Tinnitus Neural Mechanisms and Structural Changes in the Brain: The Contribution of Neuroimaging Research

Abstract

Introduction Tinnitus is an abnormal perception of sound in the absence of an external stimulus. Chronic tinnitus usually has a high impact in many aspects of patients' lives, such as emotional stress, sleep disturbance, concentration difficulties, and so on. These strong reactions are usually attributed to central nervous system involvement. Neuroimaging has revealed the implication of brain structures in the auditory system. Objective This systematic review points out neuroimaging studies that contribute to identifying the structures involved in the pathophysiological mechanism of generation and persistence of various forms of tinnitus. Data Synthesis Functional imaging research reveals that tinnitus perception is associated with the involvement of the nonauditory brain areas, including the front parietal area; the limbic system, which consists of the anterior cingulate cortex, anterior insula, and amygdala; and the hippocampal and parahippocampal area. Conclusion The neuroimaging research confirms the involvement of the mechanisms of memory and cognition in the persistence of perception, anxiety, distress, and suffering associated with tinnitus.

Keywords: auditory cortex; functional neuroimaging; limbic system; neural networks; tinnitus.

Fig. 1

Red boxes/solid lines indicate areas of increased functional connectivity: amygdala, prefrontal cortex, supramarginal areas, temporal medium supra marginal gyrus (tmsm), brainstem, basal ganglia, hippocampus, left para hippocampal areas, and cerebellum. Light gray boxes and dashed lines indicated areas of decreased functional connectivity: left prefrontal cortex, fusiform gyrus, primary auditory cortex (PAC) and occipital areas.