Researchers from Mass General Brigham and the École Polytechnique Fédérale de Lausanne (EPFL) have developed a promising new type of auditory brainstem implant (ABI) that could significantly benefit patients with Neurofibromatosis type 2 (NF2) and other severe inner ear abnormalities who cannot receive cochlear implants. The research, published in Nature Biomedical Engineering, represents the culmination of a decade-long collaboration between Mass Eye and Ear and EPFL scientists.
Revolutionary Design Addresses Current Limitations
The new ABI features an elastic, multilayer construct that includes ultra-thin platinum electrodes and silicone, representing a novel design approach that allows the device to conform closely to the brainstem's curved surface. This represents a significant advancement over conventional ABIs currently used in patients with NF2, which rely on stiff electrodes that struggle to conform to the curved surface of the cochlear nucleus in the brainstem.
Current conventional ABIs provide only modest benefits, typically offering basic sound awareness to aid lip reading. The rigid design also causes side effects like discomfort that discourages long-term use, limiting their clinical effectiveness.
Advanced Manufacturing and Precise Stimulation
The novel soft electrode design was developed using advanced thin-film processing techniques, enabling closer contact with neural tissue and more precise stimulation of the brainstem's sound-processing region. These implants bypass damaged auditory structures and directly stimulate the brainstem to restore auditory function.
Promising Preclinical Results
In preclinical tests conducted in Switzerland, two macaques received the implants and underwent several months of behavioral testing. The results demonstrated that the animals could consistently distinguish between different patterns of stimulation, indicating high-resolution auditory perception—a promising sign for eventual human use.
"While cochlear implants are life-changing for many, there remains a group of patients for whom current technology falls short," said study co-senior author Daniel J. Lee, MD, FACS, Ansin Foundation Chair in Otolaryngology at Mass Eye and Ear. "Our research lays the groundwork for a future auditory brainstem implant that could improve hearing outcomes and reduce side effects in patients who are deaf and do not benefit from the cochlear implant."
Clinical Implications
The development addresses a critical unmet need for patients with NF2 and other severe inner ear abnormalities who cannot benefit from cochlear implants. With further tests and trials, researchers hope this technology will provide a more effective treatment alternative than currently available options, potentially transforming outcomes for this patient population who have limited therapeutic choices.
