An exploratory analysis of the tinnitus magnitude equation (TMe). An adaptation level theory based measure of tinnitus therapy outcome

Background

In this study we undertook an exploratory analysis of a new method for quantifying change in perceived intensity of tinnitus: the tinnitus magnitude equation (TMe). The TMe is based on Adaptation Level Theory (ALT) and is the difference between the product of Tinnitus Function Index (TFI) questions asking tinnitus loudness, awareness, and annoyance (intrusiveness scale) before and after therapy.

Methods

This is a secondary analysis of anonymized data. In part 1. Two sets of 3 questions (n = 126) were compared for internal consistency and content validity. A triplet of questions from the Tinnitus Sample Case History Questionnaire (TSCHQ) and a triplet from the TFI that were candidate measures for calculating the adaptation level (AL) to tinnitus and magnitude were compared. In part 2. Change in AL, the magnitude of treatment effect, was compared to the change in TFI total score (n = 155).

Results

The 2 sets of questions from the TSCHQ and TFI were broadly equivalent, but the TFI triplet items had higher internal consistency. Moderate convergent validity was found between the TMe and TFI. Interim criteria for responsiveness were determined relative to anchor and distribution-based measures that characterize magnitude from a small change or greater (41% of participants) to a very large change (15% of participants).

Conclusion

The TMe is a novel approach to the assessment of tinnitus that could address the need for a robust measure of tinnitus perception. Further evaluation and validation of the measure is needed.