New Approaches in Hearing Research

About 15 million people in Germany suffer from hearing impairments. Among older adults, hearing loss is the most common sensory impairment. However, even children and newborns can suffer from hearing loss, such as inner-ear deafness. In such cases, acoustic signals are not transmitted to the auditory nerve. In this situation, inner-ear prostheses—known as cochlear implants (CI)—can help. They stimulate the auditory nerve using electrodes. However, both older and very young patients may still have some residual hearing, particularly in the low-frequency range.

"REDIHEAR" Project

Professor Dr. Waldo Nogueira Vazquez, head of the Hearing Prosthetics Research Group at the Department of Otolaryngology at Hannover Medical School (MHH), aims to shed light on how residual hearing can be more accurately assessed and preserved, how electrical stimulation via the cochlear implant interacts with acoustic signal transmission, and how these findings can be used to develop a novel hearing prosthesis. For his “REDIHEAR” project, the scientist has now been awarded the “ERC Consolidator Grant” from the European Research Council (ERC), one of the European Union’s highest research grants for excellence. He will receive a total of approximately two million euros over five years.

Assess and preserve residual hearing

If some residual hearing remains, hearing aids and a cochlear implant (CI) can be used simultaneously in the same ear. In this approach, known as combined electroacoustic stimulation (EAS), the hearing aid amplifies low frequencies acoustically, while the CI electrically stimulates the mid- and high-frequency ranges. The inner ear processes the acoustic and electrical stimuli simultaneously. The downside: During CI implantation, the highly sensitive structures of the cochlea—and thus residual hearing—can be damaged. The scientist now aims to develop objective diagnostic tools that determine the extent of hearing potential, particularly in newborns, and simultaneously monitor low-frequency hearing during implantation.

Interaction between hearing aids and cochlear implants

To optimally coordinate residual hearing and the cochlear implant, Professor Nogueira Vazquez plans to investigate the fundamental mechanisms of interaction between electrical and acoustic stimulation throughout the entire auditory pathway, from the cochlea to the auditory cortex in the brain. “In addition, READIHEAR will test a novel hearing prosthesis that utilizes the interaction mechanisms between acoustic and electrical stimulation via minimally invasive electrodes,” he explains. These electrodes will no longer be located deep inside the cochlea, as has been the case until now, but rather at the entrance or even completely outside it.

Hearing loss impairs communication

“Hearing loss significantly impairs communication and can cause frustration, loneliness, and isolation among those affected,” says Professor Nogueira Vazquez. He is convinced that these new developments will benefit a large number of people with hearing loss throughout their lives. “This ranges from young children, who will benefit from improved hearing diagnostics, to older adults, who will find the new, gentler EAS technology helpful in treating their age-related hearing loss.”

Keyword: Cochlear Implant

A cochlear implant (CI) can help with inner-ear deafness or severe hearing loss. The prerequisite is that the auditory nerve itself is still intact. The CI captures sound waves from the outside via a microphone, converts them into electrical signals, and transmits them to the electrodes in the cochlea. These stimulate various sections of the auditory nerve, which then relays the stimuli to the brain, where the actual auditory perception occurs.

(Published on April 13, 2022)