The Pathophysiologic Mechanism of Tinnitus

Tinnitus represents a phantom auditory sensation without an external sound source. The reported prevalence of tinnitus estimates 15-20% in world population. Although severe tinnitus might be associated with deterioration of quality of life, depression and anxiety, treatment modalities of tinnitus have not been established yet. Considering the heterogeneity of tinnitus, a single theory or a hypothesis cannot sufficiently explain the mechanism of tinnitus. Thus, diverse theories and studies had been conducted to elucidate the secret of tinnitus. Degeneration of outer hair cell in the peripheral auditory system is known to be associated with tinnitus, while auditory plasticity theory, upregulation of excitation of central auditory structures explains the role of the central auditory pathway in the generation of tinnitus. In addition, somatosensory and limbic autonomic nervous systems are also deeply involved with the pathogenesis of tinnitus. Herein, recent pathophysiologic theories and remarkable studies of tinnitus were reviewed. Understanding of the mechanism of the tinnitus generation might be the cornerstone in the development of tinnitus treatment.