Photo: La Fondation Pour l’Audition

eurekalert.org

M. Charles Liberman, PhD, whose research forever changed the way experts understand  the underlying causes of hearing loss, has been awarded the Scientific Grand Prize from the France-based La Fondation Pour l’Audition.

The award is one of the highest honors given in hearing science and was presented to Dr. Liberman in a ceremony in Paris, France, on October 20, 2022. The Scientific Grand Prize carries a €100,000 honorarium.

La Fondation Pour l’Audition is a public-interest foundation that is committed to bringing together research, health care and disease prevention for hearing loss. As part of this mission, it rewards and supports pioneering hearing researchers.

Dr. Liberman, the Harold F. Schuknecht Professor of Otolaryngology–Head and Neck Surgery at Harvard Medical School, previously served as the director of the Eaton-Peabody Laboratories at Mass Eye and Ear for more than 25 years, where he remains an investigator. In his five-decade career, Dr. Liberman has led cutting-edge research into the pathological causes of hearing loss rooted in the inner ear. In 2009, Dr. Liberman co-discovered a phenomenon called cochlear synaptopathy, also referred to as “hidden hearing loss,” a landmark discovery that has since informed the global understanding of the causes of hearing loss.

“Dr. Liberman’s research upended the dogma of what was known about the cause of hearing loss in the inner ear, and that work has had a profound and lasting impact throughout the field of hearing science,” said Mark A. Varvares, MD, FACS, chief of Otolaryngology–Head and Neck Surgery at Mass Eye and Ear and the John W. Merriam/William W. Montgomery Professor and Chair of Otolaryngology–Head and Neck Surgery at Harvard Medical School. “His body of work and leadership at Mass Eye and Ear propelled the Eaton-Peabody Laboratories into the premier hearing research center in the world, and we congratulate him on this well-deserved recognition of his impressive career and lasting contributions.”

Transformative Discovery of Hidden Hearing Loss

Hearing loss affects more than 5 percent of the world’s population, an estimated 430 million individuals, according to the World Health Organization.

One of the more common complaints hearing clinicians receive from patients is difficulty hearing in noisy environments. However, many of these patients do not show measurable hearing loss deficits on an audiogram, widely considered the gold standard hearing test. The audiogram measures the loss of hair cells, the sensory cells inside the inner ear. Dr. Liberman and Sharon Kujawa, PhD, the  Sheldon and Dorothea Buckler Chair in Otolaryngology–Head and Neck Surgery at Mass Eye and Ear and Professor of Otolaryngology–Head and Neck Surgery at Harvard Medical School, uncovered the basis of this discrepancy in 2009 when their seminal study showed that noise exposure and aging first damage the synapses, which connect the hair cells to auditory nerve fibers and ultimately carry neural signals to the brain. This hearing damage is now known as cochlear synaptopathy. Since audiograms measure hair cell function, this synaptic loss is typically undocumented, inspiring the popular term “hidden hearing loss.”

Dr. Liberman’s research has also shown that it is possible to successfully reestablish the connections between hair cells and auditory nerve fibers in animal models by administering therapeutics called neurotrophins. This work has led biotechnology companies to develop new therapies for treating hearing loss in people.