Tinnitus

“Tinnitus aurium” (latin for ringing of the ears) or simply “tinnitus” describes the phenomenon of an auditory perception such as ringing, hissing or buzzing without the presence of any external source of sound. The sensation of this sound can be unilateral, bilateral but tinnitus can also be perceived within someone’s head (Erlandsson and Dauman, 2013; Langguth et al., 2013; Roberts et al., 2010). Typically, tinnitus is classified as either subjective or objective. In the case of objective tinnitus an endogenous source of sound can be identified, which is perceptible by another person for instance an examiner (Hall et al., 2011). Objective tinnitus is rather rare (Tunkel et al., 2014) and can be caused for example by an abnormal blood flow or rhythmic muscle contractions (Langguth et al., 2013; Møller, 2007). If such an internal origin of sound does not exist and the sound is only perceived by the affected person, it is classified as subjective tinnitus (Baguley et al., 2013; Erlandsson and Dauman, 2013). A consistent perception of this auditory phantom sound for at least three (Hall et al., 2011) respectively six months (Mazurek et al., 2010) is considered as a chronification. The most common causes for the development of tinnitus are cochlear damages towards noise trauma, presbyacusis or ototoxic medication (Langguth et al., 2013) and in particular hearing loss (Mazurek et al., 2010; Moore et al., 2017). In about 80% of cases, tinnitus is accompanied by some degree of hearing loss (Norena et al., 2002), whereby the frequency spectrum of maximum hearing loss usually overlaps with the perceived tinnitus pitch (Eggermont, 2007; Eggermont and Tass, 2015; Schecklmann et al., 2012). 

A cure for tinnitus?

With a prevalence of approximately 10 to 15%, tinnitus occurs relative frequently in the global population, whereas the elderly generation is particularly affected. Moreover, 2 - 3% of people concerned are significantly suffering from this phantom sound perception (Baguley et al., 2013; Hall et al., 2011; Heller, 2003; Langguth et al., 2019). In many cases tinnitus is accompanied by comorbidities such as depression (Salazar et al., 2019), anxiety disorders (Pattyn et al., 2016), sleep disorders (Croenlein et al., 2016), lowered quality of life (Nondahl et al., 2007; Weidt et al., 2016) or hyperacusis (Cederroth et al., 2020; Rosing et al., 2016; Schecklmann et al., 2014b) as well as altered auditory processing e.g., for speech perception (Jagoda et al., 2018) or sound source localization (Hyvärinen et al., 2016).

Due to varieties in phenotype and etiology, the effects of currently available treatment approaches for tinnitus are only observed in a small number of patients – to date there is no effective treatment respectively cure for tinnitus (Hesse, 2016; Kleinjung and Langguth, 2020; Zenner et al., 2017). Several treatment approaches exist, these range from different sound therapies like noise generators, maskers or hearing aids (Hoare et al., 2014; Searchfield et al., 2017; Sereda et al., 2018) to cochlear implants (Peter et al., 2019; Ramakers et al., 2015), neurofeedback training (Güntensperger et al., 2017) and attempts in developing an appropriate drug therapy (Langguth et al., 2019) or the application of different non-invasive neuromodulation techniques (for an overview see Langguth, 2020). Tinnitus as a heterogenous condition with different causes and pathologies not fully understood yet, hampers the quest in finding a cure. Currently Cognitive Behavioral Therapy (CBT) is the prevailing treatment option with the best evidence by providing people appropriate coping strategies in order to deal with their tinnitus and therefore improving quality of life (Cima et al., 2012; Fuller et al., 2020). Personalization of treatments or individual treatment schedules might be a solution to account for tinnitus heterogeneity and variability in treatment effectiveness (Cederroth et al., 2019). The personalization of treatment approaches is already deployed in multifactorial neuropsychiatric diseases such as depression (Cuijpers et al., 2012) or schizophrenia (Buckley and Miller, 2017). Due to various phenotypes in tinnitus it has already been suggested to neglect treatment effects on a whole group level and rather take individual results into account (Tyler et al., 2007). 

(Text taken and modified from "Towards a Moment of Silence: Individualization of Acoustic Stimulation and Repetitive Transcranial Magnetic Stimulation in Tinnitus" by Stefan Schoisswohl; 10.5283/epub.45974)