Tinnitus distress is associated with enhanced resting-state functional connectivity within the default mode network

The default mode network (DMN) has been confirmed to be involved in chronic tinnitus perception. Tinnitus distress may be associated with abnormal functional connectivity (FC) within the DMN regions. The goal of this study was to determine whether tinnitus disrupted the FC patterns within the DMN as measured by using resting-state functional magnetic resonance imaging approach.

Resting-state functional magnetic resonance imaging scans were acquired from 40 chronic bilateral tinnitus patients and 41 healthy controls. Both were age, sex, and education well-matched with normal hearing. Two important DMN regions, the anterior cingulate cortex and posterior cingulate cortex, were chosen as seed regions to detect the FC patterns within the DMN and then determine whether these changes were linked to clinical measures of tinnitus such as tinnitus duration and tinnitus severity.

Compared with healthy controls, chronic tinnitus patients manifested significantly enhanced FC between the anterior cingulate cortex and left precuneus, which was correlated with the tinnitus duration (r=0.451, p=0.007). Moreover, enhanced FC between the posterior cingulate cortex and right medial prefrontal cortex in tinnitus patients was positively correlated with the tinnitus distress (r=0.411, p=0.014).

Chronic tinnitus patients showed disrupted FC patterns within the DMN regions which are correlated with tinnitus distress. Increased resting-state connectivity pattern of the DMN may play a pivotal role in neuropathological features underlying chronic tinnitus.