Aberrant Functional and Causal Connectivity in Acute Tinnitus With Sensorineural Hearing Loss

Abstract

The neural bases in acute tinnitus remains largely undetected. The objective of this study was to identify the alteration of the brain network involved in patients with acute tinnitus and hearing loss. Methods: Acute tinnitus patients (n = 24) with hearing loss and age-, sex-, education-matched healthy controls (n = 21) participated in the current study and underwent resting-state functional magnetic resonance imaging (fMRI) scanning. Regional homogeneity and amplitude of low-frequency fluctuation were used to investigate the local spontaneous neural activity and functional connectivity (FC), and Granger causality analysis (GCA) was used to analyze the undirected and directed connectivity of brain regions. Results: Compared with healthy subjects, acute tinnitus patients had a general reduction in FC between auditory and non-auditory brain regions. Based on FC analysis, the superior temporal gyrus (STG) revealed reduced undirected connectivity with nonauditory brain regions including the amygdala (AMYG), nucleus accumbens (NAc), the cerebellum, and postcentral gyrus (PoCG). Using the GCA algorithm, increased effective connectivity from the right AMYG to the right STG, and reduced connectivity from the right PoCG to the left NAc was observed in acute tinnitus patients with hearing loss. The pure-tone threshold was positively correlated with FC between the AMYG and STG, and negatively correlated with FC between the left NAc and the right PoCG. In addition, a negative association between the GCA value from the right PoCG to the left NAc and the THI scores was observed. Conclusion: Acute tinnitus patients have aberrant FC strength and causal connectivity in both the auditory and non-auditory cortex, especially in the STG, AMYG, and NAc. The current findings will provide a new perspective for understanding the neuropathophysiological mechanism in acute tinnitus.

Aberrant Frequency Related Change-Detection Activity in Chronic Tinnitus

“…The index of this interpretation was the MMN. In accordance with the present investigation, a recent study found aberrant functional connectivity in the auditory and non-auditory cortex, especially in the superior temporal gyrus (Cai et al, 2020). Other studies suggested different interpretations of the cause of tinnitus occurrence.…”

Alterations of brain activity and functional connectivity in transition from acute to chronic tinnitus

“…To our knowledge, this is the first study to identify the central processing network and neural predictors for the development of tinnitus by using source localization and functional connectivity methods. Although a number of previous studies on chronic tinnitus have been published and many pathophysiological models have been developed (Chen et al, 2017; Chen et al, 2018; Vanneste, Song, & De Ridder, 2018; Vanneste, To, & De Ridder, 2019), few studies have investigated central plasticity in acute tinnitus (Cai et al, 2019; Cai et al, 2020), especially the dynamic changes to neural processing in the transition period from acute to chronic tinnitus. This issue is crucial to clarify central neural characteristics of acute and chronic tinnitus, which is important in identifying neural predictors for the development of tinnitus and prevent transition from acute to chronic.…”

“…Although a number of previous studies on chronic tinnitus have been published and many pathophysiological models have been developed, few studies have investigated central plasticity in acute tinnitus (Cai et al, 2020; Stolzberg et al, 2013), especially the dynamic changes to neural processing during transition from acute to chronic tinnitus. This issue is crucial to clarifying the central neural characteristics of acute and chronic tinnitus, which is important in identifying neural predictors for the development of tinnitus and prevention of transition from acute to chronic tinnitus.…”

Functional Magnetic Resonance Imaging Reveals Early Connectivity Changes in the Auditory and Vestibular Cortices in Idiopathic Sudden Sensorineural Hearing Loss With Vertigo: A Pilot Study

“…However, some recent studies reported no significant difference in the ReHo value between the ISSNHL patients and the healthy controls in any brain region. The various neuroimaging methods employed and the participants’ heterogeneity may have contributed to the inconsistent results ( Cai et al, 2020 ; Chen et al, 2020 ).…”