Does aberrant connectivity underlie the experience of misophonia?
Abstract
Misophonia is a condition characterized by an extreme aversion to certain ordinary sounds, such as chewing or breathing. These sounds are typically innocuous but elicit strong feelings of anger, anxiety, and disgust as well as physiological stress in people with misophonia. This misophonic reaction to “trigger” sounds is also marked by increased activity in regions of the brain that process sound, ascribe salience, and regulate emotion (Kumar et al., 2017; Schroder et al., 2019). It has therefore been theorized that aberrant connectivity between these brain regions (particularly the anterior insula, auditory cortex, amygdala, and hippocampus) may underlie the experience of misophonia. The current work addressed two hypotheses related to this overarching theory. In the first study, we examined resting-state connectivity in people with varying degrees of sound sensitivity and demonstrate that people with clinical misophonia may have reduced functional connectivity within this network in comparison to those with sub-clinical sensitivity to sound. In the second study, we show preliminary evidence of reduced phonemic perceptual narrowing in misophonics. Since perceptual narrowing is thought to be a behavioural correlate of synaptic pruning during development, this trending result provides indirect evidence for atypical neural connectivity in misophonia. Taken together, the studies implicate a potential developmental mechanism of abnormal salience attribution in misophonia and highlight the importance of studying individual differences in the misophonic experience. These findings also inform the neural and perceptual characterization of misophonia, and since misophonia is not yet listed as a psychological disorder in diagnostic manuals, such findings are an important step towards understanding and classifying misophonia.