ABSTRACT

Spasmodic dysphonia (SD) is focal dystonia involving intrinsic laryngeal muscles. It occurs because of a disorder in laryngeal motor neuron control during speech. Voluntary speech is affected, while involuntary actions such as loughing, crying, or coughing are not affected. An irregularity in organization in the central nervous system is observed in the pathophysiology of the disease. Some genetic mutations are found be responsible, and the disease is inherited in an autosomal dominant manner. There are two types of the dissease: adductor and abductor. The adductor type is more frequent. The diagnosis is usually delayed because of lack of exact objective criteria. Laryngeal electromyography (EMG) is the test that provides the most valuable diagnostic results. Injecting botulinium toxin into the densest muscle is the treatment of choice.