Long-term Outcome of Cochlear Nerve Deficiency Patients after Cochlear Implantation and its Predictive Model Based on Machine Learning

Introduction Cochlear nerve deficiency (CND) is a condition in which the cochlear nerve is thin or absent, often associated with inner ear malformations (IEM), and the outcome of cochlear implantation (CI) varies greatly. We aimed to assess the postoperative development of auditory and speech perception in CND patients with modiolar deficiency-type malformations after 3-year follow-up.

Methods Sixty-seven CND patients with modiolar deficiency-type malformations and seventy CND patients with normal cochlea who underwent CI surgery were retrospectively reviewed. Modiolar deficiency-type malformations included common cavity (CC), cochlear hypoplasia (CH, including CH-I and CH-II) and incomplete partition-I (IP-I). Categorical auditory performance (CAP) and the infant-toddler meaningful auditory integration scale (IT-MAIS) or MAIS were used to assess auditory ability.

Results All patients demonstrated improvements in auditory ability and speech intelligibility after CI. For CND patients with modiolar deficiency-type malformations,there were no significant differences in CI outcomes at any time point according to the malformation type. The number of nerve bundles within the internal auditory canal (IAC) showed significant differences at 12, 24 and 36 months after CI (p<0.05). Patients with one nerve bundle had relatively poor CI outcomes.

Conclusions  Our results identified that a greater number of nerve bundles and a larger VCN area were associated with better CI outcomes. The number of nerve bundles and VCN area can predict CI outcomes in patients with CND. These findings can help surgeons in selecting the side for CI and provide reasonable expectations for the outcomes of CI surgery.

Publication History

Article published online:
12 May 2023