Stress can make spasms more severe. Speech sounds are strained and full of effort. Spasms do not occur when whispering, laughing, singing, speaking at a high pitch, or speaking while breathing in. Vibration cannot occur when cords are open so production of sound is difficult. Also, the open position allows air to escape during speech.
Speech sounds are weak, quiet, and whispery.
Spasms do not occur when laughing or singing. The exact cause of spasmodic dysphonia is not known. Most cases are believed to be caused by a nervous system disorder, and may occur with other movement disorders. Spasmodic dysphonia may be a genetic disorder, or may begin following an upper respiratory infection, injury to the larynx, a long period of voice use, or stress. In addition to a complete medical history and physical examination, examination of the vocal folds by fiberoptic nasolaryngoscopy may be performed.