Long-term reactions to pulsatile tinnitus are marked by weakened short-range functional connectivity within a brain network in the right temporal lobe.

BACKGROUND

There have been recent efforts to characterize brain functional activity features in patients with pulsatile tinnitus (PT). These efforts have revealed evidence of aberrant functional connectivity (FC) of the right middle temporal gyrus (MTG) in PT patients with prolonged disease duration.

PURPOSE: To assess the possible predictive effect of aberrant FC of MTG in PT patients with prolonged disease duration.

STUDY TYPE: Retrospective.

POPULATION: Thirty-four patients with recent-onset PT (RPTIN), 24 patients with long-term PT (LPTIN), and 35 age-, gender-, and education-matched healthy controls were enrolled.

FIELD STRENGTH/SEQUENCE: 3.0T MRI system and echo-planar imaging (EPI) sequence, 3D brain volume imaging (BRAVO) sequence.

ASSESSMENT: Functional MRI data preprocessing was performed in Data Processing & Analysis for Brain Imaging (DPABI) and Statistical Parametric Mapping (SPM) 8. The FC analyses were conducted using the software REST.

STATISTICAL TESTS: One-way analysis of covariance was conducted between three groups with age and gender as covariates, and post-hoc analysis was used to identify the sources of group effects. Pearson's correlation analysis was conducted for the z-values of altered FC strength in the PT group and the clinical data.

RESULTS

Among hubs belonging to the executive control network, the default mode network (DMN), and limbic network, the strength of FC was mainly decreased in the patient groups compared with normal controls (P < 0.05). Relative to RPTIN patients and normal controls, LPTIN patients were further characterized by significantly decreased FC between several short-range brain regions adjacent to the seed (P < 0.05). Finally, disease duration was negatively correlated with decreased FC between the seed and right fusiform gyrus/parahippocampal gyrus, right inferior frontal gyrus, and right MTG (a brain area adjacent to the seed region).

DATA

CONCLUSION

Long-term reactions to PT mainly involved weakened short-range FC, especially within a functional network in the right temporal lobe.

LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.