Misophonia Research Is Taking Off

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On May 16, 2023, an all-day online event entitled CARE for Misophonia took place. CARE stands for Conversations about Research for Everyone, and this title perfectly reflected the goals of the event, in which scientific information was presented in highly understandable ways.

Often conferences are for researchers to see the work of colleagues. This event went beyond that and focused on presenters communicating with those with misophonia and their families. Zach Rosenthal of the Duke Center for Misophonia and Emotion Regulation (CMER), along with the organizations soQuiet and the International Misophonia Research Network formed a planning committee including international misophonia advocacy groups, and invited moderators who helped ensure that attendees' questions were answered.

What is so exciting about the research? I will try to highlight as much of the work as I am able in a short post, but I encourage you to view the event for yourself and draw your own conclusions. Presentations and panel discussions were and remain free and can be viewed here anytime.

Misophonia and Brain Processes

In my opinion, these presentations offered stronger evidence that misophonia is a brain disorder. I am not commenting on how it should be categorized for purposes of diagnostic coding; however, I think we can safely say now that the neurological underpinnings of misophonia are important to understand as they will inform treatment. Sukhbinder Kumar, who has been one of the most prominent neuroscientists in this field and who had an early interest in the disorder, has already helped us to understand that misophonia is a brain disorder. In the past, he has proposed increased connectivity in brain areas associated with emotion processing, defensive motivational systems (freeze/flight/flight), and motor areas of the brain to auditory and visual areas. Kumar has also found differences in sensory processing, particularly in interoception. Interoceptive awareness refers to how much or how little an individual feels their internal functioning, such as heartbeat. More evidence that misophonia is a brain disorder comes from Heather Hansen. While most misophonia studies have limited trigger sounds to those that are generated by others, and particularly those that are oral-nasal centric, Hansen presented work that moves us away from this idea. In her studies, she has demonstrated that a wide variety of sounds can be triggering (i.e., not just oral/nasal sounds). She also expanded on Kumar's work regarding motor processing. Rather than motor areas in the brain being limited to those connected to oral/nasal, she found that connectivity also existed between the sensory cortex by using a finger-tapping exercise.

Prashanth Prabhu presented a neurophysiological model of misophonia and explained the audiologist’s role in the context of the new research. In addition to the audiologist’s importance in terms of ruling out other audiological disorders and being able to diagnose misophonia, Prabhu demonstrated how sound (sensory information) enters the ear and is then processed in the brain. His model is one that demonstrates how sensation turns into perception and meaning-making in misophonia. Prabu brings up an important issue that is often left out of misophonia research, which is that of sensory/auditory gating. Auditory sensory gating refers to the neural systems that modulate responses to repetitive stimuli, essentially inhibiting attention to unnecessary auditory information. Prabhu suggests that a deficit in this ability may contribute to an overloaded auditory system that is processing sounds that should be "gated out."

Nicolas Davidenko presented another fascinating study that included sound perception and visual processing. In this study, mismatched auditory and visual stimuli changed the individual’s negative reactivity to a trigger sound. For example, if one listens to the sound of chewing while viewing a recording of footsteps in the snow, via auditory and visual integration the perception of what one is hearing changes. This was also one of the only studies that meaningfully considered the role of visual processing in misophonia. This is an essential study to follow up on, as it demonstrates that perception is highly complicated, variable, and may inform the treatment of misophonia.

Genetics of Misophonia

Until recently, there was only one study of misophonia and genetics. 23andMe identified one genetic marker associated with misophonia (i.e., rage associated with chewing). This genetic marker is located near the TENM2 gene, which is involved in brain development. The genetic marker associated with this trait is just one piece of the puzzle and does not mean that non-genetic factors do not also play a role. In addition, bear in mind that "rage associated with chewing" is hardly a complete description of misophonia, especially given Hansen's new work expanding the descriptions of misophonia triggers beyond oral/nasal sounds. Dirk J.A. Smit presented his work consisting of genetic correlations between the 23andMe data and auditory, psychiatric, and developmental disorders and personality traits.

Misophonia was significantly correlated with tinnitus (ringing in one or both ears), depression, post-traumatic stress disorder (PTSD), and Generalized Anxiety Disorder. There were no genetic correlations with ADHD, OCD, and psychotic disorders. Interestingly, misophonia was negatively correlated with autism spectrum disorder (ASD). What do we make of this? I would look at this as a preliminary genetic study that is restricted by the limitations of the 23andMe study's methods. However, it is an important step toward understanding misophonia on a deeper level, as well as what it may share genetically with other disorders. This will hopefully help with diagnostic classification and treatment down the line.

How Common Is Misophonia?

I have heard many people refer to misophonia as a "rare" disorder. However, that turns out to be very unlikely. A rare disorder in the United States is defined as one that affects less than 200,000 people. Estimates in the United States for cases of misophonia have been higher than one might think — as high as 20%. If this were true this would indicate that 1 in 5 people in the U.S. have misophonia, potentially 70 million Americans. Jane Gregory presented her study on the prevalence of misophonia in the UK. Similar to the U.S. estimates, she found that 18% of the general population has misophonia symptoms, according to a new validated measure: the Selective Sound Sensitivity Syndrome Scale (S-Five). We await further studies, but it is looking like while misophonia may be little-known, it is not rare.

Misophonia Sounds

Jamie Ward presented a very interesting study challenging the idea that misophonics have strong aversive reactions to specific trigger sounds. Using machine learning, profiles of sound-response patterns were generated, and it seems that the sounds that trigger those with misophonia may be less specific in this study. Those with misophonia reacted to typical trigger sounds as well as other sounds. Along with Hansen's work, we see again that perhaps what misophonia sounds may be more complex than we've thought. Ward suggests that there is a "distinctive reaction to most sounds that ultimately becomes most noticeable for a sub-set of those sounds."

Misophonia Essential Reads

People With Misophonia Add Value to Research

Misophonia: What Does Treatment Mean to You?

Misophonia in Children

Andrew Guzick presented his work on misophonia and children that explores the general mental health of children with misophonia, and the impact of misophonia on families. Not surprisingly, misophonia negatively impacts family functioning, and a child with misophonia experiences a decrease in quality of life similar to that of children with anxiety disorders.

Studies of misophonia specifically in children are still sparse. Developing children are difficult to study (as they change quickly) and ethical considerations are often greater for the population. However, I cannot express the need for a greater understanding of misophonia in children, and hope to see this soon. Guzick mentions the need for the study of cultural groups as well.

Take-Home Message

More evidence demonstrates that misophonia is a brain-based disorder related to connections between auditory and visual areas of the brain with areas mediating emotions, sympathetic nervous system arousal, motor and sensory processing. Misophonia is not uncommon, though it is still less known than we would like it to be. Genetic studies are limited but suggest that there are correlates with tinnitus, anxiety, and PTSD, but not with Autism Spectrum Disorder (ASD) or OCD. An ability to alert to and filter out unnecessary auditory stimuli may be a factor in misophonia. Another study demonstrated that when auditory and visual stimuli are mismatched, perception changes. This paves the way for more research in this area. Beyond the repetitive nature of sounds, there is still disagreement in terms of what constitutes a misophonia trigger. One study suggests there may be a more generalized aversion to sound and another supports that oral-nasal sounds are not the only triggers. Misophonia has a negative impact on socialization and is highly stressful for families and children.