BOTULINUM TOXIN IN THE TREATMENT OF RECALCITRANT MUTATIONAL DYSPHONIA

Mutational falsetto is the failure of the normal drop in vocal pitch a t puberty. Voice therapy almost always achieves an appropriate pitch; however, in cases of failure, surgical treatment has also been recomme nded. We report a case of a 47-year-old man with an above-average fund amental frequency and a thin voice quality in the absence of any signs of androgen insufficiency. Laryngeal examination revealed atrophy of the vocalis muscle. Voice therapy was unsuccessful in achieving a stab le voice. Injection of 15 units of botulinum toxin into each cricothyr oid muscle initially resulted in aphonia, but the voice returned by 1 week. Average fundamental frequency was 84 Hz at 1 week, 104 Hz at 1 m onth, and 100 Hz at 1 year. We hypothesize that mutational dysphonia i s an habitual dysfunction of the voice with inappropriate activation o f the cricothyroid muscle and disuse of laryngeal adductor muscles. Te mporary deactivation of the cricothyroid muscle enforces adoption of a more appropriate vocal mechanism. Botulinum toxin as an adjunct to vo ice therapy should be considered before surgical alteration of the glo ttis in patients with recalcitrant mutational falsetto.