Auditory Brainstem Implantation (Abi) in Prelingually Deaf Children

Objective: To demonstrate the effectiveness of auditory brainstem implantation even in very small children (ABI) with prelingual deafness for restoration of hearing and speech.

Methods: A 12 channel ABI system, which has proofen effectiveness and safety in neurofibromatosis patients since the past 16 years was used for implantation. The pediatric ABI program started in 2009 at different centers. Meanwhile 21 implantations in 20 children, 8 male and 12 female were performed by the first author. One child had a successful revision surgery after a fall on the implant side and breakdown of the system. The mean age was 3.5 years, median 3. The youngest was 1.25, the oldest 6.5 years. Surgery was performed in supine position using a retrosigmoid approach and multimodal neuromonitoring. In all cases intraoperative E-BERA were recorded.

Results: The preoperative evaluation with high resolution MRI and CT revealed in 13 children aplasia of the cochlear nerve. The others had cochlear dys-aplasia together with hypoplasia of the 8th nerve or syndromal lesions like Goldenhar Syndrome. In most cases surgery was difficult due to complete or partial occlusion of the lateral recess of the forth ventricle. In 75% branches of the AICA or the vessel itself were crossing the implant site and had to be dissected. In every case the electrode paddle was small enough to fit properly into the recess. E-BERA recordings could be derived in each case. There were no neurologic complications and only minor surgical complications as subcutaneous CSF leaks in 4 children. All children in whom the device was activated so far regained sound awareness and insisted using the implant all day. 4 of them already regained word recognition and Ling sound detection. 58.8% had CAP scores better than 3, 23.5% equal to 3 and 17.6% below 3. Three started to use speech and one is even bilingual.

Conclusion: ABI is a safe and successful surgical procedure for restoration of hearing and speach in prelingual deaf children. Precious time of plasticity of the auditory pathways should be used as early and intensively as possible. Therefore in doubtful CI candidates ABI should be the primary indication.