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Do you have auditory sensitivity? Auditory sensitivity, or hyperacusis, occurs when a person is overly sensitive to sounds. The most common cause of hyperacusis is damage to the inner ear due to aging or exposure to loud noise. For the most part, individuals with auditory sensitivity have been told there is not much that can be done for their condition and, besides taking simple steps like wearing headphones, they simply need to “deal with it.” A new study, however, shows promise for helping those with auditory sensitivity.
The study was published in the July 2022 edition of the journal Proceedings of the National Academy of Sciences (PNAS). The study was led by University of Colorado Anschutz Medical Campus researchers Andrew Mecca and Giusy Caprara, PhD, in the laboratory of Anthony Peng, PhD. The researchers focused on the gating spring, which is a tiny, nanometer-scale protein structure that mechanically opens and closes an ion channel in sensory hair cell cells in response to sound vibrations.
For years, hearing researchers have hypothesized that the gating spring can act as a controller of the ion channel’s activity. The purpose of the study was to test this hypothesis and further explore the function of the gating spring in modulating the sensitivity of the channel. The researchers found that modifying a physical property of the gating spring—its stiffness—can control how much the channel opens and closes in response to sound vibrations in the inner ear. In particular, the study revealed that a specific type of signaling molecule called cyclic adenosine monophosphate (cAMP) reduced the stiffness of the gating spring and thereby decreased the channel’s sensitivity.
This study marks the first time a physiological mechanism for controlling gate spring stiffness has been identified. Peng, associate professor at the University of Colorado School of Medicine and senior author of the study, said, “Identifying the underlying mechanism of this process—how it works physiologically and mechanically—provides an avenue for future research and provides an opportunity for the field to develop a new type of drug that can be used to prevent a type of hearing loss that occurs from exposure to very loud sound.” One possible application of the new research is to help people protect their hearing from the effects of loud noise. This marks an important step forward in the field of audiology.
The findings of the study hold promise for people who suffer from auditory sensitivity as well. If a medication were developed that could modify the gating spring, it may be able to decrease auditory sensitivity. This could bring great relief to those who struggle with hyperacusis. In addition, this new research opens a door for a better understanding of how the auditory system functions in general and how it protects sensory cells from potential damage.