The researchers’ goal is to uncover the causes of acquired hearing loss and to find possible treatments

With a new five-year, $3.2 million grant from the National Institute on Deafness and Other Communications Disorders, researchers at Case Western Reserve University and Mass Eye and Ear will study what causes acquired hearing loss (AHL) and after Find new ways to protect yourself from it.

According to the Centers for Disease Control and Prevention, AHL is one of the most common health conditions among older adults. Although hearing aids can help, there is no known cure for AHL and in many cases scientists are still unclear about the exact cause.

AHL significantly impairs quality of life and leads to increased social isolation, depression and cognitive decline. Untreated hearing loss is associated with a higher risk of dementia, with even mild untreated hearing loss doubling the risk.

“We anticipate that if successful, this could reveal new strategies for preserving human hearing by regulating mitochondrial calcium levels,” said Ruben Stepanyan, assistant professor in the department of otolaryngology at Case Western Reserve School of Medicine.

Understanding hearing loss

An important factor in hearing is the health of the cochlear hair cells – sensory cells in the inner ear that detect sound vibrations and send electrical signals to the brain. These cells are packed with mitochondria, or microscopic energy-producing components.

According to previous peer-reviewed research, hearing loss may be due to damage caused by mitochondrial dysfunction. Hair cell health depends on balanced calcium levels, which are partially regulated by mitochondria. Loud noises can cause calcium levels to rise too high and put strain on the hair cells of the cochlea.

This study will examine how calcium overload from noise exposure can damage cochlear hair cells and contribute to hearing loss, and identify new therapeutic targets for treatment.

Part I

Researchers will use a specific type of mouse models that are more susceptible to calcium overload and early hearing loss to evaluate how overstimulation from loud noises affects the structure and function of cochlear hair cells.

They will use advanced three-dimensional imaging technology as well as novel machine learning-based 3D data analysis approaches to study the structure of mitochondria in these cells and understand how they change under stress.

Part II

Researchers will then test whether preventing calcium overload in the mitochondria can protect hearing by testing other types of mouse models with reduced mitochondrial calcium to see if they may be more resistant to noise damage.

The ultimate goal is to find ways to prevent hearing loss due to noise exposure and aging, which could help millions of people protect their hearing as they age.”

Artur Indzhykulian, assistant scientist at Mass Eye and Ear’s Eaton-Peabody Laboratories and assistant professor of otolaryngology at Harvard Medical School