Brain Responses to Sounds: Misophonia vs. Hyperacusis

A new fMRI study of 91 young adults has identified distinct and overlapping brain patterns in misophonia and hyperacusis, providing biological evidence that these often-confused sound tolerance disorders involve different neural mechanisms. The work, led by researchers at the University of Illinois Urbana-Champaign, shows misophonia involves unusual cross-talk with the brain’s visual system, while hyperacusis points to a deficit in the brain’s internal volume control system.

Separating Two Disorders in the Brain Scanner

Misophonia and hyperacusis are both characterized by extreme reactions to everyday sounds, but their triggers differ. Misophonia is typically provoked by specific, often human-generated sounds like chewing or tapping. Hyperacusis involves a lowered tolerance for sound volume, where noises most people find comfortable are perceived as unbearably loud and painful. Because symptoms overlap and the conditions often co-occur, diagnosis and treatment can be challenging.

To separate their neural foundations, Namitha Jain, Shagun Ajmera, and colleagues recruited participants into four clear groups: those with misophonia only, hyperacusis only, both conditions, and controls with no sound sensitivity. Inside an fMRI scanner, all participants listened to 90 emotionally charged sounds from a standardized database, ranging from pleasant to unpleasant to neutral. Their task was simply to rate how positive or negative each sound felt, allowing researchers to observe brain activity during real-time sound processing.

Misophonia: When Sounds Activate the “Mind’s Eye”

The brain scans revealed a signature pattern for misophonia. When processing unpleasant versus neutral sounds, individuals with misophonia—whether they had hyperacusis or not—showed unusually high activation in visual association areas of the brain. Furthermore, there was reduced functional connectivity between the salience network (which flags important stimuli) and the visual network.

“This suggests atypical cross-modal sensory involvement,” the authors note. In simpler terms, trigger sounds in misophonia may involuntarily activate parts of the brain involved in visualization or contextual memory, possibly explaining the intense, often visual disgust associated with seeing someone chew. This finding moves beyond the auditory system, implicating a broader sensory integration problem. For more on the lived experience of this condition, particularly in families, see our article on Understanding Childhood Misophonia: Parent Experiences.

Hyperacusis: A Faulty Volume Control Circuit

In contrast, the hyperacusis group displayed a different neural signature. Their primary distinction was reduced connectivity between key hubs of the salience network and regions in the frontal cortex responsible for executive control and regulation.

This impaired link between the “alarm bell” and the “control center” suggests a deficit in top-down regulation. The brain in hyperacusis may struggle to modulate the perceived intensity or emotional impact of sounds once they are flagged as salient. This neural pattern aligns with the core symptom: an inability to tolerate ordinary sound volumes. The role of central brain structures in sound sensitivity is further explored in our piece on the Tinnitus and Hyperacusis: Dorsal Cochlear Nucleus Role.

Comorbid Cases Show a Combined Pattern

The group with both misophonia and hyperacusis showed neural features associated with each disorder. This finding is vital clinically, as it confirms that comorbidity is not a third, separate condition but a combination of two distinct neural profiles. It explains why individuals with both disorders experience the specific distress of misophonia triggers alongside a general hypersensitivity to volume.

Implications for Diagnosis and Future Treatment

These findings have direct practical implications. By providing objective neural markers, this research helps validate the subjective experiences of patients and supports the development of clearer diagnostic criteria. Clinicians can be more confident in distinguishing between these disorders, even when they co-occur.

More importantly, the distinct mechanisms point toward different treatment targets. Interventions for misophonia might benefit from strategies that address cross-modal sensory associations or the visual-emotional component of reactions, such as certain cognitive behavioral therapies. For hyperacusis, treatments aimed at strengthening top-down regulatory circuits—potentially including neurofeedback or sound therapy designed to retrain auditory processing—could be more effective. The pursuit of targeted neural interventions is also active in related fields, as seen in research on Deep Brain Stimulation Reduces Tinnitus in Rats.

The study, published in Cognitive, Affective, & Behavioral Neuroscience, establishes a foundation for moving from symptom-based descriptions to mechanism-based definitions of sound tolerance disorders. As lead author Fatima Husain noted, combining this neural data with behavioral measures will be the next step in refining models and guiding interventions.

Source: Jain N, Ajmera S, Shahsavarani S, et al. Differential brain responses to affective sounds in misophonia and hyperacusis: A task-based fMRI approach. Cogn Affect Behav Neurosci (2026). doi:10.3758/s13415-026-01435-z. PMID: 41981382.