Rage against the eating machine. (Photographer: Darwin bell)
Science

(Dis)comfort in sound.

by James MacLachlan

We’ve all sat at the dinner table with someone with eating habits that annoy us far more than they should; crunching, chomping, sipping, and slurping – they all contribute to a reaction that some of us can’t stop ourselves from experiencing. But there are some people in the world that experience this feeling on another level.

A team of neurologists from Newcastle University’s Institute of Neuroscience have discovered that the phenomenon in humans that makes us despise the sound of others eating, among other things, is a genuine ailment related to how our brains process these sounds and not just an irrational hatred of them.

Misophonia, derived from the Greek words misó- meaning hate, –phon-, meaning sounds, and concluded with the suffix -ia, which makes the noun a condition, (much like anorexia, trichotillomania, or schizophrenia, for example), is, as the scientists call it, an ‘affective sound-processing disorder characterised by the experience of strong, negative emotions (anger and anxiety) in response to everyday sounds, such as those generated by other people eating or drinking.

In their article ‘The Brain Basis for Misophonia’ published earlier this week in the journal ‘Current Biology’, the scientists document their experiment which involved examining the brains of twenty people that had Misophonia and twenty-two people that did not. The participants of the study were made to listen to various ‘unpleasant’ sounds, such as screaming, sounds considered to be ‘neutral’, like rain, and what people consider their ‘trigger’ sounds, such as the noises people make when eating or breathing. While in general, none of the test subjects particularly enjoyed listening to the trigger sounds, when those that had Misophonia listened to these noises they started to perspire and their hearts rates increased.

Through analysis of MRI brain scans taken during the experiment, the researchers could see that certain regions of the Misophonic test subjects’ brains reacted stronger to the stimuli than those without the condition. This was due to a high number of blood-oxygen-level-dependent responses flooding the Anterior Insular Cortex, which affects our interoceptive perception and emotion processing. The Anterior Insular Cortex was not only more active whilst the trigger sounds were heard, but also interacted with the other sections of the brain more than usual. The scientists believe this over-interaction with the other sections of the brain contributed to the ‘exaggerated responses’ in some people.

The scientists concluded that the trigger sounds heard by the subjects with Misophonia were associated with abnormal functional connectivity between the Anterior Insular Cortex and a network of regions of the brain responsible for the processing and regulation of emotions. Such regions include the Ventromedial Prefrontal Cortex, Posteromedial Cortex, Hippocampus, and Amygdala.

Like other many other psychological conditions, Misophonia is uncommon, and the more that is found out about them through research, the better. This will allow us to understand how the brain works in a more significant way and may possibly allow us to develop treatments for them in the future. Because, remember everyone, ‘knowledge is power’.

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