A new brain scan study attempts to explain why some people hate the sound of someone chewing food so loudly or breathing heavily and sort of fly into a rage when they hear those sounds.

A team from Newcastle University reported on why some individuals suffer misophonia, a disorder marked by a hatred of sounds including eating, chewing, or repeated pen clicking. These so-called “trigger sounds” can prompt a fight-or-flight response.

Brain Activity In Misophonia Sufferers

In the research, the team played a range of sounds from neutral to undesirable, and the neurological reactions of misophonia patients differed from others. The study covered 20 misophonic individuals and 22 without the condition in multiple UK centers.

Magnetic resonance imaging scans showed that the patients had changes in their brain activity once they heard trigger sounds.

The MRI scans also demonstrated that these patients have abnormal connections between the frontal lobe and anterior insular cortex, or AIC, the brain area that is and known to be involved in emotion processing and integrating human senses with emotions.

When given trigger sounds, activity in normal subjects goes up in the AIC but down in the front lobe, while it rises in both areas in misophonic individuals — reflecting an abnormality of a control mechanism governing the front lobe and AIC.

Going Into Overdrive

Lead author and neuroscience professor Dr. Sukhbinder Kumar said this is the first time the brain structure and function of misophonia sufferers were seen different from the rest.

“This study demonstrates the critical brain changes as further evidence to convince a skeptical medical community that this is a genuine disorder,” he said in a statement.

Patients go into overdrive when they hear trigger sounds, Kumar told BBC News, with anger as a response for the most part.

“[T]he dominating emotion is the anger — it looks like a normal response, but then it is going into overdrive.”

Olana Tansley-Hancock, a 29-year-old from the UK, has been suffering the condition for over two decades. She feels hers is a relatively mild case unlike other people she knows, and she has learned to cope through using earplugs.

“Anyone eating crisps is always going to set me off, the rustle of the packet is enough to start a reaction,” she recounted.

The team hopes to next identify the brain markers for the trigger sounds to potentially help treat related neurological conditions as well as allow people to self-regulate how they react to such sounds once the exact brain activity is identified.

The findings were discussed in the journal Current Biology.

A separate study last month conducted by researchers from the University of Manchester and U.S. National Institutes of Health revealed that chewing food well can protect from illness.

Chewing was seen helpful in stimulating the T helper 17 cells, an immune cell that is very important in protecting the mouth from bacterial and fungal infections. Damage resulting from the act can pave the way for good bacteria to respond to the Th17 cells, although it remains unclear how mastication actually releases these cells inside the mouth.