Laryngeal Resistance in Abductor Spasmodic Dysphonia

Detailed Summary

This study will investigate and compare the air stream during voice production in patients with abductor spasmodic dysphonia and in normal volunteers. People with abductor spasmodic dysphonia have uncontrolled muscle spasms during speech, resulting in a weak voice. A better understanding of the abnormalities of this disorder may help in the development of more effective treatments. Healthy volunteers and patients with abductor spasmodic dysphonia may be eligible for this study. Candidates will have a physical examination and medical history. (Patients will be videotaped and voice-recorded during the medical interview for review by specialists who will identify the type and severity of their speech disorder.) All candidates will also undergo a procedure called flexible fiberoptic laryngoscopy to record the movement of the vocal folds during speech, breathing and other tasks such as singing, whistling and prolonging vowels. For this test, the inside of the nose is sprayed with an anesthetic (lidocaine) to numb the nasal cavity and a decongestant (oxymetazoline) to widen the nasal passage. Then, a thin flexible tube called a nasolaryngoscope is passed through the nose to the larynx (voice box). A camera attached to the eyepiece of the nasolaryngoscope records the movements of the vocal folds. Participants will then have an airway interruption test to detect pressure changes in the voice box during production of continuous sounds. A nose clip is placed over the subject's nose and two sensor devices are placed on the neck to pick up changes in movement and position of the vocal cords during voicing. A mouthpiece is placed in the mouth, and subjects are asked to say "ah" continuously at a specified sound level. This voicing is repeated 33 times with periodic breaks. Patients only will also be given an injection of botulinum toxin. These injections are effective, in varying degrees, in about 60 percent of patients with abductor spasmodic dysphonia. This study will use a different approach to botulinum toxin injections to test their effect in patients with pressures higher than normal. Rather than inject the posterior cricoarytenoid muscle or the cricothyroid muscle, as is typically done, the thyroarytenoid muscle, which closes the voice box, will be injected on one side. A second one-sided injection may be given after 2 or 3 weeks if no effect is seen after the first injection. Speech will be recorded at each visit to measure any change in symptoms after the injection.

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