Disruptions of default mode network and precuneus connectivity associated with cognitive dysfunctions in tinnitus

Tinnitus—a perception of sound without an external source—is linked to changes in brain connectivity, but prior findings have been inconsistent. In a comparison of 20 chronic tinnitus patients and 20 matched controls, no significant differences in resting-state functional connectivity were found between groups. However, cognitive test scores correlated with connectivity between the default mode network and precuneus and regions including the superior parietal lobule, supramarginal gyrus, and orbitofrontal cortex. Tinnitus distress was associated with connectivity between the precuneus and the lateral occipital complex. These results suggest that cognitive difficulties in tinnitus may stem from altered brain coupling, possibly because constant attention to the tinnitus sensation occupies neural resources.

Study at a glance

Abstract

Tinnitus is the perception of a ringing, buzzing or hissing sound “in the ear” without external stimulation. Previous research has demonstrated changes in resting-state functional connectivity in tinnitus, but findings do not overlap and are even contradictory. Furthermore, how altered functional connectivity in tinnitus is related to cognitive abilities is currently unknown. Here we investigated resting-state functional connectivity differences between 20 patients with chronic tinnitus and 20 control participants matched in age, sex and hearing loss. All participants underwent functional magnetic resonance imaging, audiometric and cognitive assessments, and filled in questionnaires targeting anxiety and depression. Significant differences in functional connectivity between tinnitus patients and control participants were not obtained. However, we found significant associations between cognitive scores and functional coupling of the default mode network and the precuneus with the superior parietal lobule, supramarginal gyrus, and orbitofrontal cortex. Further, tinnitus distress correlated with connectivity between the precuneus and the lateral occipital complex. This is the first study providing evidence for disruptions of default mode network and precuneus coupling that are related to cognitive dysfunctions in tinnitus. The constant attempt to decrease the tinnitus sensation might occupy certain brain resources otherwise available for concurrent cognitive operations.