Abstract: Objective To investigate the influence of unilateral cochlear implantation on bilateral residual hearing. Methods A total of 29 children with severe to profound hearing loss participated in this study and were divided into two groups on the basis of pre-implantation computed tomography findings: Group A, with large vestibular aqueduct syndrome, and Group B, without large vestibular aqueduct syndrome. Pure tone audiometry and behavioral audiometry were performed pre- and post-operatively. Thresholds at 250; 500; 1 000; and 2 000 Hz were analyzed. Results Bilateral residual hearing,mainly in the low frequency region, was observed at different frequencies before and after cochlear implantation. The retention rate was decreased with the increase of frequency, and the retention rate at 2000Hz was significantly lower than that of the other frequencies. The pre-operative retention rate was statistically significant with the post-operative retention rate, but the post-operative retention rate of each time node had no statistically significant difference(Wald χ2=3.384, P=0.336), the residual hearing retention rate in each time node in the implanted ear and the non-implanted ear was statistically significant(Wald χ2=0.031, P=0.002), and there was no significant difference in residual hearing between Groups A and B. Conclusion Partial residual hearing may be preserved after cochlear implantation in pediatric patients with severe to profound hearing loss. Residual hearing at lower frequencies was less affected than that at higher frequencies. After a prolonged period following cochlear implantation, residual hearing remains relatively stable. Unilateral implantation had little effect on residual hearing in the non-implanted ear. Residual hearing in children with large vestibular aqueduct syndrome can fluctuate in the short term after cochlear implantation.

Key words: Large vestibular aqueduct syndrome, Cochlear implantation, Residual hearing