Misophonia vs Hyperacusis: Brain fMRI Differences

A new fMRI study from the University of Illinois Urbana-Champaign reveals how the brains of people with misophonia and hyperacusis respond differently to unpleasant sounds. The research, published in *Cognitive, Affective, & Behavioral Neuroscience*, provides the clearest neural evidence yet for why these often-confused conditions are distinct, even when they co-occur.

Mapping Brain Activity in Four Distinct Groups

Led by researcher Namitha Jain and senior author Fatima Husain, the team recruited 91 young adults and categorized them into four groups: those with misophonia, those with hyperacusis, those with both conditions, and a control group with no sound sensitivities. The goal was to separate the neural signatures of each profile.

Inside an fMRI scanner, participants listened to 90 emotionally charged sounds from a standardized database, including unpleasant noises like screams, neutral sounds, and pleasant ones. As they heard each sound, they rated how unpleasant or pleasant it felt. The researchers then analyzed whole-brain activation and the functional connectivity between specific brain networks.

Misophonia Shows Atypical Cross-Modal Sensory Involvement

A clear pattern emerged for misophonia. When processing unpleasant versus neutral sounds, individuals with misophonia—whether they had hyperacusis or not—showed hyperactivation in visual association areas of the brain. Simultaneously, they exhibited reduced connectivity between the salience network (which flags important stimuli) and the visual network.

“This suggests atypical cross-modal sensory involvement,” the authors note. In essence, a trigger sound like chewing may involuntarily recruit brain areas responsible for vision, possibly related to mental imagery or a heightened, multisensory reaction. The salience network, which should help manage the emotional priority of the sound, appears less engaged with these visual regions. This neural pattern supports the common experience in misophonia where specific, often visual-associated sounds trigger disproportionate anger or disgust.

Hyperacusis Points to Impaired Top-Down Regulation

The hyperacusis group displayed a different neural deficit. Compared to both controls and the misophonia group, they showed reduced connectivity between hubs of the salience network and frontal control regions in the brain. These frontal areas are critical for top-down regulation—the cognitive process of modulating emotional and physiological responses.

This impaired connectivity indicates a breakdown in the brain’s ability to down-regulate the significance of loud or intense sounds. Where the misophonia group showed preserved connectivity here for general unpleasant sounds, the hyperacusis group did not. This finding aligns with the core symptom of hyperacusis: a physical discomfort or pain from sounds that are objectively loud, suggesting a failure in the brain’s internal volume control system.

This focus on network connectivity aligns with other research exploring cerebellar and broader network roles in hearing disorders.

The Comorbid Group Combines Both Neural Patterns

For participants diagnosed with both misophonia and hyperacusis, the brain scans showed a combination of the patterns found in each separate condition. They exhibited the visual cortex hyperactivation and altered salience-visual connectivity seen in misophonia, alongside the impaired salience-frontal connectivity characteristic of hyperacusis. This provides direct neural evidence that comorbidity is not a third, indistinct condition, but a co-occurrence of two distinct neural profiles.

Practical Implications for Diagnosis and Treatment

These findings have direct consequences for clinical practice. The overlap in symptoms—where both disorders involve distress from sound—has long complicated diagnosis. This study offers objective neural markers that could help differentiate them.

“Disentangling their neural bases is essential for improving diagnosis and treatments,” the researchers state. For misophonia, interventions that address cross-modal associations or retrain the salience network’s response to specific triggers may be most effective. For hyperacusis, therapies aimed at strengthening top-down regulatory pathways and frontal lobe control could be more appropriate. Understanding these differences prevents a one-size-fits-all approach.

This mechanistic understanding complements ongoing work in personalized sound-based therapies and adds clarity to the neural models discussed in our earlier article on affective sound processing.

A Foundation for Future Research

The study, available with the DOI 10.3758/s13415-026-01435-z (PMID: 41981382), establishes a clear framework. Jain, Husain, and their colleagues call for future research to combine this type of neural data with detailed behavioral measures. This will refine mechanistic models and directly guide the development of targeted interventions, moving beyond symptom management to address the root brain-based causes of these debilitating sound tolerance disorders.