Patient description: A 22-year-old Caucasian man came to the Clinic with a history of tremors since a year ago. The tremor was first in his right hand while holding something. Later the tremor became continuous and extended to both hands and legs and even at rest. The Kayser-Fleischer' ring was detected in the ophthalmologic exam. The physical exam revealed jaundice, hepatosplenomegaly and hypotonia of the upper limbs. He had a constant smile on his face, however, he has aggressive behavior according to his parents' explanation. His laboratory study was significant for a low serum caeruloplasmin (0.05 g/l), and a raised 24 hour urine copper excretion (120 μg/24 h). Wilson disease was confirmed by high liver copper concentration (305 μg/g dry weight of liver).

Clinical trial eligibility criteria: eligible ages (years): 18.0-80.0,  Voice Disorders Patients with Spasmodic Dysphonia will meet the following 1. No structural abnormalities affecting the larynx such as vocal fold nodules, polyps, carcinoma, cysts, contact ulcers, inflammation (laryngitis). 2. Symptoms of adductor or abductor spasmodic dysphonia present during speech and not apparent at rest, 3. Symptoms of adductor or abductor spasmodic dysphonia less evident during whisper, singing or falsetto. 4. Symptoms of adductor or abductor spasmodic dysphonia become worse with prolonged speaking, practice or anxiety. 5. Reflexive and emotional aspects of voice function are unaffected, such as coughing and laughter or crying. Patients with Muscular Tension Dysphonia will meet the following 1. Increased phonatory muscle tension in the paralaryngeal and suprahyoid muscles on palpation, 2. Constant elevation of the larynx in the neck during speech. 3. A consistent hypertonic laryngeal posture for phonation, either an open posterior glottic chink between the arytenoid cartilages on phonation, an anterior-posterior squeeze (pin hole posture) or ventricular hyperadduction. 4. A normally appearing larynx. Patients with vocal tremor will have tremor isolated to the larynx without noticeable tremor of the head and pharynx. Tremor of the vocal folds should be evident during a prolonged vowel and also noticeable in the larynx during connected speech containing vowels  Subjects in all three groups will be without: 1. Cardiac, pulmonary, neurological, psychiatric or speech and hearing problems as determined by medical history and examination by a physician and an EKG. Any patient with a history of airway obstruction will be excluded from the study. 2. Reduction in the range of vocal fold movement during non-speech tasks such as whistling suggesting either paralysis or paresis, joint abnormality or neoplasm. 3. No smokers or tobacco users will be included in the study. 4. mucosal changes such as vocal nodules or polyps. 5. Subjects with a history of a psychiatric disorder, under the care of a psychiatrist, or on medications for treatment of a psychiatric disorder will be excluded from study. Examples of psychiatric disorders to be excluded are: somatoform disorders, conversion disorders, currently under treatment for a major depression, or a history of schizophrenia or a bipolar disorder. However, a history of a previous episode of a minor reactive depression would not a person from participation. 6. Subjects taking carbonic anhydrase inhibitors, cimetidine, hydrochlorthiazide, nicotine, quinidine, ranitidine, sodium or calcium bicarbonate and triamterene must either discontinue these medications or be excluded from study. 7. Subjects with grade 2 or higher hepatic or renal dysfunction will be excluded from study. 8. Pregnant women will be excluded from the study as it is not known if the study drugs are harmful to the fetus. If a woman becomes pregnant during the study, she will be removed