Disrupted local neural activity and functional connectivity in subjective tinnitus patients: evidence from resting-state fMRI study

Abstract

Purpose: The study aimed to investigate the abnormal alterations of both the intra-regional brain activity and inter-regional functional connectivity (FC) in patients with subjective tinnitus (ST) using resting-state functional MRI (rs-fMRI) methods.

Methods: Twenty-five ST patients and 25 normal controls (NCs) were included and underwent resting-state functional magnetic resonance imaging scans. ReHo, fALFF, and seed-based FC were calculated and compared between ST patients and NCs. Meanwhile, correlation analyses were calculated between altered connectivity and clinical data in ST patients.

Results: Compared with NCs, ST patients exhibited increased ReHo and fALFF values in the right middle temporal gyrus (MTG), and the ReHo values were also increased in the right cuneus. In contrast, decreased ReHo values in ST patients were observed in the right middle frontal gyrus (MFG) and left cerebellar anterior lobe. Considering these brain areas with altered ReHo and fALFF clusters as seeds, the right MTG (ReHo) exhibited decreased connectivity with the right MFG, lingual gyrus, and left cerebellar posterior lobe, besides, the right cuneus showed decreased connectivity with the right MTG. In ST patients, the decreased FC between the right MTG (ReHo) and the right MFG was also positively correlated with the Tinnitus handicap inventory score (r = 0.675, P = 0.001).

Conclusion: The present study revealed that ST patients had altered regional neural activity and inter-regional connectivity in partial auditory and non-auditory brain regions, mainly involving the default mode network and audio-visual network, which could further improve our understanding of the neuroimaging mechanism in ST.

Keywords: Fractional amplitude of low-frequency fluctuation; Functional connectivity; Regional homogeneity; Resting-state functional magnetic resonance imaging; Subjective tinnitus.