Misophonia study finds why chewing sounds make some people angry

If you feel irrationally angry or upset at certain sounds, particularly the noises that result when someone chews with their mouth open, you may have misophonia. Though the hypersensitivity to these sounds has been popularly known for several years, research into the condition is still slim, but a new study from Newcastle University is helping change that.

Misophonia is a condition in which certain trigger sounds, most often ones involving chewing, can cause an involuntary and usually intense emotional reaction to the noises, including anger, a fight or flight response, and even the need to leave the room due to an urge to fight the person making the noise.

The issue can be milder in some misophonia sufferers and severe in others, with the latter group often suffering from isolation in an effort to avoid trigger sounds. Though it's unclear how many people experience misophonia, Newcastle University lists the estimate at between 6- and 20-percent of people.

The new study has found the potential reason why some people experience this hypersensitivity, with researchers identifying a 'supersensitized brain connection' that links parts of the brain related to the throat, mouth, and face. This marks the first time this abnormal connection has been found in people who report misophonia symptoms.

Using scan data, the researchers found that people who have misophonia experienced increased communication between the brain's motor control and auditory cortex when exposed to their trigger sounds. Likewise, the researchers also found evidence that the same kind of communication takes place with visual parts of the brain, meaning misophonia may also include visual triggers.

In explaining the significance of this, the study's lead author Dr. Sukhbinder Kumar said:

What surprised us was that we also found a similar pattern of communication between the visual and motor regions, which reflects that misophonia can also occur when triggered by something visual. This led us to believe that this communication activates something called the 'mirror system', which helps us process movements made by other individuals by activating our own brain in a similar way – as if we were making that movement ourselves.

We think that in people with misophonia involuntary overactivation of the mirror system leads to some kind of sense that sounds made by other people are intruding into their bodies, outside of their control.