By Erin Kohnke

BU News Service

For most people, a cozy cafe offers a place to relax with a cup of joe, hunker down and focus on work or friends. Patrons clack on their keyboards, tap on their phones, sip from their mugs and chew on their finger sandwiches. Most people barely register these ambient sounds.

But for someone suffering from a condition called misophonia, meaning “hatred of sound,” certain everyday sounds can evoke deep visceral reactions — disgust, rage or even panic. Misophonics hear the sounds of a cafe not as soft background noise but more like fingernails scraping on a chalkboard.

The phenomenon may have existed for as long as human beings have been able to hear, but it was characterized in 2001 by a husband and wife team of auditory neurologists at Emory University. The scientists, Pawel and Margaret Jastreboff, named the condition misophonia.

People afflicted with this condition don’t mind most noises, but they loathe a few particular sounds. Most often, they can’t bear certain repetitive, human-made sounds like eating, drinking, breathing and tapping. These sounds don’t merely annoy misophonics. They trigger a primal distress response marked by sweating, heart-pounding and heavy breathing — in other words, the classic fight-or-flight response.

One possibly undiagnosed case is Jolie Spatz, box office manager at a theater in Kansas City, who suffers from symptoms similar to misophonia. She can’t stand nose-blowing, gum-smacking or loud chewing.

“I usually have to put my headphones in just so that I don’t crawl out of my skin,” she said. “It just makes me insane.”

No one knows how many people suffer from misophonia since no formal diagnosis exists. One study of college undergraduates estimates that it affects up to 20 percent of young adults. Misophonia symptoms tend to creep in around 12 or 13 years of age, although some people develop it later in adulthood. In one study, about 22 percent of misophonics said the condition ran in their families.

While hearing impairment can make some sounds uncomfortable, misophonia lies in the upper levels of the brain, not in the ears. According to Margaret and Pawel Jastreboff, abnormal connections between sound processing and emotional centers in the brain might provoke this unusual response.

In the years since the Jastreboffs named the condition, brain scientists have found a few clues about its biological underpinnings.

In 2017 a team of researchers headed by Sukhbinder Kumar at Newcastle University in the UK recruited 20 people with misophonia and 22 people without the condition. The researchers then put them in an fMRI machine and had them listen to three sets of sounds. The first set consisted of common misophonia triggers, like eating and breathing. The second set contained sounds that commonly annoy non-misophonics, like people screaming or babies crying. And the third set was comprised of neutral sounds, like rain.

As the participants listened to these sets of sounds, the researchers scanned their brains to look for patterns of activity while also measuring heart rate and sweating. Both groups reacted similarly to the neutral and commonly annoying sounds. But when they heard the trigger sounds, the misophonics’ heart rates and sweating spiked — clear markers that their fight-or-flight responses had kicked in.

The researchers also noticed differences in their subjects’ brain activity. While listening to the trigger sounds, misophonics showed greater activation in an area of the brain called the anterior insular cortex. The more they stressed out, the more active this brain area became.

Neuroscientists believe this portion of the brain processes how sensations from the external environment, like sounds, affect internal bodily states, like heartbeat.

“[It’s] the interface between sensation and emotional reaction,” explained University of Iowa neuroscientist Phillip Gander, a co-author on Kumar’s study. In misophonia, this interface seems to get easily overwhelmed.

Other than overactivation, the researchers found additional strange activity in this part of the misophonic brain. The anterior insular cortex communicated abnormally with emotion-processing centers and a network of brain structures that activate when you direct your attention inwardly — for instance, when you reflect on things like your life and your memories. This inner attention network deactivates when something in the environment snaps your attention back to the outside world.

Most people make this rapid transition between inner and outer attention without getting stuck. That’s not the case in the misophonic brain, according to Kumar’s study. They found that when the misophonics heard a trigger sound, both inner and outer attention networks activated, forcing the patients to experience internal and external sensations at once. Kumar’s group guessed that this simultaneous activation might throw misophonics into an emotional feedback loop, their distress ping-ponging between the present offending sound and their past stressful memories of it.

Kumar’s study is one of very few neuroimaging experiments on misophonics. With such scant data, it’s not clear to some auditory neuroscientists that misophonia should even be classified as a new disorder.

One researcher, Richard Tyler of University of Iowa, believes that misophonia is a misnomer for a previously characterized disorder called hyperacusis, which involves over-activation of the auditory system. In hyperacusis, sounds feel painfully loud.

To Tyler, the Jastreboffs made an unnecessary and incorrect distinction.

“Somebody’s trying to come up with a new name to sound clever,” Tyler said. “Being bothered by certain sounds and frequencies has been known in the hyperacusis literature for decades.”

But Kumar’s study aligns with the Jastreboffs’ prediction: misophonia involves areas of the brain used in sound perception, whereas hyperacusis involves more “primitive” areas used for sound sensation. The sound sensation pathway involves the ears and parts of the brainstem that bring sounds to the brain. In hyperacusis, an abnormality in the sensation pathway makes general sounds feel too loud.

On the other hand, the sound perception pathway involves areas the brain uses to interpret the meaning of these sound sensations. In misophonia, an abnormality in the perception pathway causes an emotional reaction to specific patterns of sounds.

Due to lack of data and explicit diagnostic criteria, no one currently knows how to treat misophonia. This means misophonics have to fend for themselves. Many individuals report spending up to three hours a day battling their symptoms, according to a survey by Romke Rouw of the University of Amsterdam and Mercede Erfanian of Maastricht University in the Netherlands. They found that misophonics commonly deal with their panic and rage by avoiding encounters with people, the main source of these vile sounds. In extreme cases, misophonics in the survey reported acting out violently against people making the trigger sounds. Many suffer impaired concentration in class, work, or the movie theater, where crunching popcorn and tapping feet can sound earsplitting.

“I don’t understand how people can’t hear that, or why they’re not annoyed by their own sounds,” Spatz said. “I think that’s what makes me want to punch them — [but] I would never actually do that.”

Unfortunately for misophonics, the symptoms seem to worsen over time. Sufferers may even become sensitive to new trigger sounds. Gander believes this indicates a strong learning component to the condition.

“It can generalize from ‘I hate when my dad makes this stupid throat-clearing sound’” to all of the sounds that the dad makes and to similar sounds made by other people, Gander said. “[There’s] some sort of association that’s made between the sound and an aversive reaction.”

If new associations between sounds and unpleasant reactions can be learned, then can existing reactions be unlearned? In a 2014 paper, the Jastreboffs proposed un-teaching misophonic stress by pairing trigger sounds with pleasant sound sensations, such as music or audio from the sufferer’s favorite movie. The misophonic patient would then hopefully learn to associate the previously upsetting sound with a positive feeling.

With neurologists paying more attention to this condition, misophonics can begin to hope for new and better treatments. Gander said that nailing down what’s going on in the misophonic brain represents the crucial first step in devising therapeutic strategies.

“Identifying some brain mechanisms likely involved with misophonia should start the ball rolling with treatment options,” Gander said. “Now you’ve got a target.”