electrode array. Setting: Cochlear implant (CI) program at a tertiary otologic center. Patients: Fifty-eight adults were included in the study; 29 were implanted with CI422 or CI522 and 29 were implanted with CI532. Each CI532 recipient was matched to a CI422/522 recipient in terms of age and preoperative hearing thresholds for comparison purposes. Main Outcome Measures: Consonant-Nucleus-Consonant (CNC) words, AzBio sentences, residual audiometric thresholds, and Speech Spatial Qualities (SSQ) questionnaire collected 6 months postoperatively were used to characterize outcomes. Pulse duration, maxima, impedances, and overall charge measurements were used to characterize programming parameters. Results: Postoperative unaided low frequency pure-tone average (LFPTA) was significantly better for the CI532 group. CNC scores were significantly better for the CI532 group. Impedances and pulse duration were significantly lower for the CI532 group, but there was no difference in overall charge between the groups. Conclusion: The CI532 group showed either similar or statistically superior results on all measures when compared with the CI422/522 suggesting that the CI532 electrode may be an advantageous substitute for the CI522.

Outcomes for a clinically representative cohort of hearing-impaired adults using the Nucleus® CI532 cochlear implant

“…Mean low frequency shifts were considerably better compared to the older CI512 device [4,29] and in line with values reported for lateral wall and mid-scala electrode arrays [10,19,38,39]. This is in agreement with the recent data reported by Holder et al [10] showing slightly better hearing preservation for the CI532 compared to a matched group of users of the Cochlear CI422 and 522 straight electrode arrays. A large variability in the speech recognition results was observed, even though the data set represented a group of subjects with the same electrode array positioned within the scala tympani.…”

“…In comparison to other hearing preservation data reported for the CI532, median losses of less than 30 dB HL for a low frequency average of 250 and 500 Hz were larger than those reported in the literature [9-11, 36, 37]. Mean low frequency shifts were considerably better compared to the older CI512 device [4,29] and in line with values reported for lateral wall and mid-scala electrode arrays [10,19,38,39]. This is in agreement with the recent data reported by Holder et al [10] showing slightly better hearing preservation for the CI532 compared to a matched group of users of the Cochlear CI422 and 522 straight electrode arrays.…”

“…Previous studies using the Slim Modiolar electrode array showed consistent perimodiolar placement and scala tympani insertions in at least 87% of the patients assessed with imaging [1][2][3]. They reported hearing preservation is better than with older perimodiolar and straight designs, but possibly not as good as hybrid or electroacoustic devices that are specifically designed for hearing preservation [2,3,[9][10][11].…”

“…It is thinner, less stiff and is 60% of the volume of Cochlear's previous precurved Contour Advance® array used in the Nucleus CI512; this reduces insertion forces and the potential for trauma [21,22]. Due its reduced size, it can be inserted through the round window, which has been shown to be beneficial for ensuring initial scala tympani placement and results in better hearing preservation and improved speech perception scores [2,10,20]. Previously reported gains in postoperative speech perception and quality of life measures with the Nucleus CI532 are in line with those reported for other devices and are potentially better than with earlier Cochlear devices [3,10,23].…”

Simpler and effective radiological evaluations for modiolar proximity of a slim modiolar cochlear implant electrode

“…The new slim modiolar electrodes (e.g., CI532 or CI632) combine the slim electrode diameter of slim-straight electrodes and the modiolus-hugging feature of conventional perimodiolar electrodes. This new commercially available slim modiolar electrode ensures better modiolar proximity 1 , 2 and provides substantial preservation of residual hearing 3 – 11 . For modiolar hugging electrodes, better auditory performance depends on the final intracochlear positioning of the electrode array, such as scalar location and modiolar proximity 12 , 13 .…”