Sensorineural Tinnitus: Its Pathology and Probable Therapies

Abstract

Tinnitus is not a single disease but a group of different diseases with different pathologies and therefore different treatments. Regarding tinnitus as a single disease is hampering progress in understanding of the pathophysiology of tinnitus and perhaps, more importantly, it is a serious obstacle in development of effective treatments for tinnitus. Subjective tinnitus is a phantom sound that takes many different forms and has similarities with chronic neuropathic pain. The pathology may be in the cochlea, in the auditory nerve, or, most commonly, in the brain. Like chronic neuropathic pain tinnitus is not life threatening but influences many normal functions such as sleep and the ability to concentrate on work. Some forms of chronic tinnitus have two components, a (phantom) sound and a component that may best be described as suffering or distress. The pathology of these two components may be different and the treatment that is most effective may be different for these two components. The most common form of treatment of tinnitus is pharmacological agents and behavioral treatment combined with sound therapy. Less common treatments are hypnosis and acupuncture. Various forms of neuromodulation are becoming in use in an attempt to reverse maladaptive plastic changes in the brain.

Figure 1

Schematic display of the alpha and the gamma network. Connections with a significant group difference were plotted as edges in the networks. The nodes were named as LF (left frontal), RF (right frontal), LT (left temporal), RT (right temporal), LP (left parietal), RP (right parietal), ACC (anterior cingulate cortex), and PCC (posterior cingulate cortex) (modified from Schlee et al., 2009 [9]).

Figure 2

Schematic displays of alpha and gamma networks for persons with tinnitus of short and long duration. LF: left frontal, RF: right frontal, LT: left temporal, RT: right temporal, LP: left parietal, RP: right parietal, ACC: anterior cingulate cortex, and PCC: posterior cingulate cortex (modified from Schlee et al., 2009 [9]).

Figure 3

Targets of axons from cells in the nucleus tractus solitarius. Composite of different investigators description of the pathways from the NTS. PGi: Paragigantic nucleus (from Møller, 2014 [10]).

Figure 4

Hypothetical description of the difference between catastrophizing and noncatastrophizing in tinnitus (from Møller, 2014 [10]).