Role of Neurotransmission and Functional CNS Networks in Spasmodic Dysphonia

This study will examine how the brain controls speech in patients with spasmodic dysphonia, a voice disorder that involves involuntary spasms of muscles in the larynx (voice box), causing breaks in speech. Although the causes of spasmodic dysphonia are unknown, recent studies found changes in brain function in patients with the disorder that may play a role in its development. People between 21 and 80 years of age with adductor spasmodic dysphonia may be eligible for this study. Candidates are screened with the following procedures: Medical history and physical examination. Nasolaryngoscopy to examine the larynx. For this test, the inside of the subject s nose is sprayed with a decongestant and a small, flexible tube called a nasolaryngoscope is passed through the nose to the back of the throat to allow examination of the larynx. The subject may be asked to talk, sing, whistle and say prolonged vowels during the procedure. The nasolaryngoscope is connected to a camera that records the movement of the vocal cords during these tasks. Voice and speech recording to measure the type and severity of voice disorder. Subjects are asked questions about their voice disorder and their voice is recorded while they repeat sentences and sounds. Participants undergo positron emission tomography (PET) and magnetic resonance imaging (MRI) of the brain, as follows: PET: A catheter is placed in a vein in the subject s arm to inject a radioactive substance called a tracer that is detected by the PET scanner and provides information on brain function. \[11C\]flumazenil is used in one scanning session and \[11C\]raclopride is used in another. For the scan, the subject lies on a bed that slides in and out of the doughnut-shaped scanner, wearing a custom-molded mask to support the head and prevent it from moving during the scan. For the first scan the subject lies quietly for 60 minutes. For the second scan, the subject lies quietly for 50 minutes and is then asked to say sentences d