One for One or One for All? A Comparison of the Tinnitus Functional Index and the Client Oriented Scale of Improvement in Tinnitus as Outcome Measures

Background: The purpose of the Client Oriented Scale of Improvement in Tinnitus (COSIT) is to set treatment goals and assess individual outcomes. The Tinnitus Functional Index (TFI) was developed as a comprehensive questionnaire to measure individual and population responses to tinnitus therapies. Purpose: To investigate the convergent validity and responsiveness of the COSIT and TFI. Study Sample: A secondary data analysis of COSIT and TFI measures from 99 participants who used sound-based therapy with hearing aids or earphones was undertaken. Data Collection and Analysis: Athematic analysis of COSIT goals was applied. Nonparametric statistical methods were used to measure convergence of COSIT “change with treatment scores” and “final scores” to change in TFI scores pretreatment and posttreatment and the final TFI scores with treatment. The level of agreement between the measures was determined using receiver operating characteristic curves. Treatment responsiveness was determined by comparing treatment-related change in total scores and subscales for responders versus nonresponders. Responders were classified as having >13-point change in the total TFI score and COSIT “change” score of >2 (3 = slightly better to 5 = much better). Results: The five most common COSIT goals were reducing tinnitus impact by addressing (1) well-being, (2) hearing, (3) sleep, (4) focus, and (5) context. The TFI and COSIT change scores and TFI and COSIT final scores showed moderate to strong agreement. The COSIT classified a higher percentage (78 percent) of participants as responders than the TFI did (43 percent). There was a fair agreement between the clinically meaningful change scores for TFI and COSIT (κ = 0.29). Conclusions: The TFI and COSIT measured similar constructs, and both differentiated responders from nonresponders. Our results are consistent with the COSIT being an ideal “one for one” tool because of its high responsiveness to individual goals. The TFI is better suited as a “one for all” questionnaire because of its universal content. Clinical trials should consider use of both the COSIT and TFI because of their different, but complementary, strengths.