spasmodic dysphonia (laryngeal dystonia)

Voice disorder caused by involuntary movements of one or more muscles of the larynx. Classification: 1) adductor spasmodic dysphonia 2) abductor spasmodic dysphonia 3) mixed spasmodic dysphonia Etiology: 1) unknown 2) once thought to be psychogenic a) psychogenic forms of spasmodic dysphonia exist b) most cases of spasmodic dysphonia are neurogenic 3) may co-occur with other movement disorders a) blepharospasm b) tardive dyskinesia c) oromandibular dystonia d) torticollis e) tremor 4) may occur following an upper respiratory tract infection, injury to the larynx, a long period of voice use, or stress Epidemiology: 1) can affect anyone 2) first signs most often occur 30-50 years of age 3) women appear to be affected more often than men Genetics: 1) some cases may run in families 2) possible gene on chromosome 9 that may contribute Pathology: 1) adductor spasmodic dysphonia - spasms cause the vocal folds (or vocal cords) to slam together & stiffen - spasms make it difficult for the vocal folds to vibrate & produce voice 2) abductor spasmodic dysphonia, - spasms cause the vocal folds to open - the vocal folds can not vibrate when they are open - the open position of the vocal folds also allows air to escape from the lungs during speech 3) mixed spasmodic dysphonia - involves muscles that open the vocal folds as well as muscles that close the vocal folds Clinical manifestations: 1) adductor spasmodic dysphonia - words are often cut off or difficult to start (dysarthria) - speech may be choppy & sound similar to stuttering - commonly described as strained or strangled & full of effort - spasms are usually absent while whispering, laughing, singing, speaking at a high pitch or speaking while breathing in - stress often makes the muscle spasms more severe 2) abductor spasmodic dysphonia, - voice often sounds weak, quiet & breathy or whispery - spasms are often absent when laughing or singing 3) mixed spasmodic dysphonia - features of both adductor & abductor spasmodic dysphonia Special laboratory: - fiberoptic nasolaryngoscopy Management: 1) no cure; treatment is symptomatic 2) voice therapy may reduce some symptoms, especially in mild cases 3) surgery: severing the recurrent laryngeal nerve may improve the voice of many for several months to several years but the improvement is often temporary 4) psychological counseling 5) Botox injections directly into the affected muscles of the larynx a) generally improve the voice for a period of 3-4 months after which the voice symptoms gradually return b) injections every 3-4 months are necessary to maintain a good speaking voice c) may relieve the symptoms of both adductor & abductor spasmodic dysphonia

General

dysphonia dystonia vocal cord dysfunction; inducible laryngeal obstruction

References

Spasmodic Dysphonia http://www.nidcd.nih.gov/health/voice/spasdysp.asp