Dissociable effects of hyperacusis and misophonia severity imply different mechanisms of decreased sound tolerance

Objective: It is thought that decreased sound tolerance can be subdivided into distinct types including misophonia (involving specific trigger sounds) and hyperacusis (broader in profile). However, there are few established methods for differentially assessing these disorders and this is complicated by the fact that some measures (e.g. the HQ Hyperacusis Questionnaire) were developed before the concept of misophonia was accepted. Design/Study sample: We took a group of N 1 / 4 119 participants with misophonia (varying in severity) and asked them about the presence of hyperacusis (based on a scoping review definition). Results: Scores for some items on the HQ were correlated with scores for misophonia severity (e.g. social impact of sound) and others with scores for hyperacusis (e.g. ability to concentrate in noise). Similarly, some trigger sounds were more indicative of hyperacusis (e.g. dishes being stacked) and others were more indicative of misophonia in the absence of hyperacusis (e.g. chewing). Conclusions: These double dissociations provide compelling evidence for separable forms of sound intolerance. Moreover, our research suggests that a single-item question about hyperacusis is associated with other characteristics of hyperacusis, even when assessed 18 months later.