Key Points

The device uses micrometer-scale platinum electrodes embedded in silicone, forming a pliable array just a fraction of a millimeter thick.

This novel approach, published in Nature Biomedical Engineering, enables better tissue contact, potentially preventing off-target nerve activation and reducing side effects.

Over the last couple of decades, many people have regained hearing functionality with the most successful neurotech device to date: the cochlear implant.

But for those whose cochlear nerve is too damaged for a standard cochlear implant, a promising alternative is an auditory brainstem implant (ABI).

"Designing a soft implant that truly conforms to the brainstem environment is a critical milestone in restoring hearing for patients who can't use cochlear implants. Our success in macaques shows real promise for translating this technology to the clinic and delivering richer, more precise hearing," said Stephanie P. Lacour, head of Head of the Laboratory for Soft Bioelectronic (LSBI) Interfaces at EPFL.

Rather than simply relying on surgical tests, the researchers ran extensive behavioural experiments in macaques with normal hearing.

This allowed them to measure how well the animals could distinguish electrical stimulation patterns as they would with natural acoustic hearing.

"Our main idea was to leverage soft, bioelectronic interfaces to improve electrode-tissue match," explained Alix Trouillet, a former postdoctoral researcher at EPFL and co-first author of the study. "If the array naturally follows the brainstem's curved anatomy, we can lower stimulation thresholds and maintain more active electrodes for high-resolution hearing."

Beyond conformability, the soft array's flexible microfabrication means it can be reconfigured for different anatomies.

Although these findings are promising, the path to a commercially available soft ABI will require additional research and regulatory steps, said authors.

- IANS