High-resolution prosthetic hearing with a soft auditory brainstem implant in macaques

Area of Science:

• Neuroscience
• Biomedical Engineering
• Auditory Neuroscience

Background:

• Individuals with damaged cochlear nerves cannot use cochlear implants and often rely on auditory brainstem implants (ABIs).
• Current ABIs provide sound awareness but limited speech intelligibility, highlighting a need for improved auditory prosthetics.

Purpose of the Study:

• To engineer and evaluate a dual-site (brainstem and cortex) implantable system for auditory perception.
• To investigate auditory perception evoked by electrical stimulation of the cochlear nucleus using a novel soft multichannel ABI.

Main Methods:

• Fabrication of a soft multichannel auditory brainstem implant using thin-film processing.
• Implementation of a dual-site system stimulating both the brainstem and cortex in a macaque model.
• Collection and analysis of behavioral responses to electrical stimulation over several months.

Main Results:

• The soft multichannel ABI provided high-resolution auditory percepts.
• Spatially distinct stimulation sites elicited cortical responses resembling frequency-specific tuning.
• Behavioral data demonstrated precise discrimination between stimulations from adjacent channels.

Conclusions:

• Soft multichannel ABIs can generate detailed auditory percepts and distinct neural responses.
• This technology shows promise for improving auditory rehabilitation in individuals with profound hearing loss unsuitable for cochlear implants.