Most people can recall a time when a certain sound annoyed them – say when your office mate was repeatedly clicking his pen – but some people find such sounds utterly unbearable. And new research suggests that brain abnormalities may explain why.
Brains in overdrive
People with a disorder called misophonia have an intense hatred of specific sounds, such as chewing, breathing or repeated pen clicking. These triggers can cause an immediate and strong "fight or flight" response in those with the disorder.
Read: Brain disorders
"I hope this will reassure sufferers," the study's senior author Tim Griffiths said in a news release from Newcastle University.
"I was part of the sceptical community myself until we saw patients in the clinic and understood how strikingly similar the features are," he added. Griffiths is a professor of cognitive neurology at Newcastle University and University College London in the United Kingdom.
The researchers conducted brain scans of 20 people with misophonia. They also conducted brain scans on 22 healthy people for comparison. Among those with the condition, brain scans showed an abnormality in their emotional control mechanism that puts their brains into overdrive when they hear trigger sounds.
The scans also revealed that brain activity in people with the disorder originates from a different connectivity pattern in the frontal lobe. This area normally suppresses an abnormal reaction to sounds, the study authors explained.
Abnormal emotional reactions
In addition, the researchers found that trigger sounds had physical effects, such as increased heart rate and sweating in people with misophonia.
The findings may help eventually lead to treatments for this condition, said Griffiths. The study may also prompt researchers to look for similar changes in the brain in other disorders associated with "abnormal emotional reactions", he said.
Read: Brain harmonics
Study leader Sukhbinder Kumar added that "for many people with misophonia, this will come as welcome news, as for the first time we have demonstrated a difference in brain structure and function in sufferers". Kumar is also from the Institute of Neuroscience at Newcastle University and University College London.
Kumar said people with this disorder had very similar signs and symptoms. "Yet, the syndrome is not recognised in any of the current clinical diagnostic schemes. This study demonstrates the critical brain changes as further evidence to convince a sceptical medical community that this is a genuine disorder," he said in the news release.
"My hope is to identify the brain signature of the trigger sounds – those signatures can be used for treatment, such as for neuro-feedback for example, where people can self-regulate their reactions by looking at what kind of brain activity is being produced," Kumar said.
The findings were published in the journal Current Biology.
QUIZ: What is the most irritating sound?
The perception of sound
Stressed women sensitive to sound