28.8K  56K  Cable/T1    (Get RealPlayer) Voice is generated by airflow from the lungs as the vocal folds are brought close together. The vocal folds vibrate when air is pushed past them with sufficient pressure. Without normal vibration of the vocal folds in the larynx (voice box), the sound of speech is absent. In spasmodic dysphonia, abnormal or dystonic muscle contractions can affect the muscles that close (adduction) or open (abduction) the laryngeal mechanism causing the voice to break or to have a tight, strained or strangled quality. The two types of recognized spasmodic dysphonia are adductor spasmodic dysphonia and abductor spasmodic dysphonia. Adductor SD causes an intermittent excessive closing of the vocal folds during vowel sounds in speech; while in abductor SD, there is a prolonged vocal-fold opening during voiceless consonants. The control problems of the vocal cords result in different speech symptoms in the two types of disorder. In the more common adductor type, speaking causes abnormal involuntary excessive contraction of the muscles that bring the vocal cords together affecting the air-flow through the vocal folds. The condition causes a tight voice quality, often with abrupt initiation and termination of voicing resulting in a broken speech pattern and short breaks in speech. These symptoms are most easily heard on vowels, liquids (l and r), or semivowel sounds (w and y). In the abductor type, there is an overcontraction of the muscles that separate the vocal cords, resulting in a breathy, whispering voice pattern. Usually the voiceless consonants are prolonged, and are produced with excessive breathiness as affected persons experience difficulties in closing the vocal folds to produce vowels following voiceless consonants (p, t, l, s, f, h, th). Sounds such as "s," "h," or "k" preceding open vowels as in home, coffee, and puppy are usually most affected. There may also be a breathy voice quality, uncontrolled pitch elevations on vowel initiation, difficulty coordinating breathing with speech, and excessive air loss while speaking. There are three subtypes of SD have been identified by clinicians. One is a combination of adductor and abductor symptoms in which an individual may demonstrate both types of spasms as he/she speaks. In a second subtype, SD symptoms are accompanied by a voice tremor. A third subtype involves a primary voice tremor that is so severe the patient experiences adductor voice stoppages during the tremor. Symptoms may improve or disappear when whispering, singing, or using a high voice. Reflexive and emotional aspects of the voice, such as coughing, laughing, or crying, are usually not affected. Many of the symptoms vary during the day, become aggravated by certain speaking situations such as talking on the phone or increase during stressful situations. Symptoms are action-induced and not apparent at rest. Although it can start any time during a life, spasmodic dysphonia seems to begin frequently in the 40- to 50-year-old group and more often in women than men. If spasmodic dysphonia causes any type of impairment, it is because muscle contractions interfere with normal function. Features such as cognition, strength, and the senses, including vision and hearing, are normal.