Producing a human voice requires precise regulation of airflow from the lungs to the oropharynx in tandem with the glottic posture. The vocal folds need to be in the correct compliance to display their dynamic vibratory properties. Dysphonia can be caused by factors that affect the glottis’s vibratory nature (such as a laryngeal cyst) or its aerodynamic structure (such as vocal fold paralysis). However, a functional voice problem should be considered when vocal quality declines without corresponding changes in anatomy or the nervous system. Up to 40% of dysphonia cases referred to a multidisciplinary voice clinic may be due to functional voice problems. Even when the anatomy is regular, changes in laryngeal muscle tension are thought to lead to changes in laryngeal function. Now, when people talk about functional dysphonia, they usually say muscle tension dysphonia (MTD). Research from Italy indicated that functional dysphonia was present in over 90% of kids whose dysphonia was caused by a vocal fold injury.