Cochlear Implantation in Pediatrics: The Effect of Cochlear Coverage

The effect of insertion depth and position of cochlear implant (CI) electrode arrays on speech perception remains unclear. This study aimed to determine the relationship between cochlear coverage and speech performance in children with prelingual hearing loss with CI. Pure tone audiometry (PTA) and speech audiometry, including speech reception threshold (SRT) using spondee words and speech discrimination score (SDS) using phonetically balanced monosyllabic words, were tested. The Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scales were also used. Thirty-one ears were implanted with the FLEX 28 electrode array, and 54 with the FORM 24 were included in the current study. For the studied ear, the mean cochlear duct length was 30.82 +/- 2.24 mm; the mean cochlear coverage was 82.78 +/- 7.49%. Cochlear coverage was a significant negative predictor for the mean pure tone threshold across frequecnies of 0.5, 1, 2, and 4 kHz (PTA4) (p = 0.019). Cochlear coverage was a significant positive predictor of SDS (p = 0.009). In children with cochlear coverage >= 82.78%, SDS was significantly better than in those with coverage < 82.78% (p = 0.04). Cochlear coverage was not a significant predictor of the SRT, CAP, or SIR. In conclusion, the cochlear coverage of the CI electrode array has an impact on the users' SDS. Further long-term studies with larger sample sizes should be conducted to address the most critical factors affecting CI recipients' outcomes.