2.1. Study Protocol
voice
Randomization: Following the completion of informed consent, thirty-three participants were randomized to one of two groups, i.e., the traditional (Assessment protocol: Baseline data collection for both groups included the maximum phonation time (MPT) (in seconds) and the maximum airflow volume (MAV) (in ml). The MAV was determined using the KAYPENTAX Phonatory Aerodynamic System 6600 (Pentax Medical, Montvale, NJ, USA) and was used to determine an individual MPT goal for each participant. Each participant’s MAV was divided by a standard airflow rate of 80 mL/s; 80 mL/s approximates the lower end of the standard airflow rate (70–200 mL/s) described by Hirano [Usability evaluation: A three-step mixed-method approach was employed to evaluate the usability of the app. First, a usability testing session was conducted at the beginning of the participant’s first study visit. The purpose was to understand their initial impression and the challenges of using the app. During testing, participants were asked to complete the first VFE exercise on the app by following a voice-prompted scenario. The participants were asked to share their thoughts by using the “think-aloud” protocol while they interacted with the app [App features: The app was provided at no cost and app access was discontinued following study completion. The app consisted of customized sets of VFE videos. Participants were assigned the video set which matched their gender and vocal range. The VFE program consists of four exercises. The fourth exercise, divided into five tasks, was performed on certain musical notes which matched with the participant’s habitual vocal range. The first exercise and all the fourth exercise tasks require the user to maximally sustain each note and document the time in seconds. This is referred to as the maximum phonation time (MPT). In this application, the user/participant starts a clinician-modeled video of each VFE task. Clinician modeling is vital as the VFEs are performed on a specific vocal posture known as the semi-occluded vocal tract [Intervention: Following baseline data collection, participants in both groups met with a research assistant to learn Vocal Function Exercises (VFEs), as described by Stemple (1994) [Outcome measures: The primary outcome measure was adherence to the home practice of voice therapy, as measured by the number of missed home practice voice therapy ‘tasks’. Each exercise and its attempt constituted a ‘task’. The VFE protocol consists of four exercises and each exercise is completed twice (Usability assessment measures: The usability survey included the System Usability Scale (SUS), the Health Information Technology Usability Evaluation Survey (Health-ITUES), and the user version of the Mobile Application Rating Scale (uMARS) [Blinding: Participants were blinded to the study objective and knowledge of the primary outcome measure, i.e., adherence. Participants were informed that the focus of the study was to compare the effectiveness of two delivery methods of voice therapy, as measured by the post-intervention MPT. The participants were not blinded for the group assignment because they either received or did not receive the app. 