If your parents ever told you to turn down the volume on the TV or radio to avoid “hurting” your ears, they were right. Exposure to loud noises – whether over time or due to a single, very loud noise – can indeed lead to hearing loss. In fact, according to surveys, it is estimated that 24 percent of the U.S. adult population suffer from noise-induced hearing loss. That’s 40 million people!
Hearing loss, especially noise-induced, is not limited to older adults. Research also indicates that 17 percent of U.S. teenagers (aged 12 to 19) may suffer from noise-induced hearing loss as well.
Patients experiencing noise-induced hearing loss may also suffer from tinnitus, which is a perceived ringing or buzzing sound in the ears. The U.S. Centers for Disease Control estimate that nearly 15 percent of the U.S. population (over 50 million people) experience tinnitus in some form, with about 20 million people struggling with chronic tinnitus. Approximately 2 million Americans experience even more extreme, debilitating cases of tinnitus.
While tinnitus has been linked to hearing loss in some individuals, the exact cause of the condition remains unknown for many patients who suffer from this annoying and sometimes life-disrupting hearing disorder. Ongoing research attempts to unlock the causes of and treatments available for tinnitus.
One recent study uncovered groundbreaking information that could change the game for patients who suffer from both noise-induced hearing loss and tinnitus. In the study, Shaowen Bao, PhD of the University of Arizona and colleagues analyzed the brains of mice with noise-induced hearing loss. Following noise-induced hearing loss in the mice, researchers observed inflammation in the mice’s auditory cortex of the brain, which is where sound is processed.
They found that noise-induced hearing loss is linked to increased levels of molecules called pro-inflammatory cytokines, as well as being associated with the activation of non-neuronal cells called microglia in the primary cortex. The research further indicates that in mice suffering from noise-induced hearing loss, a cell-signaling molecule called tumor necrosis factor alpha mediates neuroinflammation, tinnitus, and synaptic imbalance. Neuroinflammation is inflammation in the brain and nervous system.
When researchers experimented with pharmacological blockage of the tumor necrosis factor alpha molecule, they found that this blockage prevented tinnitus in the mice with noise-induced hearing loss. Based on these findings, the researchers believe that neuroinflammation may be the next area to explore in order to treat tinnitus and other hearing loss-related disorders.
While further research must be done to establish the connection between neuroinflammation and tinnitus in humans, this study marks an important development in the research of tinnitus therapies and treatments. It points to neuroinflammation as a possible risk factor for tinnitus, which would be valuable information for audiologists and other hearing health care specialists as they assess their tinnitus patients and explore possible treatment options.
To learn more about the connection between tinnitus, noise-induced hearing loss, and neuroinflammation, or if you believe you may be suffering from hearing loss, tinnitus, or another hearing disorder, we encourage you to contact our audiology practice today. We look forward to taking care of you!