Do obesity and weight loss affect vocal function?

Obesity may be associated with increased tissue bulk in the laryngeal airway, neck, and chest wall, and as such may affect vocal function. Eight obese and eight nonobese adults participated in this study; the obese participants underwent bariatric surgical procedures. This mixed-design study included cross-sectional analysis for group differences and longitudinal analysis for multidimensional changes in vocal function from four assessments collected over 6 months. No significant differences were detected between groups from the preoperative assessment. Further, no changes were detected over time for acoustic parameters, maximum phonation time, laryngeal airway resistance, and airflow during a sustained vowel for either group. Only minor differences were detected for strain, pitch, and loudness perceptions of voice over time, but not between groups. Phonation threshold pressure (PTP), at comfortable and high pitches (30% and 80% of the F0 range) changed significantly over time, but not between groups. Examination of individual data revealed a trend for PTP at 30% F0 to decrease as body mass index decreased. PTP may be informative for assessing vocal function in clients who present with obesity and voice symptoms.