Assessing outcomes of tinnitus intervention

It has been estimated that as many as 50 million Americans do experience or have experienced tinnitus. For approximately 12 million of these individuals, tinnitus makes it impossible for them to carry out normal everyday activities without limitation. These are the patients that present to audiology clinics for assessment and management. The tinnitus evaluation includes the measurement of acoustical characteristics of tinnitus and the impact that this impairment has on health-related quality of life (HRQoL). Tinnitus is a disorder that often occurs as a result of auditory system impairment. The impairment for some can impart an activity limitation and a participation restriction (i.e., tinnitus-related disability or handicap, respectively). The goal of tinnitus management is to reduce, or eliminate, activity limitations and participation restrictions by reducing or eliminating a patient's perception of tinnitus or their reaction to tinnitus. Implicit in this statement is the assumption that there exist standardized measures for quantifying the patient's tinnitus perception and their reaction to it. If there existed stable and responsive standardized tinnitus measures, then it would be possible to compare a patient's tinnitus experience at different time points (e.g., before and after treatment) to assess, for example, treatment efficacy.

The purposes of the current review are to (1) describe psychometric standards used to select outcome measurement tools; (2) discuss available measurement techniques and their application to tinnitus evaluation and treatment-related assessment within the domains established by the World Health Organization's International Classification of Functioning, Disability and Health; (3) list and briefly describe self-report tinnitus questionnaires; (4) describe how valuation of tinnitus treatment can be assessed using economic models of treatment effectiveness; and (5) provide future directions including the development of a tinnitus outcomes test battery and treatment-related study designs.

Retrospective literature review

Although psychometrically robust measures of tinnitus HRQoL do exist, there is no unanimity in, for example, what tests should be included in the tinnitus assessment, and how studies of HRQoL should be conducted. The current authors suggest that future studies employ more rigorous designs and contain (minimally) the following characteristics: (1) utilization of randomized control groups and blinding; (2) appropriate statistical testing including "dropouts" that should be used in an "intention to treat" analysis rather than elimination from the final data set; (3) long-term follow-up assessment to evaluate responsiveness; (4) appropriate inclusion criteria to avoid "ceiling" and "floor" effects; and (5) suitable sample sizes based on the application of power analyses.