Subjective voice assessment
Vocal outcomes were evaluated using the Mandarin Chinese versionĀ of the Voice Handicap Index-30 (VHI-30) questionnaire. It is a self-evaluation form adapted from the American Speech Language Hearing Association [14] that has 30 questions in 3 domains (functional, physical, and emotional). This form was translated and validated in Mandarin Chinese [15]. The possible response to each of the 30 questions is: never (0 points), almost never (1 point), sometimes (2 points), almost always (3 points), and always (4 points). A total score of 10 or less was considered normal, and a score higher than 10 indicated a poor voice-related outcome.