Spasmodic dysphonia is a type of dystonia. Dystonia is a term which describes involuntary contraction of muscles. In spasmodic dysphonia the muscle group affected are those of the larynx, or voice box.
Patients with spasmodic dysphonia often describe symptoms including:
Strangled voice quality
Pressed voice quality
Strained voice quality
Some patients note increase in symptoms during times of stress or hardship. Conversely symptoms may improve when individuals sing, laugh, or even after an alcoholic beverage.
Spasmodic dysphonia can be divided into patients with adductor-type spasmodic dysphonia or abductor type spasmodic dysphonia. Adductor-type SD accounts for the symptoms of strained or strangled voice while abductor spasmodic dypshonia creates a breathy voice. Over 80% of patients with SD have the adductor – type, Less than 20% have the abductor type, and a small portion a mixed type which symptoms of both.
Treatment for spasmodic dysphonia usually involves vocal fold injections with botox, which are performed in office. Botox is a substance that prevents a muscle from contracting. The effect of botox usually lasts for a period of three to six months. Botox is specifically directed at the muscles which cause symptoms. Injections of botox may be placed transorally or through the neck skin. An EMG may be used to help direct application of the botox. For patients with adductor type spasmodic dysphonia injections are usually directed towards the thyroarytenoid, vocalis, or lateral cricoarytenoid muscles. Patients with abductor type spasmodic dysphonia are assisted with botox injections to the posterior cricoarytenoid muscle. Injections to the false vocal folds and interarytenoid muscles have been described as well.
Surgical options also exist for management of this disease. More commonly patients with adductor type SD undergo surgery. One surgical option for spasmodic dypshonia is myectomy, where some of the laryngeal muscles are precisely cut using a laser, with the end goal of improving the voice.
Another surgical option is a laryngeal “deinnervation-reinnervation” procedure. In this surgery specific branches of the recurrent laryngeal nerve that control vocal fold movement are cut and re-rerouted.