A comparative study reveals distinct patterns of resting-state activity in tinnitus and chronic pain

Tinnitus and chronic pain, as two perceptual disorders frequently accompanied by negative emotions, significantly impair patients' daily functioning and overall well-being. However, the neurophysiological mechanisms that account for their frequently observed clinical similarities have yet to be fully elucidated.

The study enrolled a total of 56 participants, including 18 tinnitus patients and 19 chronic pain patients, alongside 19 healthy controls. We computed the fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo) from resting-state fMRI data to quantify localized brain activity intensity and neural synchronization.

Statistical analysis suggested a significant elevation in fALFF within the calcarine cortex of tinnitus patients compared to healthy controls (p < 0.05, FDR-corrected). In contrast, chronic pain patients exhibited notable increases in both fALFF and ReHo in the inferior frontal gyrus (IFG). Direct comparisons between patient groups suggested that tinnitus patients had higher fALFF in the inferior temporal gyrus (ITG), supplementary motor area and fusiform gyrus, but lower fALFF in the right IFG, precuneus, and caudate nucleus. Regarding ReHo, patients with tinnitus exhibited significantly elevated ReHo values in the supplementary motor area, while demonstrating reduced ReHo in both the precuneus and caudate nucleus (all p < 0.05, FDR-corrected).

The observed differences between tinnitus and chronic pain in brain regions including the prefrontal cortex, ITG, and fusiform gyrus provide neuroimaging correlates associated with the two conditions. These findings may inform future neuromodulation targets and support clinical differential diagnosis.