A Review and a Framework of Variables for Defining and Characterizing Tinnitus Subphenotypes

Abstract

Tinnitus patients can present with various characteristics, such as those related to the tinnitus perception, symptom severity, and pattern of comorbidities. It is speculated that this phenotypic heterogeneity is associated with differences in the underlying pathophysiology and personal reaction to the condition. However, there is as yet no established protocol for tinnitus profiling or subtyping, hindering progress in treatment development. This review summarizes data on variables that have been used in studies investigating phenotypic differences in subgroups of tinnitus, including variables used to both define and compare subgroups. A PubMed search led to the identification of 64 eligible articles. In most studies, variables for subgrouping were chosen by the researchers (hypothesis-driven approach). Other approaches included application of unsupervised machine-learning techniques for the definition of subgroups (data-driven), and subgroup definition based on the response to a tinnitus treatment (treatment response). A framework of 94 variable concepts was created to summarize variables used across all studies. Frequency statistics for the use of each variable concept are presented, demonstrating those most and least commonly assessed. This review highlights the high dimensionality of tinnitus heterogeneity. The framework of variables can contribute to the design of future studies, helping to decide on tinnitus assessment and subgrouping.

Differences in characteristics between people with tinnitus that seek help and that do not

“…They extracted 94 different variables which were processed in a framework of the most commonly used variables in subtyping. Tinnitus severity, hearing ability, age, and depressive symptoms were found to be the top four variables that were significant or important for classification 6 . However such characteristics can cover many domains such as demographic, audiological or psychological measures.…”

“…It is commonly believed that one of the explanations of the heterogeneity might be the existence of subtypes of tinnitus patients. Several attempts have been made to define these subtypes, but clinically usable types remain to be found 6 . In a recent review on tinnitus subtyping, the authors identified 64 articles that had reported on tinnitus subtyping 6 .…”

“…Several attempts have been made to define these subtypes, but clinically usable types remain to be found 6 . In a recent review on tinnitus subtyping, the authors identified 64 articles that had reported on tinnitus subtyping 6 . They extracted 94 different variables which were processed in a framework of the most commonly used variables in subtyping.…”

Multidisciplinary Tinnitus Research: Challenges and Future Directions From the Perspective of Early Stage Researchers

“…Due to the lack of an objective measure and the limited understanding of the mechanisms, research on tinnitus heterogeneity and tinnitus subtypes most often focuses on phenotypic heterogeneity of people with tinnitus; that is measurable traits that vary across individuals with tinnitus. These traits can include both general individual characteristics (not specific to people with tinnitus) such as demographics (e.g., gender) and co-existing conditions (e.g., hearing problems), and tinnitus-specific characteristics such as related to the tinnitus perception or its impact on the affected individual (Langguth et al, 2007;van den Berge et al, 2017;Genitsaridi et al, 2020;Van der Wal et al, 2020).…”

Quality of Life and Psychological Distress in Portuguese Older Individuals with Tinnitus

“…Regarding tinnitus management, while in younger adults, especially those presenting a normal standard audiometry, it is useful to have the evaluation of extended high frequency audiometry, usually this is not the case for those older than 65, according to our study results. These findings are important contributions for tinnitus subtyping, as in younger adults hearing loss in higher frequencies is likely to play a role in tinnitus pathophysiology, but this effect is probably reduced in older individuals [ 22 ]. Several studies have focused on the consequences of hearing on QoL, including in the older adult population with hearing loss [ 23 , 24 , 25 ].…”