Evaluation of binaural processing skills in pediatric cochlear implant users with incomplete partition Type-2

The aims of the present study were to evaluate binaural auditory skills in bimodal and bilateral pediatric cochlear implant (CI) users with incomplete partition type-II (IP-II) and to reveal the effect of IP-II on performance by comparing the results to pediatric CI users with normal cochlear morphology. Forty-one CI users (mean age 8.8 ± 1.9) were grouped as bimodal (BIM-IP) and bilateral (BIL-IP) users with IP-II; bimodal (BIM-N) and bilateral (BIL-N) users with normal cochlear anatomy. Speech perception in noise and sound localization skills were compared under two conditions; binaural (bilateral or bimodal) and monaural (first CI alone). BIM-IP and BIL-IP showed no performance difference in binaural tasks. BIM-N group showed remarkable poor performance in comparison to the groups of BIL-IP (p=.007), BIM-IP (p<.001) and BIL-N (p=.004) in terms of speech in noise skills. In sound localization abilities, similar significant differences were found between the group of BIM-N and the groups of BIL-IP (p=.001), BIM-IP (p<.001) and BIL-N (p=.004). All of groups showed statistically significant improvements in binaural condition on both of tasks (p<.05). We revealed that bilateral and bimodal pediatric CI users with IP-II benefitted from implantation as well as bilateral users with normal anatomy. Residual hearing potential differences might have explained the poor performance of bimodal users with normal cochlear morphology. To best of our knowledge, it is the first study to unveil binaural performance characteristics in children diagnosed with a specific inner ear malformation subgroup.