Misophonia is a neurobehavioral syndrome phenotypically characterized by heightened autonomic nervous system arousal and negative emotional reactivity (e. g., irritation, anger, anxiety) in response to a decreased tolerance for specific sounds. The aims of this review are to (a) characterize the current state of the field of research on misophonia, (b) highlight what can be inferred from the small research literature to inform treatment of individuals with misophonia, and (c) outline an agenda for research on this topic. We extend previous reviews on this topic by critically reviewing the research investigating mechanisms of misophonia and differences between misophonia and other conditions. In addition, we integrate this small but growing literature with basic and applied research from other literatures in a cross-disciplinary manner.

The soundscape is defined by the International Standard Organization (ISO) 12913-1 as the human’s perception of the acoustic environment, in context, accompanying physiological and psychological responses. Previous research is synthesized with studies designed to investigate soundscape at the ‘unconscious’ level in an effort to more specifically conceptualize biomarkers of the soundscape. This review aims firstly, to investigate the consistency of methodologies applied for the investigation of physiological aspects of soundscape; secondly, to underline the feasibility of physiological markers as biomarkers of soundscape; and finally, to explore the association between the physiological responses and the well-founded psychological components of the soundscape which are continually advancing. For this review, Web of Science, PubMed, Scopus, and PsycINFO were searched for peer-reviewed articles published in English with combinations of the keywords ‘soundscape’, ‘environmental noise/sound’, ‘physiology/physiological’, ‘psychology/psychological’, and ‘perceptual attributes/affective/subjective assessment/appraisals’. Previous research suggests that Electrocardiography (ECG) and Vectorcardiography (VCG) biometrics quantifying Heart Rate (HR), stimulus-locked experimental design, and passive listening with homogeneous populations are predominantly applied to characterize the psychophysiology underlying the soundscape. Pleasantness and arousal are the most frequent psychological descriptors for soundscape subjective appraisals. Likewise, acoustic environments are reported to inconsistently evoke physiological responses with great variability among studies. The link between the perceptual attributes and physiological responses of soundscape vary within and among existing literature. While a few studies detected a link between physiological manifestations of soundscape and the perceptual attributes, the others failed to validate this link. Additionally, the majority of the study findings were limited to one or two physiological responses.

A protocol for characterizing urban soundscapes for use in the design of Soundscape Indices (SSID) and general urban research as implemented under the European Research Council (ERC)-funded SSID project is described in detail. The protocol consists of two stages: (1) a Recording Stage to collect audio-visual recordings for further analysis and for use in laboratory experiments, and (2) a Questionnaire Stage to collect in situ soundscape assessments via a questionnaire method paired with acoustic data collection. Key adjustments and improvements to previous methodologies for soundscape characterization have been made to enable the collation of data gathered from research groups around the world. The data collected under this protocol will form a large-scale, international soundscape database.

Objective: Misophonia is a neurophysiological disorder, phenotypically characterized by heightened autonomic nervous system arousal which is accompanied by a high magnitude of emotional reactivity to repetitive and pattern-based auditory stimuli. This study identifies the prevalence of psychiatric symptoms in misophonia sufferers, the association between severity of misophonia and psychiatric symptoms, and the association between misophonia severity and gender. Methods: Fifty-two misophonia sufferers, 30 females (mean age= 40.93 ± 15.29) and 22 males (mean age= 51.18 ± 15.91) were recruited in our study and they were diagnosed according the criteria proposed by Schröder et al The participants were evaluated by the A-MISO-S for the severity of misophonia and the MINI to assess the presence of psychiatric symptoms. Results: The most common comorbid symptoms reported by the misophonia patients were respectively PTSD (N = 8, 15.38%), OCD (N = 6, 11.53%), MDD (N = 5, 9.61%), and anorexia (N = 5, 9.61%). Misophonia severity was associated with the symptoms of MDD, OCD, and PTSD as well as anorexia. There was an indication of a significant difference between men and women in the severity of misophonic symptoms. Conclusion: Our findings highlight the importance of recognizing psychiatric comorbidity among misophonia sufferers. The presence of these varying psychiatric disorders’ features in individuals with misophonia suggests that while misophonia has unique clinical characteristics with an underlying neurophysiological mechanism, may be associated with psychiatric symptoms. Therefore, when assessing individuals with misophonia symptoms, it is important to screen for psychiatric symptoms. This will assist researchers and clinicians to better understand the nature of the symptoms and how they may be interacting and ultimately allocating the most effective therapeutic strategies.

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.