2018 Volume 30 Issue 1 Pages 4-12
Abductor spasmodic dysphonia (AbSD) is characterized by voice breaks, an involuntary breathy voice quality and difficulty coordinating respiration with phonation. The phenomenon is caused by the involuntary abduction of the bilateral vocal folds with inadequate and excessive activity of the bilateral posterior cricoarytenoid muscle (PCA). We herein report 2 patients (a 29- and 39-year-old woman) with AbSD whose condition was improved surgically by hemilateral thyroplasty type III (shortening of the thyroid lamina and rendering the vocal folds relaxed). The effects of the surgery on their voice quality were conserved for a long time (2 years in the 29-year-old and 5.5 years in the 39-year-old). Shortening the vocal fold through this surgery might suppress the excessive sensitivity of the muscle spindles of the PCA, thereby enabling control of the abnormal abductor movement of the vocal folds during speech.