Auditory Brainstem Implants
For nearly three decades, surgical rehabilitation of severe to profound hearing loss has been successfully accomplished using cochlear implantation. An array inserted in the cochlea can send electrical signals generated by a sound processor to the central auditory pathways. The sound processor encodes sound and speech and sends it using electromagnetic signaling to the implanted device. At University Hospitals Rainbow Babies & Children's Hospital and UH Cleveland Medical Center, the cochlear implant team has implanted over 1,000 patients since its inception. However, this technology relies on the anatomical presence of the hearing organ or cochlea; the part of the inner ear that hears.
In rare or unusual circumstances such as absent development of the cochlea or the auditory nerve, cochlear implantation is not feasible or beneficial. In the fall of 2014, a collaborative effort between the departments of Neurosurgery, Otolaryngology and Audiology and led by Maroun Semaan, MD, successfully placed an auditory brainstem implant (ABI) in a teenager with absent cochleae. The activation, captured on camera, was viewed by millions of people worldwide. Unlike the cochlear implant, the ABI stimulates the auditory nucleus in the brainstem. This device is currently approved for use in patients with neurofibromatosis type 2. These patients develop benign tumors known as Schwannomas that destroy both their auditory nerves. Implantation of patients with congenital absence of their cochleae or auditory nerves remains investigational and is part of conducted trials or compassionate use under IRB approval. This is the first reported ABI placement in an adolescent with congenital deafness secondary to absent cochlear development.