Development and psychometric validation of a questionnaire assessing the impact of tinnitus on significant others

Introduction- Despite evidence showing that tinnitus can have a detrimental impact on significant others (SOs), no standardized self-reported measure is currently available that specifically assesses the presence of third-party disability for tinnitus. The aim of this study was to develop and assess the psychometric properties of a newly developed self-reported measure for SOs of tinnitus and assess how scores could be meaningfully interpreted. Methods- The research consisted of two phases. During Phase I, the Consequences of Tinnitus on Significant Others Questionnaire (CTSOQ) was developed using the The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidance. Phase II included the assessment of psychometric properties of the CTSOQ including the construct validity, internal consistency, interpretability, and responsiveness. Pairs of 194 individuals with tinnitus and their SOs completed a series of online questionnaires. SOs completed the CTSOQ measure while individuals with tinnitus completed measures related to tinnitus distress, anxiety, depression, insomnia, and quality of life. Results- A 25 item CTSOQ was developed using a formative model. The questionnaire validation process indicated good psychometric properties with an internal consistency of .93 and inter-item correlation of .60. Support was found for the construct and discriminative validity of the measure. Floor and ceiling effects were negligible. Scores can be meaningfully interpreted to indicate mild, significant, or severe effect of tinnitus on SOs. The questionnaire was also found to be responsive to treatment-related changes. Conclusions- The CTSOQ was found to have sufficient measurement properties suggesting that it is a suitable measure of third-party disability for SOs of individuals with tinnitus. Further research should be initiated to measure face validity and what scores reflect clinically meaningful change.