Tinnitus severity is related to changes in functional connectivity between precuneus and inferior temporal gyrus

Previous studies have reported that symptoms of tinnitus are associated with changes in brain functional connectivity (FC). Most prior work has focused on static functional connectivity (SFC), while only a few investigations have examined dynamic functional connectivity (DFC). The goal of the present study was therefore to further explore whether DFC is altered in patients with tinnitus by applying sliding-window and clustering analysis techniques.

Investigations were performed for 60 patients with tinnitus and 53 healthy controls (HC) using the sliding-window and k-means clustering methods. A two-sample t-test was used to determine whether there were significant differences between groups and Spearman correlation analysis was used to investigate the potential relationship between group differences in DFC and scores on clinical assessment scales.

The DFC standard deviation (DFC-SD) between left precuneus and right inferior temporal gyrus (ITG) was significantly reduced in the patients with tinnitus compared to the HC (T = 4.52, p < 0.001, FDR), and the reduction showed a significant negative correlation with scores on the Tinnitus Questionnaire (TQ) scale (r = - 0.287, p = 0.026). Additionally, the clustering analysis revealed that the tinnitus group exhibited a longer mean dwell time (MDT) in the hyper-connected state (p = 0.003), and which was significantly negatively correlated with the reduction in DFC-SD between and ITG and precuneus (r = -0.344. p = 0.007) and positively correlated with TQ score (r = 0.309, p = 0.016).

The variability in DFC between precuneus and ITG shows significant relationships with symptom severity and state configurations, and may be a potential new imaging biomarker for diagnosing tinnitus and predicting the severity of symptoms.