Comparison of long-term speech and impedance outcome of cochlear implantation in prelingual deaf paediatric patients between cochleostomy and round window insertion.

Objectives: To compare long-term impedance and functional outcomes between the round window and cochleostomy approaches in cochlear implantation patients.

Methods: Ninety prelingually deafened children who underwent unilateral cochlear implantation participated in this prospective observational study. Participants were divided into round window and cochleostomy groups. Impedance and speech perception were assessed at switch-on, and at 6, 12, and 24 months.

Results: Impedance was similar between groups except at switch-on, where the cochleostomy group had higher basal turn impedance (2.41 vs 1.32 kΩ). At 24 months, speech outcomes were as follows: word recognition in quiet (round window 96.2 per cent, cochleostomy 95.3 per cent), word recognition in noise (round window 88.8 per cent, cochleostomy 87.4 per cent), sentence recognition (round window 78.2 per cent, cochleostomy 77.3 per cent), and vowel recognition (round window 91.2 per cent, cochleostomy 90.1 per cent).

Conclusion: No significant differences in impedance or speech outcomes were found between the round window and cochleostomy groups, except for higher basal-turn impedance at switch-on in the cochleostomy group, indicating more fibrosis.