Usefulness of MRI and EABR Testing for Predicting CI Outcomes Immediately After Cochlear Implantation in Cases With Cochlear Nerve Deficiency.

OBJECTIVE

Cochlear nerve deficiency (CND) is often associated with poor cochlear implant (CI) outcomes, and patients with CND may be candidates for auditory brainstem implantation (ABI). The purpose of this study was to identify investigations which predict CI outcomes immediately after cochlear implantation to recommend ABI within the critical period of auditory development when cochlear implantation precedes ABI.

STUDY DESIGN

Retrospective case review.

SETTING

Cochlear implant centers at tertiary referral hospitals.

PATIENTS

Nineteen children with CND who underwent cochlear implantation and intraoperative electrically evoked auditory brainstem response (EABR) testing.

INTERVENTIONS

Diagnostic and therapeutic.

MAIN OUTCOME MEASURES

Preoperative MRI and intraoperative EABR were used to evaluate relative diameter of the vestibulocochlear nerve (CN8) compared to the facial nerve (CN7) at the cerebellopontine angle and presence of evoked wave Vs (eVs) with typical latency, respectively. Correlation between 2-year postoperative categories of auditory performance (CAP) scores and results of MRI and EABR were evaluated.

RESULTS

Each classification using MRI or EABR was significantly associated with the CI outcomes. Combination of the MRI and EABR results allowed better discrimination between poor CI users and moderate to good CI users than either examination used separately. All children in "CN7 > CN8/negative eV" showed ≤3, while all in "CN7 ≤ CN8/positive eV" achieved ≥3 in the postoperative CAP score.

CONCLUSIONS

Combination of MRI and EABR results allows prediction of CI outcomes immediately after cochlear implantation. This should facilitate management decision making for auditory implantation in children with CND.