Mimicry in misophonia: A large-scale survey of prevalence and relationship with trigger sounds.

BACKGROUND: Misophonia is often referred to as a disorder that is characterized by excessive negative emotional responses, including anger and anxiety, to "trigger sounds" which are typically day-to-day sounds, such as those generated from people eating, chewing, and breathing. Misophonia (literally "hatred of sounds") has commonly been understood within an auditory processing framework where sounds cause distress due to aberrant processing in the auditory and emotional systems of the brain. However, a recent proposal suggests that it is the perceived action (e.g., mouth movement in eating/chewing sounds as triggers) of the trigger person, and not the sounds per se, that drives the distress in misophonia. Since observation or listening to sounds of actions of others are known to prompt mimicry in perceivers, we hypothesized that mimicking the action of the trigger person may be prevalent in misophonia. Apart from a few case studies and anecdotal information, a relation between mimicking and misophonia has not been systematically evaluated. METHOD: In this work, we addressed this limitation by collecting data on misophonia symptoms and mimicry behavior using online questionnaires from 676 participants. RESULTS: Analysis of these data shows that (i) more than 45% of individuals with misophonia reported mimicry, indicating its wide prevalence, (ii) the tendency to mimic varies in direct proportion to misophonia severity, (iii) compared to other human and environmental sounds, trigger sounds of eating and chewing are more likely to trigger mimicking, and (iv) the act of mimicking provides some degree of relief from distress to people with misophonia. CONCLUSION: This study shows prevalence of mimicry and its relation to misophonia severity and trigger types. The theoretical framework of misophonia needs to incorporate the phenomenon of mimicry and its effect on management of misophonia distress.

The Motor Basis for Misophonia.

Misophonia is a common disorder characterized by the experience of strong negative emotions of anger and anxiety in response to certain everyday sounds, such as those generated by other people eating, drinking, and breathing. The commonplace nature of these "trigger" sounds makes misophonia a devastating disorder for sufferers and their families. How such innocuous sounds trigger this response is unknown. Since most trigger sounds are generated by orofacial movements (e.g., chewing) in others, we hypothesized that the mirror neuron system related to orofacial movements could underlie misophonia. We analyzed resting state fMRI (rs-fMRI) connectivity (N = 33, 16 females) and sound-evoked fMRI responses (N = 42, 29 females) in misophonia sufferers and controls. We demonstrate that, compared with controls, the misophonia group show no difference in auditory cortex responses to trigger sounds, but do show: (1) stronger rs-fMRI connectivity between both auditory and visual cortex and the ventral premotor cortex responsible for orofacial movements; (2) stronger functional connectivity between the auditory cortex and orofacial motor area during sound perception in general; and (3) stronger activation of the orofacial motor area, specifically, in response to trigger sounds. Our results support a model of misophonia based on "hyper-mirroring" of the orofacial actions of others with sounds being the "medium" via which action of others is excessively mirrored. Misophonia is therefore not an abreaction to sounds, per se, but a manifestation of activity in parts of the motor system involved in producing those sounds. This new framework to understand misophonia can explain behavioral and emotional responses and has important consequences for devising effective therapies.SIGNIFICANCE STATEMENT Conventionally, misophonia, literally "hatred of sounds" has been considered as a disorder of sound emotion processing, in which "simple" eating and chewing sounds produced by others cause negative emotional responses. Our data provide an alternative but complementary perspective on misophonia that emphasizes the action of the trigger-person rather than the sounds which are a byproduct of that action. Sounds, in this new perspective, are only a "medium" via which action of the triggering-person is mirrored onto the listener. This change in perspective has important consequences for devising therapies and treatment methods for misophonia. It suggests that, instead of focusing on sounds, which many existing therapies do, effective therapies should target the brain representation of movement.

EEG Responses to auditory figure-ground perception.

Speech-in-noise difficulty is commonly reported among hearing-impaired individuals. Recent work has established generic behavioural measures of sound segregation and grouping that are related to speech-in-noise processing but do not require language. In this study, we assessed potential clinical electroencephalographic (EEG) measures of central auditory grouping (stochastic figure-ground test) and speech-in-noise perception (speech-in-babble test) with and without relevant tasks. Auditory targets were presented within background noise (16 talker-babble or randomly generated pure-tones) in 50% of the trials and composed either a figure (pure-tone frequency chords repeating over time) or speech (English names), while the rest of the trials only had background noise. EEG was recorded while participants were presented with the target stimuli (figure or speech) under different attentional states (relevant task or visual-distractor task). EEG time-domain analysis demonstrated enhanced negative responses during detection of both types of auditory targets within the time window 150-350 ms but only figure detection produced significantly enhanced responses under the distracted condition. Further single-channel analysis showed that simple vertex-to-mastoid acquisition defines a very similar response to more complex arrays based on multiple channels. Evoked-potentials to the generic figure-ground task therefore represent a potential clinical measure of grouping relevant to real-world listening that can be assessed irrespective of language knowledge and expertise even without a relevant task.