Why People Experience Irritation At Common Sounds

It’s natural to feel annoyed by disruptive or repetitive noises, but there are some people who are more than simply annoyed by loud breathing or chewing — they become intensely upset, and even angry, about certain noises. These folks have misophonia, a disorder characterized by extreme reactions to sounds, especially sounds produced orally, like chewing, breathing, or whistling. New research suggests that misophonia, also known as “selective sound sensitivity syndrome,” is indeed a real disorder, and that the brains of people who have misophonia process “trigger” sounds differently than those without the disorder.

Published last week in Current Biology, the study used MRI scans to analyze the brain activity of 42 people, some with misophonia and some without. Researchers had the subjects listen to sounds that fell into three categories: “Neutral” sounds, like rain or a boiling kettle; “unpleasant” sounds, like a woman screaming or a baby crying; and “trigger”sounds, like eating and breathing. They found that when misophonic participants listened to the trigger sounds, their brains responded differently from those who aren’t misophonic. MRIs revealed that that an abnormality in the part of the brain that regulates emotions led the brains of misophonic subjects “to go into overdrive” upon hearing trigger sounds, according to a press release. Trigger sounds also had an unusually extreme physical effect on misophonic subjects, causing sweating and increased heart rate.

People with misophonia experience extreme distress when they hear trigger noises; their reactions can involve anger, anxiety, and even panic attacks. And yet some in the medical establishment are still skeptical of the disorder, which was first named in 2001. This study would seem to lend credibility to the condition. “For many people with misophonia, this will come as welcome news as for the first time we have demonstrated a difference in brain structure and function in sufferers,” lead researcher Dr. Sukhbinder Kumar of the Institute of Neuroscience at Newcastle University said in a press release. He continued, “Patients with misophonia had strikingly similar clinical features and yet the syndrome is not recognised in any of the current clinical diagnostic schemes. This study demonstrates the critical brain changes as further evidence to convince a skeptical medical community that this is a genuine disorder.”

Co-author Dr. Tim Griffiths added, “I hope this will reassure sufferers. I was part of the skeptical community myself until we saw patients in the clinic and understood how strikingly similar the features are.” The researchers are hopeful that this new data will someday contribute to effective treatment for misophonia. Although the study showed that there is a neurological basis for misophonic subjects’ intense reactions to trigger noises, it did not reveal why these particular sounds— chewing, drinking, whistling, and so on — are triggering in the first place.