Altered intra- and interregional synchronization in resting-state cerebral networks associated with chronic tinnitus.

Yu-Chen Chen,Richard Salvi,Gao-Jun Teng,Xu Feng,Cheng Qian,Wenqing Xia,Jian Zhang,Xiang-Yu Yang,Chun-Qiang Lu,Xiao-Wei Li,Jian Wang

doi:10.1155/2015/475382

Abstract

Objective. Subjective tinnitus is hypothesized to arise from aberrant neural activity; however, its neural bases are poorly understood. To identify aberrant neural networks involved in chronic tinnitus, we compared the resting-state functional magnetic resonance imaging (fMRI) patterns of tinnitus patients and healthy controls. Materials and Methods. Resting-state fMRI measurements were obtained from a group of chronic tinnitus patients (n = 29) with normal hearing and well-matched healthy controls (n = 30). Regional homogeneity (ReHo) analysis and functional connectivity analysis were used to identify abnormal brain activity; these abnormalities were compared to tinnitus distress. Results. Relative to healthy controls, tinnitus patients had significant greater ReHo values in several brain regions including the bilateral anterior insula (AI), left inferior frontal gyrus, and right supramarginal gyrus. Furthermore, the left AI showed enhanced functional connectivity with the left middle frontal gyrus (MFG), while the right AI had enhanced functional connectivity with the right MFG; these measures were positively correlated with Tinnitus Handicap Questionnaires (r = 0.459, P = 0.012 and r = 0.479, P = 0.009, resp.). Conclusions. Chronic tinnitus patients showed abnormal intra- and interregional synchronization in several resting-state cerebral networks; these abnormalities were correlated with clinical tinnitus distress. These results suggest that tinnitus distress is exacerbated by attention networks that focus on internally generated phantom sounds.

Highlights

Subjective tinnitus, a phantom sound, is often described as a ringing, hissing, or buzzing sensation [1]
Since tinnitus often persists even after sectioning the auditory nerve [4] and since tinnitus masking profiles differ from external sounds [5], aberrant neural activity in the central nervous system (CNS) rather than the cochlea is believed to play a major role in its development and maintenance [6,7,8]
Participants were excluded if they reported suffering from hyperacusis, Meniere’s diseases, or pulsatile tinnitus or if they had a past history of heavy smoking, alcoholism, stroke, head injury, Parkinson’s disease, Alzheimer’s disease, major depression, epilepsy, or other neurological or psychiatric illness, major medical illness, MRI contraindications, and severe visual impairment

Summary

Introduction

Subjective tinnitus, a phantom sound, is often described as a ringing, hissing, or buzzing sensation [1]. Patients with chronic tinnitus often suffer from sleep disturbance, depression, and anxiety, conditions that negatively impact the quality of life [3]. Since tinnitus often persists even after sectioning the auditory nerve [4] and since tinnitus masking profiles differ from external sounds [5], aberrant neural activity in the central nervous system (CNS) rather than the cochlea is believed to play a major role in its development and maintenance [6,7,8]. The fact that some patients are constantly aware of their tinnitus and find it extremely disturbing suggests that attentional or emotional neural networks may contribute to the severity of tinnitus distress [12]

Methods

Results

Discussion

Conclusion