Tinnitus distress is linked to enhanced resting-state functional connectivity from the limbic system to the auditory cortex.

Summary

Because tinnitus is so often accompanied by anxiety and emotional distress, this study tested whether that comorbidity reflects abnormal connections from limbic structures (amygdala, hippocampus) to the auditory cortex. Using resting-state fMRI and Granger causality (a directional connectivity measure), tinnitus patients showed abnormal amygdala/hippocampus-to-auditory-cortex connectivity versus controls. Critically, the strength of connectivity FROM the amygdala TO auditory cortex correlated directly with tinnitus distress scores, and hippocampus-to-auditory-cortex connectivity correlated with how long the tinnitus had lasted.

Key findings

• Directional (amygdala/hippocampus → auditory cortex) connectivity is abnormal in tinnitus.
• Amygdala-to-auditory-cortex connectivity strength correlates directly with tinnitus distress/handicap scores.
• Hippocampus-to-auditory-cortex connectivity correlates with how long the tinnitus has persisted, consistent with a memory-encoding role.