You hear your spouse breathing nearby and you instantly get angry. Your 6-year-old yawns and it triggers a fight-or-flight reaction in you. You avoid restaurants because you can't stand the sound of chewing. Sounds other people don't even seem to notice, drive you up a wall. You might have misophonia.
What is misophonia?
People with misophonia are affected emotionally by common sounds — usually those made by others, and usually ones that other people don't pay attention to. The examples above (breathing, yawning, or chewing) create a fight-or-flight response that triggers anger and a desire to escape. Misophonia is little studied and we don't know how common it is. It affects some worse than others and can lead to isolation, as people suffering from this condition try to avoid these trigger sounds. People who have misophonia often feel embarrassed and don't mention it to healthcare providers — and often healthcare providers haven't heard of it anyway. Nonetheless, misophonia is a real disorder and one that seriously compromises functioning, socializing, and ultimately mental health. Misophonia usually appears around age 12, and likely affects more people than we realize.
What causes misophonia?
New research has started to identify causes for misophonia. A British-based research team studied 20 adults with misophonia and 22 without it. They all rated the unpleasantness of different sounds, including common trigger sounds (eating and breathing), universally disturbing sounds (of babies crying and people screaming), and neutral sounds (such as rain). As expected, persons with misophonia rated the trigger sounds of eating and breathing as highly disturbing while those without it did not. Both groups rated the unpleasantness of babies crying and people screaming about the same, as they did the neutral sounds. This confirmed that the misophonic persons were far more affected by specific trigger sounds, but don't differ much from others regarding other types of sounds.
The researchers also noted that persons with misophonia showed much greater physiological signs of stress (increased sweat and heart rate) to the trigger sounds of eating and breathing than those without it. No significant difference was found between the groups for the neutral sounds or the disturbing sounds of a baby crying or people screaming.
The brain science of misophonia
The team's important finding was in a part of the brain that plays a role both in anger and in integrating outside inputs (such as sounds) with inputs from organs such as the heart and lungs: the anterior insular cortex (AIC). Using fMRI scans to measure brain activity, the researchers found that the AIC caused much more activity in other parts of the brain during the trigger sounds for those with misophonia than for the control group. Specifically, the parts of the brain responsible for long-term memories, fear, and other emotions were activated. This makes sense, since people with misophonia have strong emotional reactions to common sounds; more importantly, it demonstrates that these parts of the brain are the ones responsible for the experience of misophonia.
The researchers also used whole-brain MRI scans to map participants' brains and found that people with misophonia have higher amounts of myelination. Myelin is a fatty substance that wraps around nerve cells in the brain to provide electrical insulation, like the insulation on a wire. It's not known if the extra myelin is a cause or an effect of misophonia and its triggering of other brain areas.
There is some good news regarding misophonia
Misophonia clinics exist throughout the US and elsewhere, and treatments such as auditory distraction (with white noise or headphones) and cognitive behavioral therapy have shown some success in improving functioning. For more information, contact the Misophonia Association.