Misophonia: Supersensitive Brain Connection Causes Hatred of Noises
By NEWCASTLE UNIVERSITY
Publishing today, in the Journal of Neuroscience,
lead author Dr. Sukhbinder Kumar, Newcastle University Research Fellow in the
Biosciences Institute said: “Our findings indicate that for people with
misophonia there is abnormal communication between the auditory and motor brain
regions — you could describe it as a ‘supersensitized connection’.
“This is the first time such a connection in the brain has been
identified for the condition.”
Misophonia, which means literally ‘hatred of sound’, is a
condition in which sufferers experience intense and involuntary reactions to
certain sounds made by other people, referred to as ‘trigger’ sounds. Trigger
sounds are often the sound of someone chewing, breathing or speaking and for
sufferers, usually related to mouth, throat, or facial activity.
Their reaction is often extreme, and tends to consist of a
combination of anger, disgust, fight-or-flight response, sometimes an urge to
hurt the person making the sound or to leave the situation.
The condition is common affecting anywhere between 6% to 20% of people. Those with the more severe forms can find themselves unable to tolerate family, work, public or social situations.
Previously, misophonia had been considered a disorder of sound
processing. This new research suggests that alongside this there is an abnormal
type of communication between the brain’s hearing center, the auditory cortex,
and the areas of the ventral pre-motor cortex that are responsible for movement
of the face, mouth, and throat.
In response to trigger or neutral sound, scans on people with
misophonia showed that the brain’s auditory cortex (hearing center) responded
similarly to people without the condition, however, people with misophonia
showed increased communication between the auditory cortex and the motor
control areas related to the face, mouth, and throat. These motor control
regions were strongly activated by trigger sounds in people with misophonia in
response only to their trigger sounds, but not to other sound types or in
people without the condition.
Dr. Kumar adds: “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 leads 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.
“Interestingly, some people with misophonia can lessen their
symptoms by mimicking the action generating the trigger sound, which might
indicate restoring a sense of control. Using this knowledge may help us develop
new therapies for people with the condition.”
Tim Griffiths, Professor of Cognitive Neurology at Newcastle
University, who is a senior author on the study and also a neurologist, added:
“The study provides new ways to think about the treatment options for
misophonia. Instead of focusing on sound centers in the brain, which many
existing therapies do, effective therapies should consider motor areas of the
brain as well.”
The team will be further investigating whether this understanding
can help develop more effective treatments for misophonia in the future.
Reference: “The Motor Basis for Misophonia” by Sukhbinder Kumar,
Pradeep Dheerendra, Mercede Erfanian, Ester Benzaquén, William Sedley, Phillip
E. Gander, Meher Lad, Doris E. Bamiou and Timothy D. Griffiths, 30 June
2021, Journal of Neuroscience.
DOI:
10.1523/JNEUROSCI.0261-21.2021
