MRI Brain Changes in Hyperacusis Patients

A new systematic review of brain imaging studies has mapped the neural footprint of hyperacusis. Researchers Rania Alkahtani, Reem Elbeltagy, and Zuhal Y. Hamd analyzed 11 MRI-based studies and found consistent, large-scale changes in brain structure, function, and connectivity. Their work, published in *Frontiers in Human Neuroscience*, moves us beyond viewing hyperacusis as just an ear problem and frames it as a complex brain condition.

How the Brain Imaging Evidence Was Compiled

The team conducted a systematic review to gather all available magnetic resonance imaging (MRI) evidence on hyperacusis. They included studies that used three main techniques: structural MRI (sMRI) to measure brain volume, functional MRI (fMRI) to observe brain activity, and diffusion tensor imaging (DTI) to assess the integrity of neural pathways. A total of 11 studies met their strict criteria. To quantify the strength of the findings, the researchers calculated standardised mean differences (SMDs). An SMD above 0.8 is typically considered a large effect; many findings in this review far exceeded that threshold.

Auditory Brain Regions Are in Overdrive

The fMRI results were the most striking. Studies consistently reported significantly increased neural activity in people with hyperacusis when they processed sound. The hyperactivity was concentrated in core auditory regions: the Heschl’s gyrus, the superior temporal gyrus, and the parahippocampal area. The effect sizes for this hyperactivity were exceptionally high, with SMDs greater than 5.0. This indicates an exaggerated, almost amplified, neural response to everyday auditory input, providing a clear biological correlate to the experience of sound intolerance.

This aligns with existing theories that frame hyperacusis as a problem of excessive gain in the central auditory system. You can explore this concept further in our article on Tinnitus and Hyperacusis: A Unified Theory.

Structural Changes Point to Impaired Sound Control

Where fMRI showed what the brain is *doing*, structural MRI revealed changes in the brain’s *architecture*. The most notable finding was a reduction in grey matter volume in the right supplementary motor area (SMA). This region is not primarily for hearing; it’s involved in movement planning and, critically, in the modulation and gating of sensory signals. The SMD for this reduction was 2.10, a very large effect. A less robust SMA could mean a diminished ability to filter or dampen incoming sounds, allowing them to overwhelm the system.

Disrupted Connectivity in Auditory Pathways

The DTI data added a third dimension: communication. This technique showed altered microstructural integrity in critical auditory pathways, including connections to and from the medial geniculate nucleus and the inferior colliculus. These are essential relay stations in the brain’s sound-processing highway. Disrupted connectivity here suggests the neural networks for hearing are not communicating efficiently, which may contribute to the distorted and distressing perception of sound characteristic of hyperacusis. For a deeper look at related developmental brain changes, see How Tinnitus and Hyperacusis Develop in the Brain.

From Brain Maps to Better Patient Care

These findings have direct implications for how we understand and treat hyperacusis. First, they confirm the condition is multisystem, involving not just auditory circuits but also regions tied to sensory modulation, attention, and emotion. This explains why hyperacusis so often co-occurs with anxiety and leads to social withdrawal.

Practically, this evidence supports a shift toward integrated diagnostic protocols. Assessment should move beyond the audiogram to consider central auditory processing and emotional health. Treatment strategies must be multidisciplinary. While sound therapy aims to retrain auditory pathways, cognitive-behavioral therapy is needed to address the distress and avoidance. The structural and connectivity findings also provide a strong rationale for therapies that promote neuroplasticity.

Emerging neuromodulation approaches, which target specific brain networks, are a logical next step. The review’s identification of a weakened supplementary motor area, for instance, could guide non-invasive brain stimulation protocols. Learn more about this frontier in our article on Non-Invasive Neuromodulation for Tinnitus Relief.

The research by Alkahtani and colleagues consolidates a decade of brain imaging into a coherent picture. Hyperacusis is marked by a hyperactive auditory cortex, structural deficits in control regions, and faulty neural connections. This triad of evidence firmly establishes the condition in the brain and charts a course for more effective, neuroscience-informed interventions.

Source: Alkahtani R, Elbeltagy R, Hamd ZY. (2026). MRI-based brain changes in hyperacusis: a systematic review. Front Hum Neurosci. doi:10.3389/fnhum.2026.1785826.