Tinnitus and the triple network model: a perspective
Clin Exp Otorhinolaryngol. 2022 Jul 11. doi: 10.21053/ceo.2022.00815. Online ahead of print.
Tinnitus is defined as the conscious awareness of a sound without an identifiable external sound source and tinnitus disorder as tinnitus plus associated suffering. Chronic tinnitus has been anatomically and phenomenologically separated into three pathways: a lateral "sound" pathway, a medial "suffering" pathway, and a descending noise-canceling pathway. Here, the triple network model is proposed as a unifying framework common to neuropsychiatric disorders. It proposes that abnormal interactions among three cardinal networks, the selfrepresentational default mode network (DMN), the behavioural relevance-encoding salience network (SN) and the goal-oriented central executive network (CEN), underlie brain disorders. Tinnitus commonly leads to negative cognitive, emotional, and autonomic responses, phenomenologically expressed as tinnitus-related suffering, processed by the medial pathway. This anatomically overlaps with the SN, encoding the behavioral relevance of the sound stimulus. Also, chronic tinnitus can become associated with the self-representing DMN and becomes an intrinsic part of the self-percept. This is likely an energy-saving evolutionary adaptation, by detaching tinnitus from sympathetic energy-consuming activity. Eventually, this can lead to functional disability by interfering with the CEN. In conclusion the three pathways can be extended to the triple network model explaining all tinnitusassociated co-morbidities. This paves the way for the development of individualized treatment modalities.