According to new research from the University of Illinois, those who experience tinnitus, a bothersome ringing, buzzing or whooshing sensation in the ears, process emotions differently than others.
Previous studies have determined that tinnitus, which affects roughly 50 million Americans according to the American Tinnitus Association, can lead to increased stress, anxiety, irritability and depression. Each of these ailments is affiliated with the brain’s emotional processing systems.
There are several causes of tinnitus, such as overexposure to sounds over 85 decibels (a lawnmower) and it is often associated with some degree of hearing difficulty.
Fatima Husain, professor of speech and hearing science at the University of Illinois who led this new research, used functional magnetic resonance imaging (MRI) brain scans to analyze how tinnitus affects the brain’s ability to process emotions. Her team reviewed scans from three groups of participants: those with mild-to-moderate hearing loss and mild tinnitus, those with mild-to-moderate hearing loss without tinnitus, and a control group of those close in age without hearing loss or tinnitus.
Each participant was made to listen to the same set of 30 pleasant, 30 unpleasant, and 30 emotionally neutral sounds (such as a water bottle opening) while in the MRI machine. After hearing each sound, the participant pressed a button to categorize it as pleasant, unpleasant, or neutral.
Husain found that participants with tinnitus and normal hearing responded more quickly to emotion-inducing sounds than to neutral sounds while participants with hearing loss had a similar response time to each type of sound.
To the researchers’ surprise, those with tinnitus were generally slower to react to sounds than those with normal hearing. The measured activity in the amygdala, the region of the brain associated with emotion processing, was lower in the tinnitus and hearing loss participants than in those with normal hearing. Those with tinnitus also showed higher levels of activity than those with normal hearing in the parahippocampus and the insula—two regions of the brain associated with emotion.
“We thought that because people with tinnitus constantly hear a bothersome, unpleasant stimulus, they would have an even higher amount of activity in the amygdala when hearing these sounds, but it was lesser,” said Husain. “Because they’ve had to adjust to the sound, some plasticity in the brain has occurred. They have had to reduce this amygdala activity and reroute it to other parts of the brain because the amygdala cannot be active all the time due to this annoying sound.”
Husain is planning future research to better understand how to increase tinnitus patients’ quality of life.
Original Source: Medical Xpress
Last updated: August 12, 2014