Tinnitus is a phantom sound perception without an identifiable sound source. It is characterized by sensory components such as perceived loudness and pitch, the laterality (uni- or bilateral), the tinnitus type (pure tone or noise-like) and associated emotional components, such as distress and mood changes. Functional imaging studies using positron emission tomography (PET), functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and quantitative electroencephalography (qEEG) have demonstrated the involvement of not only the auditory brain areas such as the primary- and secondary auditory cortices but also several non-auditory brain areas. Also, many researchers have explained these auditory and non-auditory brain areas as constituents of separable subnetworks, each reflecting a specific aspect of the tinnitus percept and tinnitus-related distress.
In this talk, I would like to introduce theories explaining the pathogenesis of tinnitus. Also, results found primarily by qEEG-based source localization and functional connectivity studies will be discussed.