Daily Phonotrauma Index: An Objective Indicator of Large Differences in Self-Reported Vocal Status in the Daily Life of Females With Phonotraumatic Vocal Hyperfunction

Abstract

Purpose: The purpose of this study is to evaluate if the Daily Phonotrauma Index (DPI) can quantitatively discriminate large differences in overall vocal status in the daily life of patients with phonotraumatic vocal hyperfunction (PVH). Method: For 1–4 weeks, 23 females with PVH wore an ambulatory voice monitor and answered three vocal status questions (i.e., difficulty producing soft, high-pitched phonation; discomfort; and fatigue) at the beginning, at 5-hr intervals, and the end of each day. DPI values were obtained for each patient's time periods of worst and best self-rated vocal status, and data for the group were analyzed for significant changes using a linear mixed-effects regression model. Results: The DPI was significantly lower during periods self-rated as “best vocal status” compared to during periods self-rated as “worst vocal status” (mean difference in DPI = 0.53) with a medium-to-large effect size (Cohen's d = −0.68). Conclusions: In a group of patients with phonotraumatic lesions, the DPI indicated lower potential for phonotrauma during time periods of better vocal status compared to time periods of worse vocal status. Assuming that a large portion of variance in vocal status for patients with PVH is associated with the extent to which voicing is phonotraumatic, these results support the validity of obtaining estimates of DPI for much shorter time periods (i.e., an estimate every 2 min of voicing) than previous studies (i.e., a single estimate for the entire day or week). Future work can investigate the DPI's use for in-clinic assessment/treatment and ambulatory biofeedback and can gain further insights into phonatory mechanisms that underlie DPI via comparisons with other physiologically relevant measures and computational vocal fold modeling.