Mass Eye and Ear researchers believe that tinnitus, a condition that affects more than 10% of adults worldwide, is linked to undetectable auditory nerve loss. Their study suggests that even people with normal hearing tests can suffer from this hidden hearing loss, paving the way for new treatments focused on neural regeneration.
Groundbreaking research by Mass Eye and Ear links tinnitus to undetected auditory nerve damage, challenging conventional thinking and opening new avenues for treatment through auditory nerve regeneration .
A new study by Mass Eye and Ear researchers shows that people who report tinnitus, which manifests as ringing in the ears (more than 1 in 10 adults worldwide), experience loss of the auditory nerve that cannot be detected by traditional hearing tests. It became clear. This work, National Institutes of Health (NIH) to a public eye and ear researcher at the Eaton Peabody Laboratory (EPL) for research on cochlear synaptopathy, commonly referred to as “hidden hearing loss.” The results of this study, which provide a deeper understanding of the causes of tinnitus, are published today (November 30) in the journal Science. scientific report.
How tinnitus affects quality of life
“In addition to the annoyance of constant tinnitus and other sounds, the symptoms of tinnitus can be debilitating for many sufferers, causing sleep deprivation, social isolation, anxiety and depression, negatively impacting work performance and “The quality of the system has deteriorated significantly,” the senior said. Author Stéphane F. Maison, Ph.D., CCC-A, principal investigator at Mass Eye and Ear, member of Mass General Brigham, and clinical director of the Mass Eye and Ear Tinnitus Clinic. “Tinnitus cannot be cured until we fully understand the mechanisms underlying its development. This research is the first step toward our ultimate goal of stopping tinnitus.”
Rethinking tinnitus and hearing loss
Dr. Stephen F. Maison, CCC-A, Research Scientist at Mass Eye & Ear's Eaton Peabody Research Institute and Clinical Director of Mass Eye & Ear's Tinnitus Center. Credit: Mass Eye and Ear
Many people with hearing loss report hearing sounds such as buzzing, buzzing, ringing, or even roaring in their ears. It has long been believed that these symptoms, known as tinnitus, occur as a result of maladaptive plasticity in the brain. In other words, the brain attempts to compensate for hearing loss by increasing activity, resulting in the perception of phantom sound, tinnitus. However, until recently, this idea was challenged, as some tinnitus patients have normal hearing tests.
However, in 2009, researchers at Mass Eye & Ear discovered cochlear synaptopathy, demonstrating that even patients with normal hearing tests can have significant auditory nerve damage, discrediting this hypothesis. has been revived. Given the paradigm shift in how researchers and clinicians think about hearing loss, Maison and his team believe that such hidden damage is associated with tinnitus symptoms experienced by a cohort of participants with normal hearing. I tried to determine if this is possible. By measuring auditory nerve and brainstem responses, the researchers found that not only was chronic tinnitus associated with loss of the auditory nerve, but participants also showed hyperactivity in the brainstem.
Towards a potential treatment for tinnitus
“Our study supports the idea that tinnitus can be caused by loss of the auditory nerve, including in people with normal hearing,” Maison said.
As for future directions, the researchers aim to capitalize on recent work aimed at regenerating the auditory nerve through the use of drugs called neurotrophins.
“The idea that researchers might one day be able to restore lost sounds to the brain and perhaps reduce the brain's hyperactivity, along with retraining, certainly brings hopes for a cure closer to reality. “, Maison added.
References: “Evidence of Cochlear Neurodegeneration in Normal Hearing Subjects with Tinnitus,” Vasilkov, V et al., November 30, 2023. scientific report.
DOI: 10.1038/s41598-023-46741-5
Funding: This research was supported by grants from the NIDCD (P50 DC015857) and the Lauer Tinnitus Research Center at Mass Eye and Ear.
