The study recently published in Communications Engineering, a Nature Portfolio journal.

Conductive hearing loss, which most commonly happens in childhood, occurs when sounds do not reach the inner ear. Sound waves are blocked in the outer or middle ear due to ear infections, blockages or structural abnormalities.

"Treatment for conductive hearing loss can include corrective surgeries and implantable hearing aids, which can be very invasive, especially for pediatric patients," Moghimi said. "Flexible hearing aids offer a noninvasive alternative."

To produce vibrations strong enough to reach the cochlea, the part of the inner ear responsible for hearing, the research team designed a flexible hearing aid. The device uses micro-epidermal actuators to create vibrations on the skin behind the ear, which then travel directly to the inner ear, bypassing the ear canal.

For the study, 10 participants between the ages of 19 and 39 wore earplugs and earmuffs to simulate conductive hearing loss. Researchers then tested arrays of the actuators to enhance the vibration strength, improve the quality of sounds and control the direction of the vibrations.

"We found that using an array of these actuators, rather than a single one, significantly enhances the strength and quality of the vibrations, leading to better hearing outcomes," Moghimi said.

Moghimi also noted that improving hearing in children can reduce delays in language and speech development and boost educational development.

"This technology has the potential to improve the quality of life for children with hearing impairments and transform the way we approach pediatric hearing aids," Moghimi said.

The research team will next focus on a larger study to further evaluate the efficacy and safety of the device in children and adults.