People with persistent ringing in their ears — a condition called tinnitus — may process emotions in the brain differently from people who do not have the condition, according to a new study.
Using fMRI scans, researchers looked at people's brain activity while the patients listened to pleasant, unpleasant and neutral sounds. The study included people with tinnitus, people who had hearing loss but not tinnitus and people with normal hearing.
The investigators found that when they played the pleasant and the unpleasant sounds, the amygdala, a brain region associated with processing emotions, had less activity in the tinnitus and hearing-loss patients than in people with normal hearing. When researchers played the pleasant sounds, tinnitus patients had more activity than people without tinnitus in two other brain regions associated with emotion, the parahippocampus and the insula.
"The amygdala isn't the only player," when it comes to processing emotional sounds in people with tinnitus, study researcher Fatima Husain, a professor at University of Illinois at Urbana-Champaign, told Live Science. [10 Things You Didn't Know About the Brain]
About 50 million people in the United States have tinnitus, according to the American Tinnitus Association. These patients hear phantom sounds that are not real, including whines, whooshing noises, train whistles and cricket chirps, but not regular speech. Silence often exacerbates the condition, Husain said.
About 90 percent of people with tinnitus also suffer from hearing loss of varying degrees, whereas about 50 percent of people with hearing loss suffer from tinnitus, she said.
The difference in the emotional processing of sounds in people with tinnitus compared to people without the condition likely stems from the brain's adjustment to tinnitus, Husain said. The burden of constantly having to process incessant phantom sounds may get redistributed among the amygdala and other parts of the brain, so that the amygdala does not have to be active all the time, she said.
The people in the study with tinnitus had a mild form of the condition, which did not prevent them from functioning normally. About 80 percent of all tinnitus patients overcome their condition and are no longer bothered by it. Such patients still tend to experience phantom noises comparable to having a loud air conditioner on in one's apartment, Husain said.
"The majority of people who have tinnitus are quite okay with it," she said."If something else is grabbing their attention, then they are fine with it."
However, for the remaining 20 percent of tinnitus patients, the condition seriously interferes with their lives, often making it hard to sleep and making them depressed and anxious, Husain said.
The researcher said she hopes her study helps scientists better understand tinnitus so they can ultimately improve patients' quality of life.
There is currently no cure for the condition. "There are therapies to manage it," Husain said. "But the sound itself won't disappear."
The study was published June 3 in the journal Brain Research.