Development and Preliminary Validation of the EASE: A Tool to Measure Perceived Singing Voice Function

Abstract

Most voice self-rating tools are disease-specific measures and are not suitable for use with healthy voice users. There is a need for a tool that is sensitive to the subtleties of a singer's voice and to perceived physical changes in the singing voice mechanism as a function of load. The aim of this study was to devise and validate a scale to assess singer's perceptions of the current status of their singing voice. Ninety-five vocal health descriptors were collected from focus group interviews of singers. These were reviewed by 25 currently performing music theater (MT) singers. Based on a consensus technique, the number of descriptors was decreased to 42 items. These were administered to a sample of 284 professional MT singers using an online survey to evaluate their perception of current singing voice status. Principal component analysis identified two subsets of items. Rasch analysis was used to evaluate and refine these sets of items to form two 10-item subscales. Both subscales demonstrated good overall fit to the Rasch model, no differential item functioning by sex or age, and good internal consistency reliability. The two subscales were strongly correlated and subsequent Rasch analysis supported their combination to form a single 20-item scale with good psychometric properties. The Evaluation of the Ability to Sing Easily (EASE) is a concise clinical tool to assess singer's perceptions of the current status of their singing voice with good measurement properties. EASE may prove a useful tool to measure changes in the singing voice as indicators of the effect of vocal load. Furthermore, it may offer a valuable means for the prediction or screening of singers "at risk" of developing voice disorders.