A new study reveals the motor basis for misophonia, a condition that causes exceptionally negative responses to sounds such as chewing, providing an insight into new potential treatments.
Sitting down to eat with your family or a friend is a pleasant experience for most. Good food, company and perhaps a drink; it’s the simple pleasures that can deliver the most precious moments. But for some – between 6 and 20% of people – this utopian scene can lead to inexplicable rage and, at its worst, the urge to lean across the table and deliver a right hook so powerful it knocks the salad flying straight out of your unwitting compatriot’s grinning mouth.
The cause of this fury stems from a condition known as misophonia, which is stimulated by ‘trigger’ sounds typically originating from facial activity; most famously the sound of chewing. Misophonia can be experienced so severely that it can affect relationships and prevent sufferers from engaging in social situations. Until recently, the mechanism for this condition was poorly understood.
A recent study from researchers at Newcastle University (UK) has identified a neurological link – the first to be associated with the condition – that provides a clear hypothesis for the mechanism of misophonia. Led by Sukhbinder Kumar, the findings provide a new avenue for therapies to treat and control the condition.
To explore the neurological connections responsible for misophonia, the research team used fMRI to monitor the responses, when exposed to triggers, of several sites in the brains of controls and misophonia sufferers.
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Surprisingly, the team found that response to trigger sound caused no noticeable difference between the response of the auditory cortex in both controls and misophonia sufferers. Instead, they identified increased connectivity between the auditory and ventral pre-motor cortex in the brains of people with the condition, both in general and especially in response to trigger sounds.
The ventral pre-motor cortex is responsible for orofacial movements, movements of the mouth and face, suggesting the involvement of the ‘mirror system’ in misophonia. The mirror system allows humans to interpret the actions of others by stimulating their own brains in a similar way, mimicking the neural processes that control the actions observed.
Kumar explained how this could tie into misophonia, stating “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.”
An established technique for controlling misophonia is for people to copy the action that is triggering them. Previously unaware of why this technique works, now the team believes that by copying the action, a sense of agency and control is returned, lessening the feeling of violation that can lead to rage.
The team plans to continue their exploration of misophonia to uncover further avenues for new treatments. “The study provides new ways to think about the treatment options for misophonia. Instead of focussing on sound centers in the brain, which many existing therapies do, effective therapies should consider motor areas of the brain as well,” Kumar noted.
So, if you experience these responses, know that you don’t need to reach for a boxing glove at dinner and try copying the sound that so infuriates you.
For more information and advice on misophonia, check out: www.healthline.com/health/misophonia.