Mary Ann Merranko went to see one of her favorite bands, Rusted Root, at the now defunct venue The Beehive in Oakland in 2001.
She made her way to the front of the crowd and ended up right next to the speaker. When she emerged onto Forbes Avenue later that night, she noticed a ringing in her ears.
“I thought this’ll clear up in a few hours,” said Merranko, now 63, of Morningside. “I never went to the doctor. I kept thinking it’ll clear itself up.”
A decade and a half later, that ringing has never gone away. Merranko has tinnitus.
“Most people think that … because it’s perceived as a ringing in the ear, something has changed in the ear,” said Karl Kandler, director of the Auditory Research Group at the University of Pittsburgh. “In most cases, tinnitus doesn’t arise in the ear, but it actually arises from changes or plasticity in the brain.”
Plasticity is the brain’s ability to change. It’s how we store memories and learn new skills. But plasticity can also have negative effects, like when a loud noise shocks the nerves responsible for auditory processing into reorganizing themselves.
“The reorganizations are such that there is a hyperactivity in that area. So the area becomes more excitable,” which produces the sensation of a ringing, said Kandler.
Research has shown that exposure to white noise – noise containing many frequencies, such as the roar of a crowd or the hum of an air conditioner – can freeze brain plasticity in young children and animals whose brains are still developing.
White noise could "also freeze the abnormal plasticity that occurs after hearing loss and may lead to tinnitus,” Kandler said.
He and his team found that mice that received white noise therapy immediately after being exposed to loud noises that would normally cause tinnitus did not develop symptoms.
“We think the reason why it works in our mouse model is because we started right afterwards,” said Kandler. “Now we’re trying to figure out how long after the damaging sound exposure can we start the white noise therapy to prevent it.”
Four weeks after the noise trauma event is likely too late, he said, which is why most human tinnitus patients don’t benefit from sound therapy.
He said one way to prevent the development of tinnitus after noise trauma is to expose oneself to moderate noise, white or otherwise.
“You should not keep your ear quiet; you should not go to a quiet environment,” Kandler said.